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NO TOP END POWER

Posted: Mon Aug 23, 2010 3:41 pm
by bigstevey
Hi There
I have an alloy barrel 185 kit, I am using a 25mm PHBL with the following jetting:
120 main, 55 pilot, 50 idle, I am running a Sterling exhaust. The engine runs lovely and smooth but has not got a lot of top end power.
Any ideas gratefully received. 8-)

Re: NO TOP END POWER

Posted: Mon Aug 23, 2010 5:16 pm
by Skar
Has it recently lost power or has it always been like that? What kind of speed can you get out of it and what gearing does it have?

Re: NO TOP END POWER

Posted: Mon Aug 23, 2010 5:35 pm
by bigstevey
Its been like this since the carb was put on. I fitted the jets as per the Cambridge Lambretta jetting guide fro a 186 with an expansion pipe. It has LI 125 gears and it will do about 30 in top. I hope this helps :biggrin:

Re: NO TOP END POWER

Posted: Mon Aug 23, 2010 5:53 pm
by bsso78
Is it screaming when its flat out?

Re: NO TOP END POWER

Posted: Mon Aug 23, 2010 7:17 pm
by bigstevey
No it seems to be bogging down as if its too rich or something. :)

Re: NO TOP END POWER

Posted: Mon Aug 23, 2010 7:41 pm
by Skar
I'm no expert but that 120 main sounds way too big, pilot and idle are in the ball park though I think... try a 100?

/edit

Just found this, dunno what exhaust he had but it may be a starting point?
Just had my scoot on Dyno. I thought I'd share my settings for other 25mm users

53 choke
53 pilot
AQ262 atomiser
102 main
D22 needle (2nd Clip up)

I was originally running through a modified air box, but have now changed for a remote filter.

Re: NO TOP END POWER

Posted: Mon Aug 23, 2010 8:01 pm
by bigstevey
Fantastic. Yeah it does sound a bit big compaired to those settings. Thanks very much for your help.

Re: NO TOP END POWER

Posted: Mon Aug 23, 2010 8:08 pm
by rocho68
had the same problem , identical set up , ended up with a 98 main jet , try it , it worked for us !

Re: NO TOP END POWER

Posted: Mon Aug 23, 2010 8:20 pm
by bigstevey
thanks I will give it a go.

Re: NO TOP END POWER

Posted: Mon Aug 23, 2010 9:28 pm
by drunkmunkey6969
Rather than jumping from a a120 to a 100, for the cost of a few jets....try coming down 115, 110, 108, 105, 102, 100...etc...and keep it on whatever is the richest one it can stand.

Not sure what you mean by 55 pilot and 50 idle?? Im guessing you mean pilot and choke?

Any ideas on atomiser/needle/clip? Are you running a filter?