ESE's works engine tuner

[wobbly]

Exhaust Gas Technologies in USA, clamp on Stinger ( exposed tip - is fastest ) probe with mini K plug is easyest,and are the only commercial egt with a guarantee.
DynoJet is easy to datalog egt,they have a input box specifically for sensors, then you have a readout on screen with warning capability etc.

[Matt@TYGA]

Thanks again Wobbly. I'll get in touch with them.

Should make my life a little easier

[lodgernz]

I would for sure use the 75% and 100% area guidelines.
But try this as a thought process.
The guideline lengths relied on 125cc square engines with really high bmep.
So modify the duct length total of 2X Bore by your actual numbers.
First the bmep.Say yours is 12Bar and the Aprlia is 15Bar,so we have 53X12/15 = 42.4.
Then we have the bore to stroke ratio 42.4 X45/53 = 36
So now assume your effective bore is 36
Times 1.5 = the 75% area position = 54 and the 100% position = 2X36 = 72
So this gives a slip on transition length of only 72-54= 18
Make this 22 long with the smallest CSA at say 50.
Seems reasonable to me,but the real proof is in the mach number at peak power of the 75% CSA = 0.8
Do the lengths come close to achievable ?


But I have never seen a duct in a competition type engine that is too long.
Plenty that are way too short - especially those that have a female header plug in as part of the cylinder.
Having the really good guide of 75% smallest and 100% again at the header makes choosing the areas simple, and they work.
I would be interested to see the result of using both bmep and bore/stroke shortening multipliers in a severely oversquare project.
In the example I did ,the lengths seem quite usable , if the actual cylinder is a bit longer then I doubt it would have much negative effect.

Thanks Wobbly. I'm struggling to get my head around those numbers, but I'll juggle them a bit and see what pops out the end.

[wobbly]

Here is the Aprilia RSA125 Pack file zipped.

[jonny quest]

but my opinion is that the best piston shape is an angled edge,its width = the squish,then a flat top.
Will be testing that soon - WOBBLY

I've had the same thought, and have been meaning to try that.

Tyga, look into YZ125 piston 06-18. And that head shape. I've found that design to work the best.

[SwePatrick]

It costed just under 900 euros, but one should know that the one I chose to do was considered to be very complicated piece to manufacture because of the many small channels I designed

For one or two cylinders?

If my new cylinder works well i might reverse engineer it and get one casted.

[Matt@TYGA]

So a couple of extra choices here with toroid chamber.

The toroid is pretty severe in an effort to keep the volume as is but bring the plug close to the firing line of the squish.

The first sticks with the dome top piston, whereas the second is essentially the same piston with the top of the dome turned off flat, and the plug lowered.

The volume and squish area of all these designs is identical by the way. Just playing with shapes.

Any thoughts?

The plan is to machine inserts for the VHM head covers and test the theories on the NSR150SP.

Also have an extended and water cooled spigot for the exhaust port to try. The plan wuld be to test the pipe we have, and then have a pipe with a header shorter by the same amount as the spigot is longer, so that the tuned length doesn't change.

All very exciting, just need 25 hours a day, 8 days a week to get it all done.

Anyway, better get on with boring work.

Cheers,

Matt.

[jfn2]

Wobbly:

"but my opinion is that the best piston shape is an angled edge,its width = the squish,then a flat top.
Will be testing that soon" - WOBBLY

In a paper from Pune, India (sae # 931510) they were testing different combustion chambers and also different piston dome shapes and they found that the shape of the dome with the dome angle the same as the squish angle then a small deflector upwards than a flat top to work the best. I tried this on a Yamaha KT100 engine and it seems to work well but I do not have any proof.

[Frits Overmars]

In a paper from Pune, India (sae # 931510) they were testing different combustion chambers and also different piston dome shapes and they found that the shape of the dome with the dome angle the same as the squish angle then a small deflector upwards than a flat top to work the best.I did not succeed in locating SAE 931510. What was the BMEP of the tested engine?

[Haufen]

Wobbly:

"but my opinion is that the best piston shape is an angled edge,its width = the squish,then a flat top.
Will be testing that soon" - WOBBLY

In a paper from Pune, India (sae # 931510) they were testing different combustion chambers and also different piston dome shapes and they found that the shape of the dome with the dome angle the same as the squish angle then a small deflector upwards than a flat top to work the best. I tried this on a Yamaha KT100 engine and it seems to work well but I do not have any proof.


I did not succeed in locating SAE 931510. What was the BMEP of the tested engine?

and what were the criteria that defined "what works best"

[jfn2]

Frits:
The paper is titled 'Study of the Effect of Combustion Chamber Design on Performance of the Small Two Stroke Gasoline Engine'
Authors were.... Marathe, Chikhalikar, Malekar, Sarveswaran by Bajaj Auto Ltd, Pune, India.
Engine was a 2 stroke s.i. engine forced air cooled used for 2 wheeler (scooter) application
57 x 57mm bore and stroke
145.45 cc
cr= 10:1
22* BTDC (constant at all speeds)
rotary valve
20mm carb

Here are some pages I hope answers most questions.

[Muhr]

For one or two cylinders?

If my new cylinder works well i might reverse engineer it and get one casted.

For one! Of course, it's not the most economical, but the expectation that this will be an optimal cylinder is low. I have CFD the shit out of this cylinder so should give me a lot of data.

[jfn2]

I left out some of the pages because they dealt with emissions. On the last page it says all combustion chambers were tested at the same ignition timing. Conclusions were:
combustion chamber has significant influence on emission, SFC and power output.
Deflector type combustion chamber is found to be the best in respect of emissions, SFC and power output. Faster burning rate is observed with this combustion chamber due to its typical geometry.
Combustion chamber having no squish zone is found to be inferior than all other combustion chambers with squish.
Further work as out lined above will be undertaken to assess the effectiveness of different combustion chambers with respect to emission levels and fuel economy.

[Haufen]

On the last page it says all combustion chambers were tested at the same ignition timing.

Thanks for sharing the paper.

Ouch. That's a bit like comparing the laptimes of three riders on three bikes, then running one in the dry, one in the wet and the last one in the snow and then concluding that the rider who rode in the dry is the fastest by far because he had the fastest bike.

If you want to compare combustion chambers, ignition timing should be adjusted for max torque (MFB50@ ~8deg ATDC) at a fixed A/F ratio. You can then vary e.g. A/F ratio and note when engine knock begins (leaning) or how rich you can get before 4-stroking occurs (richening).

What has been done in this paper is to check which combustion chamber performed best for a given spark timing and carburetor setting. And that is not always the same chamber as when you'd "max out" each chamber. The "winner" might probably have been the same in both cases, but much more and also smaller differences could have been discovered in the mid-field. Did they even write if the bowl on the asymmetric chamber was near the exhaust port or near the boost port? This in itself can already make a considerable difference.

[wobbly]

Yes I agree Haufen.
If I have learned anything,the most significant from dyno work for years now its that Jan told me all his pipe testing was inconclusive as the fueling
wasn't optimized for each change.
I wasnt till the egt was baselined for each new pipe, then changed to produce max power did the real potential of each design emerge.

In that paper I can see that the so called " deflector " setup would help power etc, as the squish action is in fact being directed up at the plug.
But approaching the limit, an offset chamber is a complete waste of time.
This idea was sold to Yamaha by that burgler of the first order Doctor Joe.
It showed up on the TZ250G head, and that would severely detonate before even getting close to the correct jetting.
One side has no MSV, the other side is huge - maybe fine for an outboard , but no free lunch for a race engine.

Matt - the toroid as you have drawn it is exactly as I have used in all manner of race engines with great success.
The latest being the record breaking TZ350 LSR engine. ( PS,get the water closer to the threads ).
But again, as it allows much leaner and or much greater advance to make more reliable power without deto ( every case is different ), simply swapping from a hemi may not produce instant results.
The angle/flat top is exactly what I am soon to test, but not with a toroid as the KZ kart rules include a compression cc measurement thru the plug hole at TDC and this design traps
air at the highest point doing this.

[Haufen]

The angle/flat top is exactly what I am soon to test, but not with a toroid as the KZ kart rules include a compression cc measurement thru the plug hole at TDC and this design traps
air at the highest point doing this.

Just curious, do the kz rules allow only one spark plug hole? and do you have to have an actual spark plug in each of them or can you put an aluminium insert in the "measuring hole" during operation?

Thanks for the pack file. Although I get an error trying to import it on V5.6.9, I can already confirm deviations on the port shape and roof angles of the main transfer ports and deviations on the roof angle of the boost port (at least, and so far). I will see if I can get the sim running and do a re-evaluation on the molds I made before providing any numbers. Looks like there were at least some small changes made after Jan left.

[2T4TSim]

Here is the Aprilia RSA125 Pack file zipped.

Many thanks Wobbly for this RSA file. After the evening to reload it completely in Dat2t , it runs and is much better than what I expected form my Pit-lane readinds...

Regards
Alain

[wobbly]

The tech people use a threaded screw in gauge that has a smaller hole down the middle.
The volume of the smaller hole is the same as the plug threads.
This was introduced as some smartarse ( not me for once ) was running a smaller chamber volume than was allowed, then drilling blind holes at an angle from the threads.
This then measured correctly to the top of the plug hole with a burette , but was a smaller volume within the chamber , with the spark plug installed.

Not that this is really relevant , as in the case of the KZ engines , no one runs the minimum allowable volume, as this completely kills the overev power.
If the gauge wasnt used you could also release the trapped air from a toroid using an angled drilled hole into the highest point.

There is also a semi " stock appearing " rule ( even though I cant find the actual words ) that means the parts of the engine must " look " like those shown in the homologation papers.
Extra holes are not allowed, even though " removing material " is allowed but adding anything isnt.
This is why my attempt to feed cold water into the cylinder by moving the transfer hose to point at the boost port ( with a new threaded hole ) was rejected.

PS Edit - I have version EngMod 5.6.9e, the latest.
Neels put out this update recently and was concerned other versions would not open packs if not up to date.

[jfn2]

On the last page of this paper they said they are extending the experimentation with MBT ignition timing. Also we have to remember this was done in the early 90's with possibly thinking of the 70's.

[TZ350]

336537336538336539336536336541336540

NF4 MC21 Exhaust and Vertical port angles.

336531336532336533336534336535

Comparison of transfer port angles between a Honda RS125 NF4 and NSR250 MC21 cylinder.

[TZ350]

336531336532336533336534336535

Comparison of transfer port angles between a Honda RS125 NF4 and NSR250 MC21 cylinder.



336537336538336539336536336541336540

Honda NF4 RS125 and NSR250 MC21 Exhaust and Vertical port angles.


336558 336557 336556

With the Power Valve set to open at 96deg ATDC thee is significant gaps around the PV blades.

The PV's are fiddly and difficult to get in and out so I cut a damaged cylinder to make a jig to make it easier for welding and grinding them to a closer fit.

[190mech]

Thanks for the cut cylinder pictures TZ350!It gives us a real view of how a decent port layout should look!!

[Frits Overmars]

Matt - the toroid as you have drawn it is exactly as I have used in all manner of race engines with great success. The latest being the record breaking TZ350 LSR engine. ( PS,get the water closer to the threads ...
The angle/flat top is exactly what I am soon to test, but not with a toroid as the KZ kart rules include a compression cc measurement thru the plug hole at TDC and this design traps air at the highest point doing this....
Not that this is really relevant , as in the case of the KZ engines , no one runs the minimum allowable volume, as this completely kills the overev power.What would the true combustion volume of your toroid head need to be in order to pass the KZ-test?
You might give it a try Wob; I've seen surprising results from low compression ratios.

[husaberg]

Thanks for the cut cylinder pictures TZ350!It gives us a real view of how a decent port layout should look!!
336546336547336551336548336549336550

What should be mentioned is Yamaha Suzuki and Cagiva would have liked to emulate the wide well curved transfer ports of both the Honda and more importantly the Aprilia.
Only they couldn't as the cylinder spacing and bore centers did not allow them to this there want the room. Hence they often used 6 main transfer ports
Yes they could have did it on the 125's and 250 v twins, but those bikes were only generally given hand me down tech from the 500's.
Both the Honda and the Aprilia layouts allowed for more room. thus more power and more championship wins

[Frits Overmars]

What should be mentioned is Yamaha Suzuki and Cagiva would have liked to emulate the wide well curved transfer ports of both the Honda and more importantly the Aprilia.What never ceases to amaze me is the inner curvature of the Honda transfer ducts. Even in their most recent race engines it was only 12 mm at its tightest point,
compared to a constant 22,6 mm radius for the Aprilia's inner curvature - that's almost twice as big, which makes a big difference in flow attachment.
336552

[husaberg]

What never ceases to amaze me is the inner curvature of the Honda transfer ducts. Even in their most recent race engines it was only 12 mm at its tightest point,
compared to a constant 22,6 mm radius for the Aprilia's inner curvature - that's almost twice as big, which makes a big difference in flow attachment.
336552

I was under the impression they got it a bit better later on. That NF4 certainly doesnt compare well when overlaid with the Aprilias
They were still however better than most of the other japanese engines even if not as good as the Aprilia.
I think their lack of radius could in part be due to their perserverence with their giagantic bridged exhaust.
Which was likely by then weakness in design that due to corporate pride that they were not allowed to change even if the designer wished too.
I am inclined to hope (at least) they had trialed it, as they certainly had the resouces to have tested every possible solution and permutation to death.
Put it this way they certainly would have had a few Aprilia customer cylinders available for evaluation.
Just as they had a complete RGB500 when they were building the NR500.

I also recall Honda in the mid 90's had some intersting limits placed arround development of the GP bikes by the companies senior managers with regards to pollution and fuel efficiency that likely other manufacturers were not saddled with either. HRC were also hamstrung in regards to the NF4 RS125s in which it was a modified CR125 platform, they were only permitted to make radical changes every 5 years or so at most. That existing platform, like your own at Aprilia entailed the cylinders to be made to fit around the confines of the existing stud pattern.

What surprised me most of the Japanese was with Yamahas development was how often they changed their porting from bridged to 3 port and 7 transfer to 8 and more with every permutation between with changes back and forth with v angle when they earlier had had what would be classed as the best solution of a tripple ex with 5 transfers. They also abandoned the 54x54 bore and stroke for about 25 years as did Suzuki

There was a story from Burgess that they trialled an Ohlins for on the NSR500, not one change was made to the fork set up from what was delivered, yet Doohan lapped a second a lap quicker, There of course was never going to be any chance of him racing with it fitted but it shows that Honda was not prepared to race with a fork that was substantially quicker if it was not from a Honda owned company like Showa was.

[Muhr]

Checking what you can expect from the conrod before destroying the new cylinder
below 50cc conrod at 19000 rpm. Wonder what would happen at 30000 rpm? (but there may be other materials):D

[Vannik]

Checking what you can expect from the conrod before destroying the new cylinder
below 50cc conrod at 19000 rpm. Wonder what would happen at 30000 rpm? (but there may be other materials):D

The maximum stress is a modeling stress, caused by the sharp transition in the recess radius, real stress is probably less. Also it is a Von Mises stress, used for fatigue and not outright failure. What does the major principle stress look like?

[Muhr]

The maximum stress is a modeling stress, caused by the sharp transition in the recess radius, real stress is probably less. Also it is a Von Mises stress, used for fatigue and not outright failure. What does the major principle stress look like?

Well, of course, not the whole truth, looked at shape optimization.
(Seems to go in pieces at 24000)

[TZ350]

336546

What should be mentioned is Yamaha Suzuki and Cagiva would have liked to emulate the wide well curved transfer ports of both the Honda and more importantly the Aprilia.



What never ceases to amaze me is the inner curvature of the Honda transfer ducts. Even in their most recent race engines it was only 12 mm at its tightest point,
compared to a constant 22,6 mm radius for the Aprilia's inner curvature - that's almost twice as big, which makes a big difference in flow attachment.
336552

Thanks for the heads up about the inner transfer duct radius.

336558 336557 336556

With the Power Valve set to open at 96deg ATDC there are significant gaps around the PV blades.

The PV's are fiddly and difficult to get in and out so I cut a damaged cylinder to make a jig to make it easier for welding and grinding them to a closer fit.

[wobbly]

Thats a good point Frits.
The min allowable volume is 13cc TOP.
But I know the magic number to shoot for is actually 13.6.
Below this you loose overev, above this the mid ( 10,000 ) is compromised.
So if I can do a toroid that measures 13cc on the bench, but actually has 0.6cc trapped as air above the threads we could have a winner.
Onto the CAD right now.
Cheers Big Ears.

[2T4TSim]

Many thanks Wobbly for this RSA file. After the evening to reload it completely in Dat2t , it runs and is much better than what I expected form my Pit-lane readinds...

Regards
Alain

All my apologizes Wobbly for the mistake.

Thanks again

Regards
Alain

[lodgernz]

336559. .

[husaberg]

Thanks for the heads up about the inner transfer duct radius.

336558 336557 336556

With the Power Valve set to open at 96deg ATDC thee is significant gaps around the PV blades.

The PV's are fiddly and difficult to get in and out so I cut a damaged cylinder to make a jig to make it easier for welding and grinding them to a closer fit.

It might pay to spell out to the others that your new engine is a complete reversal of your previous incarnations of the ESE AC GP125
From memory the top end is completely std road NSR, the pipe is a stock 93ish RS Honda. The Carb is a 28 with a 24 venturi OKO.
but the bottom end is modified with a larger rotary valve a different gearbox and a de-stroked crank with a wider crankcase to accommodate a different gearbox and a more modern cylinder.
Normally you would have had a cylinder with hundreds of hours work and development. yet you are close to matching the best output obtained with the previous incarnations.
Is this correct?

[wobbly]

So here is the pack file of Robs GP-NSR110 Mod by me, to generate the power curve as published previously.
Rob or anyone can ask for details on any input for explanation.
As I said the ports ( including the RV ) are all "stock " as set up originally.
First page to explain is the Engine.
I went for 12 Bar at 12500 as this is what the STA say the ports are capable of.
Thus we have a fairly low bmep, and on AvGas this will happily take the 16.5:1 com input, used on short kart tracks where acceleration between corners is far more important than overev power..
This is proven by the TuBMax output with the stinger size optimized and a "normal " ignition curve that starts at 25* under the pipe
then heads for 15* at peak power.
The Ex length input is 10mm, to look at the Mach in Pipe 2 = the stinger nozzle.

[TZ350]

It might pay to spell out to the others that your new engine is a complete reversal of your previous incarnations of the ESE125

From memory the top end is completely Standard road NSR the pipe is a stock 93ish RS Honda.

Normally you would have had a cylinder with hundreds of hours work and development. yet you are close to matching the best output obtained with the previous incarnations. Is this correct?

Yes you are right, this current engine is pretty stock and with Wobs suggestions they may be the equal of my previous best efforts with the Beast.

336564 336566

Team ESE have two of these GP/NSR 110cc engines running and more in the process of being being built.

All have 48mm de-stroked cranks.

The Standard production engine has no real additional tuning and is as simple as possible. Basically it is just fitting a NSR250 cylinder to a GP100 bottom end.
1978 Suzuki GP100 engine.
Std Suzuki GP 24mm inlet tract and carb. Polished but not ported.
Inlet RV closing point increased from 65 to 80 atdc.
Yamaha 115mm c/c RD400 con rod.
Re plated std road going Honda NSR250 cylinder and head. 12:1 CR
Cylinder position adjusted so the Exhaust opens 80 ATDC.
Transfers then open 115 ATDC. (This is just the fortunate way it works out with the shorter stroke.)
Std Honda RS125 pipe. NF4
Modified 1975 TS125 5 speed gearbox.
Ignitec Digital Ignition.

336567 A Team ESE basic GP/NSR110 in a NF4 RS125 chassis.

27 RWHP as measured on a DynoJet.

These so called standard production Team ESE engines are basically as standard as possible to keep things simple and this is the engine that Wobbly has been simulating and developing a pipe and nozzle for.

The Beast H2o 110cc engine has more bells and whistles:-

This engine was originally a 1978 air cooled Suzuki GP100, latter run as an air cooled 125 which made a reliable every day 28 RWHP. (31 on the dyno).
And now has:-
Kawasaki KE175 rotary valve with 32mm inlet tract.
Inlet opens 140 BTDC Closes 85 ATDC.
EFI fuel injection with 24mm throttle body.
48mm de stroked crank.
55% balance factor, was aiming for 50 but stuffed up.
Yamaha 115mm c/c RD400 con rod.
Massive crankcase volume.
Re plated road going Honda NSR250 cylinder. Exhaust port shape modification to make it look like a RS125.
Cylinder position adjusted so the Exhaust opens 80 ATDC.
Transfers then open 115 ATDC. (This is just the fortunate way it works out with the shorter stroke.)
VHM head with torroidal head insert. 14:1 CR
Std Honda RS125 pipe. NX4
Modified 1985 TS125 6 speed gearbox.
Eight plate clutch.
Dry sump gear box with oil mist spray.
Ignitec Digital Ignition.

336568 the Beast. MC18 chassis.

31 RWHP as measured on a DynoJet. I felt it was a lot of work for not much gain over the std 27RWHP Team ESE engines.

I will keep the "Beast" as a EFI development donkey and all out tuning test bed, just for the fun of it.

I expect that the std setup with Wobs suggested improvements will make great advancements to the keeping it simple approach and will be the way to go for the team bikes.


So here is the pack file of Robs GP-NSR110 Mod by me, to generate the power curve as published previously.
Rob or anyone can ask for details on any input for explanation.
As I said the ports ( including the RV ) are all "stock " as set up originally.
First page to explain is the Engine.
I went for 12 Bar at 12500 as this is what the STA say the ports are capable of.
Thus we have a fairly low bmep, and on AvGas this will happily take the 16.5:1 com input, used on short kart tracks where acceleration between corners is far more important than overev power..
This is proven by the TuBMax output with the stinger size optimized and a "normal " ignition curve that starts at 25* under the pipe
then heads for 15* at peak power.
The Ex length input is 10mm, to look at the Mach in Pipe 2 = the stinger nozzle.

336565

[TZ350]

336559. .

By golly, that factory NF4 racing cylinder is not very symmetrical is it!

[Vannik]

By golly, that factory NF4 racing cylinder is not very symmetrical is it!

Can that be because the photo is not in line with the bore center line?

[TZ350]

Yes I guess so.

[Muhr]

Thats a good point Frits.
The min allowable volume is 13cc TOP.
But I know the magic number to shoot for is actually 13.6.
Below this you loose overev, above this the mid ( 10,000 ) is compromised.
So if I can do a toroid that measures 13cc on the bench, but actually has 0.6cc trapped as air above the threads we could have a winner.
Onto the CAD right now.
Cheers Big Ears.

just an explanation for others who may not be used to karting 11cc + 2cc thread insert

[Tim Ey]

Thats a good point Frits.
But I know the magic number to shoot for is actually 13.6.

10,19:1 :eek5: Really?

[jbiplane]

Comparison of transfer port angles between a Honda RS125 NF4 and NSR250 MC21 cylinder.

I have 3d scanner and can make precise 3D mesh of cutted cylinder if someone sent me :)
This mesh can be used to make precise 3D CAD model if someone will spend time for.

[F5 Dave]

10,19:1 :eek5: Really?
No 11.8, as said includes plug hole for easy measurement.

[lodgernz]

Can that be because the photo is not in line with the bore center line?

This is a better view, but the picture is much worse. The B ports are not too bad, a bit too much kick at the back perhaps, and the right-hand A port is spot on I think, but the left-hand A port front edge is kicking way too far back. Maybe two minutes with a port grinder could have made quite a difference to that engine.

336589

[wobbly]

Yes the rules state 11cc actual combustion chamber volume, and a standard gauge is used that has 2cc added for the plug threads.
So 13 cc to the Top Of the Plug hole.
I use a digital burette and depending upon the tune and track,mostly shoot for 13.6 = 11.6 chamber vol.
This is due to the idiotic straight line PVL homologated ignition, so the engine has way too much advance past peak power,.
To to combat this the pipe is very short and you can run less static timing or less cc to get extra overev capability.
Minimum track rpm is about 10,000 with peak power at 13500,and it must rev to around 14800 to enable short gearing and to eliminate extra gear changes between corners.
We must use pump fuel here, in Europe its 100 octane unleaded race gas.

[TZ350]

This is a better view, the right-hand A port is spot on I think, but the left-hand A port front edge is kicking way too far back.

336589


336590

It might be that the cut is not perfectly square and we are seeing the remains of the curved part at the front of the A port. If the cut is not square horizontally one front edge of the A port will lean forward more than the other. I will have to check.

[jfn2]

Also I don't think your lines are showing the top of the ports. If you look closer I think you can see where the real tops are pointing. I think your lines are only showing the beginning of the flow side surface or the end of the flow surface so to speak.

[Pursang]

Perhaps the offsets can put a bit of 'swirl' in the rising column, rather than an inertia free "dead" lump of charge.

Swirl is a big deal in the poppet valve world.

Cheers, Daryl

[lodgernz]

Also I don't think your lines are showing the top of the ports. If you look closer I think you can see where the real tops are pointing. I think your lines are only showing the beginning of the flow side surface or the end of the flow surface so to speak.

OK, I've moved the line a little so you can see better. Think I got it right.

336591

[TZ350]

Good spotting, symmetric port shape is important. You might be onto something.

I will have another look at the original piece, maybe face it back a bit in the lathe so the cut is definitely square.

[trevor amos]

Could it be possible that the port casting is perfectly ok, but the bore is off-set and/or miss-aligned from initial manufacture, does happen?

Trevor

[TZ350]

Anything is possible, away at the moment, give me a day or three to get back and I will look at it a bit closer.

[Vannik]

I will have another look at the original piece, maybe face it back a bit in the lathe so the cut is definitely square.

When you have faced it and taken a new pic - would there be a chance to use it in Dat2T Help files?

[TZ350]

Yes of course...

[Muhr]

Would have been interesting if the japs had a vortex theory, or any other exciting thing going on. but feels like something in the manufacturing gone wrong as the wall thicknesses of C trans indicate and uncentrated borr as a result.
As Trevor suggested

[jfn2]

Here is possibly another way to look at the angles. Done with molds sitting on top of the case with piston propped up at port height.

[philou]

Cylinder Metrakit 50 cc for Derbi engine (lathes machining)

336605

[Muhr]

Cylinder Metrakit 50 cc for Derbi engine (lathes machining)

336605

May have been inspired ...

[husaberg]

May have been inspired ...
If you ask Jan or Frits the hooked B ports might be more to do with the stud position that was forced on them by managements insistence that it still bolt on every 125 made back for 20 years or so.

[jamathi]

If you ask Jan or Frits the hooked B ports might be more to do with the stud position that was forced on them by managements insistence that it still bolt on every 125 made back for 20 years or so.

I was perfectly happy with the Aprilia's B-ports and ducts.
They were unchanged from 1997 until I retired!
Also on the RSA!

[Frits Overmars]

I was perfectly happy with the Aprilia's B-ports and ducts.
They were unchanged from 1997 until I retired!
Also on the RSA!It was mainly the leading edge of the A-ports that was hampered by the stud positions and the coolant ducting.

[Muhr]

It was mainly the leading edge of the A-ports that was hampered by the stud positions and the coolant ducting.

What would you or Jan have liked to do if the room had been given? More angle or area?

[wobbly]

I want to try a piston timing edge radius.

Anyone got any ideas on the need to move the cylinder by what amount if say I use R1.5.

This in effect means the ports start to open 1.5mm sooner, but instead of a sharp transition from " closed " to "open" we now have a very gradual

uncovering ( or covering for that matter ) of the flow area.

Am I overthinking this and should simply move the cylinder 1.5mm and see what happens.

[husaberg]

It was mainly the leading edge of the A-ports that was hampered by the stud positions and the coolant ducting.
Can you point to it?
Because I was thinking of the hook at the bottom of the picture that seems to be pushed around the Stud position?

[Matt@TYGA]

I want to try a piston timing edge radius.

Anyone got any ideas on the need to move the cylinder by what amount if say I use R1.5.

This in effect means the ports start to open 1.5mm sooner, but instead of a sharp transition from " closed " to "open" we now have a very gradual

uncovering ( or covering for that matter ) of the flow area.

Am I overthinking this and should simply move the cylinder 1.5mm and see what happens.

I think on this question, both options need testing and a full report written :msn-wink:

But it's an interesting thing to look at.

Did a quick sketch and lets say that a sharp edged piston has just closed/opened the port, there would still be an opening (depending on piston size, dome radius etc). The dimensions I chose are just some numbers, so meaningless at this point, but let's just say that the flow is parallel to the port roof (for measurements sake) then the opening available is not 1.5mm, so I don't think I'd make the 1.5mm move of the cylinder.

Maybe changing the cylinder height 1mm would work, as this seems to give a similar open area at first opening.

I'd just give it a go first and then have a play.

Matt.

[Frits Overmars]

If you ask Jan or Frits the hooked B ports might be more to do with the stud position that was forced on them by managements insistence that it still bolt on every 125 made back for 20 years or so.
I was perfectly happy with the Aprilia's B-ports and ducts. They were unchanged from 1997 until I retired. Also on the RSA!

It was mainly the leading edge of the A-ports that was hampered by the stud positions and the coolant ducting.

What would you or Jan have liked to do if the room had been given? More angle or area?This room was finally given with the design of the RSA. It was mainly used to sharpen the radial angle; the A-port's leading edges were angled more backwards,
away from the exhaust port. The picture shows how the RSA's exhaust-side studs are wider apart and further away from the A-ports than the RSW-studs.
336633

[jamathi]

This room was finally given with the design of the RSA. It was mainly used to sharpen the radial angle; the A-port's leading edges were angled more backwards,
away from the exhaust port. The picture shows how the RSA's exhaust-side studs are wider apart and further away from the A-ports than the RSW-studs.
336633

The transfer ducts were exactly the same.....Y-type....
Cooling was improved, which gave more power!

[Frits Overmars]

I want to try a piston timing edge radius. Anyone got any ideas on the need to move the cylinder by what amount if say I use R1.5.
This in effect means the ports start to open 1.5mm sooner, but instead of a sharp transition from " closed " to "open" we now have a very gradual uncovering ( or covering for that matter ) of the flow area. Am I overthinking this and should simply move the cylinder 1.5mm and see what happens.You could use my tried and trusted 45°-bent feeler gauge Wob. It will handle any piston edge radius and any port edge radius as long as the port's roof angle is not steeper than 45°. Just pinch it between piston and port with its hand-held end vertical, measure from cylinder top deck to piston and subtract 1 mm from the measured value. This will give you an easily measurable dimension that can directly be compared to any other port height value. EDIT: picture updated following Wobbly's advice.

[Haufen]

I want to try a piston timing edge radius.

Anyone got any ideas on the need to move the cylinder by what amount if say I use R1.5.

This in effect means the ports start to open 1.5mm sooner, but instead of a sharp transition from " closed " to "open" we now have a very gradual

uncovering ( or covering for that matter ) of the flow area.

Am I overthinking this and should simply move the cylinder 1.5mm and see what happens.

I'd lower the cylinder by half the measure of the radius as a start. Then compare the curve shapes between that setup and no radius and then decide if it's okay or in which direction and by how much the cylinder is going to be moved next.

[wobbly]

I use the same setup Frits, just changing the feeler to 0.7mm gives 1mm port change - easyer for my brain to handle when measuring.
I have found a piston 0.5mm higher than stock and was planning on CNC cutting a 0.5mm rad on the timing edge, without moving the cylinder.
But i will now draw that feeler gauge scenario and see what numbers come up.

[wobbly]

OK - so did the CAD exercise and using the feeler method it seems that its easy.
If I have a 0.5mm rad then I need to drop the cylinder 0.25 ( rounded ).
I can do this without machining the cylinder base.
But with a piston that has a 0.5mm higher timing edge , I can do a 1mm rad and not change the cylinder at all.
An easy first test to see what happens, although I still have to do a special head insert to get the bore edge geometry and cc correct.

[TZ350]

When you have faced it and taken a new pic - would there be a chance to use it in Dat2T Help files?

Sure thing, here you go .....

336646

Top half of a Honda NF4 RS125 cylinder.

[lodgernz]

Sure thing, here you go .....

336646

Top half of a Honda NF4 RS125 cylinder.

Defo a bit of an issue with this one

[TZ350]

Defo a bit of an issue with this one

Yes looks like it. Probably not the only one. Like you say, a bit of work with the grinder may pay dividends.

[Muhr]

OK - so did the CAD exercise and using the feeler method it seems that its easy.
If I have a 0.5mm rad then I need to drop the cylinder 0.25 ( rounded ).
I can do this without machining the cylinder base.
But with a piston that has a 0.5mm higher timing edge , I can do a 1mm rad and not change the cylinder at all.
An easy first test to see what happens, although I still have to do a special head insert to get the bore edge geometry and cc correct.

Would be interesting to see a real test of rounded piston edge. Always have some doubts about VHM's tests and especially how they choose to zero.
with a feeler gauge pressed against the back of the cylinder. Assuming it's a 0.2mm, it might give more "duration" and still manage within the rules. but if it is better with the same duration, it does not tell.

[karter444]

Hi Wobbly
what lenght and ID do you recommend for a kz2 B/C stinger ,when using the size you recommend do you lose any power below peak ie from 10,000 to 13,500
cheers Richard

[wobbly]

Stingers on a KZ are a real can of worms, so much so that I use two different versions depending upon the track.
But in any case the shorter you make the U bend the better the power.

There is a rule for a MAX of 50mm of stinger sticking into the mufflers much bigger perforated inner.
Cut off the welded on washer, and move it back right to the very start of the bend.
Then cut off the tube at 25mm from the washer face - this is the same length as the slip on length inside the muffler.
On the other end that slips into the pipe spigot - again cut it off as short as you can to allow it to just slip in all the way.

As far as ID goes I use a genuine TM 28/28 OD tube with an insert pressed into the pipe slip fit end.This is 22.8 ID and 20mm long with 45* chamfers at each end.
The chamfer on the pipe side matches the 24.4 ID of the rear cone,and the other end simply matches the 26 ID of the tube.
This U bend is for tracks that favor higher rpm or in fact need a shit load of overev to allow deleting gearchanges between corners.
There is only a very small loss below peak , when run against a stock 26/28 TM tube.

For tracks needing more bottom end I use the TM 28/26 stepped stinger , just cut short as above , or if you can get them the 28/28 tubes made by ELTO with 1.5mm wall.
With this smaller ID tube I use a 24mm ID insert - this makes a little better top end,with the same bottom.

[TZ350]

336658

So here is the pack file of Robs GP-NSR110 Mod by me, to generate the power curve as published previously.
Rob or anyone can ask for details on any input for explanation.
As I said the ports ( including the RV ) are all "stock " as set up originally.
First page to explain is the Engine. I went for 12 Bar at 12500 as this is what the STA say the ports are capable of.
Thus we have a fairly low bmep, and on AvGas this will happily take the 16.5:1 com input, used on short kart tracks where acceleration between corners is far more important than overev power..
This is proven by the TuBMax output with the stinger size optimized and a "normal " ignition curve that starts at 25* under the pipe then heads for 15* at peak power.
The Ex length input is 10mm, to look at the Mach in Pipe 2 = the stinger nozzle.


I have version EngMod 5.6.9e, the latest. Neels put out this update recently and was concerned other versions would not open packs if not up to date.

...........

[wobbly]

Hey Rob, last time I looked over 40 downloads of the GP-NSR110 file.
I am assuming that they must all have the new version of the code as no one has complained about not being able to open it ?

As far as the NF4 ports are concerned,I think the biggest gain would be to use a kit type piston with the ring pin at the middle and grind the rear wall
of the B ports to equalize and narrow the boost port dividers.
At the same time aim the ground walls to 1/3 of the bore radius from the boost port face.
Currently they are very steeply aimed at about 2/3 toward bore center line - very last century.

[koba]

Hey Rob, last time I looked over 40 downloads of the GP-NSR110 file.
I am assuming that they must all have the new version of the code as no one has complained about not being able to open it ?


I downloaded it and tried with an older version.
It does import some data but errors on heaps too.
I figured I'd worry about that later.

All of this is incredibly interesting btw, thanks!

[dutchpower]

Both NSR 110 and Apr.RSA zero download :weep:

[TZ350]

Hey Rob, last time I looked over 40 downloads of the GP-NSR110 file.
I am assuming that they must all have the new version of the code as no one has complained about not being able to open it ?

Ok ... I installed the latest EngMod2T (May) updates Neels had sent out and I also made sure the "un ziped pack file" went into the "C" drive "2Stroke" directory before I tried to unpack it with Dat2T.

It looks like the unpack option is going to work for me now, so will run a simulation.

336664

Yep, that worked, thanks Wob.

Now to have a good look through it to understand what you did and how it improved my original simulation then figure out how to convert it to cut metal.

[JanBros]

Frits, you once wrote :


The total angle.area of the transfers divided by the total scavenged volume per cylinder (cubic capacity plus combustion volume) determines at which rpm the engine starts running out of breath. Revving it much higher does not make much sense

I bellieve it was on pitlane.

but I don't realy understand as mathematicaly this can't be true : the units are mm2 devided by mm3 ?

for the RSA : Tr A.A = 110315 , SV = 124.8, CCV = 8.6 110315/(124.8+8.6) = 828 ??

[RomeuPT]

Hello

http://www.underdogsracing.com/fospipe/

Seems not working. It is sometimes usefull for me to give a first insight.

Are there other links with the same thing?

Maybe it's time for me to build my calculator?

Cheers

[Frits Overmars]

Frits, you once wrote : ..... I bellieve it was on pitlane.
but I don't realy understand as mathematicaly this can't be true : the units are mm2 devided by mm3 ?
for the RSA : Tr A.A = 110315 , SV = 124.8, CCV = 8.6 110315/(124.8+8.6) = 828 ??Jan, the unit for angle.area is not mm² but °mm². It's all in the name: angle, multiplied by area. And if you take rpm into consideration, the angle.area becomes a time.area.
Below is that part of Pit-Lane once more, plus another couple of links. There is more to be found on the subject; you'll just have to find the time to search for it :p.

http://www.pit-lane.biz/t3173p543-gp125-all-that-you-wanted-to-know-on-aprilia-rsa-125-and-more-by-mr-jan-thiel-and-mr-frits-overmars-part-2-locked

http://www.pit-lane.biz/t4072p578-gp125-all-that-you-wanted-to-know-on-aprilia-rsa-125-and-more-by-mr-jan-thiel-and-mr-frits-overmars-part-3-locked

336665

[JanBros]

I know where it comes from Frits, I copy all interesting stuff people like you say into files like "cylinders" , "Heads" or "Pipes". that's where I copied it from :msn-wink:

So I guess now it was just a reverse of the STA formula ? I thought you were pointing to a way of knowing the max (over)rev before power would drop significantly, but ofcourse the torque drops anyway after it has reached it's max. must ....read ... better ...:Oops:

[JanBros]

Hello

http://www.underdogsracing.com/fospipe/

Seems not working. It is sometimes usefull for me to give a first insight.

Are there other links with the same thing?

Maybe it's time for me to build my calculator?

Cheers

or you can use mine : http://users.telenet.be/jannemie/FOS%20PIPE%20black.xlsm

[RomeuPT]

or you can use mine : http://users.telenet.be/jannemie/FOS%20PIPE%20black.xlsm

Great. I kinda remebered that there was an alternative somewhere.

Many Thanks dude

[karter444]

Stingers on a KZ are a real can of worms, so much so that I use two different versions depending upon the track.
But in any case the shorter you make the U bend the better the power.

There is a rule for a MAX of 50mm of stinger sticking into the mufflers much bigger perforated inner.
Cut off the welded on washer, and move it back right to the very start of the bend.
Then cut off the tube at 25mm from the washer face - this is the same length as the slip on length inside the muffler.
On the other end that slips into the pipe spigot - again cut it off as short as you can to allow it to just slip in all the way.

As far as ID goes I use a genuine TM 28/28 OD tube with an insert pressed into the pipe slip fit end.This is 22.8 ID and 20mm long with 45* chamfers at each end.
The chamfer on the pipe side matches the 24.4 ID of the rear cone,and the other end simply matches the 26 ID of the tube.
This U bend is for tracks that favor higher rpm or in fact need a shit load of overev to allow deleting gearchanges between corners.
There is only a very small loss below peak , when run against a stock 26/28 TM tube.

For tracks needing more bottom end I use the TM 28/26 stepped stinger , just cut short as above , or if you can get them the 28/28 tubes made by ELTO with 1.5mm wall.
With this smaller ID tube I use a 24mm ID insert - this makes a little better top end,with the same bottom.

thanks Wobbly for all the info saves a whole lot of testing when someone else has done the hard yards
cheers Richard

[F5 Dave]

And a lot of stuff you wouldn't have thought worth testing.

[F5 Dave]

Friday night musical interlude.

When Kate starts singing you realise she was wasted with that other band.


https://youtu.be/6bLOjmY--TA

[peewee]

hey guys maybe one of you clever buggers can say what you think of my idea to allow more fuel to pass through this float valve. ive drilled it out to 3.6mm which is about as big as it can be and still allow to needle to plug the hole. If the fuel has to go through a 3.6mm diam hole that is 2.75 long, what if I grinded it like a funnel so the fuel only has to pass through a 3.6mm hole for say .5mm. does this sound like it could let more fuel through ? I would just try it and see but maybe someone has already tried it and knows the answer. first photo is how it is now. second photo is my idea what I could do

[F5 Dave]

If you want to pass an actual gas through there then the idea has merit. Petrol however isn't so compressible.

[wobbly]

Peewee, both Keihin and Dellorto and Amal make float valves withe 4.2 and or 4.5 hole size.
Might be easyer to adapt one with no mods.
I have tried drilling / reaming them before, and could not get them to ever seal again.

[husaberg]

hey guys maybe one of you clever buggers can say what you think of my idea to allow more fuel to pass through this float valve. ive drilled it out to 3.6mm which is about as big as it can be and still allow to needle to plug the hole. If the fuel has to go through a 3.6mm diam hole that is 2.75 long, what if I grinded it like a funnel so the fuel only has to pass through a 3.6mm hole for say .5mm. does this sound like it could let more fuel through ? I would just try it and see but maybe someone has already tried it and knows the answer. first photo is how it is now. second photo is my idea what I could do


Peewee, both Keihin and Dellorto and Amal make float valves withe 4.2 and or 4.5 hole size.
Might be easyer to adapt one with no mods.
I have tried drilling / reaming them before, and could not get them to ever seal again.

What about using a kart diaphragm/pulse pump and leaving the float valve as close to STD.
https://ssli.ebayimg.com/images/g/fqcAAOSwhvFZBCxr/s-l1600.jpg (https://www.google.co.nz/url?sa=i&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwjqncGDy_7aAhUJv5QKHafQCGMQjRx6BAgBEAU&url=http%3A%2F%2Fwww.ebay.com%2Fbhp%2Fpulse-fuel-pump&psig=AOvVaw2bX_tpaWmQi71W71mg3YnI&ust=1526159810360826)
PS I would be checking the flow rate out of the tank as well.
http://www.mikunioz.com/shop/df62-702-fuel-pulse-pump-65-lph-dual-outlet/

[Grumph]

Peewee, both Keihin and Dellorto and Amal make float valves withe 4.2 and or 4.5 hole size.
Might be easyer to adapt one with no mods.
I have tried drilling / reaming them before, and could not get them to ever seal again.

It is a hell of a lot easier to use the big ones Wob mentions - if you're using gravity feed. And Husa's correct to say check the flow rate of the whole system - how big's your tap ? tank breather ?

I've always found it unneccesary to go bigger if you're using pump feed. I'll qualify that by saying electric or mechanical pump - and not on a kart...

[husaberg]

It is a hell of a lot easier to use the big ones Wob mentions - if you're using gravity feed. And Husa's correct to say check the flow rate of the whole system - how big's your tap ? tank breather ?

I've always found it unneccesary to go bigger if you're using pump feed. I'll qualify that by saying electric or mechanical pump - and not on a kart...
I am pretty confident that 65l/h should belts and braces
http://www.mikunioz.com/shop/df62-702-fuel-pulse-pump-65-lph-dual-outlet/

[wobbly]

The thing to get "right " with a fuel supply system is the ratio of pressure head to float valve size.
When you only have a tank sitting just above the carb , then the head can be as little as 150mm.
So in this case I had to demand from Lectron that they fit their so called "high flow " valves that are still only 3.5mm.
They were saying I didnt know what I was talking about , until I sent a phone video of a RZ400 racebike making 100RWHp on the dyno.
Doing an all gear run, the clear bowls were less than 1/2 full when clicking into 6th gear using the stock 3mm size.

Using a pulse pump on karts , the current system is to use a 3mm float valve ( 125 making 50 sprocket Hp ) but a return line to the tank is fitted from a Y on
the carb , this gives a head of around 400mm all the time.
And you MUST have consistent fuel bowl level all the time to get reliable jetting, when chasing the weather all day as I do.

Using full pump pressure ( 3.5 psi ) and a 2mm valve would overflow the bowl, as even the slightest bump would shake the floats and allow a high pressure "squirt " past the needle.
Jetski engines use this system, but they dont run over sharp bumps , with high vertical acceleration .

[peewee]

husa ive checked flow from tank more than once. 3.75L per min. more than plenty I would say. I had previously been using the 65L mikuni pump but since I recently made a new aluminum fuel tank I wanted to keep it simple and go gravity from tank directly to carb. and I did have problems with the 65L fuel pressure squirting past the needle and flooding the crankcase like wob said. I believe it was because I was using a 2.5mm valve. once I switched to a 2mm valve it didn't flood the engine nearly as bad. still I would rather just keep it simple with a short hose from tank to carb

wob ive never seen a keihin with removable float valve. ive never seen a delorto valve but im doubting it would screw into my lectron carb, that uses mikuni valves. maybe the needle itself would fit in the mikuni valve and allow me to drill the passage hole bigger ? hard to say without seeing delorto parts. ive got a pwk laying around but its needle diam (slightly over 6mm) is to large to fit in the mikuni valve, otherwise this may be a option. then again maybe I could grind down the four fins on the side of the pwk needle until it fits in the mikuni valve, the bore out the valve hole to 5mm or so.

also I have this other bowl with a stand alone inlet but its made for a jap bike with carb angled to the left side. my carb angles to the right and it hits the shock spring. so I would have to cut of the inlet side of the bowl and weld it back on to the other side of the bowl. this should solve all my problems but nothings ever easy with custom bikes :facepalm:

[lodgernz]

What about using a kart diaphragm/pulse pump and leaving the float valve as close to STD.
https://ssli.ebayimg.com/images/g/fqcAAOSwhvFZBCxr/s-l1600.jpg (https://www.google.co.nz/url?sa=i&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwjqncGDy_7aAhUJv5QKHafQCGMQjRx6BAgBEAU&url=http%3A%2F%2Fwww.ebay.com%2Fbhp%2Fpulse-fuel-pump&psig=AOvVaw2bX_tpaWmQi71W71mg3YnI&ust=1526159810360826)
PS I would be checking the flow rate out of the tank as well.
http://www.mikunioz.com/shop/df62-702-fuel-pulse-pump-65-lph-dual-outlet/

...or use 2 pumps and no floats.

[husaberg]

...or use 2 pumps and no floats.
or do like they do with dry sumps and swirl bowls and use a pump around with a reservoir .
Pretty sure some of those big old race v8s used to use a pump around with two pumps.

Another option is the old school extra float bowl like they used to do with the old pomy shitters.

Some of the old pommy bikes and those with Dellortos used to use twin feeds to the carb.

Ages ago I posted a pic of one where Amal MK2 were converted to use remote floats on the Cosworth challenge
Plus one where a guy grafted on fuel bowl and needles off a Valiant to go on a Harley with Anal concentrics.

But I am throwing random shit out there
KISS is get a bigger needle and seat fitted better still get a custom bowl made with additional capacity and a bigger float and needle valve and better floats



Using a pulse pump on karts , the current system is to use a 3mm float valve ( 125 making 50 sprocket Hp ) but a return line to the tank is fitted from a Y on
the carb , this gives a head of around 400mm all the time.
And you MUST have consistent fuel bowl level all the time to get reliable jetting, when chasing the weather all day as I do.

Using full pump pressure ( 3.5 psi ) and a 2mm valve would overflow the bowl, as even the slightest bump would shake the floats and allow a high pressure "squirt " past the needle.
Jetski engines use this system, but they dont run over sharp bumps , with high vertical acceleration .
336674
BELL

Most road race karts use motorcycle engines equipped with conventional float chamber carburettors, which of course means that some type of fuel pump must be installed. The pump which I recommend is a pulse type unit manufactured in America by Outboard Marine Corporation. The type 'AY' pump (Part No. 385784), designed for 60-100 hp outboard motors, is the most readily available and easily capable of supplying the required fuel volume for even the hottest TZ250 engines. To ensure a good strong pulse, the pulse tube connecting the crankcase with the pump must be short (i.e., no longer than 4in) and of small internal diameter. (Most fittings require >/4in bore tube.). If you find the pump will not supply sufficient fuel (this usually only occurs when pulse tubes longer than recommended, and very wild inlet port timings approaching 200°duration, are used), you can fit a small 150cc auxiliary fuel tank to gravity feed straight into the carburettor fuel inlet. The auxiliary tank fills at low rpm and keeps the carburettor full at high speeds when pump pulses are weak. Common plastic tubing is best for the pulse line as it is much stiffer than neoprene tube, hence it conveys a stronger pulse to the pump.Unlike automobile carburettors, motorcycle carburettors will not tolerate even very low fuel pressure before they give way to flooding. Being designed for gravity feed operation, their float system is not capable of shutting off fuel flow through the needle and seat at a pressure as low as 1 psi. Therefore, when a pulse pump is fitted, you will have to incorporate a fuel by-pass line, and also perhaps a pressure regulator, in your fuel system. (FIGURE 5.7). The by-pass line should be of the same internal diameter as the fuel line, and installed such that it is at a level approximately 6-12 inches higher than the carburettor fuel inlet. It must tee-off within one or two inches of the fuel inlet and discharge excess fuel in the top of the fuel tank. These precautions will ensure the fuel will not take a path of low resistance and return to the fuel tank, starving the engine.


Personally I would rather just place a simple restriction on the feed and return lines rather than change a seat or fit a proper regulator.
Just as they used to do on waste gate controllers with a needle tap valve.

PS are you sure its 100%the supply that was the issue on the Yamaha with Lectrons and not the vibes upsetting the floats and levels adding as well?

[wobbly]

The Yamaha with the so called high flow 3.5mm Lectron seats when rerun on the dyno with load control , would pull for 10 secs at peak power in 6th.
When watching the clear bowls the level would drop a little and stay there, whereas before they went below 1/2 full - very scary.
That RZ had a long stroke Banshee crank rebalanced with Mallory, and did not have any discernible vibes.

What thread is needed Peewee, I will measure the Dellorto ones I have here.

https://www.dellorto.co.uk/shop/dellorto-motorcycle-carburettors-parts/carburettor-parts/phbephb-parts/methanol-needle-valve/

[F5 Dave]

The thing to get "right " with a fuel supply system is the ratio of pressure head to float valve size.
When you only have a tank sitting just above the carb , then the head can be as little as 150mm.
So in this case I had to demand from Lectron that they fit their so called "high flow " valves that are still only 3.5mm.
They were saying I didnt know what I was talking about , until I sent a phone video of a RZ400 racebike making 100RWHp on the dyno.
Doing an all gear run, the clear bowls were less than 1/2 full when clicking into 6th gear using the stock 3mm size.

Using a pulse pump on karts , the current system is to use a 3mm float valve ( 125 making 50 sprocket Hp ) but a return line to the tank is fitted from a Y on
the carb , this gives a head of around 400mm all the time.
And you MUST have consistent fuel bowl level all the time to get reliable jetting, when chasing the weather all day as I do.

Using full pump pressure ( 3.5 psi ) and a 2mm valve would overflow the bowl, as even the slightest bump would shake the floats and allow a high pressure "squirt " past the needle.
Jetski engines use this system, but they dont run over sharp bumps , with high vertical acceleration .
The old dynojet100 I use doesn' have a brake but the all gears run has been a very valuable tool. Many times it has shown a weakness in carb feed on different bikes.

On the flatslide 24mm mikuni one might choose to use for buckets, the float jet can be any size, but the horizontal drilling that feeds the float jet is like 2mm.
Have to drill out a brass ball bearing and then the horizontal hole. But that breaks through so you have to devcon the outside where it breaks out and drill again. Then block where ball was.

This restores power to all gears.

Gee you have me worrying about the 35mmPWKs fitted to my 100hp 496 RZ.

[Grumph]

[QUOTE=husaberg;1131097847]

Personally I would rather just place a simple restriction on the feed and return lines rather than change a seat or fit a proper reguhat.

My personal favourite setup for multiple carbs on methanol is pump feed - usually a Facet 4 - 6LB pump - with a return line T'd off very close to the carbs.
In that return line I fit a Hilborn idle bypass - usually with the 2nd softest spring in the kit.
This gives a measured 1.1 - 1.2 psi at the carbs. Which motorcycle gravity feed carbs will accept happily.
Used with 3/8in bore fuel lines this system has enough capacity that I've never seen fuel starvation on a dyno.

[katinas]

Again positive tests with KTM SX 65 "rounded piston" on track. Today first place in qualification, at first round of European junior championship in Ukraine.

[Frits Overmars]

Again positive tests with KTM SX 65 "rounded piston" on track. Today first place in qualification, at first round of European junior championship in Ukraine.Well done Katinas 336690

[katinas]

Thanks Frits very much for your insights and advise.
First tests was in Belgium and boy has opportunity to try two bikes: one 18' KTM out of the box, other old bike with new rounded piston.
Very interesting, after tests boy said that he really want new 18' KTM chassis with old rounded piston engine in, so the new engine piston was rounded 0,8 mm, cylinder lightly tuned (cleaned) and lowered 0,4 mm. Head copied to piston roundness and restored volume.
I think is the basis to try this on others engines and maybe try to left sharp piston edge just at C. But it would be more difficult to modified the head.

[peewee]

The Yamaha with the so called high flow 3.5mm Lectron seats when rerun on the dyno with load control , would pull for 10 secs at peak power in 6th.
When watching the clear bowls the level would drop a little and stay there, whereas before they went below 1/2 full - very scary.
That RZ had a long stroke Banshee crank rebalanced with Mallory, and did not have any discernible vibes.

What thread is needed Peewee, I will measure the Dellorto ones I have here.

https://www.dellorto.co.uk/shop/dellorto-motorcycle-carburettors-parts/carburettor-parts/phbephb-parts/methanol-needle-valve/

:wings: I have some great news for anyone that use these shitbox lectrons. last night I got looking at the needle in that stand alone inlet bowl, turns out its a 3.5mm mikuni oring (push in) style float valve. the needle was nearly the same length as the needle in the screw in type valve, although its a bit larger diam. so I grinded down the wings until it just slipped into my 3.5mm style valve. the new needle allows a much larger valve hole, nearly 4.5mm. so I hogged out the hole to 4.37mm to start with and put it to the bench test against my 3.5mm (bored out to 3.6).

with carb fully assembled as it would be on the running engine and 1.9l fuel in the tank it was .115L per 15sec with 3.6mm hole and standard needle. with hole bored to 4.37mm and rubber tip needle, flow was .228L per 15sec. nearly double :laugh:. for both tests the 6 holes around the sides were bored to about 2.5mm or slightly larger. im going to punch out the center hole to about 4.5mm and test again. I think this modified valve may work like a peach for what I need. first two photo is with the 4.37 hole and grinded down needle. other two photo show the valve I got the needle from and it compared to the standard needle

wob ill figure out what the thread size is and get some length measurements. maybe theres something even better that would work but maybe this grinded down rubber tip needle and the hole bored to 4.4mm or so may do the trick. unless the rubber melts off once it touches methanol or nitro :shit:

[peewee]

well I think this is about as much as im going to get from this valve. bored the hole to exact 4.5mm and made it funnel in quit a bit which may not of done any good but why not give it a try. slightly over 2.3L per 15sec. a small flow increase over the 4.37mm hole. maybe if I can bend the tab arms alittle and let the needle drop away from the hole slightly more then maybe it can give more flow, as long as the floats can still push the arms up enough to stop the flow.

[TZ350]

Great work peewee...

[peewee]

thnx mate. maybe somebody could find it usefull. with the amount of people using these carbs for methanol you would think lectron would of just made their own larger float valves. the inlet nipple and passage to the float valve is suprising small also. makes no sense

[philou]

I found this picture

Honda 125 NSR JC20/22

336704

[TZ350]

Thanks philou ... interesting pic.

[dutchpower]

Again positive tests with KTM SX 65 "rounded piston" on track. Today first place in qualification, at first round of European junior championship in Ukraine.

Beter have that place in Loket ( 21-07-2018 )

Then SE /SW/NE/NW best top 10 coming together for EMX 65 champion ship

NW is the strongest group

[katinas]

Beter have that place in Loket ( 21-07-2018 )

Then SE /SW/NE/NW best top 10 coming together for EMX 65 champion ship

NW is the strongest group

Today, again good race with "rounded piston", first win in NE group. We are very surprised.

[wax]

Here is a question unrelated to single cylinder buckets but i think its the best place in the world to ask.
Im setting up an engine, it is a triple engine with three lumps on the flywheel and one pickup.
The zeeltronic ignition i have would run it but it would fire every time it sees a lump. So that would mean three sparks per cylinder per revolution.
Two of i am not concerned about. The one firing at just before tdc is the one i want of course. The next is when the piston is 120 degrees down the cylinder heading down. The one that has me worried is the one at 240 degrees of crankshaft revolution. Ie 60 degrees of the stroke when the piston is coming up. I know the compression is very low at this point and it may not be an issue Heck the exhaust port would still be open. The one i am worried about would most likely be firing about 225 degrees at the latest when you consider the advance in the equation. Whats every ones thoughts on this. Jan, wobbly ,all you other boffins

[TZ350]

The one firing at just before tdc is the one i want of course. The next is when the piston is 120 degrees down the cylinder heading down. The one that has me worried is the one at 240 degrees of crankshaft revolution. Ie 60 degrees of the stroke when the piston is coming up.

If I understand this right......

180 - 60 = 120

120 plus 5 to 20 deg advance = 125 to 140 BTDC

So wasted spark is firing 140 deg BTDC and we know that wasted sparks firing at 200 BTDC are not a problem. I would be tempted to give it a go. Whats the worst that can happen? A bit of a Whoooosh out of the carb and exhaust. Any problems should show up pretty quickly before any engine damage.

[wax]

If I understand this right......

180 - 60 = 120

120 plus 20 deg advance = 140

So wasted spark is firing 140 deg BTDC and we know that wasted sparks firing at 200 BTDC are not a problem. I would be tempted to give it a go. Whats the worst that can happen? A bit of a Whoooosh out of the carb and exhaust. Any problems should show up pretty quickly before any engine damage.

Yes but its firing earlier in the stroke btdc so you would subtract the advance not add it wouldn't you.

[TZ350]

336710

I have been working hard to get the Suzuki GP/NSR110 setup along the lines Wobbly has suggested. Here I am trying to get the compression, squish and port timing correct.

336713

In an effort to get the high compression called for and a troidal head shape I machined the original NSR head back as far as it is possible to go.

With the shorter stroke crank the spigot is necessary because you can only shorten the cylinder so far before running out of sealing area around the top edge of the cylinder.

336711 336712

The center is pretty ugly and the plug is surprisingly recessed, they must be recessed like this on all the NSR250 heads.

To get the plug further into the cylinder and so more in the turbulent gas area a projected nose plug would be the go.

If anyone knows of a projected nose resistor equivalent for the NGK BR10E's heat range, I would love to hear about them.

[wobbly]

TeeZee, why have you mentioned the port timing - I did not change it from the original spec.
All I did was put a radius on the bore edge/transfer duct entry in the input as this has a better flow coefficient - Aprilia did this for a reason.

Looking at the head,it would be simple to spot face the plug seal surface,to get the plug body slightly protruding into the chamber.
And of course you know what im gong to say about the plug type.

Re the triple with 3 lobes and one pickup.I have heard of this being done before, apparently with no issue.
But of course the CDI sees this as 3x the rpm. so coil charge time is limited at high rpm.
Ask Mr Zeel if he can reflash the chip, to use the system that is easily selected in an Ignitech CDI P4.
Cylinder 1 lobe can be slotted to make two lobes, the trailing edge of this double lobe identifies cylinder one,the next lobe is cylinder 2 the next cylinder 3 - but of course you need 3 cdi circuits.

[TZ350]

And of course you know what I am going to say about the plug type.

Didn't want to confuse the search for a projected nose plug by specifying more than the size, reach, resistor and heat range.


Looking at the head,it would be simple to spot face the plug seal surface,to get the plug body slightly protruding into the chamber.


Will look at that, I will have to be careful not to go too deep and expose a bit of plug thread on one side.



TeeZee, why have you mentioned the port timing - I did not change it from the original spec.

No but building a new engine that matches the original specs requires some care.

To keep the original bike on the track, I am building up a new engine (it may take a while) to the original specs plus the planed improvements based on the EngMod simulation and will swap it in when I am finished. It is no easy thing to get the port timing (cylinder height position), squish and compression ratio right because any changes in one interact with the others.

336718 original engine that the porting specs and EngMod simulation is based on.

336719 new engine being built to the original specs plus the planned improvements.

[wobbly]

Any projected nose plug will have a horrible long, thick ground electrode.
Dont even think about using one - I have seen many of the Iridium EIX plugs drop the fat ground electrode off and wreak havoc the instant you see a little deto.
Real race plugs like the 7376 have a platinum fine wire that is laser welded to the body, its one reason they are expensive - but way cheaper than a rebuild and I
have never seen or heard of a fine wire dropping off.

If you are worried about the plug body exposed threads ,then the alloy exposed threads of the head are just as likely to overheat and cause pre ignition or deto issues.
To my way of thinking welding up the angled existing threads and putting in a new straight setup would make all the problems go away.

[husaberg]

I have been working hard to get the Suzuki GP/NSR110 setup along the lines Wobbly has suggested. Here I am trying to get the compression, squish and port timing correct.

In an effort to get the high compression called for and a troidal head shape I machined the original NSR head back as far as it is possible to go.

With the shorter stroke crank the spigot is necessary because you can only shorten the cylinder so far before running out of sealing area around the top edge of the cylinder.

The center is pretty ugly and the plug is surprisingly recessed, they must be recessed like this on all the NSR250 heads.

To get the plug further into the cylinder and so more in the turbulent gas area a projected nose plug would be the go.

If anyone knows of a projected nose resistor equivalent for the NGK BR10E's heat range, I would love to hear about them.

One way arround the angled plug is to cut the top off and weld in an incert

336726336727336728336729336730336731

http://forums.everything2stroke.com/threads/49513-How-It-s-Done-Projects-around-the-Shop/page46


Another is to use a NSR125 Cylinder head which is a straight plug
However to use that you have to use a NSR125 Cylinder as well for some reason the head bolt pattern is different from the 250.
(Bren learnt this after i said no i think it will fit):whistle:
Some models of the NSR are restricted and i don't really know how well the others stack up against the MC 16/18/21
the bottom stud partern is the same but the water cooling deck is slightly different.
I do have some port maps somewhere.

[wax]

TeeZee, why have you mentioned the port timing - I did not change it from the original spec.
All I did was put a radius on the bore edge/transfer duct entry in the input as this has a better flow coefficient - Aprilia did this for a reason.

Looking at the head,it would be simple to spot face the plug seal surface,to get the plug body slightly protruding into the chamber.
And of course you know what im gong to say about the plug type.

Re the triple with 3 lobes and one pickup.I have heard of this being done before, apparently with no issue.
But of course the CDI sees this as 3x the rpm. so coil charge time is limited at high rpm.
Ask Mr Zeel if he can reflash the chip, to use the system that is easily selected in an Ignitech CDI P4.
Cylinder 1 lobe can be slotted to make two lobes, the trailing edge of this double lobe identifies cylinder one,the next lobe is cylinder 2 the next cylinder 3 - but of course you need 3 cdi circuits.

it already has 3 cdi circuits so thats not an issue. However if you decide to use one pick up it then fires all three at the same time.
Thanks wobbly
Im pulling 8000 so i guess thats the same as 24000 rpm for the coil so quite a bit

[lodgernz]

One way arround the angled plug is to cut the top off and weld in an incert
Another is to use a NSR125 Cylinder head which is a straight plug
However to use that you have to use a NSR125 Cylinder as for some reason the head bolt pattern is different.
(Bren learnt this after i said no i think it will fit):whistle:
Some models of the NSR are restricted and i don't really know how well the others stack up against the MC 16/18/21
the bottom stud partern is the same but the water cooling deck is slightly different.
I do have some port maps somewhere.

Or one of these:
https://www.vhm.nl/en/catalog/engine-parts/cylinder-parts/cylinder-heads/aa33054/properties/g+c+a+nr+view

If you contact Matt at Tyga, he can possibly get you one, so you don't have to buy the pair. Still expensive, but solves that problem.

[Frits Overmars]

Yes but its firing earlier in the stroke btdc so you would subtract the advance not add it wouldn't you.No, TZ350 is right. You may want to look at it this way: let's say ignition occurs at 20° before TDC. The spark before that came 120° earlier; that's 140° bTDC.


it already has 3 cdi circuits so thats not an issue. However if you decide to use one pick up it then fires all three at the same time. Im pulling 8000 so i guess thats the same as 24000 rpm for the coil so quite a bitHow difficult can it be to add two pickups? The coils will thank you for it by not becoming fried.


welding up the angled existing threads and putting in a new straight setup would make all the problems go away.The toroid chamber layout aggravates the disadvantage of the angled plug, so straightening it will be more important than before; otherwise all your other efforts may be more or less canceled out. I would not work on an engine with the plug shrouded like that.

[TZ350]

The toroid chamber aggravates the disadvantage of the angled plug. I would not work on an engine with the plug shielded like that.

Would I have been better off leaving it with the original hemispherical chamber shape?

Starting with another NSR head I could make one with a bath tub shape if that would be better then my attempt at a toroid. I can un shroud the plug a bit more.

[Frits Overmars]

Would I have been better off leaving it with the original hemispherical chamber shape?
Starting with another NSR head I could make one with a bath tub shape if that would be better then my attempt at a toroid. I can un shroud the plug a bit more.I'm not criticising the toroid; I'm criticising the angled plug. 'Unshrouding the plug a bit more' is not the way to build a winner. Don't compromise. Sorry if I'm being blunt.

[speedpro]

Im setting up an engine, it is a triple engine with three lumps on the flywheel and one pickup.

Why not one lump? Configure the one lump as TDC on whatever cylinder and tell the ECU you need 2 other sparks, on 2 other ignition channels, 120deg apart. Sorry, not familiar with Zeeltroinic so not sure that can be programmed or if the channels are available. Certainly the Link ECU I'm currently playing with can do it.

Or a multi tooth trigger wheel with a missing tooth to identify where in the crank revolution it is. Again, identify TDC for a cylinder in relation to the missing tooth and the others 120deg apart. Still assuming seperate ignition channels.

[speedpro]

I have straightened up a RGV 250 plug in a head I was using, reshaped the chamber, exactly the same compression, and got instant horsepower everywhere.

As Frits said - 3 pickups would be the simplest answer, mounted on a nice billet backing plate for symmetry.

[JanBros]

One way arround the angled plug is to cut the top off and weld in an incert


don't weld it in, just transform it so you can use replacable inserts. Have done it with a KR1S head

http://i52.tinypic.com/20f6q9d.jpg

http://i53.tinypic.com/op1ms0.jpg

http://i53.tinypic.com/kevk36.jpg

[Matt@TYGA]

Or one of these:
https://www.vhm.nl/en/catalog/engine-parts/cylinder-parts/cylinder-heads/aa33054/properties/g+c+a+nr+view

If you contact Matt at Tyga, he can possibly get you one, so you don't have to buy the pair. Still expensive, but solves that problem.


I can certainly get the individual parts that you need from VHM, but they're not particularly cheap as you'll know. But then you can experiment with head shapes by turning up new inserts. So the head cover is a one time deal.

I'd say that you're on the right track with welding in an insert, as long as you don't disrupt the coolant flow through the head.

I have a few MC21 heads kicking around with deto damage that could be used for your project.

The NSR's through the years were restricted in different ways. The MC16 has small carbs and small ports. Makes around 40hp peak at the wheel in a not particularly exciting way, but does have reasonable midrange. The MC18 '88 was restricted by limiting the opening of the exhaust valves. Simply pull a plug apart and get decent mojo. The MC18 '89 needs a splice of the wiring to change ignition timing and exhaust valve operation, as does the '90~'93 MC21. The MC28 needs a pocket full of cash to derestrict by way of an HRC ignition card.

Going back to the MC18. The cylinders are pretty good and will make reasonable power right off the bat. The heads (as stock) have angled plugs to compensate for various clearance issues, but if you do a lot of searching then the HRC F3 kit used central located plugs. This may well be what you're looking for. I don't have any MC18 barrels handy as just used the only undamaged one I had to rebuild an engine recently. May have a head but unlikely to be the kit type.

All cylinders from MC16 through to MC28 share the same stud pattern on the bottom side.

You could try Gecko Motorcycles in the UK. Dan has a lot of NSR F3 stuff and may have what you need. He's a good chap and I'm sure that you could work a decent deal with him.

Hope that helps.

Matt.

[jasonu]

Would I have been better off leaving it with the original hemispherical chamber shape?

Starting with another NSR head I could make one with a bath tub shape if that would be better then my attempt at a toroid. I can un shroud the plug a bit more.

Why not completely weld the buggar up then re drill and thread the SP hole and re cut the dome?

[jbiplane]

Hi guys. I want produce some pistons by 5-axe CNC milling.
I know piston should be conical from the side and oval from the bottom. Somebody could help me to find production drawings, formulae or whatelse?

[Haufen]

Hi guys. I want produce some pistons by 5-axe CNC milling.
I know piston should be conical from the side and oval from the bottom. Somebody could help me to find production drawings, formulae or whatelse?

I think a general guideline can only get you so far. Personally, I'd try to get a piston which works well in a similar application, have the material analyzed and the shape measured to the detail you need. Use high Si content to make the pistons resistant to cold seizure (as they don't expand that much).

[husaberg]

I can certainly get the individual parts that you need from VHM, but they're not particularly cheap as you'll know. But then you can experiment with head shapes by turning up new inserts. So the head cover is a one time deal.

I'd say that you're on the right track with welding in an insert, as long as you don't disrupt the coolant flow through the head.

I have a few MC21 heads kicking around with deto damage that could be used for your project.

The NSR's through the years were restricted in different ways. The MC16 has small carbs and small ports. Makes around 40hp peak at the wheel in a not particularly exciting way, but does have reasonable midrange. The MC18 '88 was restricted by limiting the opening of the exhaust valves. Simply pull a plug apart and get decent mojo. The MC18 '89 needs a splice of the wiring to change ignition timing and exhaust valve operation, as does the '90~'93 MC21. The MC28 needs a pocket full of cash to derestrict by way of an HRC ignition card.

Going back to the MC18. The cylinders are pretty good and will make reasonable power right off the bat. The heads (as stock) have angled plugs to compensate for various clearance issues, but if you do a lot of searching then the HRC F3 kit used central located plugs. This may well be what you're looking for. I don't have any MC18 barrels handy as just used the only undamaged one I had to rebuild an engine recently. May have a head but unlikely to be the kit type.

All cylinders from MC16 through to MC28 share the same stud pattern on the bottom side.

You could try Gecko Motorcycles in the UK. Dan has a lot of NSR F3 stuff and may have what you need. He's a good chap and I'm sure that you could work a decent deal with him.

Hope that helps.

Matt.
How do the JC20 and JC22 Ports stack up against the various NSR250s Matt.

My old port maps for the various 125 NSRs are on an old external hard drive that is not working.
As they are straight plug but as i mentioned they fit the bottom stud paterens but not the top.



One way arround the angled plug is to cut the top off and weld in an incert

336734336735336736336737336738336739



http://forums.everything2stroke.com/threads/49513-How-It-s-Done-Projects-around-the-Shop/page46


Another is to use a NSR125 Cylinder head which is a straight plug
However to use that you have to use a NSR125 Cylinder as well for some reason the head bolt pattern is different from the 250.
(Bren learnt this after i said no i think it will fit)
:whistle:
Some models of the NSR are restricted and i don't really know how well the others stack up against the MC 16/18/21
the bottom stud partern is the same but the water cooling deck is slightly different.
I do have some port maps somewhere.





don't weld it in, just transform it so you can use replacable inserts. Have done it with a KR1S head
http://i52.tinypic.com/20f6q9d.jpg.



http://i53.tinypic.com/op1ms0.jpg



http://i53.tinypic.com/kevk36.jpg[/QUOTE]
As was shown above by Janbros you could also make the inserts removable and make sure the water flow is even arround the plug.<strike></strike>

[Matt@TYGA]

How do the JC20 and JC22 Ports stack up against the various NSR250s Matt.

My old port maps for the various 125 NSRs are on an old external hard drive that is not working.
As they are straight plug but as i mentioned they fit the bottom stud paterens but not the top.

I don't have the port maps for the JC20 or 22, but I gather that the case stud pattern is the same as NSR250 and also NSR150. I've been asking a couple of blokes in France if they have the port maps, but so far not forthcoming. They're using our 150 pipe on their 125's, but would rather be able to compare the porting and possibly think of something a little different.

[husaberg]

I don't have the port maps for the JC20 or 22, but I gather that the case stud pattern is the same as NSR250 and also NSR150. I've been asking a couple of blokes in France if they have the port maps, but so far not forthcoming. They're using our 150 pipe on their 125's, but would rather be able to compare the porting and possibly think of something a little different.
I had the French ones they were very restricted i remember that bit.
Grumph i think was given a flash drive that i think had them on it?
From what i seen it was like a lot of the different euro makets had different specs.
I think a lot of the euro ones were made in Italy engine parts and all.
the JC22 had longer studs on the top as the JC22 had a thicker head casting.
th bottom stud parrn is the same as i have a 250 cylinder sitting on one here but the water feed is slightly different but nothing major.
I had a good google and i cant find anything at the moment other than the stuff in the TRX project.
336768336769I had the French ones they were very restricted i remember that bit.
Grumph i think was given a flash drive that i think had them on it?
From what i seen it was like a lot of the different euro makets had different specs.
I think a lot of the euro ones were made in Italy engine parts and all.
the JC22 had longer studs on the top as the JC22 had a thicker head casting.
th bottom stud parrn is the same as i have a 250 cylinder sitting on one here but the water feed is slightly different but nothing major.
I had a good google and i cant find anything at the moment other than the stuff in the TRX project.
336768336769336770
Malossi do a 65mm bore kit and cylinder for them not sure if they have a operational PV
http://www.2strokeparts.de/shop/product_info.php?pName=rennzylinder-malossi-181-ccm-honda-nsr-125&SESS=
which would make a 360 NSR twin

[wax]

No, TZ350 is right. You may want to look at it this way: let's say ignition occurs at 20° before TDC. The spark before that came 120° earlier; that's 140° bTDC.

How difficult can it be to add two pickups? The coils will thank you for it by not becoming fried.

The toroid chamber layout aggravates the disadvantage of the angled plug, so straightening it will be more important than before; otherwise all your other efforts may be more or less canceled out. I would not work on an engine with the plug shrouded like that.
The confusion is i am talking atdc and you and tz are talking before lol, I think we are both saying the same thing.
why am i doing it this way ? i already have the ignition, im just saving money if possible

[wax]

Why not one lump? Configure the one lump as TDC on whatever cylinder and tell the ECU you need 2 other sparks, on 2 other ignition channels, 120deg apart. Sorry, not familiar with Zeeltroinic so not sure that can be programmed or if the channels are available. Certainly the Link ECU I'm currently playing with can do it.

Or a multi tooth trigger wheel with a missing tooth to identify where in the crank revolution it is. Again, identify TDC for a cylinder in relation to the missing tooth and the others 120deg apart. Still assuming seperate ignition channels.
The flywheel has three lumps and one pick up. The ignition i have is a 3 channel ignition. I can buy another but i am just trying to make what i have work

[TZ350]

Why not completely weld the buggar up then re drill and thread the SP hole and re cut the dome?

I was trying to keep it simple.


I have straightened up a RGV 250 plug in a head I was using, reshaped the chamber, exactly the same compression, and got instant horsepower everywhere.

That is very interesting.


I'm not criticising the toroid; I'm criticising the angled plug. 'Unshrouding the plug a bit more' is not the way to build a winner.

For the sake of simplicity the whole engine is compromised. The basic aim for the team engines was to use a NSR250 cylinder and Std NSR head with a minimum of modification and no porting work at all. A lot of bang for your buck approach .... a 20 for 80 situation.

336772 Cylinder and head modification is basically limited to turning 2.5mm of both. (with a 48mm de stroked crank for 110cc.)

The aim is a good reliable "Team" engine that see's a lot of track time and is easily copied by anyone who might want too.

Now we are trying to improve them with Wobbly's guidance using EngMod.

Head insert ...centralize the plug .... :scratch: ... I like it but how to do this in an easily replicated way, there will be an answer.


Don't compromise. Sorry if I'm being blunt.

336773

I hear you, and this is an absolutely un compromised (within the limits of my resources) GP-NSR110 engine that is bluntly a pain in the arse and not very easily replicated at all by anyone. With a lot of time on the dyno and not much track action.

But it is totally fun though, I love it. It is a "rainbow engine", where you just know there is going to be a big pot of gold at the end of the rainbow.

[philou]

the JC22 had longer studs on the top as the JC22 had a thicker head casting.

Studs JC20 42,5 mm
Studs JC22 47,5 mm

[Frits Overmars]

For the sake of simplicity the whole engine is compromised. The basic aim for the team engines was to use a NSR250 cylinder and Std NSR head with a minimum of modification and no porting work at all. A lot of bang for your buck approach .... a 20 for 80 situation. The aim is a good reliable "Team" engine that sees a lot of track time and is easily copied by anyone who might want to. Now we are trying to improve them with Wobbly's guidance using EngMod. I completely respect your reasoning TeeZee. Having fun is the best argument I can think of. 'Don't compromise' is just the competitive mentality I inherited from Jan Thiel. And I bet Wobbly has the same uncompromising attitude.

[Matt@TYGA]

I had the French ones they were very restricted i remember that bit.
Grumph i think was given a flash drive that i think had them on it?
From what i seen it was like a lot of the different euro makets had different specs.
I think a lot of the euro ones were made in Italy engine parts and all.
the JC22 had longer studs on the top as the JC22 had a thicker head casting.
th bottom stud parrn is the same as i have a 250 cylinder sitting on one here but the water feed is slightly different but nothing major.
I had a good google and i cant find anything at the moment other than the stuff in the TRX project.
336768336769I had the French ones they were very restricted i remember that bit.
Grumph i think was given a flash drive that i think had them on it?
From what i seen it was like a lot of the different euro makets had different specs.
I think a lot of the euro ones were made in Italy engine parts and all.
the JC22 had longer studs on the top as the JC22 had a thicker head casting.
th bottom stud parrn is the same as i have a 250 cylinder sitting on one here but the water feed is slightly different but nothing major.
I had a good google and i cant find anything at the moment other than the stuff in the TRX project.
336768336769336770
Malossi do a 65mm bore kit and cylinder for them not sure if they have a operational PV
http://www.2strokeparts.de/shop/product_info.php?pName=rennzylinder-malossi-181-ccm-honda-nsr-125&SESS=
which would make a 360 NSR twin

I may be wrong, but I recall seeing silly things such as plates across the carb insulator with a hole half the size of the carb, and rumours that the CDI was restricted somehow. But I'm thinking that the cylinders were probably the same for all markets.

The coolant spigot is at an angle compared to the NSR250 and 150, probably to clear a bit of frame or something.

The NSR150 was also designed and built in Italy, using (as far as I know) the NSR125 as the base engine design.

I've seen the Malossi stuff. There's a Malossi dealer here in Thailand and I was considering using the Malossi cylinder a few years ago, right up until they told me the price. Yes I think you're correct in that they don't use an exhaust valve.

I think Polini also had a big bore cylinder for the 125. Slightly smaller bore but had a valve. However, wasn't super interested in going any bigger on the bore without going longer on the stroke too.

The latest thing that I have been told is that here in Thailand, in the "open class" drag racing, the latest fad is using an NSR150 cylinder on an LS125 bottom end, but bored out to 70mm. I have no other info at this stage other than they're using a steel liner. I presume that they've stroked it too, but by how much I have no idea. I'm waiting for the dates to come out for the next race and I'm gonna go along and have a peek.

The Thais do some pretty crazy stuff. Not all of it useful, but definitely 10 out of 10 for effort and enthusiasm. Trouble is that most of their engines tend to explode at least once during the day :-)

[jonny quest]

Matt, you may know this. I see a lot of 2 stroke pipes on the drag bikes in Thailand that are cone pipes with a beautiful bright blue colouring.

What metal are the pipes and how do they get that blue! They look titanium, but I'm assuming they're not.

[wobbly]

I think it depends upon how you look at it TeeZee.
Making a long rod crank, adding a gearbox spacer , making a bigger RV cover.
Welding up a plug thread is a walk in the park - you dont even need to pick up a vernier , just a tig torch.

[Matt@TYGA]

Matt, you may know this. I see a lot of 2 stroke pipes on the drag bikes in Thailand that are cone pipes with a beautiful bright blue colouring.

What metal are the pipes and how do they get that blue! They look titanium, but I'm assuming they're not.

There are a handful of guys building Ti pipes here in Thailand. I know a couple of them quite well. The bluing process can be done on Ti and also stainless. It seems that the people that do it guard the process, but I'm guessing that it's something to do with heat and reaction to oxygen. We had some stainless tubes done just to see how they'd look. Not too bad but the price was a bit silly.

They can even do rather complicated patterns if one wishes. We had some stainless silencers that looked like Rupert The Bear's trousers. Always made me chuckle.

[andra_rgv120]

.....

The latest thing that I have been told is that here in Thailand, in the "open class" drag racing, the latest fad is using an NSR150 cylinder on an LS125 bottom end, but bored out to 70mm. I have no other info at this stage other than they're using a steel liner. I presume that they've stroked it too, but by how much I have no idea. I'm waiting for the dates to come out for the next race and I'm gonna go along and have a peek.

The Thais do some pretty crazy stuff. Not all of it useful, but definitely 10 out of 10 for effort and enthusiasm. Trouble is that most of their engines tend to explode at least once during the day :-)

Honda Nova Dash 125 (same bottom-end as LS 125 ???)
10s sec quarter mile, very impressive :clap::clap::clap:



https://www.youtube.com/watch?v=THoECJhMSl8

[philou]

the cylinders were probably the same for all markets.


In France a 125 is limited to 15 Cv.

For 125 NSR, the French cylinders are different from the others. English cylinder are better

336775

[jonny quest]

https://www.google.com/search?q=thailand+2+stroke+drag+bikes&prmd=ivsn&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj5iL7vvInbAhWB5oMKHdZ0BR4Q_AUIESgB&biw=360&bih=560#imgrc=T7HNl1PdKfz5BM:

I think it's some sort of acid mixture that give the pipe that color.

Those drag bikes launch hard for such skinny tires!

[husaberg]

In France a 125 is limited to 15 Cv.

For 125 NSR, the French cylinders are different from the others. English cylinder are better

336775

You beauty what forum was that on i tried for about twenty minutes last night with no luck.

[Matt@TYGA]

In France a 125 is limited to 15 Cv.

For 125 NSR, the French cylinders are different from the others. English cylinder are better

336775

A great find!

[Matt@TYGA]

Honda Nova Dash 125 (same bottom-end as LS 125 ???)
10s sec in quarter miles, very impressive :clap::clap::clap:

The Dash125 and LS125 are similar, but not identical. The crank for one is different. The drag boys use a modified LS crank in the Dash cases.

I heard a story that the LS engine started life as a Dash, with HRC intervention. Small mods here and there, such as the crank for example. Not sure on the other differences.

I used to have a Dash some 15+ years ago, but it got nicked one night from outside my grotty apartment block. I have two LS's in the shed, but never done more than park them and throw a blanket over. One day I'll dig them out........

[TZ350]

336779336776336777336778

I have a Gilardoni cylinder, and like the NSR125 cylinder head I looked at, the head stud pattern is different and will not fit the NSR250 MC21 or MC18 cylinder. So no easy answer for a MC21 center plug there. Also the NSR125 cylinder spigot is a larger diameter than the MC21's.

These would be great cylinders to use but I have not found it easy to get more of them. Suitable MC21 and MC18 cylinders are much easier to find. The Gilardoni is ear marked for a very trick (no compromises) 100, just waiting on the crank to be finished.

[Muhr]

https://www.google.com/search?q=thailand+2+stroke+drag+bikes&prmd=ivsn&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj5iL7vvInbAhWB5oMKHdZ0BR4Q_AUIESgB&biw=360&bih=560#imgrc=T7HNl1PdKfz5BM:

I think it's some sort of acid mixture that give the pipe

It may be Bluing Stainless Steel (heat treatment)

[TZ350]

336780

On a standard NSR MC21 head the plug is quite shrouded. I was surprised at how ugly shrouded the standard NSR250 MC21 heads are.

336781

Following Wobblys suggestion I spot faced the plug seat back 2.5mm. Maybe a good idea for any standard NSR250 head too.

The idea of a one off lots of work bespoke center plug rainbow head is pretty useless when you are building several engines and looking for repeatable practicality.

When I have figured out how to produce easily repeatable no compromise center plug heads I will be able to make a back to back dyno comparison with my original modified NSR head, and maybe with a completely standard one too, it will be interesting to see how that goes.

[F5 Dave]

Geez check out the drag dude with no gloves and legs like Kate Moss.

[TZ350]

If anyone can sell me a HONDA NOVA DASH 125 RS motor (or several) bottom ends. I would be interested. I don't need the cylinder or head so older motors that have seen better days would be Ok for what I need.

[husaberg]

Geez check out the drag dude with no gloves and legs like Kate Moss.
Sounds like you were........;)

[andra_rgv120]

The Dash125 and LS125 are similar, but not identical. The crank for one is different. The drag boys use a modified LS crank in the Dash cases.

I heard a story that the LS engine started life as a Dash, with HRC intervention. Small mods here and there, such as the crank for example. Not sure on the other differences.

I used to have a Dash some 15+ years ago, but it got nicked one night from outside my grotty apartment block. I have two LS's in the shed, but never done more than park them and throw a blanket over. One day I'll dig them out........

Thank you for the information matt

[andra_rgv120]

By the way, i found this interesting video, honda nova dash beat honda rs ( rs 125 motor in dash chassis) in drag race


http://www.youtube.com/watch?v=jItknOf4eUs

Race start @7:27

How Is it possible street/production based engine beat gp125 engine?

[jonny quest]

Honda vowed to never make another 2 stroke! Surprised they are still producing them

[SwePatrick]

How Is it possible street/production based engine beat gp125 engine?

Everything can happen in dragracing, This race i would say it was a bad start of the looser.

[F5 Dave]

Geez first time I launched my RS125 in anger it was insane how long you have to let the clutch out so tall is first gear. After about what seemed like 10seconds of launch I let go of the last 1/2mm of clutch travel and it bogged.

Nothing a 60 tooth rear sprocket wouldn't fix.

Beat RS125 round kart track on my 50. He just couldn't get going.

[jasonu]

After about what seemed like 10seconds of launch I let go of the last 1/2mm of clutch travel and it bogged.
.

Sounds like all your bikes....

[Matt@TYGA]

The guys here spend an absolute fortune on their drag bikes.

I've helped out on a couple of occasions with one of the guys who was kicking ass.

Starting with a Dash125 motor, they'd mill out the cases and around the reed valve area, weld bits in here and there and fit an NSR150 (or similar) reed valve.

The crank pin hole would be welded up and rebored at a new stroke. Also rings welded onto the crank wheels to increase the inertia.

The cylinder would have a new liner popped in and ported. Strangely though, back then they always insisted on a single exhaust port. Also, their measuring of the ports was a little suspect as they'd use a ruler to check.

Spent one day at a test with this guy. I was helping to set up an Ignitech on his 160cc racer. By the end of the day he'd set a new 1/4 mile record and highest top speed......and I'd sold 20 ignition units :-)

It was a little strange as I was the only foreigner there, and plugging the bike into a laptop.......well, I may as well have been dressed as a clown doing cartwheels down the strip.......every time the bike came back and I plugged it in, a crowd gathered to see what was going on. Quite daunting but amusing all the same.

[jonny quest]

How much HP are those bikes making Matt?

[Matt@TYGA]

How much HP are those bikes making Matt?

No one that I know of has put one on the dyno, so don't know.

Offered free dyno time to my friend, but he never showed up.

The one thing that helps is that they cut and drill everything and get the bikes down to about 60kg, and the riders are around 45kg (including helmet, fingerless gloves and flipflops).

Sorry, can't answer that one, but I too would really like to know.

[andra_rgv120]

.....

Also rings welded onto the crank wheels to increase the inertia.

....


welded like this???

[sispeed]

Hello, a little offtopic a Vid to my 2 race in Hockenheim.
Bike with some useful insights from this forum Aircooled RD 250.
Thank you for all the useful informations her

https://youtu.be/W7Guq3WK7XI
Regards Siggi

[TZ350]

Loved the video .... the sound brought back memories.

[TZ350]

.
It has taken a while but I have finally cracked the true Arduino analog output problem my project had, now hopefully my EFI project can move forward, or at least to the next road block.

336823

My current EFI efforts to use an Arduino Nano to read the analogue signal from a MAP sensor in the crankcase and find the Difference between the Highest and Lowest reading and output the difference as an analogue pseudo MAP signal to the EFI (electronic fuel injection)'s CPU (central processing unit). Ran into problems when I found that the Arduino so called analog output was really just a PWM signal so pretty useless for what I wanted to do.

The Arduino talks about “analogue” output on their card but they are fibbing a little bit because it is really PWM, pulse width modulation and not analogue at all. So not at all useful for use as a true analogue output but PWM is pretty good for controlling electric motors, LED’s etc.

336821

Arduino PWM (Analog) Tutorial:- https://www.arduino.cc/en/Tutorial/PWM

336822 336824

To get true analogue output with the Arduino Nano you need a DAC, digital to analogue card like the AdaFruit MCP4725 and AdaFruits software library add on.

336826

AdaFruit MCP4725:- https://www.adafruit.com/product/935

AdaFruit Tutorial:- https://cdn-learn.adafruit.com/downloads/pdf/mcp4725-12-bit-dac-tutorial.pdf

336825

AdaFruit Library:- https://learn.adafruit.com/mcp4725-12-bit-dac-tutorial/using-with-arduino

Hopefully I will get to try it all out on my bike over the weekend....... :)

[philou]

I have a old cylinder mugen for honda 125 cr 1986

Would you draw a port map and angle scavenge port ?

336827

[sispeed]

Loved the video .... the sound brought back memories.

Thank you TZ350. Hope you make progress with the EFI but sounds promising with the DAC

[husaberg]

.
It has taken a while but I have finally cracked the true Arduino analog output problem my project had, now hopefully my EFI project can move forward, or at least to the next road block.

336823

My current EFI efforts to use an Arduino Nano to read the analogue signal from a MAP sensor in the crankcase and find the Difference between the Highest and Lowest reading and output the difference as an analogue pseudo MAP signal to the EFI (electronic fuel injection)'s CPU (central processing unit). Ran into problems when I found that the Arduino so called analog output was really just a PWM signal so pretty useless for what I wanted to do.

The Arduino talks about “analogue” output on their card but they are fibbing a little bit because it is really PWM, pulse width modulation and not analogue at all. So not at all useful for use as a true analogue output but PWM is pretty good for controlling electric motors, LED’s etc.

336821

Arduino PWM (Analog) Tutorial:- https://www.arduino.cc/en/Tutorial/PWM

336822 336824

To get true analogue output with the Arduino Nano you need a DAC, digital to analogue card like the AdaFruit MCP4725 and AdaFruits software library add on.

336826

AdaFruit MCP4725:- https://www.adafruit.com/product/935

AdaFruit Tutorial:- https://cdn-learn.adafruit.com/downloads/pdf/mcp4725-12-bit-dac-tutorial.pdf

336825

AdaFruit Library:- https://learn.adafruit.com/mcp4725-12-bit-dac-tutorial/using-with-arduino

Hopefully I will get to try it all out on my bike over the weekend....... :)

Isn't this all you need?
https://learn.sparkfun.com/tutorials/analog-to-digital-conversion

[TZ350]

Isn't this all you need? https://learn.sparkfun.com/tutorials/analog-to-digital-conversion

No ...

Great site though, thanks.

ADC, analog to digital conversion is for reading an analogue signal into the microprocessor. All the Arduino's have this.

DAC, digital to analogue conversion is so a microprocessor can talk out to the real world in the same way that we see/hear things.

Only the Arduino DUE has that and it's a 3.3 volt system so useless for 0-5 Volt signals. All the other Arduino's call their digital PWM output, Analog. But its not, it only pretends to be.

PWM is like Analog, well maybe to a blind man galloping past on a camel. PWM is totally useless if you need a real analog signal.

[jonny quest]

I have a old cylinder mugen for honda 125 cr 1986

Would you draw a port map and angle scavenge port ?

336827

What are you going to do with that cylinder? Interested in selling it?

[husaberg]

No ...

Great site though, thanks.

ADC, analog to digital conversion is for reading an analogue signal into the microprocessor. All the Arduino's have this.

DAC, digital to analogue conversion is so a microprocessor can talk out to the real world in the same way that we see/hear things.

Only the Arduino DUE has that and it's a 3.3 volt system so useless for 0-5 Volt signals. All the other Arduino's call their digital PWM output, Analog. But its not, it only pretends to be.

PWM is like Analog, well maybe to a blind man galloping past on a camel. PWM is totally useless if you need a real analog signal.
I thought the Map sensor just fed out a raw Voltage signal? So what does that circuit i posted do to them because i am well confused? does it just chop them?
i remember years ago there was a circuit that Dick Smith used to sell when it was just a shop like Radio shack it was used to drive CRO oscilloscopes etc Dick smith used to sell it on the basis it would turn voltage into a digital signals that could be modulated i think it was a function generator? this was years ago mind you so i might be a little fuzzy.

[TZ350]

I thought the Map sensor just fed out a raw Voltage signal? So what does that circuit i posted do to them because i am well confused? does it just chop them?

Chops them.

The Arduino reads analog in Ok but outputs a chopped (PWM) on/off signal at varying frequency. Just the "On" time varies so its suitable for electric motors etc. Much like a VSD.

For a 5 Volt Arduino.
The Analog input is a voltage that changes to anywhere between 0 to 5 Volts. ........... Green Line
The Output is PWM and it is either 0 Volts or 5 Volts, only the "time on" changes. ....... Red Line

336828 Analog is the green line and PWM the red.

The MAP sensor outputs a green line. I think the MAP sensor is "Piezo capacitive", anyway it is a 3 wire device with some circuitry so it gets 5 Volts in and outputs a varying analog 0 to 5 Volt signal that represents manifold pressure. Also MAP sensors measure absolute pressure as opposed to gauge pressure.

The EFI's CPU expects and understands a green line, not a red one, with a red line all it sees is 5 Volts.

[Carel H]

TZ: a PWM signal is a volume signal, to compare it with water. There is a fluctuating hose (the PWM signal, timeslice * voltage), with a restrictor, to control the flow, flowing in a leaking barrel, resulting in a variable level in the barrel. The restrictor (output to barrel) and the leak (barrel to ground) are resistors, the barrel is a condensor. You're 3 parts away from a PWM---DAC, the size of the parts a compromise between ripple and response time.

[TZ350]

Yes, Carel H, great analogy I like it. I have tried making low pass filters for converting PWM to Analog, but not very successfully.

Basically I was trying to smear out a 5 Volt. square wave of varying frequency to look like a contiguous liner wave of varying voltage with a simple IC circuit. I couldn't make it work well enough to be useful.

[Carel H]

Yes, Carel H, great analogy I like it. I have tried making low pass filters for converting PWM to Analog, but not very successfully.

Basically I was trying to smear out a 5 Volt. square wave of varying frequency to look like a contiguous liner wave of varying voltage with a simple IC circuit. I couldn't make it work well enough to be useful.

A fixed square wave with varying frequency has a fixed "volume", but a different ripple. But what are you trying to achieve? It looks like you're trying to read an analog signal by outputting an analog signal.

By the way, if you have pins left over, you can build your own DAC, it's also just a handful of resistors. And yes, I don't like analog too.

[TZ350]

if you have pins left over, you can build your own DAC, it's also just a handful of resistors. And yes, I don't like analog too.

Yes, if I had 12 spare digital pins and 12 different value resistors I could have a 12 bit analog output by turning each on in turn. Simpler maybe, and just as effective as the MCP4725 12bit analog add on card.


what are you trying to achieve? It looks like you're trying to read an analog signal by outputting an analog signal.

336831

I am trying to read in an Analog signal from the MAP sensor, process it and then pass it out as an Analog signal to the EFI's CPU.

The Ecotrons EFI system expects a MAP signal from the inlet manifold. This is Ok for a 4T but does not work well on a 2T. Which limits a 2T to only using an Alpha-N map which I have found is problematic at low throttle settings below 25% with my 110cc tuned 2T engine.

Alpha-N maps are RPM/Throttle position = Fuel required. Simple and work well with predictable air flow.

My idea is to find the difference between maximum and minimum crankcase pressure each cycle and output this in a modified form to the EFI CPU as an indication of real airflow through the two stroke's motor.

If I can find a good way to indicate changes in air flow (charging efficiency) then I may be able to also use a Volumetric efficiency map below 25%, just like 4T's do.

When the engine is on the pipe, Alpha-N works well but when the motor is swapping between on the pipe and off Alpha-N is either correct or to rich for the motor to run. So we need a way to adjust the fueling to match the changeable air flow.

Volumetric maps are RPM/Volumetric efficiency of the motor depending on manifold pressure as measured by a MAP sensor = fueling required.

As Volumetric efficiency (a 4T concept) is directly related to "Charging plus Trapping" efficiency (a 2T concept) then knowing the air flow should be a great help. But 4T methods of measuring air flow don't work well on tuned 2T's.

The plan is to use a Volumetric efficiency map below 25% throttle position and Alpha-N above 25% similar to a 4T approach and a 2T friendly way of seeing changes in air flow.

336832

In my test setup the MAP sensor is the Analog input. The Arduino processes this Analog input and sends a 10bit value to the MCP4725 card. The meter is measuring the Analog output produced by the MCP4725 add on card.

The on/off/on toggle switch simulates the ignition trigger pulse for timing the start/end of each cycle by allowing a digital input pin to go high briefly. The trigger is connected to a digital pin configured as an interrupt. The MCP4725 feeds directly to the meter and it is also read by the Arduino on another Analog input pin so all inputs, outputs and internal processing variables can be serial line printed in real time to the PC's screen for de bugging purposes.

It has taken a while to learn about Arduinos and programming them and of course, at the moment it is just a concept and I have no idea if this is going to improve my 2T's EFI system or not until I try it.

[eldog]

http://www.aemelectronics.com/

[Frits Overmars]

My current EFI efforts to use an Arduino Nano to read the analogue signal from a MAP sensor in the crankcase and find the Difference between the Highest and Lowest readingHopefully that MAP signal will be an indication for the inhaled air mass. But if you rev the engine beyond the rpm allowed by its blowdown time.area, spent exhaust gases may cause a pressure rise in the crankcase that will easily exceed the highest useful reading, although it has nothing to do with the air breathing...

[Carel H]

=My idea is to find the difference between maximum and minimum crankcase pressure each cycle and output this in a modified form to the EFI CPU as an indication of real airflow through the two stroke's motor.

The on/off/on toggle switch simulates the ignition trigger pulse for timing the start/end of each cycle by allowing a digital input pin to go high briefly. The trigger is connected to a digital pin configured as an interrupt. The MCP4725 feeds directly to the meter and it is also read by the Arduino on another Analog input pin so all inputs, outputs and internal processing variables can be serial line printed in real time to the PC's screen for de bugging purposes.

It has taken a while to learn about Arduinos and programming them and of course, at the moment it is just a concept and I have no idea if this is going to improve my 2T's EFI system or not until I try it.

First, there is a magic pin on the ATMEGA, the arduino processor. It's called ICP1. It can capture the time of an event, so you can calculate RPM and set a switchpoint for Plan A---Plan B. This also enables you to set something like: So an engine revolution takes X clockcycles, I want to do something at 60 degrees after the triggerpoint, which is thus X / 6 after that. With this, your measurements match the crankshaft position.

Why not use the MCP4725? At 100 kilohertz I2C speed you have a transmission time of 0.0003 second and it's 5 volt tolerant.

Embedded real time programming is a sport of it's own. For example: if you design your program for an engine that does 15000 rpm, your total program should execute within 1 / 250 second, which is the absolute maximum. So scope your software and parts of it, just by setting a pin on entry and clear it on exit. You will see the wonders of a processor and that miracles don't exist.

[TZ350]

First, there is a magic pin on the ATMEGA, the arduino processor. It's called ICP1. It can capture the time of an event, so you can calculate RPM and set a switchpoint for Plan A---Plan B.

Great, very interesting. Thanks.

[philou]

What are you going to do with that cylinder? Interested in selling it?

I'm sorry, currently I do not want to sell it

[TZ350]

Hopefully that MAP signal will be an indication for the inhaled air mass.

Yes, hopefully I am onto something useful ..... fingers crossed for luck.


But if you rev the engine beyond the rpm allowed by its blowdown time.area, spent exhaust gases may cause a pressure rise in the crankcase that will easily exceed the highest useful reading, although it has nothing to do with the air breathing...

True, but in this case, so long as it does not exceed 3.5 bar the worst that happens is that it over-fuels and quenches the fire.

[Pursang]

Alpha-N maps are RPM/Throttle position = Fuel required. Simple and work well with predictable air flow.

My idea is to find the difference between maximum and minimum crankcase pressure each cycle and output this in a modified form to the EFI CPU as an indication of real airflow through the two stroke's motor.

If I can find a good way to indicate changes in air flow (charging efficiency) then I may be able to also use a Volumetric efficiency map below 25%, just like 4T's do.

When the engine is on the pipe, Alpha-N works well but when the motor is swapping between on the pipe and off Alpha-N is either correct or to rich for the motor to run. So we need a way to adjust the fueling to match the changeable air flow.

Rather than trying to accurately measure the airflow, perhaps d(RPM)/dt and/or Gforce could be more easily measured and integrated with the throttle position & RPM in the Alpha-N map.

Cheers, Daryl.

[SwePatrick]

Earlier i hinted about a project that is going on in my garage.

It´s a twin Piaggio engine with malossi case.
We have done some machining this weekend to beeing able to start fitting crankshafts etc etc.

I milled out the crankhousings to fit the new crankshafts from Roost.(47mm stroke)
Also chopped the two crankshafts so we can mate them together with a coupling.

A teaserpicture:
336844

It is still some porting to do to fit the banshee reeds, but it´s a five minute job. ;)
As we speak i´m milling a keyway in the crankshafts to keep them 180 degree apart when mounting the engine.

336845336846

[DaisyB]

Having circuit raced a Malossi C-one cased 77cc Piaggio Zip, I'd imagine that's going to be a bit of an animal!

[peewee]

What thread is needed Peewee, I will measure the Dellorto ones I have here.

https://www.dellorto.co.uk/shop/dellorto-motorcycle-carburettors-parts/carburettor-parts/phbephb-parts/methanol-needle-valve/

hey mate its m10x1.0, see what you've got that might be other options. but to be honest , it seems ive got this modified 3.5 mikuni working perfectly, atleast in the bench tests. ill try it next week on the running engine to make sure I haven't over looked something. two things I found to be very critical. once you get close to 4.5mm ( I bored from 3.5 to 4.48 in about five or six step increments), be very carefull to bore the hole perfectly round. at the end I used a 4.48mm drill bit by hand so not to bugger it. if its ovaled then your valve will be good only for the scrap heap because it likely wont seal again. other thing is, I used a 15/64" drill bit, turning only by hand , to put the ramp back into the hole so the needle tip can seal. so far it seals perfect

[jonny quest]

Looking for a set of RG400/500 oem carbs. Also electrical parts

[gamma500]

Hi Wobbly and Frits, I have a question about cylinder head water flow.

I have been searching for Yamaha gytr kit parts for 125, and I noticed that gytr head water flow is a bit different from standard Yamaha.

As you can see on the gytr head most of the water flows from the back of the cylinder and then back to the front of cylinder head.

In the std Yamaha the water outlet is at the rear of the head.

Is this gytr flow path any better than the original yamaha design?

[husaberg]

Hi Wobbly and Frits, I have a question about cylinder head water flow.

I have been searching for Yamaha gytr kit parts for 125, and I noticed that gytr head water flow is a bit different from standard Yamaha.


If i remember right the "KIT" long rod was just the std rod from an older model.

[Frits Overmars]

I used a 15/64" drill bit, turning only by hand, to put the ramp back into the hole so the needle tip can seal. so far it seals perfectInserting a suitable-diameter bearing ball and giving it a hammer tap can create a perfect seat for the float needle.


I have been searching for Yamaha gytr kit parts for 125, and I noticed that gytr head water flow is a bit different from standard Yamaha. As you can see on the gytr head most of the water flows from the back of the cylinder and then back to the front of cylinder head. In the std Yamaha the water outlet is at the rear of the head. Is this gytr flow path any better than the original yamaha design?I like the GYTR flow path, but did you notice the air bleed bolt? Because of the low-placed hose pillar, an air bubble will form in the upper part of the head, and bleeding it once in a while may not be sufficient. I'd replace the air bleed bolt with a small hose pillar and connect it to a high point in the cooling circuit, like in the RSA pictures.
336852336853336854

[peewee]

Earlier i hinted about a project that is going on in my garage.

It´s a twin Piaggio engine with malossi case.
We have done some machining this weekend to beeing able to start fitting crankshafts etc etc.

I milled out the crankhousings to fit the new crankshafts from Roost.(47mm stroke)
Also chopped the two crankshafts so we can mate them together with a coupling.

A teaserpicture:
336844

It is still some porting to do to fit the banshee reeds, but it´s a five minute job. ;)
As we speak i´m milling a keyway in the crankshafts to keep them 180 degree apart when mounting the engine.

336845336846

nice project there. is it for drag racing and where is the gear box ? some how i would like to make a twin with two ktm 250cc cylinders

[Muhr]

Does anyone have any experience with titanium conrods?

[peewee]

i dont have experience with titanium conrods but i thought they had to much elasticity for high piston speeds ?

[JanBros]

nice project there. is it for drag racing and where is the gear box ? some how i would like to make a twin with two ktm 250cc cylinders

no gearbox, it's a scooter engine so a variomatic.

[Muhr]

i dont have experience with titanium conrods but i thought they had to much elasticity for high piston speeds ?

Yes, in this case it seems to be 0.07mm for steel and 0.11mm for titanium at 9kn. should be possible to compensate for?:blink:

[wobbly]

Re the water flow scenarios.
The best setup is to have cold water into the cylinder at the boost port, that then flows over the transfers,around the exhaust duct area,then that warmed water enters
into and across the head.
Exiting again on the rear, the same side as the inlet.
This was a test I did on a TM Kart engine, by reversing the flow with a new inlet spigot on the rear of the cylinder , was worth over 1 Hp in 48.
In the original setup all the water entered under the Exhaust duct - but this lost power.
The next design used a hose around the side with the flow entering over the top of the Exhaust duct.

The test result again pointing to my assertion that designers are remiss in not having water flow over the whole transfer duct outer within the cylinder.
Jan gained power with a water channel on the transfer duct inside radius as well.

Last I heard several years ago about Ti rods was that a NASA patent had been taken up by Kurt at HotRods to use a deposition process that in effect created
a deep enough " case hardening " layer to enable needle rollers to run directly on the Titanium conrod big and small end bores.
He told me the manufacturing was a complete nightmare and doubted it was worth the effort.

[Muhr]

Last I heard several years ago about Ti rods was that a NASA patent had been taken up by Kurt at HotRods to use a deposition process that in effect created
a deep enough " case hardening " layer to enable needle rollers to run directly on the Titanium conrod big and small end bores.
He told me the manufacturing was a complete nightmare and doubted it was worth the effort.

Thank you wob
Wonder if it's a type of plasma nitriding

[190mech]

Muhr,I think the Ti rod has been tested many times,all had some drawbacks to the good old forged steel ones..
I saw this youtube vid on my favorite scooter forum that had your logo on some of the parts,is this some of your handy work?If so VERY GOOD!
https://www.youtube.com/watch?v=n8MMB_dCxOU

[philou]

I think the rod is not titanium but titanium nitride coated

[wobbly]

That is the big issue with Ti rods, any form of so called Nitriding, is no good for use with direct roller contact - no different than the equivalent surface
of a steel rod.
The ground contact surface must be at least 0,5mm deep 58 Rc in both materials, and this is a case hardening operation,a quite different process to simple gas Nitriding
that is only microns deep.
NASA developed the process to do this with Ti for the space program, and they have a technology transfer system in place for USA tech companies.
But as far as I know the HotRods guys gave up on the project - I will contact Kurt the boss and ask.

[Muhr]

Muhr,I think the Ti rod has been tested many times,all had some drawbacks to the good old forged steel ones..
I saw this youtube vid on my favorite scooter forum that had your logo on some of the parts,is this some of your handy work?If so VERY GOOD!
https://www.youtube.com/watch?v=n8MMB_dCxOU

It's a good friend of mine who produces some stuff, which I help with a few different things.


I will contact Kurt the boss and ask.

Yes, it would be interesting to hear more about that! One idea I had was to manufacture inconel inserts

[husaberg]

Does anyone have any experience with titanium conrods?

No experience but

AN Aussie was making and selling them in his classic racer with a Roller bearing crank
https://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner?p=1130416026#post1130416026

they had case hardened replaceable sleeves.
Plenty of production $T bikes have had them RC30 OW01 etc etc

MMC was meant to be the way ahead

https://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner?p=1130415632#post1130415632


Some other stuff
https://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner?p=1130415630#post1130415630

[Frits Overmars]

Does anyone have any experience with titanium conrods?
Last I heard several years ago about Ti rods was that a NASA patent had been taken up by Kurt at HotRods to use a deposition process that in effect created a deep enough " case hardening " layer to enable needle rollers to run directly on the Titanium conrod big and small end bores. He told me the manufacturing was a complete nightmare and doubted it was worth the effort.Re hardening the bearing surface in a Ti rod big end: it's not only the hardness that is important.
It's like walking on ice: no matter how hard the surface is, it also needs to be thick enough, or it will simply crack. Ti rods that do survive, have a steel big end insert.
A friend of mine, Rico Ronge, developed a nice method of welding steel to titanium. Muhr, in case you're in the Chemnitz area, he lives just around the corner.
336859 336858

[wax]

Has anyone here ever moved the anti rotation pin in a piston. I am having issues getting the right pistons and its looking like i will have to have them moved. Any body done it before ??

[Muhr]

A friend of mine, Rico Ronge, developed a nice method of welding steel to titanium. Muhr, in case you're in the Chemnitz area, he lives just around the corner.

interesting, it's something beautiful with a 45g conrod,:D regardless of whether it's better or not. is it something he's working with or more a hobby

http://laser.mace.manchester.ac.uk/uploads/tx_neofileshare/2010-08-22_16-11-33_fiberlaser_dissimilar.pdf

[Frits Overmars]

is it something he's working with or more a hobby?Both.

https://www.ronge-motorsport.de/

[shnaggs]

This may be a really stupid question, but why can a 4 stroke run Ti Rods but not a 2 stroke? Is it because of the needle bearings? Ok, then why must we use a needle bearing? Is it because we can not get oil to the bearing with pre-mix if it is not a needle bearing? Sorry, asking for a friend :yes:

[jasonu]

Has anyone here ever moved the anti rotation pin in a piston. I am having issues getting the right pistons and its looking like i will have to have them moved. Any body done it before ??

We used to do that to MB100 pistons when using them in RG400 cylinders. No big deal as long as you have access to the correct people/equipment

[Pursang]

If I can find a good way to indicate changes in air flow (charging efficiency) then I may be able to also use a Volumetric efficiency map below 25%, just like 4T's do.

I'm still of the opinion that, in simple terms, fuel delivery (and ignition management) determines the power output and that the necessary airflow will follow, unless restricted by throttling mechanisms.

But, if I was after an easy way to determine airflow through a 2 stroke, I would to use the expansion chamber restrictor as a pseudo (or actual) orifice plate. Differential pressure readings, plus a suitable correction factor, will give a good indication of the volumetric flow rate. Add temperature measurement for mass flow.

Cheers, Daryl.

[Muhr]

Both.

https://www.ronge-motorsport.de/

Thanks Frits!
That is definitely an option


This may be a really stupid question, but why can a 4 stroke run Ti Rods but not a 2 stroke? Is it because of the needle bearings? Ok, then why must we use a needle bearing? Is it because we can not get oil to the bearing with pre-mix if it is not a needle bearing? Sorry, asking for a friend :yes:

Do not know how common it is with TI conrods in 4stroke but 2 possible reasons are that they usually rev less and are often short stroke and of course crankcase lubrication

[SwePatrick]

Here:
Just place order ;)

http://www.titanium-valve.com/pdf/en/Order_form_ConRod_Moto.pdf

[wobbly]

Foul strokes use Ti rods with bearing inserts and direct oil pressure feed.
They are capable of higher terminal piston speeds than a 2T due to this superior lubrication factor.
Look at the 250 MX bikes , they rev to the moon ( not only due to the short stroke ) usually then destroying everything in sight, but rarely the rod or bearings.
Ti rods have been made with thru hardened sleeves for the needles,but this is difficult to do reliably.

[TZ350]

I'm still of the opinion that, in simple terms, fuel delivery (and ignition management) determines the power output and that the necessary airflow will follow, unless restricted by throttling mechanisms.

A few experiences with holed pistons and overheating seizures from running lean/retarded or over advanced leaves me feeling cautious and happy to let someone else explore this concept.


But, if I was after an easy way to determine airflow through a 2 stroke, I would use the expansion chamber restriction as a pseudo (or actual) orifice plate. Differential pressure readings, plus a suitable correction factor, will give a good indication of the volumetric flow rate. Add temperature measurement for mass flow.

Cheers, Daryl.

Hi Daryl, "differential pressure" across the stinger restriction, that might have promise, if my current approach does not workout I will look at your differential pressure idea, could be good, thanks.

[Frits Overmars]

I would to use the expansion chamber restrictor as a pseudo (or actual) orifice plate. Differential pressure readings, plus a suitable correction factor, will give a good indication of the volumetric flow rate.So if the pressure drops, you'll conclude that there is less air flow and you'll inject less fuel? Lean mixture = less power = less pressure = even leaner mixture...

[F5 Dave]

Chance to save weight on the rear brake?

[190mech]

Wax,
There is a good bit of info on ring pin relocation in this forum,Husa listed quite a few on this page;
https://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner/page1172

[Muhr]

No experience but


Almost forgot! thanks Husa

[Pursang]

So if the pressure drops, you'll conclude that there is less air flow and you'll inject less fuel? Lean mixture = less power = less pressure = even leaner mixture...

TZ wants an easy way to measure the instantaneous air flow through the engine....Not me, (it's a lagging indicator).

What he decides to do with the flow info is up to him.

Is the 'flow' is dropping because rider is closing throttle? (need less fuel, as above) or engine is losing revs as bike goes up a rise (need some more).

My suggestion is to tell the fuel system exactly what you are trying to achieve, (rate of deceleration, cruise or rate of acceleration) at any given combination of throttle position and RPM and inject the appropriate amount of fuel.

G-forces, the direction & rate of RPM change, or even braking pressure are relatively easy to measure.

To keep it simple for the rider, throttle position = power output (0-Max)

Might need to switch between multiple 3D FI maps or add more dimensions.

Cheers, Daryl.

[TZ350]

336903336904

The head on the left has the standard NSR250 combustion chamber shape with its heavily shrouded plug and the other one has a sort of torodial combustion chamber and unmasked plug. To unmask it, the plug seat was faced back 2.5mm and I think a bath tub shape combustion chamber may be better. Both heads are viewed from the same angle.

There may be a place for modifying std NSR heads for ordinary road bikes by facing back the plug seat to unmask it and modify the chamber to a bath tub shape.

Unfortunately up until now, for the team bikes I had not been working to a standard cylinder length. Only taking a nominal 2.5mm of the top so some are 0.2 either way. Then the heads were machined to suit. Which makes the heads not immediately exchangeable between bikes for a back to back combustion chamber comparison on the dyno. Future cylinders after having a nominal 2.5mm skimmed off the top will be finished consistently at 83mm.

[Muhr]

Hello
I am working on another project where I am looking for a tunable ignition system and exhaust valve control unit. have looked at ignitech but have no experience with the valve control unit or its software. Is there anyone who has? Or someone who has experience of any other system?

[SwePatrick]

Hello
I am working on another project where I am looking for a tunable ignition system and exhaust valve control unit. have looked at ignitech but have no experience with the valve control unit or its software. Is there anyone who has? Or someone who has experience of any other system?

Just use an aftermarket ecu for fourstrokes,, cars.
It will have all the functions needed.

I ran DTA s6pro in a car, and it had fully configurable pid loops and more for it´s aux outputs.
And was capable of high revs.
Just delete the injectors, it will run anyway ;)

[TZ350]

Hello
I am working on another project where I am looking for a tunable ignition system and exhaust valve control unit. have looked at ignitech but have no experience with the valve control unit or its software.

Totally recommend Ignitec. Team ESE use the DCP Race2 on our singles and find the PV easy to setup. If you get one I would be happy to help with answering questions on setup.

[wobbly]

The Ignitech PV servo and software is super easy to use.
The best way I have found to set it up, is to have two plugs in the wiring loom.
One is a two pin, just +/- power for the servo motor.
The second is a 3 wire with 5v ref,ground, and the pv position feedback.

You disconect the power feed, and simply rotate the servo to get full up, with no slack in the two cables.
This will show a mV reading on the screen for the up position.
Then rotate the servo for fully down, the mV is shown for that position on the screen.
So now all you have to do is input those values at the rpm you want, and you have a straight line ramp.
I always note the exact 1/2 up position of the valve in the port, especially if you have a two stage PV blade.

It seems that the servo will operate faster with no intermediate data points, but sometimes a straight line doesnt give the best power result.
So I then do 3 dyno runs with the valve fixed fully down, 1/2 way up , and fully up.
This gives you 3 best power rpm for those positions - adjust the rpm in the software to these 3 rpm and you are done.

As long as the +/- wire polarity is correct, the servo will cycle full up, then settle at full down, when powered up.
I dont like the PV software in the Race box, as it for some reason tries to zero any tiny offset reading when fully down, no matter what the hysteresis, and the motor will squeal
all the time with the correcting voltage being applied.

[Muhr]

Thank you gentlemen
You are unambiguous in your opinion.
Then Ignitech it is.:done:

[Muhr]

Re hardening the bearing surface in a Ti rod big end: it's not only the hardness that is important.
It's like walking on ice: no matter how hard the surface is, it also needs to be thick enough, or it will simply crack. Ti rods that do survive, have a steel big end insert.
A friend of mine, Rico Ronge, developed a nice method of welding steel to titanium. Muhr, in case you're in the Chemnitz area, he lives just around the corner.


48.5g with inserts is what I can handle, would be awesome to test. Where there some tests done with Aprilia?

But i'm a coward, should be able to take 5-8g if you have some balls

[Matt@TYGA]

Hello
I am working on another project where I am looking for a tunable ignition system and exhaust valve control unit. have looked at ignitech but have no experience with the valve control unit or its software. Is there anyone who has? Or someone who has experience of any other system?

Have to agree with the other replies here. The Ignitech is a breeze to use. Wobbly's method of the PV setup (on dyno) is how I do it. Gets you in the ballpark quickly.

I did have one of the early single cylinder units (for ignition timing) and also the servo control on an NSR150 some years ago, but soon changed it for a DC-CDI-P2 with on board servo control. Neater to look at and faster/easier to mess around with when just dealing with one box.

Only thing I want to play with on that is to connect both channels to the coil (a la Wobbly's suggestion) and see if more mojo is forthcoming.

[TZ350]

.
When we buy Ignitecs we used pictures to show them exactly what we want. Here are some of the pictures, they maybe helpful.

At least get a wiring harness with your P2, and maybe 100 each of the 4 parts of the wiring plugs, makes life real easy, cut away any extra wires you don't need. Also for mechanical reliability, solder the plug when you crimp it onto the wire so it wont pull off again. Their ignition pickups are real good too.

When you do the wiring use off cuts from the wiring harness to splice to the accessories like TPS and Pickup so the color codes at the plugs match.

A laptop or computer with a RS232 serial port is real handy too.

DC-CDI-P2 Race, with on board servo control. The DC-CDI takes in 12 Volts DC and internally generates its own high voltage to charge up its CDI.

We make our own Push and Go 12Volt generators from Lifan after market units. Combined with a Voltage Rectifier Regulator and a 25Volt 2500 uF capacitor you have a decent 12Volt DC generator for the Ignitec.


329021

How to make a decent light weight racing 12 Volt generator

Any PV servo from a RGV250, NSR250, Yamaha R1 etc will work.

[Muhr]

.
When we buy Ignitecs we used pictures to show them exactly what we want. Here are some of the pictures, they maybe helpful.


Thank you TZ! It does not always seem as obvious what you need when you're on their website

[jbiplane]

.
It has taken a while but I have finally cracked the true Arduino analog output problem my project had, now hopefully my EFI project can move forward, or at least to


We make our EFI + DC spark ignition compatible with http://tunerstudio.com/index.php/tuner-studio

So it completely open for experiments

http://www.homebuiltairplanes.com/forums/attachment.php?attachmentid=70738&d=1523558332
http://www.homebuiltairplanes.com/forums/attachment.php?attachmentid=70739&d=1523558549

[flyonly]

Crank Balancing

Does anyone know how dynamic crank balancing gets done? I am assuming that if you are not in good balance it will limit your engine to rev at higher rpm

Do they spin your crank at true engine rpm and have sensors to record where the lateral forces are occurring?


Sent from my iPhone using Tapatalk

[husaberg]

In France a 125 is limited to 15 Cv.

For 125 NSR, the French cylinders are different from the others. English cylinder are better

336775


A great find!

I found these
same pic with explanations
336972336973336974336975336976

More to follow
http://www.nsr125.com/derestrict.htm

https://www.125ccsportsbikes.com/forums/index.php?showtopic=77128


JC22 FOXEYE MODEL
here were two models of the NSR125; the JC20 produced between 1988 and 1994 and the JC22 Foxeye produced between 1994 and 2001. They are easily distinguished by the headlights. The JC20 had double round headlight, while the JC22 had a "foxeye" headlight hence the nickname.

Following the success of the NS125 (an earlier model to the NSR), the NSR125 JC20 was designed and assembled by Honda Italia Industriale S.p.A. in Rome, Italy. Grimeca was contracted to produce the aluminium cast frame (2-piece, die-cast, bolt together construction), wheels and brake assemblies. The engine was manufactured by Girardoni with Dell'Orto supplying the carburetor. Marzochi supplied forks and suspension while Pagani provided instrumentation and lighting. The Grimeca rear wheel was 18 inch in diameter, while the front was 17 inch and shod in Pirelli MT-45 tires.

The NSR125 JC22 is mostly of Japanese manufacturing, with the engine parts and other key elements of the running of the motorbike produced in Japan, it was then assembled in Italy and supplied to its mainly European market. Design changes saw the JC22 to receive a steel fuel tank and visual trim resembling the NR750.
REGIONAL DIFFERENCES
HISTORY AND DEVELOPMENT
While the NSR125 is mostly of Japanese manufacture, with the engine parts and other key elements of the running of the motorbike produced in Japan, t was then assembled in taly and supplied to its mainly !uropean market" #here were 2 models of the bikes the earlier model NS125R& with a 'square' headlight, produced between 1988-94 and the later foxeye' R1 model so named due to its front lights resembling that of a fo.& produced between 1994-2001" Whilst drastic changes were made to the aesthetics of the motorbike 0ery little was changed on the mechanical or engineering side"eventually however, new stricter regulations in the ! began phasing out the 2 stroke motorcycles and the NSR125 ceased production in 2001"lthough it is a common mistake to believe the NSR continued production until 2003" #his is not the case as they ceased production in 2001 but had lefto0er stock until 2003/4
There is a large problem with Derestricting certain models of the NSR125 and this is mainly dependent on where the bike was manufactured for. To tell the difference you must check your frame number.
UK
Frame number: ZDCJC22C******
Restrictions: Exhaust (http://i.viglink.com/?key=b03a7adbd49ae99bd89d2c4cb923ad63&insertId=7ffd9d6476d7b50be3f02ffcd6abd604&type=L&mid=undefined&exp=-1%3Ana%3A0&libId=jhmot0fs01000ln2000DA3lqwcsgk&loc=https%3A%2F%2Fwww.125ccsportsbikes.com%2Fforum s%2Findex.php%3Fshowtopic%3D77128&v=1&out=http%3A%2F%2Fwww.ebay.com%2Fsch%2Fi.html%3F_nk w%3Dexhaust&ref=https%3A%2F%2Fwww.google.co.nz%2F&title=How%20to%20derestrict%20an%20NSR%20-%20125cc%20Sportsbikes%20Forum&txt=%3Cspan%3EExhaust%3C%2Fspan%3E) collar, carb jets, inlet restriction plate
Required alterations: Upjet, exhaust mod, inlet plate removal
Optional alterations: Carbon reeds, change sprockets
Italy
Frame number: ZDCJC22A******
This is a full power bike and has no restrictions.
Optional alterations: Carbon reeds, change sprockets
France
Frame number: ZDCJC22B****** - can look like an 8
Restrictions: Exhaust (http://i.viglink.com/?key=b03a7adbd49ae99bd89d2c4cb923ad63&insertId=7ffd9d6476d7b50be3f02ffcd6abd604&type=L&mid=undefined&exp=-1%3Ana%3A0&libId=jhmot0fs01000ln2000DA3lqwcsgk&loc=https%3A%2F%2Fwww.125ccsportsbikes.com%2Fforum s%2Findex.php%3Fshowtopic%3D77128&v=1&out=http%3A%2F%2Fwww.ebay.com%2Fsch%2Fi.html%3F_nk w%3Dexhaust&ref=https%3A%2F%2Fwww.google.co.nz%2F&title=How%20to%20derestrict%20an%20NSR%20-%20125cc%20Sportsbikes%20Forum&txt=%3Cspan%3EExhaust%3C%2Fspan%3E), Carburetter, CDI unit, RC-Control unit
Required alterations: Upjet, exhaust mod, inlet plate removal, CDI and PV controller
Optional alterations: Carbon reeds, change sprockets
Switzerland
Frame number: ZDCJC22E******
Restrictions: so many restrictions that it is nearly impossible to derestrict and cannot even rev past 7500rpm.
Required alterations: UK or Italian engine, exhaust (http://i.viglink.com/?key=b03a7adbd49ae99bd89d2c4cb923ad63&insertId=7ffd9d6476d7b50be3f02ffcd6abd604&type=L&mid=undefined&exp=-1%3Ana%3A0&libId=jhmot0fs01000ln2000DA3lqwcsgk&loc=https%3A%2F%2Fwww.125ccsportsbikes.com%2Fforum s%2Findex.php%3Fshowtopic%3D77128&v=1&out=http%3A%2F%2Fwww.ebay.com%2Fsch%2Fi.html%3F_nk w%3Dexhaust&ref=https%3A%2F%2Fwww.google.co.nz%2F&title=How%20to%20derestrict%20an%20NSR%20-%20125cc%20Sportsbikes%20Forum&txt=%3Cspan%3Eexhaust%3C%2Fspan%3E), loom, CDI and PV controller

[guyhockley]

If you don't want to mess with Ti, you could always lighten a steel rod! :oi-grr:
I think Wobbly mentioned these ones and theorised they were a "gas flow" attempt - Rotary valve kart motors.
I'm pretty sure the later ones had the same shape reliefs each side but with an intact central web.

[wobbly]

Its not necessary to dynamically balance a 2T crank, nor is it really feasible to split the webs, install a dummy mass on the pin and spin it up.
All that will tell you is the crank is heavy opposite the pin, by the crank balance factor % you have decided upon.
Static balance with a mass hanging off the rod small end simply works - and if the chosen % causes issues then all that means is that it isnt working with the combination
of crank induced vertical/lateral engine motion, interacting with the chassis.

[jbiplane]

48.5g with inserts is what I can handle, would be awesome to test. Where there some tests done with Aprilia?

But i'm a coward, should be able to take 5-8g if you have some balls

Novadays exist software tools to make the best shapes :)

https://www.youtube.com/watch?v=5aRFcQZ1IDQ

[Muhr]

Novadays exist software tools to make the best shapes :)


Is that something you use? I have something similar

https://m.youtube.com/watch?v=lyTULzvHhXw

[TZ350]

We make our EFI + DC spark ignition compatible with http://tunerstudio.com/index.php/tuner-studio

So it completely open for experiments

http://www.homebuiltairplanes.com/forums/attachment.php?attachmentid=70738&d=1523558332
http://www.homebuiltairplanes.com/forums/attachment.php?attachmentid=70739&d=1523558549

The EMS and tuning software looks good. The plug looks the same as the Ignitec we use but the pin outs are different.

I see Alpha-N and Speed Density maps, is there also a Volumetric Efficiency map based on RPM and MAP manifold absolute pressure?

Speed Density, a "Calculation" of air speed in the throttle body. Does this calculation assume that the air is generally only flowing in one direction like it does on a four stroke. How does it account on a tuned two stroke engine for the large amount of air that often reverses direction and flows back out.

My current EFI system only supports a Alpha-N (TPS vis RPM)map for two stroke engines. This does not work well below 25% throttle position where the air flow through the engine changes dramatically depending on whether the engine is on the pipe or not.

Below 25% throttle position because of dramatic changes in air flow there, the Alpha-N map can only be correct for "On the Pipe" or "Off the Pipe" but not both and it is what is holding me back on my 2T EFI project.

I am interested in your EFI system.

If it can, how does the Aviamechanica deal with this changeable air flow situation below 25% TP in a two stroke engine?

[speedpro]

air is generally only flowing in one direction like it does on a four stroke.

When I ran the carbs on the twin it had fuel standoff about 200mm out of the carbs at certain revs. Clearly air had changed direction. It went away when the motor was "on the cam".

[TZ350]

When I ran the carbs on the twin it had fuel standoff about 200mm out of the carbs at certain revs. Clearly air had changed direction. It went away when the motor was "on the cam".

Ecotrons use a MAP sensor in the inlet tract on a 4T but says the MAP sensor becomes confused on a 2T. I wonder if it is because there is only half the time on a 2T for the MAP sensor to settle.

337006

This is the EngMod simulated transfer efficiency for my 2T engine, I guess the mass of reversion happens where you see the big dip.

[jbiplane]

Is that something you use? I have something similar
https://m.youtube.com/watch?v=lyTULzvHhXw

Hi Muhr

The software code for optimization of Autodesk and many others is made by Altair.

The other main player in optimization is Ansys.

Each known part can be made lighter using this approach :)

[Muhr]

48.5g with inserts is what I can handle, would be awesome to test. Where there some tests done with Aprilia?

But i'm a coward, should be able to take 5-8g if you have some balls

If you try to get away without welding, then you seems lose a lot of weight gain.

[Muhr]

Hi Muhr

The software code for optimization of Autodesk and many others is made by Altair.

The other main player in optimization is Ansys.

Each known part can be made lighter using this approach :)

Of course, what you wanted is the opportunity to simulate a whole rotation with all oblique loads. but we deadly may have to wait for that opportunity for a while.

[jbiplane]

The EMS and tuning software looks good. The plug looks the same as the Ignitec we use but the pin outs are different.

I am interested in your EFI system.

If it can, how does the Aviamechanica deal with this changeable air flow situation below 25% TP in a two stroke engine?

We used before ecotrons, but had problems with system openess and sometimes it burn out. So we developed our own. We can develop electronics of any level of complexity, if it worth. Says in other my company sharing the same building we make avionics http://uav-siberia.com/en/catalog/avionika/

In our EMS project we decide save on software development. So everything what can be programmed in http://www.tunerstudio.com/index.php/tuner-studio is available. All algorithms and data tables.

The very specific questions should be adressed to our EFI engineer. I will pass your message to him :)

Ignition part of our system could give you much more tuning options than Ignitech. And using 158 grammes Nissan Denso spark coils give you possibility burn out
sheet of office paper with spark.

[jbiplane]

Of course, what you wanted is the opportunity to simulate a whole rotation with all oblique loads. but we deadly may have to wait for that opportunity for a while.

With Ansys it is already possible. You can give as piston pressure vs angle for each rpm and see stresses picture in each moment. You can google for transient crankshaft analysil in Ansys.