ESE's works engine tuner

[TZ350]

OK ...... I am up for two Honda RS125 17x2.5 fronts and two 17x3.5 rears.

Failing that two matching 3.5"x17" fronts from the Suzuki GSXR range or Honda CBR for adapting to the back of the Beast.

Good idea using a front on the rear, thanks Husa, Rich, Sketch and Kick for the heads up.

[gav]

OK ...... I am up for two Honda RS125 17x2.5 fronts and two 17x3.5 rears.

Failing that two matching 3.5"x17" fronts from the Suzuki GSXR range or Honda CBR for adapting to the back of the Beast.

Good idea using a front on the rear, thanks Kick.

I'm surprised you havent built your own carbon fibre wheels yet? sheesh ...

[TZ350]

Interesting clip on pipe building, I often wondered how they get those nice neat welds.

[Kickaha]

Interesting clip on pipe building, I often wondered how they get those nice net welds.

The guy who did my chambers for Superkart did them the same way, the pipe on my Bucket was as well

[F5 Dave]

Yeah I was going to mention Eric Buell bought the whole shooting match off Barton. Found out everything was pretty crap & tried to make it work. Obviously desperation made him rethink the situation & make bikes with sewage pumps.

[Farmaken]

So this is where I am up to so far, Butterfly valve seems to be a long way from the header ID so plan B is to make up a spool valve like a Yamaha power valve and fit it in the same place as the collar which is currently on the header so that the OD of the spool is flush with the header ID when closed .

[TZ350]

That looks good, great to see the pictures, I am looking forward to seeing how it goes as I want to try making one myself.

These Honda ones seem to have the blade opening across the pipe and others in line with the header. There also looks like a small distance between the header and butterfly.

I remember Frits said its best to have the butterfly blade opening in line with the pipe as you don't want it disrupting the gas flow or getting over heated.

Opening the blade across the flow would have three big disadvantages. It would be much more of a disturbance to the flow, it would heat up the blade much more, and the flow colliding against the protruding half of the blade would constantly try to rotate it. As the flow direction is alternating so close to the cylinder, that would mean a constant hammering on the governing mechanism.

[bucketracer]

As I heard it and subject to offical confirmation.

The tide might be turning.

2-Strokes in the points racing at Mt Welly yesterday, and about time .....

The Dominic Howe was won by Dave M riding an MB100 powered RS50 prepaired by Speedpro with a 25hp 80cc stroker runner up.

And F5 was 2-Strokes 1-2 all day long.

[TZ350]

Got the head off tonight.



Doesn't look to bad in there.



Carefully re checking the squish.



And it looks like 1mm.

So the trick is to figure out how to take 0.4mm of the top of the barrel for 0.6mm static squish.



Also checked the timing to see whats needed to get the Ex opening 80 ATDC and the main Trans opening 116 and sec 114 ATDC.

[TZ350]

The EngMod2T files for STA's, Ex and Transfers for those that are interested in such things.

Even with a crazy big 38mm inlet port in this model, its still the inlet port thats limiting the power possible and even more so with one suitable for a 24mm carb.

I had a quick look at the 3Ex GP125 in Engmod.
Lifting the main Ex to 80* needs to have the B,C transfers lifted to 113.8* to get the STA near balanced again.
It will then have staggered Ex plus reverse staggered transfers,Mr Thiel would be proud.

With the finished cylinder, I will be aiming to follow Wobs advice on timing and squish best I can. But 113.8, I can't read 0.8 deg on the the deg wheel so the result will just have to be the best I can manage.

[dinamik2t]

Why use the degree wheel TZ? You can use the direct mm distance EngMod gives, 37.7mm. Take into account any pos/neg deck height, draw a line or place a barrier into the cylinder and port it that way.
I think it's pretty easier and much more accurate when measuring with the vernier or depth calipers!

On the other hand, I am not sure what's the best way to determine a cylinder's timing. Is it the exact distance from TDC, as ported above or is it where, lowering the piston, you get a glimpse of light out of the port?

A large degree wheel would be the best, by the way:

http://image.mustangandfords.com/f/3...gree_wheel.jpg

By the way, is it ok to reveal the tuned length of the piranha pipe?

[Buckets4Me]

Why use the degree wheel TZ?
A large degree wheel would be the best, by the way:

http://image.mustangandfords.com/f/3...gree_wheel.jpg

I think they have already started filing the crash knobs away to fit the larger degree wheel

[twotempi]

What would the result be with a 100cc engine ,watercooled, with no carb size restriction.

Is that potentially a better all-round configuration ??

[F5 Dave]

Certainly it is the option Mike's MB100 is with great results (head only wc so far). Has been probably the most common F4 GP winner historically, though maybe not all WC, but plenty were.

Many were Kawi or Suzukis with home WC or RG400 barrels grafted on.


Sadly my first attempt 16 years ago leaked into the triple port due to duf welding (not mine, but might as well have been me learning).

[Buckets4Me]

What would the result be with a 100cc engine ,watercooled, with no carb size restriction.

Is that potentially a better all-round configuration ??

no one has got more than 30 H/p from one yet (that I know of)

and starting over again with a new engine (what would Burt have said)