Header/Engine case problem...

I'm currently in the process of tearing down the old '82 XJ650 that I acquired last year in a cafe project. I thought the exhaust looked out of place; it obviously wasn't the stock header, just some poorly fitted pipes.

During the exhaust removal, I noticed something was strange when I had to grab two different size sockets to remove the bolts; a 10mm for the two pipes on the right side and a 13mm for the two pipes on the left.

I also noticed the left-most bolt on the the first header was less-than-straight due to a improperly sized and forcefully installed metal flange securing the pipes. I was worried these were signs that getting things right again would be far more difficult than I had anticipated.

Well it would appear my suspicions were well placed....





My question now is, obviously since there are two greatly different sized threaded holes.... how screwed am I?
And what do I do now?

 

It looks like someone stripped out the threads and drilled them one size over to re-tap, which is a pretty standard form of repair. Seeing as using the correct size studs would be preferable you can measur the larger holes and get a Heilicoil to suit it, which will give you brand new steel threads th take the original size exhaust studs. Both Helicoil and Timesert offer oversized thread repair inserts if the hile you have to work with is too big (it looks like the right size for a standard Helicoil. I prefer to use Helicoil inserts as they are approved for aviation purpoes, but any of the brands of inserts are perfectly fine to use.

In short, you are 0.00% screwed.

 

*sigh of relief*
My biggest concern is the re-drilled hole is obviously crooked. So I'm guessing the re-drilled hole will have to be re-drilled.... again? I'm a little apprehensive about having to do anything that could potentially make a small problem into a big one... Is this something a machine shop would do?

 

A machine shop would fix that with no problem at all. Might set you back $100 or so.

 

The only time you'd really be screwed with an Xj is if you crack your engine block--- oh wait, a couple hundred bucks and you drop in another engine.

Naaah, these bike are easy. You may have to find a new part but everything is still available either through here, xj4ever, eBay, etc..... You may have to search and/or wait, but you certainly wont be screwed

Yours is a common issue. Do it yourself, or take it to a machine shop. I do most of my own work, but I personally would go to a shop for that simply to make sure it's dead-on accurate

Davr

 

I wouldnt worry about it at all...

Unless you really want to use the "proper" studs/nuts...

 

+1 to that, if it works, it's not going to work any better after a lot of work and money

 

If you can thread it back in and tighten it down, though......I'd do that. Oh, yeah.....had two bikes like that---

 

The previous owner re-drilled the left side, and proceeded to strip the new drills completely as well... So at this point I couldn't secure new bolts in that side, even if I felt confident. Big thanks to you guys, always a great feeling to fall back on the XJ Bikes thread for friendly advice.