ESE's works engine tuner

[Frits Overmars]

Better way to do it is to use a flat plate of clear plastic. Using a thin wipe of grease glue the plate to the head surface and using ATF fill it to the top of the threads.
Clean it up and repeat turned over with the plug in , and a plate with a hole in it.

I use a perspex plate with two 5 mm Ø holes in it, about 15 mm apart: one hole to administer the oil, the second hole to let the air bubble out. It's much easier that way.

[sniemisto]

Oh boy, I haven’t tough enough about head volume accuracy needed on 50cc calculations, even how easy it is to see with simple calculations.

I have just placed head upside down with spark plug in place. Sealed plexiglass with grease, then filled through hole by pouring hydraulic oil with 5ml syringe.

I have made assumption that excluded squish volume is about same as piston dome top. That is very rough assumption and off course not true.
My 4cc head is something else in reality.

Now I need to buy burette and measure true head volume from assembled engine like you described.


I need to correct that 80C egt temp drop was mainly done by jetting up main from 120 to 128.
Advancing ignition did slow down egt rise, but on long 6th gear run it still end up almost same 680C as with more delayed curve.

[Muhr]

I have lived in the belief that cavity / protrusion take each other out on a spark plug. Maybe not the case?
In any case, it is more important to have your method and have it as a reference
when trying different things. Buying an expensive tool is definitely not a must but makes it quite easy.

[F5 Dave]

Make sure you bolt the barrel down as small engines have through bolts rather than base studs.

[wobbly]

Thanks Frits , great to learn something every day.
Guess I will be drilling a second hole in my prespex.

[speedpro]

I used syringes of oil and measured the plunger travel with calipers. Accurate enough for me.

[wobbly]

Yea well SpeedPro , the engines you were dealing with would not even notice 0.5cc either way.
A 50 + Hp 125 on the other had will self destruct instantly with that sort of error if it wasnt for airport weather stations ,egt and deto datalogging.

[Muhr]

Make sure you bolt the barrel down as small engines have through bolts rather than base studs.

Thanks for your reply, 3,2cc head is thing that I like to test also.

And it can be really problematic with these through bolts when you start raising the compression. on the motor in the picture, we first pulled out the threads on the nuts and when we changed to stronger, we pulled out the threads in the block after which we had problems that the stud bolts stretched. Finally we put helical threads and made new stud bolts M7 (original M6) in SS 2242 (AISI-SAE H13)If I remember correctly.

[speedpro]

Yea well SpeedPro , the engines you were dealing with would not even notice 0.5cc either way.
A 50 + Hp 125 on the other had will self destruct instantly with that sort of error if it wasnt for airport weather stations ,egt and deto datalogging.

True. The engines weren't particularly highly tuned although the last one started to head in the right direction. I did get repeatable results, and always took at least 4-5 separate measurements. Variation was easily less than .15cc

[TZ350]

Yea well SpeedPro , the engines you were dealing with would not even notice 0.5cc either way.
A 50 + Hp 125 on the other had will self destruct instantly with that sort of error if it wasn't for airport weather stations ,egt and deto datalogging.

Its true, Buckets are not at the very pointy end of development but SpeedPro was the first to make a verified 30 RWHP. He did it with a Honda MB100 commuter bike engine. Output was tested on Team ESE's dyno jet dyno.

[wobbly]

Not a critic of SpeedPro at all - i was involved in some of his projects and he always produced fine work.
Just my view is you use a hypo if you cant afford/justify a burette , and you use a burette if you cant afford/justify a digital titrator.

[andreas]

Does someone know about chassis geometry/tuning? Or what's relevant for turning. my bike wants to go straight, I have to pry the bars out in all corners or I have to lean over (quite drastically). This can be a tire issue? Or something else that can be altered?

[husaberg]

Does someone know about chassis geometry/tuning? Or what's relevant for turning. my bike wants to go straight, I have to pry the bars out in all corners or I have to lean over (quite drastically). This can be a tire issue? Or something else that can be altered?

Raise the rear lower the front put on a sharper profile front tire and or smaller front wheel lower profile or a narrower tire. Experiment with a higher front pressure. Shorten the wheelbase. Take off the steering damper or set to zero.
Buy the Foale chassis book or the Bradey book or any of Camerons books.
Countersteer as well.
but anything you can do to lessen the trail will help from what you describe.

[wobbly]

Drop the forks thru the tripples to lower the front.
Next big change is to reduce the trail with different tripple offset and/or change to a lower section height front tyre ie a 50 down from 60.
Lifting the rear is last ditch , as it affects the squat geomerty.

[andreas]

Aha, thanks Husa, indeed the bika came with a jack up kit at the rear, and the front end was dropped about 10mm. I set it back to standard because I hated the riding position, even lowered the rear some, and the changes in handling from this was too small for me to notice. The tires are Pirelli supercorsa, and I'm inclined to think a narrower front will help some. The Foale book, i'll try and find it.