Lots of smoke, oil dripping on ground

M

Mikeyx

New member
Well, the headline pretty much sums it up.

The dripping takes place at the rear of the engine - close to the linkage. 'Oil' here refers to thin dark grey fluid. Smoke generation is abnormal and is greyish, not blueish.

So, is the gasket between the engine casings gone? Or are there two separate leaks (crank seal & case gasket)?

EC300, 2009.


EDIT: I just discovered that while replacing the cylinder I had mixed the two vent fittings. I had installed the one with smaller orifice to the transmission side, and it was completely clogged.
 
Last edited:
Could be any gasket or seal that contains gearbox oil. Usually the clutch gasket is metal cored so it is a lot stronger than the centre case gasket.
 
I would say that the 'oil leak' outside seems to come from a bearing on the swing arm shaft. Either a swing arm bearing or from the triangular thingy in the linkage.

I have been struggling for hours to remove the crank seal (hellowa problems removing the case, woodruff key, crank seal itself).
 
I also need to replace the scored sleeve/bushing (don't know proper terminology..) which is there between the crankshaft and seal.

I have been wondering... my bike has been different every f***king day. One day it runs perfectly, the next day it is slightly out of tune, and the following day it feels sluggish. Maybe there has been an oil-air leak through the scored bushing?
 
Mikeyx said:
I also need to replace the scored sleeve/bushing (don't know proper terminology..) which is there between the crankshaft and seal.

I have been wondering... my bike has been different every f***king day. One day it runs perfectly, the next day it is slightly out of tune, and the following day it feels sluggish. Maybe there has been an oil-air leak through the scored bushing?
Click to expand...
do you have the choke on the handle bars or on the carb. if it is on the bars with a cable lots of us found it better to switch to the carb mounted choke switch for the symptoms you have described
 
Okay... there was coolant in the crank case. Got some 100 ml or so from the drain. Apparently 'smoke' was coolant after all.

I guess there are several possibilities here?

- cylinder bottom gasket
- cylinder head o-rings
- engine case gasket(s)
 
Check all three of those. Use a straight edge and look for flat surfaces. Over-tighening and or over-heating can cause warpage and poor gasket problems.
 
The cyl bottom gasket was soaked with coolant, making the gasket swollen and softened (non OEM part).

There was one crack as well, but it may have occurred when removing the cylinder.

Rear nuts had been tightened with a torque wrench. Upon disassembly, the front nuts were much easier to loosen.
 
Mikeyx said:
The cyl bottom gasket was soaked with coolant, making the gasket swollen and softened (non OEM part).

There was one crack as well, but it may have occurred when removing the cylinder.

Rear nuts had been tightened with a torque wrench. Upon disassembly, the front nuts were much easier to loosen.
Click to expand...

Sounds like you will need to split the cases. Check the case halves where the coolant passage is in front of the crank case. It is likely you are leaking coolant into the crank case where this passage is. Use a quality gasket and I would add a small amount of Yamabond around this passage.

I had a similar issue after reassembly of the case halves on my 2011.
 
Sorry, just noticed you mentioned the leak appears to be at the base gasket for the cylinder. Hopefully a new base gasket will be the fix.
 
I received a new gasket from motocrosscenter.com. It is made of completely different material compared with the failed one (sourced from gasgas-outlet.de). The previous gasket was kind of 'paper'...
 
I did not find any source for the 'oil' dripping down. I guess it -most likely- originated from the grease applied on the swing bolt?

Sold the bike yesterday, and now I'm a happy owner of a 2018 Husky TE300i.

OMG how much technology has developed (electric starter, TPI, BALANCING SHAFT). A completely different riding experience!
 
You must log in or register to reply here.

Similar threads

F
EC250 Leaking oil through powervalve cover
Replies
9
Views
3K
Fast
F
Back
Top