RB20 dyno

[ArKaTxU]

Not bad out the box

One thing I query is your gear ratio 4.8 yet only get 68Mph @8600
Doesn't calc out ??

PROB A 3RD GEAR RUN

in 3rd its ok.

[RinB]

I believe it is a 3rd gear run just wanted to clarify

[carlos fandango]

What jetting are you running, and what was your Air/Fuel graph like? Did Readspeed discuss lean/rich spots with you or what jetting changes could be made? Top end power after the peak seems a bit rough, any further info?

Jetting tmx35
slide 6
57 needle top clip washer under
22.5 pilot
320 main

It is set up to run rich (safe), which i think is the reason for the bumpy peak?
Im not really interested in the figures (except for pub talk) I just wanted the carb set up, for piece of mind. the only difference from my set up was a 320 main for a 310 and a washer under the clip.
It still feel rich at quarter throtle.
my main concern after thinking afterwards was the flat spot at 5200 rpm, and what causes it?
A friend had his ts1 ( tmx35 & devtour) dynoed at diablos and he has the same flat spot.
So, is it the tmx, in particular the atomiser as this cant be change unlike the delly, or am i barking up the wrong tree.
This was my first dyno so had a lot to take in on the day, which is why i didnt ask Jerome
I know Jerome prefers dellys to mikunis ,as they are "easier to manipulate" on the dyno

[Bufficus]

slide 4

It still feel rich at quarter throtle.

I think that's why it feels rich at quarter throttle, the slide is possibly too rich.

A number 6 slide is used for most Lambretta applications.

I recently took the dremmel to a number 6 slide and removed more material on my TS1 too make it leaner at 1/4 throttle.

It was already on a 58 needle top clip, but was still too rich. I had nowhere else to go needle wise. I should add it is not a standard barrel.

[carlos fandango]

slide 4

It still feel rich at quarter throtle.

I think that's why it feels rich at quarter throttle, the slide is possibly too rich.

A number 6 slide is used for most Lambretta applications.

I recently took the dremmel to a number 6 slide and removed more material on my TS1 too make it leaner at 1/4 throttle.

It was already on a 58 needle top clip, but was still too rich. I had nowhere else to go needle wise. I should add it is not a standard barrel.

My mistake it has a No. 6 slide not 4

[Bufficus]

You could try a 58 needle and/or a smaller pilot if you're not happy with it. Perhaps it was set up rich for safety?

This chart is helpful.

http://members.value.com.au/jamesp/TMXneedles.doc

[Chutney Brownlove]

my main concern after thinking afterwards was the flat spot at 5200 rpm, and what causes it?

Don't all two strokes have a flat spot at around 5000rpm?