Lean on right cylinder?

[RUNMYTA]

OK guys, Tell me what you think. My 99 Shee has ran lean on the right cylinder for several months now (Shee is barely riden anymore).I have cleaned the carbs about 3 times, replaced the reeds, new reed valve gaskets, new intake boots and I have checked for air leaks every possible way I know how.

 

Here is the kicker!! I can start her up 1st kick after setting for 2-3 weeks, sounds good, warm her up for a min or 2 and take off and shee pulls decent through 3rd then falls off to 1 cylinder. I rode her today and pulled the plugs, left plug looks great( maybe just a tad rich) right plug looks grey almost white!! Then I swap the plugs and shee runs decent until 3rd then falls of to one cylinder. I run her back to the house and the right plug has burned off the oil deposits and turned it white with a 30 second ride???

 

Lets hear what you think this could be?? TIA Mike

[a&sbanshee]

sounds like an ignition problem try swapping the plug wires and see if it follows it if so there is your problem as for the plugs being gray that is a sign of detination which is never good at all

[Forcefed]

ummm maybe...but if it was an ignition problem wouldn`t the "lean" plug actually be dripping wet and fouled from the ignition not lighting the fuel off?

 

Honestly man...I think you are on the right track with the airleak scenario...although since you have eliminated many possibilities with the replacement parts for the intake tract, you may need to take a step further. DO a compression check (by the book) and then have a leak down test performed...you may have very well had a crank seal go out on you (typical) and is drawing air in......maybe something to do with the head as well. A coolant leak WILL show similiar signs of a lean condition due to the superheated steam cleaning the fuel/oil off of the plugs (as well as the cylinder walls/crank ) If you confident there is nothing in the intake tract....and the ignition is not your problem ....its them time to dig a little deeper.

[bigboreshee]

Sounds like a air leak most likely. If it was a crank seal it would be on the left side considering that is the dry side where the stator is and air would come in that side. If the right side crank seal was bad you would have a rich condition on your right side from the oil coming in from the clutch side. I would try doing a leak down test. Plug off your intake and exhaust with a rubber cork or anything that makes an airtight seal. Get you a hand pump vacuum tester, put piston at bottom dead center and pump it up to no more than 9 psi and you should have no more than 1 psi per minute leakage. Use som soapy water to help find the leak. Check your cylinder base and head gasket,where top and bottom cases come together,reed gasket,and around where you sealed off intake and exhaust.

[RUNMYTA]

If it was the left crank seal (then wouldn't the left cylinder be the one that would be lean??) What about the center seal? What would happen if it was bad?? Can the center seal be replaced on a stock crank??

Edited August 28, 2004 by RUNMYTA

[boonman]

I was not aware of a center seal? Also, it wouldn't suck oil in if the oil level was low..... Is the oil level up to par? If it is, than rule out a crank seal. How is the exhaust color, and smell. Does it smell the same between both cylinders? Is it using any coolant? Are the carb tops screwed on tight? Good seal on both of them? Using a boost bottle? Stock balance tube? What? Leakdown is a good start. Compression would be next..... You could have a problem with a stuck float or something like that. Using the fuel to get up through 3rd, and then losing fuel out of the bowl? Swapping the plug wires will indicate a problem usually with the coil. Unless one of the timing tabs on the flywheel is goofed up.....