ESE's works engine tuner

[Greg85]

The KZ engine running ( illegal ) 12.7cc would have no overev power past 14,000, end of story.
The peak power generated would be used for such a short period as to be of little advantage during a lap.
Franco's factory engines all run 13.6cc to enable plenty of overev and much leaner jetting.
Running 12.7 I guarantee you would deto badly on track, and would need very rich jetting.
Using fuel to cool the squishband and not make power, is always doomed to failure.
Modifying the reeds, the exhaust manifold, the stinger , the porting and the head shape are easily capable of getting back the lost power from lowering the com.

Re the KTM 250 kart engine - this is still sitting on the workshop floor unfinished due to lack of payment.
Im happy to give you the EngMod file for it.

Thanks Wobbly for this information RE:you received my message inbox?

[peewee]

Straight in is OK Peewee. But don't continue the straight; use the biggest radius that you can fit in. You might take a look at the Aprilia head below to see what I mean.
If you have a head that will fit, try it before modifying it, or you'd be throwing away a chance to learn something.
The nooks and crannies I was talking about are too much squish clearance, a squish gap that does not follow the contour of the piston but radially opens to the outside of the bore, head gaskets with a bigger bore than the cylinder, a piston top land with too much radial clearance, etc.
Attachment 333945

well mine surely goes in straight more than just a little bit so im going to change that as i dont have a good feeling how it is now.

can you remind me again about your piston to head clearance thoughts ? seems like it was 1% of stroke i think. in the past ive done fine with 1mm on big singles but i missed the mark alittle on this latest head. from outer bore edge toward center i ended up with .93-.83-.99 (domed piston and straight squish band). .82mm would be 1% stroke. piston doesnt seem excessively heavy and rpm under load is only about 8k so i dont think theres a ton of rod stretch. and all bearings only have couple hours runtime so i consider them still in great shape

[DoldGuy]

Indeed, there are a lot of Mean Squish Velocity calculators available on the internet, but I haven't yet seen a single one that takes the dynamic stretch of a high-revving engine into account, and it makes a lot of difference whether your squish clareance is 0,6 mm or 0,06 mm. As a rule of thumb that stretch will be about 0,1% of the stroke, assuming that your crankshaft is sound. I agree with Wobbly: reduce the squish clearance until you are going to suspect that the piston may be kissing the head. Then there will be zero clearance and zero mixture in the squish band. And you won't get detonation if there is nothing there to detonate .[/QUOTE]


Found this by using TZ’s search recommendation....

Thanks TZ!

[Muhr]

Really good information, I'm going to start a little shy, then go bananas! Getting up to the RSA level is probobly many peoples goal(dream). It's just that it's damn far away!!!
I was thinking of the Van Veen

If I go whit the left web it will give 23cc more and same weight/balance factor

[Frits Overmars]

Indeed, there are a lot of Mean Squish Velocity calculators available on the internet, but I haven't yet seen a single one that takes the dynamic stretch of a high-revving engine into account, and it makes a lot of difference whether your squish clareance is 0,6 mm or 0,06 mm. As a rule of thumb that stretch will be about 0,1% of the stroke, assuming that your crankshaft is sound. I agree with Wobbly: reduce the squish clearance until you are going to suspect that the piston may be kissing the head. Then there will be zero clearance and zero mixture in the squish band. And you won't get detonation if there is nothing there to detonate .

Found this by using TZ’s search recommendation....Thanks TZ!

The 0,1% in the above text was a typo; not TZ's fault but mine. It should read 1 %. I can't edit that post anymore because it's too old, so please take care yourself: https://www.kiwibiker.co.nz/forums/s...post1131059758

If I go whit the left web it will give 23cc more and same weight/balance factor

With those flat inside web faces, that crank of yours is starting to look more and more familiar Muhr

[TZ350]

My totally un-shrouded crankshaft big end pin. An idea picked up from Frits's Aprilia crank and comments on crankcase volume.

Good cooling and lubrication with the added benefits of reduced wind-age as the con-rod passes between the wheels and extra crankcase volume.

The stroke is 48mm and the rod is 115mm C/C from a Yamaha RD400.



Other random engine bits from the Suzuki GP100, now 110cc with a dry sump gearbox, water cooling and a large RV cover from a Kawasaki KE175.

[Muhr]

With those flat inside web faces, that crank of yours is starting to look more and more familiar Muhr

I don’t know what you men! There is a crazy amount of weights on those cranks

Went through all the parts and realise I needed to make it a bitt heavier

My totally un-shrouded crankshaft big end pin. An idea picked up from Frits's Aprilia crank and comments on crankcase volume.

Good cooling and lubrication with the added benefits of reduced wind-age as the con-rod passes between the wheels and extra crankcase volume.

The stroke is 48mm and the rod is 115mm C/C from a Yamaha RD400.



Other random engine bits from the Suzuki GP100, now 110cc with a dry sump gearbox, water cooling and a large RV cover from a Kawasaki KE175.

Nice work! Allays great to get some inspiration and ideas

[F5 Dave]

To the Brains trust Inc.

I’m trying to avoid this, but I’ve been pulled into fitting an Ignitech to a TV200 roadbike. Based on the RG125/150 bottom end.

Last test is swapping out the alternator, but if not I have to dive in & cope with unknown Ignition & PV curves for an orphan machine, but you just can’t seem to get an RG/TV200 CDI.

RG150 CDI doesn’t run right it seems.
The bike has a 4 stroke stator setup with stator coils bolted to the side-cover & inverted flywheel on the crank all in gearbox oil.
My question is this:
How do you set up the static timing? Can’t think of anything that hangs out that spins at 1:1 with the crank. Take the cover off & the pulser coil goes with it.
This side of carving a hole in the sidecover & making marks on the flywheel how would you do it?
Anyone running an RG150 bottom end?
Nigel made a whole new CNC sidecover & would have undoubtedly put on a smaller flywheel arrangement so I haven’t bothered calling him.

[Yow Ling]

To the Brains trust Inc.

I’m trying to avoid this, but I’ve been pulled into fitting an Ignitech to a TV200 roadbike. Based on the RG125/150 bottom end.

Last test is swapping out the alternator, but if not I have to dive in & cope with unknown Ignition & PV curves for an orphan machine, but you just can’t seem to get an RG/TV200 CDI.

RG150 CDI doesn’t run right it seems.
The bike has a 4 stroke stator setup with stator coils bolted to the side-cover & inverted flywheel on the crank all in gearbox oil.
My question is this:
How do you set up the static timing? Can’t think of anything that hangs out that spins at 1:1 with the crank. Take the cover off & the pulser coil goes with it.
This side of carving a hole in the sidecover & making marks on the flywheel how would you do it?
Anyone running an RG150 bottom end?
Nigel made a whole new CNC sidecover & would have undoubtedly put on a smaller flywheel arrangement so I haven’t bothered calling him.

Isnt the clue in the word "static"

[F5 Dave]

Well I can dial gauge the piston but its relationship to the pulser coil is fairly parsimonious.

[Yow Ling]

Well I can dial gauge the piston but its relationship to the pulser coil is fairly parsimonious.

If you put a scope on the pulser coil you may get an indication when the pickup drops the trailing edge of the trigger bump as the flux collapses. if you print out a 360 degree strip and put it on the outside of the rotor you can read the numbers when you take the sidecover off without disturbing anything

[F5 Dave]

So like when a coil passes through a magnetic field. The passes bit is difficult. it would have to be done at least at some speed. If you could generate electricity Just by placing a coil in a field you'd solve the worlds energy problems.
I'd have to stop it at exactly the right place instantaneously and know that I had.

[speedpro]

Or have something like the FZR250 which is a threaded hole in the alternator cover. Inside the hole is an indicator pointer which lines up with marks on the rotor as it rotates. I'd have to have another look to be sure but IIRC there are 3 marks - TDC, full retard, and full advance.

[varthrix]

Hello everybody, I was going to refrain from posting until I had read the whole thread, but I'm only about 700 pages in and I have a question. Tee Zee, I saw the post about moving the ring positioning peg and that it went wrong, if you were going to do it again what approach would you pick to do it? I'm fiddling with an old Simson cylinder and to get more blowdown I need to move the ring positioning peg. I made a new cast iron liner with a bridged exhaust and currently that's what's stopping me from widening the exhaust for more blowdown.
Also I'd like to thank all the contributors, especially TeeZee, Wobbly, FritsOvermars, Speedpro and all the others for the great information on the thread.
Sorry for the stupid question but I couldn’t find anything with the search function, but it's probably my fault.
Greetings from Bulgaria.

[Frits Overmars]

I saw the post about moving the ring positioning peg and that it went wrong, if you were going to do it again what approach would you pick to do it?... Sorry for the stupid question...

Welcome Varthrix. Asking about someone's experience is not stupid; it is one of the smartest things you can do .