Can any one help please? I have just acquired a 1993 contact 320 which had been laid up for a couple of years. I have stripped and cleaned the carb, added new fuel (15ml in 1 litre as advised by Gas Gas) and fired it up. It starts first kick now and it runs pretty well, however it takes a while to for the revs to drop off once the throttle is closed. Is this typical or can anyone shed some light?

I'm guessing a partially blocked pilot jet or air passage in the circuit, or an air leak from the rubber manifold, or the flywheel side crank seal.

 

This is the usual suspects when a bike has been standing. I note you have cleaned the carb but it's best to double check, Sometimes an ultrasonic clean or soaking the jets in chemicals is the only way to clean them properly after a lay up.

Hi Steve, revisited the carb today after your suggestion and found a completely blocked idle jet. I hadn't seen it before and where as the other jets were gummed up with oil from the evaporated petrol, this was solid. I managed to unblock it with a strand of wire from an old brake cable. Needless to say its running a lot better! I also changed the trans oil, I put 650 ml (putoline light gear oil) in as suggested by a gas gas guy on you tube. Do you know if that's correct only I drained 800ml approx?

Regards

Mark

Around 625 to 650 is right, It's the same bottom end as the early air cooled bikes and was used through the txt range till 2002.

 

Bottom End Is also used in the Pampera, JCM and Alfer bikes. (Iv'e got 2 spare engines for my new project).

 

Putoline light oil or 5w30 mineral oil is fine if you can get it. Dont use ATF in these boxes though.