UpstateDoubleD
New member
Black is good. It will pull the skis with a good hook up in the grass !
Backwoods M Max
New member
What ratio is the premix? With a cloud like that it seems like the oil pump is giving you something.
UpstateDoubleD
New member
Be somewhere around 40:1 + the pump... Rings not broken in yet,,, & not many bugs in the yard now !
you do understand that running that much premix along with the oilpump is actually LEANING out that sled right?
You dont need to run the premix along with the pump. if your put- puttin around the yard your not gonna damage it but when you run it down the road or lake and open it up its gonna damage it.
I know people think more oil is safer but actually its the opposite in the gas. The gas is what keeps off detonation, not the oil. oil is only there to lube the bearings in a 2 stroke.
Add: I know someone will say"but the old stuff ran with 20;1 and 15;1 and they didnt get damaged", yes, they did but they were also jetted for that ratio.
The current machines are jetted for a 50;1 ratio so when you add that much more oil, you are reducing the gas in the fuel system, and the gas is what cools the piston and sustains detonation. smaller jets equal a leaner air/fuel ratio because the oil is taking the place of the gas.
You dont need to run the premix along with the pump. if your put- puttin around the yard your not gonna damage it but when you run it down the road or lake and open it up its gonna damage it.
I know people think more oil is safer but actually its the opposite in the gas. The gas is what keeps off detonation, not the oil. oil is only there to lube the bearings in a 2 stroke.
Add: I know someone will say"but the old stuff ran with 20;1 and 15;1 and they didnt get damaged", yes, they did but they were also jetted for that ratio.
The current machines are jetted for a 50;1 ratio so when you add that much more oil, you are reducing the gas in the fuel system, and the gas is what cools the piston and sustains detonation. smaller jets equal a leaner air/fuel ratio because the oil is taking the place of the gas.
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UpstateDoubleD
New member
Nope didn't know that, do now. But you are right, way too rich so I added the rest of my 6 gal gas can to what was in the tank and that should take way down to say 60-70:1... but thanks for the TIP !
UpstateDoubleD
New member
Finally got time to pull the airbox/Carbs and get a look at the oil pump...
All is well and back in you go !
The pump has a taper machined on the tips and the crown is rounded off a bit from the factory.
Here are images of my spare pump. Did not want to get air in the lines if it looks good.
(Click images to enlarge)
Mega Size of the one on the sled here;
This post might be helpful for those considering a top end rebuild. Get all new gaskets and parts. Be sure to suck out any antifreeze in the lower end during rebuild. Cover them holes when replacing the piston pin clips ! Take your time... Yamaha was pretty easy to get to/work on. 7 of a 10 difficulty.
So thanks everyone for the advice and tips/tricks to look for. And thanks to TY Forums for hosting us !
UpstateDoubleD
New member
Sled runs great! Starts good, smooth acceleration and plenty fast for the Fear Factor !