19 replies to this topic

[BenBeta23]

PeterB, on Sep 24 2009, 11:33 AM, said:

Hi Ben,
On my last 3 PRO 300's fitted with a Keihin carb, they always run lean with the std factory setting and pink as you found out. I use Shell V power at 50:1, nothing fancy just high octane in this part of the world. You need a larger main jet, 127 or 128. Clip on 2nd notch from bottom, std slide I thought was 35 - can't remember. JJH needle is ok for the younger splatt attack lads, GJH needle gives vastly better low end control for more, er mature riders! 45 I find too rich for pilot, use a 40. Use an Iridium plug, won't foul up.
The Keihin has no internal fuel filter, best to have an inline one fitted. Give the carb a thorough clean out just in case. Pilot (air) screw on the Keihin should be around 3/4 to one turn out, DellOrto pilot is 3.5 to 4 turns out.
Ta ta, PeterB.

Thank you very much for the advice. will give it a go.

[howie314]

Hi,

if you look for TXT engine knocking in another thread I have been having similar problems, different bike but same problems.

After three weeks getting nowhere i have boiled my problem down to oil:fuel ratio.

I was running 40:1 and managed t stop it pinking by going really rich everywhere.

Today i tried the bike with 80:1 and am now back to stock jetting and mixture screw.



As in my case you should be able to jet it to stop but will end up pretty rich.


My advice would be to try different fuel:oil mixes.

Not sure what others say, but 98 petrol is the only thing i use, preferably shell optimax.


hope this helps

[howie314]

I am assuming its two stroke of course, just re read the post.

Dobt it will help you much f its not lol.


cheers

[laser1]

Does your bike have a high compresion head? Will need higher octane if by chance it does.

[BenBeta23]

laser1, on Sep 24 2009, 11:52 PM, said:

Does your bike have a high compresion head? Will need higher octane if by chance it does.

It has an S3 racing cylinder & piston which is a higher compression cylinder, my dad says it has something to do with that, but not sure.