Leaky carb

manwithredbike · 11-01-2020, 03:56 PM

I don't mean to be starting new threads unnecessarily and have read over some older ones related to this but i would like to pick your brains a bit if you don't mind. Carbs are something i generally leave well alone unless absolutely necessary bar the odd bit of tweaking at the idle adjuster and the occasional fiddle with the idle jet mixture screws.

I put fuel additive in the bike two days ago and ran the engine to draw it through the carbs. All good seemingly. Went out to the garage today to give it a quick start up and check that all was still good to find that the starter wouldn't turn the engine. I suspected a low battery but after a few presses, the engine suddenly turned and popped making a metalic clunk. On closer inspection, i noticed a petrol stain on the floor and found it was coming from the RH carb, on the front cylinder. Also noticed then that the oil level on the oil sight guage was way too high. Obviously petrol leaking from the carb, filling the front cylinder and onwards down to the sump. I pulled out the plugs, stuck the bike into 6th and on the axle stand to check that all was turning freely, as it was. Then i spun the engine on the button and it spat out a plie of petrol from the front pot. I done a rough compression test with my thumb, good compression, front pot same as rear one.
I removed the tank which was 3/4 filled with petrol mixed with additive just to stop more petrol from draining down as there's no tap on it..

A few things i'm not sure about now. Would the fuel additive been a contributory cause in any way or just coincidental?
Is it likely (as it would seen from previous threads) that it is a float valve sticking etc and as above, would the additive have contributed i.e will the problem be solved by draining and leaving dry till after winter, using normal petrol then?
Can the float bowl be easily removed without removing the carbs if need be?
Could there be any damage done elsewhere, the metalic clunk didn't sound too healthy?

Had just put new oil in about 100 miles ago so that's done now too.

Would appreciate any advice or thoughts you might have on it.

Many thanks in advance -- Phil

11-01-2020, 03:56 PM	#1
manwithredbike aka Phil Join Date: Nov 2005 Location: derry Bike: M900 Posts: 376	Leaky carb I don't mean to be starting new threads unnecessarily and have read over some older ones related to this but i would like to pick your brains a bit if you don't mind. Carbs are something i generally leave well alone unless absolutely necessary bar the odd bit of tweaking at the idle adjuster and the occasional fiddle with the idle jet mixture screws. I put fuel additive in the bike two days ago and ran the engine to draw it through the carbs. All good seemingly. Went out to the garage today to give it a quick start up and check that all was still good to find that the starter wouldn't turn the engine. I suspected a low battery but after a few presses, the engine suddenly turned and popped making a metalic clunk. On closer inspection, i noticed a petrol stain on the floor and found it was coming from the RH carb, on the front cylinder. Also noticed then that the oil level on the oil sight guage was way too high. Obviously petrol leaking from the carb, filling the front cylinder and onwards down to the sump. I pulled out the plugs, stuck the bike into 6th and on the axle stand to check that all was turning freely, as it was. Then i spun the engine on the button and it spat out a plie of petrol from the front pot. I done a rough compression test with my thumb, good compression, front pot same as rear one. I removed the tank which was 3/4 filled with petrol mixed with additive just to stop more petrol from draining down as there's no tap on it.. A few things i'm not sure about now. Would the fuel additive been a contributory cause in any way or just coincidental? Is it likely (as it would seen from previous threads) that it is a float valve sticking etc and as above, would the additive have contributed i.e will the problem be solved by draining and leaving dry till after winter, using normal petrol then? Can the float bowl be easily removed without removing the carbs if need be? Could there be any damage done elsewhere, the metalic clunk didn't sound too healthy? Had just put new oil in about 100 miles ago so that's done now too. Would appreciate any advice or thoughts you might have on it. Many thanks in advance -- Phil __________________ .. ~