changing cylinder "foot" gasket

[marp68]

Hi

New xs owner since yesterday.

But, there is a small leak from the cylinder "foot" (is that what it is called in English?). Is this difficult to do? Can I do it without taking out the engine from the frame. Can I leave all inne part, like pistons etc, and only remove the head and cylinder? Should I try tightening the cylinder first a bit?

/Martin

 

[nj1639]

I'd re-torque the head to specification, run it and re-torque- see if that resolves it.
You can remove the engine mounting bolts and tilt the engine to the side or take the engine out completly to access the gasket. You can not remove the top end without doing one or the other.
The more times you do it, the faster you get, HA!

 

[Tz250racer]

I solved a small leak problem on the front of the lower part of the cylinder block by using Permatex RTV sealer.No more leaks.Try the easy fix first by cleaning that leaking spot fist.apply the sealer and let it dry for a couiple of days and then see if the problem is gone.

 

[ady66]

I'd clean it up and run it for a bit to see how bad it is and where it is coming from before ripping it apart - sometimes oil can find its way to the cylinder base from other sources, such as the camchain tensioner.

 

[nj1639]

ady66 is right on there.

I guess there is a bit of room between the top of the engine and the frame where one could lift the jugs enough to put a sealant under them without removing the engine if that is where it's coming from....

 

[marp68]

Okej, great tips.

Since I bought the bike yesterday i haven't had any chance yet to look closely into this matter.

M

 

[5twins]

I'm assuming you mean the gasket at the bottom of the cylinders where they meet the crankcase. That would be your cylinder "base" gasket. The main head gasket is higher up just below the spark plugs. Both are common leakers on these bikes because the head bolts come loose all the time. The reason the head bolts get loose is the rubber/metal washers Yamaha used under the 4 outside acorn nuts. You should replace those with copper or brass washers. Also, the torque value Yamaha speced for the 8 large acorn nuts was rather low, about 26 ft/lbs. Most of us use 30-35 ft/lbs on them but stick to factory specs on all the smaller ones.

 

[marp68]

Okej, thanks for the tip.

With the "4 outside acorn nuts", do you mean the outer head bolts?
And what about the inner bolts?
So, these 8 larger bolts are all cylinder bolts necessary to re-torque? Or any small bolts as well?

I intend to clean the whole engine first, and then try this.

M

 

[5twins]

The acorn nuts are nuts on studs, all the other head fasteners are bolts. I would check all the head fasteners but the 4 outside acorn nuts are the most likely to be loose. #5-#8 in the drawing below .....

 

[marp68]

Great news!

I went to Do it yourself-place and washed the bike with kinds of stuff and then used compressed water to really get it off, rubbed again and so on. It went clean and nice. And guess what, after driving home, there was no sign of leaks. So it could have been just old oil that went hot and the outer layer started dripping.

Thanks for tips. I will save them for possible problems in the future.

/Martin