ESE's works engine tuner

[TZ350]

If you look at the the torquecurve, suspiciously flat huh?

What shape were you looking for, we favor a flat curve when we can get it. Looking forward to seeing your new curve when you have the dyno clutch sorted.

Fitted a new pipe and with a little bit of fiddling found some nice wide horsepower. Rob's suggestion to increase the air correction jet diameter and up the main worked a treat.

Attachment 317487

Attachment 316551

There you are, 30hp and a good spread of power, a usable 4,500 rpm. Not bad for 70's technology.

Attachment 316090

This is my Suzuki GP125 in its 28hp and pumper carb days, those long flat 2T torque curves are a common feature for the GP.

[Yow Ling]

Hi guys. i have recently(today) rooted my kr150 cylinder and piston. i put the piston in backwards and the rings got a little intimate with the exhaust port.(im sure you can imagine what that does to the cylinder wallAttachment 317616Attachment 317617Attachment 317618) i have one option of resleving the barrel. have any of you done this before. whats involved and what sort of sleeve did you use. i have a friendly engineer neighbor so that makes doing the sleeving a little easier. what do you think?
or... is there any kr150 engine bits or parts bikes for sale around?

Cheers Harry

Hi Harry, you need to mention this is an early moder KR150 , the one with wire wheels.
You have a few options, buy a new cylinder from Malaysia, Indonesia or Thailand, Get it welded and replated , get a second hand one, last resort would be sleeving it. There is a guy on KB in New Plymouth that has or had KR's his user name is ride life or something his name is Alex

[husaberg]

Hi Harry, you need to mention this is an early moder KR150 , the one with wire wheels.
You have a few options, buy a new cylinder from Malaysia, Indonesia or Thailand, Get it welded and replated , get a second hand one, last resort would be sleeving it. There is a guy on KB in New Plymouth that has or had KR's his user name is ride life or something his name is Alex

Scotts brothers Bucket is based on a KR bottom end he may have a top end
looks like that's already sorted elsewhere as you were.

[SwePatrick]

What shape were you looking for, we favor a flat curve when we can get it. Looking forward to seeing your new curve when you have the dyno clutch sorted.

Yes a flat curve is what to wish for.
But i thought the abrupt stop in raising torque to an almost flat curve is a limiter.
And when i anlyzed the dyno rpm curve against the engine rpm curve i saw that, gear ratio altered from 10.3 to 10.6 just in the area where the curve flattens out.

'Locked' the dyno has gear ratio 10.3, no slippage.
This means when engine is revving 10300rpm the dyno revs 1000rpms.
And when slippage occur the engine revs 10600 and dyno revs 1000rpms.

A small value maybe, but it makes it 'not correct'.
I will sort this out and make a pull again to se what it does without slip.

rgds
Patrick

[ken seeber]

More Ryger thoughts. Reading a bit more about HCCI, perhaps there is some possibility that the rate of compression might be a factor. So then I got thinking about the recent Honda 2 stroke patent.



What is that complex mechanism for, why not a simple crank? So we scaled the Honda drawing, chucked it into Solidworks, scaled the stroke to 54.5, such that we could do a direct travel vs piston travel comparison with an engine (Ryger?) that has the 54.5 stroke, 90 rod and with no significant offset of the cylinder axis or piston pin.



From this, it can be seen that one side of the travels are almost identical, but there is a significant difference on the other side. Maybe this difference is what Honda was trying for, assuming (yes I know another assumption) that it was beneficial for some reason, maybe HCCI or ATAC. As the direction of rotation, it could be that the side of the Honda engine, that shows the sharper rate of travel, represents the compression stroke ie, read the plot from right to left.


Anyways, 31 days to go, unless Wobbly gets some advance info.

[tjbw]

More Ryger thoughts. Reading a bit more about HCCI, perhaps there is some possibility that the rate of compression might be a factor. So then I got thinking about the recent Honda 2 stroke patent.



What is that complex mechanism for, why not a simple crank? So we scaled the Honda drawing, chucked it into Solidworks, scaled the stroke to 54.5, such that we could do a direct travel vs piston travel comparison with an engine (Ryger?) that has the 54.5 stroke, 90 rod and with no significant offset of the cylinder axis or piston pin.



From this, it can be seen that one side of the travels are almost identical, but there is a significant difference on the other side. Maybe this difference is what Honda was trying for,

....

Nice work Ken.

Did you notice that the Honda con rod remains almost vertical throughout each rev, so piston sidethrust must be low too. But I wonder where the red line would be.

[Flettner]

Ok Frits, how are we going to build a continuous fuel injection system, not pulsed.
The old Hiborn mechanical fuel injection was crude at best but if we were to put a electronically controlled needle valve in place of the return "pill" it could work? Or as you have suggested a DC motor driven by pules width modulation.

[gravmax88]

Ok Frits, how are we going to build a continuous fuel injection system, not pulsed.
The old Hiborn mechanical fuel injection was crude at best but if we were to put a electronically controlled needle valve in place of the return "pill" it could work? Or as you have suggested a DC motor driven by pules width modulation.

KE jetronic as used by Porsche etc or a variation.......

[Flettner]

We can do better than that can't we? I don't like the big choke thing in the inlet. I guess we could just use an airflow sensor now?

[ken seeber]

Did you notice that the Honda con rod remains almost vertical throughout each rev, so piston sidethrust must be low too. But I wonder where the red line would be.

You’re right tjbw, the rod angularity is small reducing piston side thrust friction.
There are also lots of other observations about the engine:
1. It is very under square, with a bore/stroke ratio of around 0.45:1
2. The above means that the combustion chamber can be more favourable in its shape to achieve a smaller surface area/volume ratio, enhancing efficiency.
3. It does feature a spark plug, maybe indicating that it needs this to start, something the Lohman 18 cc seemed to struggle with
4. Extremely ordinary scavenge passages, maybe not an issue with the low speed, long stroke, uniflow design
5. Crankcase compression ratio of almost zero
6. Crankcase seems to have lots of nooks and crannies for lub oil to hang up in.
7. Put a bit of effort into the cooling of piston ring belt at TDC
(with the liner being “wet” at this level), maybe because there is zero cooling of this at BDC
8. Looks to be a low speed (around 3000 rpm tops) industrial engine and expensive to make
9. Maybe, if it is ATAC, they have just gone full on to achieve the lowest BSFC ever.

[tjbw]

Re Vegas - here is some cut and paste from a report on the result I did.

We were top 3 fastest thru all the sessions,

.......

I took the deto gauge off the dyno and ran the 0-5V output into the Pi datalogger, and was very surprised to find that after leaning down enough to get hits, that the only place
it deto'ed was the acceleration phase after 2nd, 3rd, 4th gearchanges, when dropping back to near peak power after overeving to 12200.
The 5th to 6th change stayed above peak power and didnt deto at all down into the shute.
So I fitted the new header with the deto button installed and the gearchange deto dissapeared completely.
That allowed another 3 jets leaner before it started again.

Get this - the egt at that level was 1390* F with no sign of deto or piston heat stress.
This is due to the fuel octane being too high for the com, and the fact that the SKUSA advance restrictor plate doesnt allow us to add enough static timing to create more power - only pipe heat.

I think I have worked the logic of the deto button - it creates turbulence in the top 1/2 of the duct, allowing the smooth flow along the floor to return easily up the duct and be aimed upward off
the ski jump at the closing Ex port.
This came from finding that having the floor of the oval/round transition spigot co linear with the duct floor, and all of the transition angle in the roof made best power.

So here is the jetting chart prior to adding the new header, based on safe deto level, not egt as I would usually use.
The Lambda ( in the muffler ) showed the kart was fastest at 13.8 :1 ( and it hardly varied anywhere within the usable power band ), going leaner or richer was slower on track.
We tested both VP C12 ( 108 octane ) and VP98, the 98 being both faster and easier to tune to the edge.

Wobbly, thanks for Vegas report, and well done.

What would be the effect of the det mushroom on egt at the det mushroom location if you didn't change jets?

I think local egt would increase, and mixture returned to the cylinder would be warmer, this combined with the turbulance you mentioned resulting in a more homogeneous mix.

[Frits Overmars]

Ok Frits, how are we going to build a continuous fuel injection system, not pulsed.
The old Hiborn mechanical fuel injection was crude at best but if we were to put a electronically controlled needle valve in place of the return "pill" it could work? Or as you have suggested a DC motor driven by pulses width modulation.

I developed the continuous injection idea for a 6,5 cc model engine that revs past 35.000 rpm, so no chance in hell that I would ever find an injector that's quick enough. I decided upon a gear pump driven by a pulse width modulated electromotor and a spring-loaded injection nozzle that I posted here before. As flow sensors, MAP sensors, Lambda sensors and the like are all too big for this engine, and as it's an unthrottled (always WOT) engine, I planned to use only an engine rpm / pump rpm lookup table. Crude as this would be, it would be an improvement on the present carburation system that depends on a pre-set (before flight) needle and exhaust pressure.
Of course such an rpm/rpm lookup table is totally insufficient if you want any throttle control and rideability.

[Yow Ling]

Ok Frits, how are we going to build a continuous fuel injection system, not pulsed.
The old Hiborn mechanical fuel injection was crude at best but if we were to put a electronically controlled needle valve in place of the return "pill" it could work? Or as you have suggested a DC motor driven by pules width modulation.

why not just pwm an injector ?

[TZ350]

A couple of years ago I copied down a long and very interesting thread on the restoration of a Saxon-chassis TZ from the NATS forum. I was given permission to put a copy of that PDF file on my website so that everyone can download it.

http://www.eurospares.com/graphics/c...axonYamaha.pdf

It is about 22MB in size.

cheers,
Michael

Interesting Post/Link.

[TZ350]

I developed the continuous injection idea for a 6,5 cc model engine.

An Ecotrons EFI system for really small engines:- http://www.ecotrons.com/products/uav-engine-efi/