85YZRacer

Member
Aug 7, 2006
46
0
before i decided to rebuild my bike, it was running extremly rich. black oil was spilling out of my exhaust everywhere. I know the bike is going to smoke a little being a 2 stroke. i was thinking that my crank bearing and seals are worn and i'm sucking in motor oil in the cylinder. but i checked the piston ring clearence and it was waaay past the worn limit. im in the process in getting my cylinder resleeved and honed for my new piston. I have a friend who told me that the way he checked to see if he was sucking oil into the cylinder was by emptying all the motor oil and then starting the bike and reving it up but NOT RIDING IT. Has anyone ever tried this before? Does it sound like this would be an ok thing to try or is it not a good idea?
 
Jan 3, 2007
1,860
0
I dont think that would be a really good idea, but because i have not heard of it dosent mean it is wrong. I would think to just redo the seals and bearings to just be on the safe side. Also, is there play in the connecting rod, if so it gives you a reason to do the seals.
 

pryor

Member
Oct 21, 2006
171
0
You could have the crank case pressure tested, or just take it apart and check it out and replace the seals. Dont run it without trans oil !!! thats nuts.
 

85YZRacer

Member
Aug 7, 2006
46
0
When you say if there is play in the connecting rod, do you mean up and down play. there is some side to side play but the connecting rod is pretty solid when you move it up and down.
 

2strokerfun

Member
May 19, 2006
1,500
1
I have heard of doing this. But I kind of figure that there will be a residual coating of oil around the seal that might still be sucked through and burned. I'd be too afraid to run the engine long enough to make sure there is no more oil being sucked through the seal.
I just tore apart my recently rebuilt engine to replace that seal because the seal didn't seal right the first time I did it. I figured that even if I tried the "no oil" test, it would only show that the seal is bad or that I'm not sure that test works. Either way I would have eventually torn it apart to replace the seal.
 

84cr125

Member
Apr 8, 2007
292
0
ive heard of doing this. Its comletely normal and would not hurt your bike untill you get on it and put it under load. Since all the major lubrication is done throgh fuel, idling the bike without and tranny oil isnt that bad. Since there will be oil in the runners in the bearings they will not be harmed, and the transmission is in neutral so no major wear will occur on the cogs. Just let the bike idle for like 20 minuites and it should clear up all the "residual coating of oil around the seal".
 

pryor

Member
Oct 21, 2006
171
0
Twenty minutes with no oil in trans? :coocoo: At least you could check the crank case for leaks when you split the case to fix the trans.
 

whenfoxforks-ruled

Old MX Racer
~SPONSOR~
Oct 19, 2006
8,129
2
Merrillville,Indiana
With a br6es plug in there and it would run! Come on please? If I did not know better and ran out to the garage,buried my slide stop until it idled(john stu does!) put the devils plug in(many who ride trails believe this is the ticket!) ran the mix at 52:1(same theory)That said,my bike would be in the trash pile after running for 20 minutes without trans fluid!UNBELIEVABLE,but true!In any 2t owners manual I have ever seen,I am guessing 10-12,of mine THAT NO 2T MX BIKE's MANUAL or at the RACE TRACK HAS THE IDLE SET! IT GIVES YOU BETTER THROTTLE RESPONSE! Rule out mechanical issues,jet your bike,set your suspension and ride!
 

fatboy570

~SPONSOR~
Feb 19, 2000
94
0
What is your oil/gas ratio? I usually run a 40:1 to 50:1. Oil/gas ratios that are too rich (20:1 to 32:1) can sometimes cause the condition you are describing, even though most 2 stroke oils are not black in color. Also, you may need to repack your silencer. The packing gets full of unburned oil and wont soak up any more. I wouldnt try running the enigine without trans oil, whether you are riding or not
 

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