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General Category => Yamaha FJ1100 / FJ1200 Running Problems => Topic started by: Miker on June 02, 2019, 07:36:46 PM



Title: Holes in my head
Post by: Miker on June 02, 2019, 07:36:46 PM
Just rebuilt the petcock on my 85 FJ1100 as the damn thing was leaking yet again.  While the tank was off, I noticed four holes in my cylinder head. Each hole is by a bolt. The metal in those areas appears thin. I've read a hole in the head can form for a number of reasons, but I’d bet on overheating due to the phoenix climate and original oil cooler.  I bought the bike with around 28k miles aka bought a bike with a tachometer with 28k miles.  Up to about 34k now.  No idea how long the holes have been there.

I was thinking I would just remove the head and JB Weld those holes.  Everything I've read says you might as well cleanup and rebuild the whole damn engine if you are going to go to the trouble of removing the head.  At the moment, I really can't afford the time or money to replace the head gasket, hone cylinders, new rings, lap valves, base gasket, etc etc etc.  Has anyone ever seen this issue on a FJ before?  How bad do the holes look and can get away with putting everything off for a while?


Title: Re: Holes in my head
Post by: big r on June 02, 2019, 07:58:55 PM
I believe those are just from the casting. Doesn't look like they are leaking any thing, if they were you would see soot or carbon around them. I am sure some one on here with more knowledge than me will chime in


Title: Re: Holes in my head
Post by: Miker on June 02, 2019, 08:06:06 PM
I believe those are just from the casting. Doesn't look like they are leaking any thing, if they were you would see soot or carbon around them. I am sure some one on here with more knowledge than me will chime in

That would make my day if that's true. They look jagged to me, so I thought they might be wear holes.  You're right they're not leaking anything.


Title: Re: Holes in my head
Post by: red on June 02, 2019, 09:24:46 PM
While the tank was off, I noticed four holes in my cylinder head. Each hole is by a bolt. The metal in those areas appears thin.  I was thinking I would just remove the head and JB Weld those holes.
Miker,

I can't say if epoxy is the right cure or not, but there are much better epoxies made for high heat applications.  I like JB Weld, too, but it does have limits.  Contact them, and ask if they have the right epoxy for you.  Contact Permatex and 3M as well; you may find an excellent answer from them, or they may tell you what product you need, if they don't make it.

If you need an all-new petcock, RPM has them.
.


Title: Re: Holes in my head
Post by: Old Rider on June 02, 2019, 11:27:10 PM
Those holes is supposed to be there. That is drainholes for water .The cylinderstuds by that holes has a rubber wrapping to protect them from rusting also.


Title: Re: Holes in my head
Post by: Miker on June 03, 2019, 01:01:52 AM
Those holes is supposed to be there. That is drainholes for water .The cylinderstuds by that holes has a rubber wrapping to protect them from rusting also.

Thanks very much. I'm really glad I don't have to rip the bike apart right now.