ESE's works engine tuner

[wobbly]

That is the acceleration rate in 6th gear for a KZ , if the run time is any shorter , the pipe does not heat up sufficiently to get repeatable results.
With the jet setup we use , the egt has hit around 520*C ( with WOT from about 8000 ) at 9000 where I start recording ,and if the main is correct for the weather it will hit 620*C by the end of the pull.
And as I said I can do 3 back to back and get the same final egt.
These numbers are also exactly what we see on the data , pulling out of a second gear corner at about 9000 , and in 6th down the shute pulling 14800.
If you dont have this scenario it gives rise to the issue that has plagued dyno operators forever " you cant run the same jetting on the dyno as at the track".
This is BS if the inertia/gearing/run time is correct.
In roadracing with a KZ ( close to a LSR run ) we can happily jet up over 650*C because the run time between peak torque and peak Hp is so short , and overev is used most of the time.

[F5 Dave]

Ah. Are KZs run on full tracks? I'm stuck thinking go-kart tracks with 30second lap times.

[wobbly]

Hamilton kart track has a mid 40s lap time and we pull 145Km/h on a good day.
Road racing on full circuits is a whole different class of racing.

[F5 Dave]

I've raced about ten kart tracks in NZ, but never been to Hamilton. Two wheels only.

[lodgernz]

I've raced about ten kart tracks in NZ, but never been to Hamilton. Two wheels only.

Andrew Stroud tried to get us in there. Not a chance.

[Peljhan]

We raced with 50cc on Grobnik Rijeka circuit in Croatia, and accelerations were like 30s long and we have 80% of the lap full throttle. Sometimes there is really strong head wind and I needed to shift from 5th to 4th on a straight because I only had 14hp. It is very different kind of racing compared to gokart tracks and I been with my bike on both.
https://www.youtube.com/watch?v=N2Trr21edn4&t=5s

[yatasaki]

14 hp is excellent actually

[TZ350]

Started digging out the eyebrow exhaust ports for the 250cc F81M pre 72 post classic racer.

Best run ever was 42 RWHP at 9,500 rpm with the single exhaust port version. It will be interesting to see if the eyebrows make a positive improvement. It could go either way.

[F5 Dave]

Rob that main port needs way more chamfer.

[TZ350]

Rob that main port needs way more chamfer.

Not finished yet, still more work to do. Main Ex timing needs to be opened up and port widened to get the needed STA.

I just had to show off my eyebrow tunneling. Did not think it could be done nicely, but it looks like it is going to work out Ok.

Speedpro helped a lot by making the initial eyebrow cut with his mill.

[SwePatrick]

Watch my space on the tube the coming days/weeks.
https://www.youtube.com/channel/UClY...NLN9TGXDqxr0EQ

I have updated my TZR250 (1KT) engine and will be searching for new higher numbers.
Longer rods with uprated bearings.
Reshaped crankhouse(welded and ported)
Reshaped heads for more possibilities to rev higher.
Larger injectors, might run methanol in the future.
Slightly increased timings
And ofcourse refurbishing, new bearings and new pistons.

[SwePatrick]

Assemble video out now!

[JanBros]

"very small amount" (of sealant on the crankcase)

@6:28

that is a lot of sealant
I only ever use so litlle, that I can still see the colour of the material under the sealant.

[speedpro]

I couldn't see what sealant you were using but I've experienced issues with using the incorrect sealant where it is contacted by fuel. I now use ThreeBond 1104 NEO plus. The spec sheet says it is suitable for use on fuel pump flanges. So far no problems. I got onto it after bumping into an ex ThreeBond employee at the supplier.

[TZ350]

.


150cc two strokes. Might be time to look at a F4 rule change to allow us two strokers to be able access more modern engines and regain some competitiveness with the fast four stroke guys.