[bogey72]

Let's hear it.

 

[bogey72]

2005 with 2000 miles.



I have just a little oil leak and I think I'll ride it for awhile and see if it worsens. Of course, I'll check my sight glass often.

 

[macbig2k1]

I don't have this problem.

I use Athena gaskets for my engines and I recommend it for my customers.



The question is, where is the oil leak?

Does the oil came from the cylinder base or from the oil line to the cylinder head?



In my opinion, the cylinder base gasket in NOT the problem.

The sealing against the engine oil is not the cylinder base gasket. The o-rings are doing this job.



Both problems (oil from the cylinder base or from the oil line) can be solved by some new o-rings/rubber rings.

The original cylinder basket o-ring is 70 x 3 mm and the oil line o-ring is 12 x 2.5 mm.



If you still have the same problem, than you should use bigger o-rings.

cylinder basket o-ring: 70 x 4 mm

oil line o-ring: 11 x 3 mm



Regards, Sebastian

Germany

 

[Larry]

I asked this once and the explanation I got was that it seems to come from the rectangular area that the timing chain resides in and not from the cylinder because an oring is located there.



So basically the oil comes from that area and then appears as though its coming from the cylinder. When actually its coming over from the timing chain area and leaking out as thought coming from the cylinder.



Mine has been leaking for 2000 miles and I have 3500 total now. Just watching it and plan on replacement this winter.

I don't have this problem.

I use Athena gaskets for my engines and I recommend it for my customers.



The question is, where is the oil leak?

Does the oil came from the cylinder base or from the oil line to the cylinder head?



In my opinion, the cylinder base gasket in NOT the problem.

The sealing against the engine oil is not the cylinder base gasket. The o-rings are doing this job.



Both problems (oil from the cylinder base or from the oil line) can be solved by some new o-rings/rubber rings.

The original cylinder basket o-ring is 70 x 3 mm and the oil line o-ring is 12 x 2.5 mm.



If you still have the same problem, than you should use bigger o-rings.

cylinder basket o-ring: 70 x 4 mm

oil line o-ring: 11 x 3 mm



Regards, Sebastian

Germany

 

[old mad max]

My 06 with 9,000+ miles has a verrrrrrrrrrrrrrrrrrrrrrry slow leak, so I just wipe off as needed.. Same with my wife's 06.... I bought new 2010 gaskets but have not bothered to put on.OMM.

 

[elime]

This is what it looks like just shy of 100 miles. I will ride another 100, maybe 200, before I bother to wipe it up.

It is an '87 with almost 19K miles on the odo.

Gooey crap is Permatex Spray On Sealant. I think it slowed the leak a little but sure didn't stop it.

 

[dmathia]

I replaced the o-rings and gaskets at 3500 miles on my 07, I'm a retired mechanic and couldn't stand it any longer. It's my opinion also that the problem is more the o-rings than the gasket. Have gone 5k since then, no leak. I used the original style gasket, the newer one wasn't available at the time.

 

[n2o2diver]

My 2005 started leaking at about 5500 miles, same time I switched to synthetic 10-40, it was leaking pretty good that I had to wipe it every day. At 6500 miles I went back to dino 20-50 and the leak stopped, now at 7200 and still no leak. I'm not saying it is the oil but that is my observation at thIs time. I can not remember off the top of my head what brand of oil, but it is that popular one sold at Wal Mart. Like RT 4 or 4T something like that.

 

[B-dub]

My 2005 started leaking at about 5500 miles, same time I switched to synthetic 10-40, it was leaking pretty good that I had to wipe it every day. At 6500 miles I went back to dino 20-50 and the leak stopped, now at 7200 and still no leak. I'm not saying it is the oil but that is my observation at thIs time. I can not remember off the top of my head what brand of oil, but it is that popular one sold at Wal Mart. Like RT 4 or 4T something like that.

Great insight. Things I've read about synthetic tends to backup your observation.



On a recent thread, after the base gasket started leaking a member of this forum checked and found head and cylinder bolts loose. He re-torqued them and the leak went away. On another thread the same thing happened, but the guy over-torqued just a couple of the bolts and it made the leak worse. So, if I were to get another base gasket leak I think I would re-torque to specification all the head bolts using the head bolt torque pattern to ensure even pressure on the head and cylinder. I would also re-torque to specification the bolts at the base of the cylinder that hold the clutch cable mount.



If, after re-torquing the fasteners it continued to leak, I would replace the base gasket and associated o-rings. If you have any mechanical experience at all It's not that hard or time consuming. With no experience I believe it's still do-able by following directions and maybe getting a little help.



I respect other's experiences and opinions, but my experience has been that the version of base gasket does make a difference. The first time I did my base gasket the parts person led me to believe the newer part number for the base gasket would supersede the older part number. I was in a hurry (first mistake) and didn't confirm by part number that I had the newer style base gasket. I know, pretty dumb of me. I did replace all the o-rings at that time. In less than 2,000 miles it was leaking again. On the second time around I simply ordered all the parts for a 2010 TW. With about 1200 miles on it now, it's as dry as a bone.



With such a variety of experiences it's hard to nail down exactly what's going on. We know from the o-rings that the oil feed to the head is around the right rear head bolt. Since the oil is under pressure there you would think that would be where the leak occurs. But I've never seen or heard of the leaks occurring there. In my experience it's always been on the left side of the cylinder around the timing chain cavity.



I don't remember seeing an oil flow chart, but believe at least some of the oil from the head returns through the timing chain cavity to keep the timing chain lubricated. I believe the action of the chain spinning flips the oil around some and this is what causes it to migrate through the most poorly sealed area of the crankcase/cylinder junction. The timing case is also open to the spinning crank and gears. As others have pointed out, other areas of the cylinder are well sealed due to the use of o-rings. The addition of beads of sealant on the newer version of the base gasket tends to act as an o-ring to better seal the area around the timing case.



Well, as you can see there is a lot of supposition going on in the 2 previous paragraphs, but it's my theory and I'm stickin' to it

, at least until you guys correct me.

 

[dmathia]

There is also an o-ring around the cylinder base. I would have preferred the new gasket, but I guess I'm lucky.

 

[macbig2k1]

Yes, you're right, there is a 0-ring around the cylinder base.



There are 3 openings with oil inside, but just 2 are double sealed by a 0-ring and the base gasket. Only the timing chain opening is single sealed.



And I've seen/written, that the leak is on the timing chain side.



These 2 indications are telling me, that the timing chain part is the weak point from the base gasket.





So, the problem should be solved with a bit engine sealing grease around the crankcase opening from the timing chain and after this on the top from the base gasket around the timing chain opening.



Regards, Sebastian

 

[bogey72]

After more riding, I've definitely got a leak at the rear right side of the cylinder base gasket. It's leaking enough that I'll have to fix it. I'm going to order the 2010 base gasket as well as all the orings and the head gasket and a few other parts mentioned in Bdubs fine post. I'm most likely going to do it myself but I do know a yamaha cycle mechanic that might do it for a few bucks. Hopefully, I can get it done in the next few weeks.

 

[n2o2diver]

Good luck with your fix. Take pictures and share if you can. I've got to get to mine one of these days too, but right now I just want to ride. I also need to do the forks but I'm dreading that to. The fork oil needs replaced and the boots too. Probably will go with the progressive spring and some preload spacers. Also bought some hi atv bars that need to go on. I ride my dub every day and down time sucks.