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E: Engine Fuel leakage

Ernesto

Active Website User
VOC Member
After almost 20 year of stop of my Comet and some main jobs done last months (new tire, battery, repaint tank, and other), I finally have done first ride round the building today.
All fine and super!!! :)
One's I come back and line the bike on the left stand I notice fuel leakage from the carb.
It look to come from the bottom crowed of the carb ( where the separate float is connected), just under the main body. Is there a gasket?
Could be something else?
Advices?
Thanks.
View attachment fuel.mp4
 
Last edited:

Bill Thomas

Well Known and Active Website User
VOC Member
Yes Ernesto, There is a washer, If it's the wrong thickness it can upset the running,
Also if you tip the carb it might alter how high the float is,
Could be just float valve dirty or sticking ?.
Well Done for the build, Cheers Bill.
 

Ernesto

Active Website User
VOC Member
Yes Ernesto, There is a washer, If it's the wrong thickness it can upset the running,
Also if you tip the carb it might alter how high the float is,
Could be just float valve dirty or sticking ?.
Well Done for the build, Cheers Bill.
Yes, could be.
I was thinking to replace the float valve idle and may be the seat too.
I'll try to line the bike on right stand and see if leakage change too.
do you have or know where to found parts catalogue for the carB?
 

TouringComet

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VOC Member
VOC Forum Administrator
VOC Forum Moderator
Another trick is to shut off the fuel petcocks as you are approaching your destination, to use up some of the fuel in the float bowls. As long as my petcocks are working, I’ve never had issues with fuel leaking out of the carbs when using the side stands.
 

Bill Thomas

Well Known and Active Website User
VOC Member
Have you ever seen the super Dave Hills Centre stand ?, If the legs are the right length,
Very easy to put on the stand and sits safe.
 

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LoneStar

Well Known and Active Website User
VOC Member
Another trick is to shut off the fuel petcocks as you are approaching your destination, to use up some of the fuel in the float bowls.
Yes, an excellent idea. I try to run it out of fuel as I come to a stop.

Fuel in the bowl evaporates and decays more quickly, so leaving the bowl empty during down time means less residue forming there, and fresher fuel from the tank for the next startup.
 

manxman

Website User
VOC Member
Ernesto, it looks more like a float problem. The float level in the bowl may be too high. You can adjust the needle clip as needed to correct this. Also if the carb is attached at an angle (and not level itself), rotating the float bowl may change its height relative to the main body, as some have suggested above.

The overflow in your video doesn’t appear to be from a “leak.” There is an overflow outlet in the main body of the carb (toward the bottom—in your video, it’s the hole just above the silver ring below the main body) to allow petrol to escape if the level is too high. This is to prevent flooding of the main body and the air intake if the float malfunctions, say.

After I tickle my carb on my Comet, some petrol will escape from the overflow. Once the bike starts running this will (should) cease and it shouldn’t begin again after you’ve stopped and cut the engine. So, I think it’s just an issue with the float—either just too high, or the float isn’t properly closing off the fuel supply when it rises.
 

MartynG

Well Known and Active Website User
VOC Member
Yes, could be.
I was thinking to replace the float valve idle and may be the seat too.
I'll try to line the bike on right stand and see if leakage change too.
do you have or know where to found parts catalogue for the carB?
Does This Help?
 

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  • amal_doc_premonobloc_parts_octobre_1956_351.pdf
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