Hello all, can anybody help??? my ossa starts on 2nd kick, but will not rev at all.I have changed the float needle and needle clip as they were the wrong ones. Iv'e cleaned the jets and i have put 2 different petrol tanks on but still it will not rev. The needle is set on the middle groove, but i do not no if it is the correct needle for the carb, and cant find reference number on the part to replace it. I no the main jet is incorrect being a 120 but thought it would have run a bit better than it does. The engine sounds like it is being starved of fuel but it tickles ok.

(carb is a amal 627) thanks oggy

Starved of fuel is your problem - main jet should be 150/160

Pilot - 25

Needle jet - 106

Needle on middle groove

Amal mark 1 concentric has only one needle type for the 2-stroke carb. There is a different length and taper needle for 4-stroke. Unlikely you have the wrong needle.

Is that Mr Moody ?

cheers woody the needle jet and the pilot jet are correct just was'nt sure with me finding 3 things wrong in the carb.

Have you got a measurement for the needle so i can check it is the correct one as if it is wrong i can order one with the main jet.

Also can you please advise me 150 or 160 on the main jet and how many turns to set the mixture screw at. thanks oggy

I think the Ossa is a 160 and Sherpas were 150 although I doubt you'd notice any significant difference between the two. Without the manual I'm going from memory but I'm pretty sure. You may find the size if you search the twinshock forum as it has been posted before.

I don't have the measurement for the needle without having one of each side by side and it will be a few days before I can do that, assuming I have a spare as my BSA is elsewhere at the moment.

If you have to order the main jet anyway, Id just order a new needle and needle jet as well for peace of mind that you don't have wear in either of those two components, otherwise you may be putting a new needle into a worn jet.

Pilot scew is personal preference really so I'd start off with one and half turns out.

thanks woody i will order them tomorrow do you know if hitchcocks will have the needle

hitchcocks will have the lot I've had great dealings with them in the past and they've never let me down.

tell them what the stuffs for and they will probably have a note of what you'd need. now the things in bits dont spoil it for a bit of tar get everything ( floats slide etc etc) then you know the job is right

Hitchcocks, Surrey Cycles, Bultaco UK, Sammy Millers, you can take your pick really, they should all have the parts in stock.

thanks for the advice i will get the new parts and let you know how i get on.