Using Oil

[memphis2857]

My 05 300 seems to use 50-100 cc of oil everytime I ride. And you can very faintly smell the oil when you first start it in the A.M. It only has about 30 hours on a complete rebuild (top to Bottom). Right Side crank seal is the first thing that comes to mind but usually when they go they GO and the bike would barely run. My question is, is there anywhere else that I am not thinking of that could pull oil into the cylinder?

 

[motopsycho87]

Check for blocked breathers, otherwise, it's the seal, most likely caused by a failed bearing.

There is a chance that the sleeve that fits into the seal was fitted without an o-ring behind it, that could cause gearbox oil to get by also.

 

[Zman]

My first guess is the crank seal on the clutch side as you thought. Is it possible that you replaced the PV bearings on the pipe side with ones that do not have any seals?

 

[Jakobi]

I'm going with the o-ring behind the sleeve on the main seal. Its bloody easy to miss upon reinstall.

 

[rosco]

Don't forget about your crankcase gasket. Not too likely but I've seen it before. If you had the cases split its possible you didn't get a good seal when putting them back together. I hope that's not what it is.

 

[Moto7man]

Here is a great video on checking a GasGas crank seal for a leak. This guy had an oil loss issue as well.

http://www.youtube.com/watch?v=w_Ms5C5TOLw

 

[memphis2857]

I'm going with the o-ring behind the sleeve on the main seal. Its bloody easy to miss upon reinstall.

Little more detail? Is it part of the seal? I guess what I am asking is do I need to order a new crank seal or can I simply put an o - ring in it? I didn't do the rebuild I bought it from a guy who had the work done (have the recipts)

 

[memphis2857]

Little more detail? Is it part of the seal? I guess what I am asking is do I need to order a new crank seal or can I simply put an o - ring in it? I didn't do the rebuild I bought it from a guy who had the work done (have the recipts)

Never mind. I watched the video. BUT that guy didn't seem to think the o - ring could cause a leak. Nonetheless I am gonna ride 1 or 2 more times then tear it down and replace the seal. Can't hurt anything....right?

 

[Jakobi]

Its similar to the counter shaft seal. The main seal rides on a bushing. The bushing the has to seal against the inner o-ring. If its damaged/omitted it will indeed leak. Also, depending on the state of things, the main bushing can wear and form a groove from where the seal runs. This could also cause a small leak.

 

[memphis2857]

OK. Thanks for your help. I have one more ride in 2 weeks then I am gonna tear into it

 

[Caravan Monster]

Unlikely as it sounds, worn piston rings can pressurise the gearbox and blow oil out of an opening. I had this happen on a TM 125 motocrosser with oil blowing out of the gearbox breather. I didn't know the piston ring would wear out in a few hours use and could not understand what was going on.

When the mixture fires at the top of the stroke, some of the combustion gases can blow past worn rings and past the main bearing oil seals, which on the drive side will result in pressurised gearbox.

In the case of the TM, a new piston ring fixed the problem and it ran well again. Not saying that's the case here, but it's something else to consider.