ESE's works engine tuner

[Brian d marge]

I have found that almost all japanese twist and go scooter ignitions have between 7 and 11 degrees set in them.....is it easy/cheap to get a second hand one in NZ?

u can buy performance ones cheaply to , but its that blasted potting in them , if anyone can figure a way to get that stuff out with out hurting the electronics ,,,Im all ears

Stephen

PDL kits for my Enfield 300 pounds Sterling , Honda CR250 free ,,,I have a few lying about , black box ... and all it does is open when the correct cvoltage is reached , Well thats another story , If I could get one with a 10 deg Static advance , cool ! but the map might be different ! ..hey ho

Stephen

[SS90]

When I looked at it in the flesh, the piston was a uniform colour all over with a grey colouring on top that looks like it was just misted over lightly with a spray gun after the piston was painted brown.

The ports are not square across the engine but are turned like a T500 Suzuki's. The rear boost/transfer port would be at the 2oclock position and the exhaust port at 7 oclock in the pic.

The dark area in the dish at 2 oclock, is that the boost/transfer port blowing straight across the piston towards the exhaust? And the lighter areas either side the mains and secondrys blowing towards the back.



My CDI unit consists of three main pieces, stator coil, black box and high tension coil. When you say the "Curve" is stored in the coil, which coil do you mean?

I will look into the possibility of a scooter ignition, thanks for the tip. I have several RM black boxes and plan to make a wiring adaptor and try them. I will get something sorted very soon as we plan another trip to the dyno at Henderson Yamaha and I might get to run my bike this time.




Dynos are becoming addictive.

.

Yea,sorry, when I refer to the "curve" stored in the box, it was a little vague!

What I meant was the fact that the CDI and the coil are the same unit on modern "twist and go's"!

Making it easy to simply swap to different boxes (coils/CDI units) in order to get different retard points (RPM), and different amounts of retard (degrees)

I first thought they would all be pretty much the same, but I learned otherwise!


Yea, with the crown of your piston, it is a little early to tell too much in regards to patterns just yet, as it does seem that your exhaust area is a little hot, and I would be presuming too much...

.....however, from what I see (and reading/seeing that you have a flat top piston), I would start to suspect that you would get some advantages by returning to a domed piston (if you where to leave the rear boost/transfers alone, and not change their angle)

I'm not suggesting you have to change your piston, as there are other solutions!

However, I am starting to go back to my original idea (a few weeks ago), that you should utilise the flat top piston, and try and combine the rear boost port and the two secondaries into one stream, and get a very high angle (right up into the combustion chamber), and try and use that dish in the piston to your advantage!

Remember that the scavenge pattern the Suzuki boys designed for this cylinder utilised a domed piston, and with a flat top, it's no longer working as designed!

If you had to run the cylinder and piston as it was, you could compensate for this changed pattern (caused by the flat top piston) by designing a chamber was better at "pushing" the wasted fuel back into the cylinder, but I think changing the rear port angles is better.... currently I do not feel you are getting the benefits that having secondary transfers normally provides!

But this is assuming too much, and I believe you need to lower the temp of the exhaust side of the crown to better see what is happening with your transfers!

[TZ350]

Honda RS125 Ports as best as I can measure them:-

(F4) (F5) Etc refers to points in the Yamaha SAE paper and can also be seen in Pic-1.

Download the SAE paper from Yamaha on Port Shapes and Power:- http://www.2stroke-tuning.nl/media/pdfjes/porting.pdf


Bore 54mm Stroke 54mm R1=27 (F5) R2=12.5 (F4). The Piston has a very slight dome.

Transfer Port Opens 41.75mm-116 ATDC Inclined Up (F3) 30Deg P1=70 P2=30.

Auxilary Type-1 (F9) Port Opens 43mm-119.5 ATDC Inclined up 15 Deg.

Boost Port Opens 43.5mm-121 ATDC Inclined up 55 Deg.


Pic-1 The Data, Pic-2 The Honda RS125 Ports, Pic-3 The tools for measuring the port angles, Pic-4 The very clean edges in the ports, Pic-5 The piston at BDC, Pic-6 The crankcase port windows.

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[SS90]

[QUOTE=TZ350;2041289]Honda RS125 Ports as best as I can measure them:-

(F4) (F5) Etc refers to points in the Yamaha SAE paper and can also be seen in Pic-1.

Download the SAE paper from Yamaha on Port Shapes and Power:- http://www.2stroke-tuning.nl/media/pdfjes/porting.pdf


Bore 54mm Stroke 54mm R1=27 (F5) R2=12.5 (F4). The Piston has a very slight dome.

Transfer Port Opens 41.75mm-116 ATDC Inclined Up (F3) 30Deg P1=70 P2=30.

Auxilary Type-1 (F9) Port Opens 43mm-119.5 ATDC Inclined up 15 Deg.

Boost Port Opens 43.5mm-121 ATDC Inclined up 55 Deg.


Pic-1 The Data, Pic-2 The Honda RS125 Ports, Pic-3 The tools for measuring the port angles, Pic-4 The very clean edges in the ports, Pic-5 The piston at BDC, Pic-6 The crankcase port windows.

.[/QUOTE=

Aweseome reading on the SAE papers Teezee!

Interesting on the port times (boost port and auxilleries opening at different times aye!)

The angles of the ports etc are pretty much (roundabout) where you should be heading..... I am just still a little unsure of flat piston at the moment.

As you know Rs125's are "square" engines, but I can't really remember ever seeing a modern port layout that differed if the engine was square or not.

(that said, I can't think of an "unsquare" modern performance two stroke engine off the stop of my head!)

From your recent reading, what does it lead you to conclude on the angles of your ports for your GP125?

[TZ350]

[QUOTE=SS90;2043797]

From your recent reading, what does it lead you to conclude on the angles of your ports for your GP125?

The transfer port and auxiliary port (upswept) angles are arse about face on the GP compared to modern thinking.

Also looking at the angles and kickers in the ports you can see how Honda and modern thinking have reduced exhaust short circuiting

I have been talking with Tomas, he will be back from Vietnam next week. He seemed to already be familiar with the modern thinking and has some experience with changing the transfer port roof angles. I will take pic's and post when he re works the cylinder.

I know we should just change one aspect at a time and dyno each step but I don't have the patience. We will give the spare GP cylinder a radical make over using all the ideas covered recently.

We are going to model our work on the RS cylinder but use the original RM-spec pipe to start with.

SS90 getting us looking in this direction has been very helpfull, it will be interesting to see what gains in driveability can be made.

I am making a modified first gear (in buckets the starts are everything) when I get that done I will strip the motor to fit it and do some mods in the case and pack the flywheel which should bring up the primary compression.

The new first driven gear will be generated with one less tooth but the same pitch circle. Makes for funny looking teeth and will probably be noisy but who cares, this is buckets. I will draw it up and have the blank water cut. Then I will turn the inside and form the driving dog slots before having it hardend.

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[TZ350]

K14 and Sully60 have both encouraged me to pay more attention to improving my riding, and they are right. There are big big gains to be made there.

Following Sullys suggestions of more pre-load on the rear shocks I found I could start getting the power on earlier. The few times I got this right the bike fair flew around the corner, but it did show up a few more handling issues and my inexperiance with the extra speed. I was arriving at the next corner before I was ready.

Whenever I got the power on early, F...ck the bike flew and caught people up quick. I want more of this and when I have got used to the extra speed, there are going to be some very sorry 4-strokes at Mt Welly.

Team ESE are planning to get down to Saturday practice's, we are all starting to get excited about our individual improvements.

I "borrowed" these pics from Tides post http://www.kiwibiker.co.nz/forums/sh...ad.php?t=97882 Pictures from Mt Wellington 19/4.

Unfortunatly I am not in the pic. I had got a good start and am out of the frame. I led the field for almost a lap before the fast boys started passing and I slowly drifted back through the field.

I was that annoying person we have all met while driving on the open road. You know the one, they go slow in the corners and speed up down the straights and its hard to get past. Well I am getting faster in the corners, much faster.

I can now see the way forward riding wise, and we are building a more drivable bike.

The next meeting should be good fun, especialy if it's wet.
.

[TZ350]

I was looking at fairings and it's occurred to me that the front of the lower fairing on a sport bike seems to share similarities to the design of the shroud in the link to aero engine cooling. Is this coincedence or by design.

I have been looking at this too, it must be design. On mine its a bit crude but I am trying to do something with the front number board and a duct attached under the top tripple clamp to direct air over the cylinder. I hope to fit a front guard from a RS125 to complete the effect. If you look hard at my bike number 14 in the pic above you might be able to make out where the duct is. It has the edges bent down, in the pic you can see one of the edges under the brake line.

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[Sketchy_Racer]

Hey guys slightly off topic, but what do you think of this, I got my bucket on the dyno after some tweaking

H100
RS125 chamber (that doesn't work)
mild porting

[TZ350]

Inspired by TZ350 I have been looking over SAE papers,

...............and Whats This!!!!

"The drop in delivery ratio caused by increasing the crankcase volume can be fairly well compensated for by tuning the exhaust and inlet systems. "

from SAE Paper:- http://www.sae.org/technical/papers/670030

didn't Speedpro say this earlier?
.

I have just been reading that paper. What you say is true but it also shows that the ratio of 1.5 becomes more important as the rev's go up.

.

[TZ350]

Hey guys slightly off topic, but what do you think of this, I got my bucket on the dyno after some tweaking

H100
RS125 chamber (that doesn't work)
mild porting

That looks pretty promising, better than our GP's.

.

[Sketchy_Racer]

Thanks TZ, I have to say I have learnt a great deal from your thread and have throughly enjoyed the posts from yourself and SS90.

With my bike the majority of the work had already been completed by F5 dave, but looking at his old dyno sheets it looks like i've managed to extract a great deal more mid range which i was after and about 1hp on the top end.

I think once I have built a chamber to suit the motor exactly, 20HP will be very achievable, while keeping the nice power curve. I am yet to try different ignition timing as well, im sure more could be picked up with that too.

I would say that given this motor is a 100cc aircooled, that you 24mm carb on your 125 is the definite limiting factor on your motor. I have a 28mm, and am looking at going slighly larger yet.

[SS90]

Hey guys slightly off topic, but what do you think of this, I got my bucket on the dyno after some tweaking

H100
RS125 chamber (that doesn't work)
mild porting

It makes peak power for a very long time, I am of the opinion that it's a credit to the tuner(s)

It would be interesting to see it with a more suitable pipe...... do you know how many RPM an "established" fast MB100 engine revs to?

I just ask that because 11,000 is VERY high speed (in my opinion) Do you intend to have the engine rev to this RPM, or are you designing a pipe for lower RPM?

As we have discussed recently, 10 FTLB (13NM) of torque is quite a bit lower than can be achieved with a 100cc engine...perhaps your new pipe design can improve on this?

what changes have you already made to the RS125 pipe?

[F5 Dave]

Good result Sketchy, that is a heap stronger across the board. The pipe I had on it originally was a cock up but it was a fun bike, the 50 the serious one. It was my first pipe design with TSR sw & I was heading for supercross power as that seemed like a good idea for kart tracks. It was quite effective on those tracks, even if the power looked odd it fair launched out of corners, but more importantly it was an absolute hoot to ride. Thanks for not posting the old curves, I'm not hugely proud of them.

I later ran the bike with another pipe & barrel setup that I borrowed. It confirmed my original fear that any more power in that old frame made it pretty scary. Hence I needed to start again.

My RGV150 sleeved 125 made a similar powercurve using RS125 pipe. But was even flatter still, made ~19 & over 16hp for 4000rpm. Strangely it felt peaky on Slipway & I was faster on my 50. Odd huh?

PS the MB/H engine will last several seasons at those revs. (as long as crank built properly) But throw some new rings in every so often hey?

[Sketchy_Racer]

It makes peak power for a very long time, I am of the opinion that it's a credit to the tuner(s)

It would be interesting to see it with a more suitable pipe...... do you know how many RPM an "established" fast MB100 engine revs to?

I just ask that because 11,000 is VERY high speed (in my opinion) Do you intend to have the engine rev to this RPM, or are you designing a pipe for lower RPM?

As we have discussed recently, 10 FTLB (13NM) of torque is quite a bit lower than can be achieved with a 100cc engine...perhaps your new pipe design can improve on this?

what changes have you already made to the RS125 pipe?

I will aim to get the peak at about 10500 - 11000 RPM. As I understand it, the dip followed by the peak in the graph is caused by the chamber not working untill well after the porting has finished working at its desired RPM and as the RS Chamber I have has no modification at all so far, I think it's volume is far greater than what optimum would be but that as much as I know so far. When I look more into the chamber, I have a better understanding as to what was wrong with the RS Chamber and what I need to build. I am looking forward to building the chamber.

I definitely believe that greater than 10 FTLBs torque is achievable with the chamber alone, also we ran out of Jet sizes so I didn't get to find out if we were at the optimum jet size for power either.

Good result Sketchy, that is a heap stronger across the board. The pipe I had on it originally was a cock up but it was a fun bike, the 50 the serious one. It was my first pipe design with TSR sw & I was heading for supercross power as that seemed like a good idea for kart tracks. It was quite effective on those tracks, even if the power looked odd it fair launched out of corners, but more importantly it was an absolute hoot to ride. Thanks for not posting the old curves, I'm not hugely proud of them.

I later ran the bike with another pipe & barrel setup that I borrowed. It confirmed my original fear that any more power in that old frame made it pretty scary. Hence I needed to start again.

My RGV150 sleeved 125 made a similar powercurve using RS125 pipe. But was even flatter still, made ~19 & over 16hp for 4000rpm. Strangely it felt peaky on Slipway & I was faster on my 50. Odd huh?

PS the MB/H engine will last several seasons at those revs. (as long as crank built properly) But throw some new rings in every so often hey?

Thanks Dave,

I have changed very little from when you had the motor, most of it was case matching and just cleaning all the ports. The only thing I did modify largely was the head, It has a completely different profile and volume now.

And I knew that after riding the H100 Chassis once it was a dog and I needed to replace it. Although my RGV chassis still has quite a bit of work before it handles like it should. All in good time.

I didn't build the new crank but I checked all the tolerances and set it up in the cases all per the Graham Bell book. I did how ever put the balance shaft back in, as in the ally frame the vibration was phenomenal! After riding yesterday I am glad I did put it back in, much much smoother.

Do you think that your gearing may have been influencing the peaky feel on your RGV125 at slipway? In the wet (yesterday) my bike felt quite peaky, but I think that is due to me dropping out of the meat of the power and in the wet made it feel like it came on hard, but I think in the dry it will feel almost flat.

And yes I will be keeping this one up to scratch, It's only running one ring and I have the other one here to put in for a freshen up probably after this season if it doesn't shit itself (touch wood)

Cheers,

-Glen

[F5 Dave]

It is odd that my 125 felt peaky at Slipway, but really flew at Taupo & felt flat, like it was (if you remember I trailed you on your RS for a while in practice, . . . until you worked out where the handbrake was, - I don't care if you had an excuse, I'm taking it as a moral victory). I had super low gearing so no that wasn't an issue at Slipway.

At those (low) revs I wouldn't be sure if 2 rings would be any disadvantage. As usual the best way would be to test it, but I doubt there is much in it. I only run one on the 50, but it spins pretty fast.