ESE's works engine tuner

[husaberg]

went out to brian thomas work shop today , i saw a 50cc Kreidler he had build ....yummmy! here is a link to some stuff he has built

http://www.themotart-journal.com/201...ollection.html

Was Brian Thomas the one that did the demo 250 Manx........

[mr bucketracer]

Was Brian Thomas the one that did the demo 250 Manx........

yes and a desmo bucket racer

[Frits Overmars]

No two-strokes anymore, but you may want to watch the Spanish MotoGP just the same: http://cricfree.tv/bt-sport-2.php

[richban]

No two-strokes anymore, but you may want to watch the Spanish MotoGP just the same: http://cricfree.tv/bt-sport-2.php

A few 2 strokes on track yesterday. Both the 300 Honda's were out and what do you know a Wobbly RZ400. Not much in it with the fast 300 but still the RZ had the legs. My bike is maybe 15hp down but the rider still needs work. The F3 field was really good. Some cool bikes out and more to come from what I here.

It is really like stepping onto a 80hp bucket. Well a heavy and does not turn as good 80hp bucket. But does do wheelies and power slides.

[Drew]

Was it Rob on the Wobbly thing? Big South African dude, top guy.

[jonny quest]

Most us cut the squish angle of our heads on the lathe. With a domed piston which is a radius... the squish angle is slightly mismatched being a straight angle.

Any performance benefit to CNC the head squish to match piston dome?

[Muciek]

There was one guy in Czech republic who tuned a moped engine to get he's degree at university and he done this kind of tests, here are the results Blue line piston angle same as head angle and red line domed piston and straight angle head and 2nd picture modified piston to get same angle as head.

[wobbly]

Rob on his RZ400 has finally got to tune it and was able to keep it under 1200* all day - a first.
His bike is way heavy compared to Andys or the 300s as it has stock wheels etc, but very trick RT suspension.
The needles in the Smartcarbs are still not "right" as Rob has resorted to sanding the things to change the Jets as such.
Now he has control of the temps we can start looking at getting it back to 1250* where it makes alot more power.

[Ocean1]

Most us cut the squish angle of our heads on the lathe. With a domed piston which is a radius... the squish angle is slightly mismatched being a straight angle.

Any performance benefit to CNC the head squish to match piston dome?

You don't need CNC gear. Just organise an adjustable tie-rod with standard rod-ends mounted between the tailstock and the cross slide.

Adjust the length to match the piston dome radius, lock the tailstock and engage the cross slide feed. Done.

[wobbly]

The squish following the piston shape by using CNC is even more important if you are pushing the limits with around 50% SAR and very tight clearance.
This also works together with the sharp edge into the bowl, and I suspect that if the tests shown were done with all this in mind the difference in performance would have been even greater.

[richban]

R
His bike is way heavy compared to Andys or the 300s as it has stock wheels etc, but very trick RT suspension.

Yeah they get really Heavy with the amount of Fuel you need for 10 laps. Mine is no feather weight. Stock wheels and all. About 120kg. Then add 7 litres of gas. Then add me. 100hp would be nice actually.

[jonny quest]

I'm waiting on some parts... won't be able to test for a few weeks. .. but for those still dyno ing right now. .. here's something to try.

About 5mm from end of squish pad, close to bowl... on squish pad.... machine a groove about .015" thick and deep.

This acts like a "trip" zone to help with turbulence. .. along the same lines as the sharp edge leading into bowl.

[Bert]

Yeah they get really Heavy with the amount of Fuel you need for 10 laps. Mine is no feather weight. Stock wheels and all. About 120kg. Then add 7 litres of gas. Then add me. 100hp would be nice actually.

You (and Speedjunkie); did bloody well all things considered.
Given where you started on Saturday afternoon (with your bucket producing more power)...

It was a great turn out of two strokers overall with a number of 250s down the pack.
I have to congratulate VMCC for there 90s carb class, it seems to be a great formula.

[wobbly]

Slots in the squish band = no free lunch = more unburned end gasses = less power = waste of time.
Been there done that.

[jonny quest]

It works on the 4strokes.

I use to build 2 stroke exhausts for a living. I was put out of business by the 4 strokes in the MX market. ... I may get whipped for saying this here... but glad I did. Business has quadrupled because of all the extra moving parts.

I taught myself how to make cone pipes. ... spent the last year teaching myself cam design. It's a lot easier grinding a cam than cutting, hammering out a pipe. (Labor wise)

But I bought myself a fun little 2 stroke to play around with again. A newer CR125. Having fun playing. ... and it really is amazing how that technology applies to both.