Another small challenge

[12960]

The bottom hex head bolt that holds the engine front cover was
stripped and fell out on the highway.

Whats the best way to fix that without too much trouble?

Can it be drilled slightly and threaded or is there a self tapping bolt that I can use?

Gerry

 

[skiteach]

I don't recall the size. Best/easiest is to Helicoil (or any other threaded insert) the threads and replace with original size. I am not aware of any oversize bolt fixes, other than retapping to another size. That may also create issues with the cover.

 

[12960]

small challenge

Is there a metric helicoil???

Gerry

 

[barryg]

Just happen to have my R90 engine sitting in my den, checked the lower threaded hole in the timing chain cover. It's pretty deep. Look up in there and see if U have any threads left. U could possibly be able to use a little longer bolt to hold the front cover. I think the bolt size given is m6x20. Find a m6x25 or30 and grind it down to fit the last few threads up in the hole. U can also possibly use a couple of extra washers to set the length. Yes there are helicoils and timeserts that can be purchased to do the fix. I would probably go with the timesert as my personal preference.

 

[RJM2096]

Is the bolt stripped or is it the block that is stripped? That makes a difference. Sometime just a new crisp bolt will work. I like Barry G idea of a long one. Might add locktite which would help hold the bolt if the threads are worn but not totally striped out.

 

[barryg]

I was going on the assumtion that the threaded hole in the timing cover was stripped. My first suggestion was kind of a get by work around fix. Would probably work for a while. If there were some good threads left up in there to use with a longer bolt. The timesert and helicoils, I consider permanent fixes. Sears Craftman Tools sells a neat standard/metric rethreading tool kit. Wouldn't hurt to run the proper size threaded tap in there and make sure the threads that are left are in good shape. A proper bottom tap would also do the job. I was a jobshop machinist/tool&die maker and automotive machinist for 30 years. I still have all my machinist tools and specialty bmw motorcycle tools to work on my own bikes. Makes it easy for me, since I have most of the tools and ability to use them. When I give a machinist type answer I'm assuming a certain degree of ability to do this type work. The front cover is a service point so I would avoid using locktite. Locktite is a good idea for a lot of applications, just not this one. Helicoil and timesert kits usually come with pretty good instructions. In fact I use locktite on the timesert insert and that is not in the directions of the instruction sheet. The bolt will never come in contact with the locktite. I'm sorry for the wordy comment, but thought a little more insight would help. Good luck with your project.

 

[barryg]

Rob Mays- My accumulation of bikes kinda mirrors yours. 94 R1100RS, 95 Road king, 71 Norton Commando, Panhead chopper, others. Just need some sport cars. Barry

 

[LOSTBOY]

A 1/4-20 American bolt is slightly larger than the stock 6mm. Run a tap in and you can avoid heli-coiling. The only drawback is that you can wind up mixing hardware if you have a lot of it removed. Just imagine what the next owner will think...

 

[12960]

bolt problem

Thanks to all for your help.

Gerry

 

[bearsfolks]

Stripped thread

I used JB Weld to fix the threads on the valve cover center bolt. Cleaned the area with alcohol, squirted the JB Weld in the hole and followed by screwing the bolt in hand tight. Later tightened the bolt with a wrench. This was 10 years ago. I have had the covers off many times since and the fix is still working.

 

[Bill Burke]

I went to the hardware store and bought a thread chaser drill bit (6mm x 1.00? don't remember the size or pitch for sure, sorry). Drilled it out and it accepted the old bolt again nicely. Worked for me.