Post carb overhaul
 

Hey,

I have just overhauled the carb on my 4PT and after putting it back together and fitting it I can´t get the bike to run. It has also been sitting for six weeks so it might not be the carb although this is the most obvious thing. Am sure I have done everything correctly and have also shown it to a mechanic who had a quick look at it and said that its ok. However, when I open the drain screw at the bottom of the float bowl nothing comes out. I have checked the fuel taps and made sure they´re on. Does anyone know if this is normal? I would have expected fuel to run straight through if you have the tank taps on and the drain screw open. It just occured to me though that maybe you need a certain level of fuel already in the float bowl for the fuel valve to open because with it completely empty the float will drop right down and close the fuel valve. Any ideas greatly appreciated.

The other possibility is that there is no spark for some reason. The battery is fully charged though and it has a decent plug. Does anybody know a way to test the coil. I remember when I owned a VW bus that there was a way to test the coil by holding the HT lead slighty away from some metal and turning it over, but I don´t remember exactly.

Many thanks,

Finian

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If there is no fuel coming out of the bowl drain screw there is no fuel in the bowl and the engine will never start.
If you pull the fuel hose from the tap and blow on it it should be possible to blow some air into / through the carburettor, by mouth. If this is not possible, look for folds in the hoses or indeed a float needle stuck in the closed position.

And of course: any fuel in the tank?

Auke

Thanks Auke,

Will have another look tonight. Have also checked most of those things, maybe the float valve is faulty and getting stuck, I did lose it for a day on my lounge floor, maybe somebody trod on it!

Finian

have a look in earlier entries about my 4PT, WEAK SPARK especially.what a saga! klaus describes what and how to check things in there, including the coil. my coil tested on the limits but i replaced it anyway with a new genuine part, also HT lead, plug and cap.tighten up all your connections. if you test the resistance and its definately duff, i can send you my old one, as far as i know it could be fine.i changed a few bits at once so it may not have been the coil at all! might save you £45 mate.

until you sort the spark out, dont worry about the carb.if you have a good spark and still no starting then you know its a fuel problem.


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dave

If its been laid-up for sometime the fuel in the fuelpump will evaporate and can be a right ba**ard to start again. Using the kickstart instead of the electric start seems to work better, but is obviously much harder work ! I've found it just takes time ......

HTH

Probabily the fuel pump is empty - just bypass it connecting directly the tubes from tank ... you may let the bike this way - what's remains in the tank that the fuel pump will catch is very few (at "eye" no more than 1-1,5 litres) and you have a thing less to worry.

To check the spark : dismount plug , holding it only by the rubber cable touch with pluc bottom's any part of the motor while kicking - if OK you will clearly see the spark.

Thanks guys, managed to get it going. For some reason the fuel wasn´t running into the float bowl properly but after opening it again, and refitting the float valve it worked. I don´t think the 4pt has a fuel pump, does it?

Dave, I wouldn´t mind your spare coil if your not using it. Mines working fine but maybe I should take a spare for Africa. Could give you some cash for it if you like.

Thanks,

Finian

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no problem mate, ill make sure it works on my bike first, then post it to you. send me a fiver to cover postage, ill email my address to you direct,after i see if it works ok, ok?

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dave

PS the 4PT doesnt have a fuel pump or kickstarter.

[This message has been edited by DAVSATO (edited 14 June 2003).]