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Vespa pinking

Posted: Fri May 18, 2012 5:30 pm
by jono
Hi help please, I have a newly re built P2 (1000 miles or so) all standard except JL and jetted to suit. Rode to southend at the weekend, heat siezed on the way there all ok after 5 mins, and above 50mph (1/2 to 2/3 throttle)it would pink badly so had to ride 100 odd miles at 45!! Thought it was a jetting problem as plug very lean, stopped at Kegra's (expensive) and up jetted it to a 122 then a 123 I think it has helped but not much. Any ideas please. cheers jono

Re: Vespa pinking

Posted: Fri May 18, 2012 5:43 pm
by bazman
What's your timing at ? May be worth retarding it and see how you get on.

Re: Vespa pinking

Posted: Fri May 18, 2012 5:54 pm
by jono
Sausage built it for me as a standard rally hack engine so 23 degrees I am guessing.

Re: Vespa pinking

Posted: Fri May 18, 2012 6:09 pm
by bazman
What type of jl pipe ?
I built a engine for mate of mine , with JL R/H thing heat siezed all the time , everything checked out ok but exhaust caused the problems!

Re: Vespa pinking

Posted: Fri May 18, 2012 6:16 pm
by jono
Yes right hand JL the reedspeed supplied version. barrell has got so hot it has melted the cowl !!

Re: Vespa pinking

Posted: Fri May 18, 2012 6:26 pm
by bazman
jono wrote:Yes right hand JL the reedspeed supplied version. barrell has got so hot it has melted the cowl !!
Funnily enough that happened as well !!
Although i ran one on my 210 malossi no problem, that's why i recomended it to him.
Have you another exhaust to try just to rule that out?

Re: Vespa pinking

Posted: Fri May 18, 2012 9:47 pm
by gaz_powell
i had the same when i built a p2 with a rebored barrel at 66.9mm with a rh jl put a 125 in it and was nipping , honed the barrel to 4 thou clearance ended up on 128 with the timing retarded to 17 deg but mate sold it shortly after so not sure what happened

Re: Re: Vespa pinking

Posted: Fri May 18, 2012 10:38 pm
by drunkmunkey6969
jono wrote:Sausage built it for me as a standard rally hack engine so 23 degrees I am guessing.
23 is toooo much, move it back.

Also seen a few problems with JL right handers.....got to confess I used the old 'rz' version with great success, but not sure now about the differences between the newer versions/copies. Some stiffle at top revs, almost like fuel starvation, some run hot....mixed results!

Re: Vespa pinking

Posted: Sat May 19, 2012 8:40 am
by jono
I can adjust the timming back and nab the pm from my wifes scooter, thanks for the replys.

Re: Vespa pinking

Posted: Sat May 19, 2012 4:35 pm
by gaz_powell
had the same with a revolver !