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Leaky carbs
Posted: Tue Jul 29, 2025 8:45 am
by Roy Hook
Morning all, I have a small amount of petrol coming from my 2-stroke oil pump cover, this is obviously coming from the carbs and running down past the oil pump, float heights are bang on, float valves and seats are new, and float bowl gaskets are new and float bowl to carb body join is dry, any ideas where this leak could be coming from, bike is 1975 S3a many thanks
Re: Leaky carbs
Posted: Tue Jul 29, 2025 9:27 am
by skub
Check fuel levels rather than float heights.
Re: Leaky carbs
Posted: Tue Jul 29, 2025 6:25 pm
by Wolfie
The overflow pipes in the float bowls can crack and leak.. Otherwise one of your new float valves may be leaking.
If the float height is set to 25mm the fuels level should be below the Gasket.
But basically only you can actually trace where the fuel is leaking from.
Re: Leaky carbs
Posted: Tue Jul 29, 2025 8:29 pm
by Triple Parts
This is very unusual as there is a fairly deep "well" behind the barrels and a drain hole that goes through the engine. So if your carbs are leaking you normally have a pool of petrol on the floor under the engine. Is the drain hole clear?
If the float bowl joints are dry and it's not coming out of the overflow pipes, are you sure it's a carb leak?