Cylinder base gasket

[mushman]

The cylinder head on my 1100EZ has been weeping oil when warm at the front/center where the small pinch bolt resides. No amount of tightening or oven-tightening even after re-torquing the head wants to remedy the problem. It's mostly an annoying cosmetic problem but since it's freezing outside with 6" of snow in the driveway I thought now is as good a time as any to just put on a new head gasket. The question is do you think I can get away with not replacing the cylinder base gasket at this time, or is just the fact that I'm releasing the downward pressure on the cylinder block going to cause that existing gasket to leak? I hate to change that one if I don't have to. I really struggle with slipping the ringed pistons back into the cylinders as easily as I'd want to, homemade ring compressors or not.

Thanks,
Mushman

82 GS1100EZ
05 KLR 650
95 Daytona 1200

[49er]

Check that your leak is definetly coming from the front screw. I have seen bikes with oil in that area when the cam cover is leaking.
It's not worth doing the head gasket alone. If your bike has high miles, there is a great risk that the base gasket will be damaged once you release the tension off the studs. Also you have a set of 24 year old rubber o rings sealing the oil galleys and another set sealing the barrells. These all need replacing.
Check that your compression is even and within spec. If it is, ride it and forget the repair until the top end needs a complete OH.

[sharpy]

leak?

More than likely it will be the two front centre head bolts that have a o-ring on them that is leaking. U can pull the cams out, do one bolt at a time and see it that fixes the problem. Just make sure the area where the o-ring sits is clean and u might be lucky. Tighten the other bolts while u there it wont hurt.

[mushman]

I did a complete overhaul about 3000 miles ago (30,000 on the clock). The cam stopper in the transmission was broke so everything was torn down, all gaskets and o-rings replaced, pistons re-rung, new valve guides and head cleaned up...the essential "new" bike. It's not the cam cover leaking. It's the area of the center 6mm bolt. I guess I could keep riding until I'm ready for more top end work but I see that as a ways down the road. It's just such a damn oily mess on the motor and the floor when parked after a ride. Feels like I've got an old Harley or '68 Bonneville dripping there. Still, I might want to pop on a new head gasket if thats the fix, hoping the cylinder base gasket doesn't leak afterwards. Of course if it does then I'd need to do the head gasket twice. Any way to keep the block tight or not worry about it?

Mushman

[Road_Clam]

The cylinder head on my 1100EZ has been weeping oil when warm at the front/center where the small pinch bolt resides. No amount of tightening or oven-tightening even after re-torquing the head wants to remedy the problem. It's mostly an annoying cosmetic problem but since it's freezing outside with 6" of snow in the driveway I thought now is as good a time as any to just put on a new head gasket. The question is do you think I can get away with not replacing the cylinder base gasket at this time, or is just the fact that I'm releasing the downward pressure on the cylinder block going to cause that existing gasket to leak? I hate to change that one if I don't have to. I really struggle with slipping the ringed pistons back into the cylinders as easily as I'd want to, homemade ring compressors or not.

Thanks,
Mushman


82 GS1100EZ
05 KLR 650
95 Daytona 1200

My 1100 would leak for about 45 seconds upon startup for your exact same spot. No amount of "re-torquing" will remedy the issue. That is a common leakage point on the GS's. Your only option is a fresh set of top end gaskets.

[tfb]

I'm with Sharpy on this one; check the O-rings which go around the two central-front head bolts. The fact that "No amount of tightening or oven-tightening even after re-torquing the head wants to remedy the problem" points to it being these O-rings.

[gs650gt]

To my experience those o-rings need to be changed at least once a season (half hour job, not necessary to remove the cams)

[Road_Clam]

To my experience those o-rings need to be changed at least once a season (half hour job, not necessary to remove the cams)

I don't understand this one.

[gs650gt]

"O-rings which go around the two central-front head bolts"

they just don't last forever. I change them twice a year to prevent the leaking.

[sharpy]

Nuts and o-rings

To my experience those o-rings need to be changed at least once a season (half hour job, not necessary to remove the cams)

Ok i was wrong you dont need to remove the cams. I own a GS1000st so my memory is jogged now and the front head nuts are reachable.

[minutemen]

I've pulled the heads off of my bikes and not replaced the base gasket many times and not had any problems.yet.I've also reused the head gaskets a few times.

[tfb]

I've pulled the heads off of my bikes and not replaced the base gasket many times and not had any problems.yet.I've also reused the head gaskets a few times.

That's what I like: a subversive approach to motorcycle maintenance! :-D

Good to hear that you can get away with this from time to time. Of course there will be those times when a recycled gasket doesn't do the job, but all that means is more of the pure joy of working on a GS engine.

[Road_Clam]

That's what I like: a subversive approach to motorcycle maintenance! :-D

Good to hear that you can get away with this from time to time. Of course there will be those times when a recycled gasket doesn't do the job, but all that means is more of the pure joy of working on a GS engine.

Maybe I would attempt this if my base gasket was like only a year old, but NO way would I jump over a dollar to pick up a dime by tearing off a 25 year old head gasket, and not replace the base gasket. Once you have the head off, it's about another 15 min of work to slide off the cyl. , and you get an opportunity to inspect the pistons for any abnormal wear.

[49er]

I'm with Road Clam on this one. If the engine hasn't been touched in 25+ years you're taking a huge gamble on time and money.
I have attempted to take the easy way out in the past with engine rebuilds and it his bitten me on the butt. Years ago, people who had high mileage auto engines would recommend just fitting new rings and bearings. Yeah right! This was commonly called a "kerosine overhaul". No account was taken of the need do the following: Rebore the block, regrind the crankshaft and camshaft, fit new oil pump, timimg chain, valve guides, valves and machine new seats. On push rod engines, the rockers needed re-grinding and cam followers replacing.
Camshaft bearings become oval as do cam follower bores. These are areas where oil pressure is lost if not remedied.
Cheers
Ian

[Road_Clam]

This was commonly called a "kerosine overhaul". Ian

It's been a LONG time since I heard this term. Mixing a 50/50 mix of Kero and motor oil and driving the vehicle for a few weeks was an "old skool" method for de-sludging and engine. I pity the rod, crank and cam bearings during this process.....