Carburetors

[trexloans]

I just had my cylinders bored new pistons. rings & stage3 port job. I ran it through clymer break in process and it seemed to be runningn lean so I put 310 mains in and tried again to find the right side cylinder running correctly plug chop shows perfect ring while left side is showing rich condition. t seems to be running rich troughout entire operating range which makes me suspect leaking float valve but I've checked the float height to be correct and the valve appears to be shutting off with no fuel running from overflow. I thought it may be the choke hanging up but I checked it by putting a small hose on the float pick up tube with bowl off and I can't blow through it with choke in the off position and can blow through in on position. I've check all jets and air passages to be correct but still have this rich operating condition on the left cylinder.

 

I've checked spark to be correct and have ruled out electrical?

 

Anyone out there have any suggestion?

[canyncarvr]

It's not uncommon, it seems A lot of tuners/dyno runs suggest the two cylinders may well not jet the same. K&N for example.

 

Certainly all number of things 'wrong' can make one cylinder breath differently from the other. Because your jetting requirements between cylinders are not exactly the same I wouldn't consider cause for a whole lot of worry if there are no other symptoms of problems.

 

A little example of something(wrong) that would cause a difference: My brand new Banshee had considerably different float settings left-to-right. Heck...maybe they all do. Anyway, the higher the float, the richer the A/F mixture (all other things equal).

Edited January 18, 2005 by canyncarvr

[trexloans]

Thanks for the reply. I was able to solve the problem. It turned out to be my plug cap causing a weak spark which in turn caused the left cylinder to have excessive fuel mixture mimicking a carb problem when it wasn't a carb problem at all. What a relief!

 

It's not uncommon, it seems  A lot of tuners/dyno runs suggest the two cylinders may well not jet the same.  K&N for example.

 

Certainly all number of things 'wrong' can make one cylinder breath differently from the other.  Because your jetting requirements between cylinders are not exactly the same I wouldn't consider cause for a whole lot of worry if there are no other symptoms of problems.

 

A little example of something(wrong) that would cause a difference:  My brand new Banshee had considerably different float settings left-to-right.  Heck...maybe they all do.  Anyway, the higher the float, the richer the A/F mixture (all other things equal).

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[Banchetta]

It's not uncommon, it seems  A lot of tuners/dyno runs suggest the two cylinders may well not jet the same.  K&N for example.

 

Certainly all number of things 'wrong' can make one cylinder breath differently from the other.  Because your jetting requirements between cylinders are not exactly the same I wouldn't consider cause for a whole lot of worry if there are no other symptoms of problems.

 

A little example of something(wrong) that would cause a difference:  My brand new Banshee had considerably different float settings left-to-right.  Heck...maybe they all do.  Anyway, the higher the float, the richer the A/F mixture (all other things equal).

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I wouldn't be giving that advise to anyone.......

[NMBANSHEE]

I wouldn't be giving that advise to anyone.......

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Neither would I

 

Have seen that problem before though----one of the main jet washers was missing when my buddy bought his banshee, he couldn't figure out why one cylinder was lean. He had me check his carbs out and I found his mising washer problem. Then all was good.