oil from muffler

[93YZproject]

Have purchased a 93yz80 as fix up project with the kids. very little 2 cycle experiannce. lot of black tar like oil coming from muffler. replaced piston and ring also new FMF muffler. Still drips this black oil out muffler although less than before. Using 24:1 gas mix with yammaha R-2 oil. Thanx in advance for any help.

 

[mmz77]

24-1 seems to have too much oil in this mixture. Mix it 32-1 which is the normal set mixture point and see if it helps. :cool:

 

[SIXSIXZERO]

i ride a yz 125, and run 32:1. also, did you clean out the power valve assy when you replaced the top end?

 

[TimberPig]

i ride a yz 125, and run 32:1. also, did you clean out the power valve assy when you replaced the top end?

There is no power valve on a 1993 YZ 80.

The oil is unburned oil from the fuel oil mix. The bike is not being ridden hard enough to burn it all off. Adjusting the mix ratio as suggested may help some, as will rejetting the bike. It is likely running rich on the air/fuel ratio as well (cure this with the rejetting), which is partially at fault for all the spooge you are seeing.

 

[flying flea]

oil's too rich.