TOPIC:

Hello all,

I've got a 79 kz650 SR and i'm getting about 24mpg right now, i'm taken apart the carbs and cleaned everything and i've done a full tune-up on the bike, checked timing, checked valve clearances... long story short, i have been running rich all across the board, especially cyclinder 2, i lowered the needles another notch to help lean out the mixture and the other cylinders appear to be good now, but i'm still very rich on #2, bike runs good and idles well, but i'm getting very poor gas milage and like i said, #2 is very rich.

Any ideas?

Thanks,
Chris

I'm not really familiar with your bike, but recently had a very rich number 2 cylinder myself. What I found was that the diaphragm in the Automatic Petcock of my bike was ruptured. It was allowing fuel to go into the carb regardless of the bike being on, or off,...and the petcock lever position made no difference on the leakage either. So, to diagnose your problem, Do you have an automatic petcock? If so try to see if you have fuel leakage coming out of the vacuum line that links to your number 2 carb. Just pull the line off of the petcock, attach a length of hose that will reach a can, or bottle that you can set on the floor next to your bike, run the hose into the can, then allow it to set over night. Check it in the morning, and if you have fuel in the can/bottle...then you have a bed petcock.
If so, be advised that you may have fuel in your crankcase oil as well. If you seem to have a really high oil level-Do an oil change before you start your bike. See my other post on "Automatic Petcock Rebuild" if you need to re-build your petcock. I found an alternative to the more expensive standard routes. Good Luck, -Jay

A bad diaphragm or check valve associated with an accelerator pump will also cause extra gas to always flow through the carburetor.

I know my petcock is good and not leaking and it was recently rebuilt.

My immediate guess was something with the accelerator pump since that is the only primary difference with that carb versus the others.

I will order a rebuild kit from Z1 and see how that fares.

Thanks,
Chris