FCR fuel leak from Accelerator Pump?

39mm FCR MX.

It looks like fuel is leaking from my accelerator pump, where the O ring mod has been done, possibly through the shaft. It is very difficult to see around the crank case vent box.

I idled the bike on the side stand for 10 minutes with no leak anywhere.

I idled the bike on my center stand for 10 minutes and no leak anywhere.

rev the bike a few times and fuel is leaking. I cannot think of where else it could be coming from. Any ideas?

I know I will have to pull it and replace the seals, any other ideas would be helpful.

Is it common to have a leak around this shaft? Anyone else had a leak here? I am just thinking there may be something I am overlooking or need to replace besides the seals.



BTW, The bike runs perfect. I have not noticed any miss in idle or hesitation.

It doesn't even seem possible that fuel could be coming from here? But there is wet fuel on the black plastic pivot piece for the accelerator pump.

Is there any fuel in the top cap? I would not think so, but am not sure. I am actually worried there may be a crack somewhere.

Simplest thing first...The last part I adjusted before noting a fuel leak was changing clip position on the fuel needle. The bolts were not loose, gasket has no marks in it. I cleaned it all up and re-installed the cap.

if the pump diaphram is ruptured it will leak like you describe.

You are absolutely correct! I pulled the carb, then decided to pull the linkage while it was off and got a squirt of fuel out of the top end of the rod from the accelerator pump. Checked the diaphragm and it is cracked. I just need to see where is the best one to purchase.

I have run into the same problem, but there doesn't appear to be any damage to the diaphragm. Any suggestions?

I have run into the same problem, but there doesn't appear to be any damage to the diaphragm. Any suggestions?

I have the same exact issue!

Are there two orings in there with the diaphragm? One sticks to lid and one sticks to body. Ive seen plenty cats take off lid and not see the o rings seperated and one falls and doesnt get seen. So the lid gets put on sans one oring. Probably the smaller flat one.

My opinion.

And keihin gasket sets dont come with an AP diaphragm. At honda they dont. I suppose elsewhere could be different.

I have the same exact issue!

You have the slant, mot MX variant. Different carb.

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