Tweaked the cam journal - How bad is it?

[vermin]

This is the first time that I have torn down a motorcycle motor this far (did the top end of a slant six mopar no problem, but that's another story . . .). So, after I removed the cam bearing caps from the head, I replaced the bolts back in the head, so I wouldn't lose 'em, you see. Bad idea. While I was gingerly forcing the head off the block, I bumped one of the cam bearing cap bolts, and this is the result:




The motor that I'm tearing down is from a parts bike, not one of my two running '89 FJ12s. This motor tear down is meant to be a "dry run" so I can learn without too much stress. Well I know what not to do, as far as those bolts are concerned.

My questions are: How bad is this? Is this going to cost a lot to fix?

Thanks,

-Chris

[andyb]

Threads screwed up or ok?  The bolts/caps are located by hollow dowel roll pin thingies that have another name that escapes me atm, so if those still snugly fit the hole that portion is ok.

The bearing surface should be fixable with a bunch of quality time polishing it back down, so long as the sides have the original clearance it should work ok.  Obviously can't leave it sticking towards the cam, though.



Note that I'm not an expert, just going by what I know of plain bearing theory, prolly missing something critical that'll cause certain death.

[weymouth399]

That shouldn't be bad to fix, if you don't want to do it. Hank Scott can perform miracles with this heads he does great work. He repaired heads I thought were junk.
Bob

[Mark Olson]

That is not a big problem, just give it a whack back into shape. check clearances. use a wrist pin or other round metal driver. The aluminum is very forgiving and will shape easily.

[Travis398]

I'll jump on the band wagon and say, it could be a lot more damaged than it is.
yes it still sucks! But you are "lucky" it's not a crack or break in the head.

[vermin]

Thanks for the input, guys. I'm going to attempt to fix this myself, and see how it goes. As far as the threads, the first two or three are damaged, and the bolt goes in at a slightly offset angle. I guess I'll try to clean the threads up a bit with a tap first. Would this type of problem be something that a helicoil could be used for if the tap doesn't work?

Again, thanks for the feedback. Much appreciated.

-Chris

[racerrad8]

Chris,
      We can take a look at it when I come over this week. I think we can get it straightened out.

Randy - RPM

[SkyFive]

Thanks for the input, guys. I'm going to attempt to fix this myself, and see how it goes. As far as the threads, the first two or three are damaged, and the bolt goes in at a slightly offset angle. I guess I'll try to clean the threads up a bit with a tap first. Would this type of problem be something that a helicoil could be used for if the tap doesn't work?

Again, thanks for the feedback. Much appreciated.

-Chris

Chris,
Use a roll thread tap not a spiral tap, you may or may not know this, I didn't. 

[carsick]

Bryan, can you explain the difference? I'm not familiar with those terms.
Doug

[andyb]

One forms threads by cutting, one forms threads by moving metal around.

Here's a better explanation.

[Firehawk068]

If you don't have the proper one, AutoZone had a "thread restorer" set in the loaner tool section........it is not the thread cutter type. they are thread chasers. It includes a variety of both standard, and metric in all the popular sizes. just pay the deposit, bring it home and use it, then return it and get your deposit back.

[SkyFive]

Bryan, can you explain the difference? I'm not familiar with those terms.
Doug

Andy nailed it. If you use a spiral tap and remove any material then use formed thread bolts (like Yamaha's) they are too loose.

[vermin]

Thanks again for all of the input! Really glad to be a part of this forum. I'm going to attempt to fix this this weekend . . .