Have been having a few problems with my bike since i got it a couple weeks ago.

bike will run 100%, but then will not tick over, when you start it again, it dies, then will not evan try and fire up.

replacing the plug cures it. until it feels peckish - and eats another plug!

was leaving the plug really oily, so;-

reset fuel screw to 3 1/2 turns out.

reset timing to original marks (was very advanced - previous owner used it to follow his son around trials, so had it advanced for better top-end.)

using silkolene comp2 premix - 60;1

today had same symptoms - but plug was not 'oiled-up', instead was black, and rather 'sooty'.

any ideas on where to start trying to track the problem down?

ta for any help

You could turn your fuel screw in more.

There's no number for this...just what works.

If you are still blackening plugs, you have to look at leaner jetting.

had a gasser contact that was like this, to cure the oild up plug we replaced the crank seals. (this might not need doing on yours) and the timing was out, the woodroof key sheared off, check that in the flywheel side, as this was the main prolbem with ours.

First the timing. Advanced means more bottomend, less topend.

Then the oil/fuel ratio: you can go leaner on the oil, try 80:1.

I run mine at 100:1.

Then the idle jet/needle and mixture screw. Turning it clockwise(in) leans out the mixture. Out means richer/more mixture.

Needle start point is 2nd clip from the top notch. The idle jet cld be 33 till 36

good luck

Ps: yes make sure your airfilter is clean and well oiled(not excessive). Cleaner is more air for the motor, better performance normally.

Edited April 4, 200521 yr by gasgas

100:1 thats dangerously lean isnt it!

i would never go more than 80:1

James

with nowadays synthetic 2-stroke oils it won't be a problem, but.. if yr doing roadwork, so yr revving the motor for longer periods i wld recommend going for a little more oil.

A lot of riders are now using bio outboard motoroils, lubing 1%.

I just lug the motor from one non-stop/trainings corner to the other. Using more oil only fouls my plug. Offcourse i cld go leaner on the jets to generate more engine heat but that makes the bike a little more jumpie.

Anyway there are more ways to a best set up, it is rider dependable in my opinion.

Another thing that should be checked before you start changing jets and things, is to make sure the exhaust is not clogged up with carbon or oil.

BTW, what kind of plug are you using? Fine wire plugs, like a platinum or gold palladium(sp?), are a little more foul resistant than the regular ones. Of course, they cost quite a bit more, too.

Good Luck, Bruce

i'm using ngk bp5es

i think this is the right plug anyway - but mainly i use 'em cos i can get 'em dead cheap!

Yeah, that should be fine.

On your gasser you should be running 62.5 cc's (ml) of oil to 5 litres of fuel. My dads got the same bike but a couple of years newer and he runs it on 70cc's (to be safe!) That wot gas gas uk recommended at the time so dont worry

Only use Fully Synthetic oil aswell, I personnally have always ran Motul 600 in my Gas Gas and its 100% deposit free and also use super unleaded fuel

Regarding Spark plug, BPR 5ES you should use coz its generally the best.

Other than that... Dunno