Sonic Carb

[nellyp]

Hi all, I have no fuel going from my tank to the carb. I have removed the supply pipe (I think) and there is nothing coming through. There is a connection under the tank that looks like an advance and retard on an old distributor, from there a pipe goes to the left side of the carb. That pipe looks like it has come off, I have tried to reconnect it but it looks like the pipe bore is too small to fit on the carb connector. Does anyone know what the pipe is for? There are 2 pipes coming off the valve at the bottom of the tank the other one goes to the other side of the carb and that is the one I took off as it looks like a feed. i weas hoping that under the tank would be a filter and that could be the metal (advance and retard looking) fittment. I kind of assume most filters on bikes are transparent but like I said this could be a filter. My life would have been so much easier if it was a blocked filter, but now my bike is in bits again. I do enjoy it because I like to see where everything is, but ohh for a manual. What woulod be perfect would be if one of you guys had a diagram of the carb (or even a manual Thai or English) that I could have access to. I suppose I could take it to the local bike shop, but I don't trust them

cheers

[macknife]

I know alot of guys on here don't completely trust the Thai mechanics here, especially with bigger bikes, but to be fair I would imagine they're sonic experts. I'm sure you could persuade the local mechanic to come to your house and sit there with him and watch him do it.

[nellyp]

I know alot of guys on here don't completely trust the Thai mechanics here, especially with bigger bikes, but to be fair I would imagine they're sonic experts. I'm sure you could persuade the local mechanic to come to your house and sit there with him and watch him do it.

Too late now I have stripped the whole thing apart and will go through everything I can. I seriously miss not having a manual though. I decided the mechanic didn't know enough about sonics as he told me to make sure the petrol tap was turned on, and thought the breather pipe was for the petrol pump

[karlos]

Without looking, i will assume the pipe that has come off is your vacuum hose and should connect to the valve under your fuel tank at one end and the carb's inlet manifold at the other end.

Some modified scooters do away with the stock manifold (with it's vacuum feed) and replace it for a 'race manifold'

This redundant vacuum line use to connected to the valve under the tank that would have restricted the fuel from passing to the carb as soon as the engine stops.

With no vacuum line the previous owner would of had to modified the valve to pass fuel continuously or have fitted a stop valve between the tank and carb.

So i conclude:-

1. you just simply need to connect the Vacuum pipe to the bike's inlet manifold

2. Buy a stock manifold

3. Take that valve apart and / or buy a new one, as they are pretty cheap

[nellyp]

Excellent. I intend cleaning the bike up as I have everything off it anyway. I will probably buy the vacuum as i don't know if it is working. Would the vacuum pipe coming off stop the supply of fuel to the carb though? That is my problem ( I believe). The bike started but would not keep the revs, I put the choke on which improved it for about 30 seconds, then it cutr out altogether. Plug is Ok and sparking too, so I am thinking fuel.

[MaiChai]

Suck the vacume pipe and petrol should start to flow. If it doesn't flow then the valve doesn't work? Good safety feature IMHO.

That is stick the vacume pipe in your mouth and suck it!

Edited April 20, 2012 by MaiChai

[nellyp]

Suck the vacume pipe and petrol should start to flow. If it doesn't flow then the valve doesn't work? Good safety feature IMHO.

That is stick the vacume pipe in your mouth and suck it!

Will the petrol only flow when you are sucking it (the vacuum pipe that is) or should it flow when disconnected but you kick it? ( the kick start not the bike)

Cheers

Neil

[karlos]

Petrol should only flow when there is a vacuum pulling on the valve through the pipe that's currently disconnected.

'Suck it and see'

Edited April 20, 2012 by karlos

[nellyp]

Petrol should only flow when there is a vacuum pulling on the valve through the pipe that's currently disconnected.

'Suck it and see'

All fixed now, replaced pipe and tube. Took a lot to get the petrol back through to the carb though

Cheers all