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Re: RB20 dyno

Posted: Tue May 12, 2009 1:26 pm
by ArKaTxU
shocky wrote:
RinB wrote: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
8-) in 3rd its ok.

Re: RB20 dyno

Posted: Tue May 12, 2009 1:41 pm
by RinB
I believe it is a 3rd gear run just wanted to clarify :)

Re: RB20 dyno

Posted: Tue May 12, 2009 6:10 pm
by carlos fandango
drunkmunkey6969 wrote: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 :oops:
I know Jerome prefers dellys to mikunis ,as they are "easier to manipulate" on the dyno

Re: RB20 dyno

Posted: Tue May 12, 2009 7:12 pm
by Bufficus
carlos fandango wrote:
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.:shock: I had nowhere else to go needle wise. I should add it is not a standard barrel.

Re: RB20 dyno

Posted: Tue May 12, 2009 7:25 pm
by carlos fandango
Bufficus wrote:
carlos fandango wrote:
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.:shock: I had nowhere else to go needle wise. I should add it is not a standard barrel.

:oops: My mistake it has a No. 6 slide not 4 :oops:

Re: RB20 dyno

Posted: Tue May 12, 2009 7:37 pm
by 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

Re: RB20 dyno

Posted: Tue May 12, 2009 7:55 pm
by Chutney Brownlove
carlos fandango wrote: 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?

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