Proper re-thread method on stripped valve cover bolts

[1980GS850]

June of the last year I had a shop service my valves and re-torque the head. Turns out that the base leak I thought was really coming from the valve cover and when I picked up the bike the mechanic said three of the valve cover bolts were stripped out. He did not fix these or call me to tell me they needed fixed which would have been nice He said bring it back in the winter, impossible to do because I have moved. Is there a proper procedure to follow for this occurrence? I have limited mechanical experience but now have a garage space that I can work in. TIA.

 

[rapidray]

I am a fan of Helicoils. Do you have the engine out of the bike? Getting access to the holes will be the biggest issue. You can search YouTube to find videos for how to install them. If the engine is in the frame & stuff is in the way will be your biggest problem.
Ray.

 

[jsandidge]

I just did one on my bike last weekend. I had to get a right angle drill attachment, and drill through from underneath. Mine was the front center one next to the cam chain tunnel. I was just barely able to get a tap and the helicoil tool in from the top side. It all worked out fine though.

 

[headsbikesmopars]

I had a stripped out center cover bolt and I drilled it out to use a bolt with nut, works well after 8 years.

 

[Kiwi Canuck]

Helicoil for sure, I've done many and mostly by hand with a cordless drill and hand tap, very important to drill and tap straight if not you will have a bigger problem.

Check youtube for videos, remember to read the instructions as breaking and removal of the insert tang is important.

Here is a sample of a kit you could get,
https://www.amazon.com/Helicoil-554...d=1484237871&sr=8-1&keywords=6mm+helicoil+kit.

If you are not comfortable doing this most small machine shops that do this kind of work will do them for about $50.00 - $75.00 per helicoil.

David.

 

[1980GS850]

Thanks guys. Luckily all three are on the outside and seem by the eye to be accessible. Can I ask, as a way to learn, why the helicoil process is necessary? I was thinking the holes could just be re-tapped and use a larger bolt, the cover itself would need to have the holes expanded to compensate. What does the number (s) on top of the bolt refer to?

 

[1980GS1000E]

Using Helicoil or similar is the proper way to repair this and it is very easy. I don't even use a drill but use a hand tap handle with the drill bit as it usually cuts the soft aluminum like butter. The number refers to the strength of the bolt.

 

[GregT]

When inserting helicoils, they really need to have pressure maintained on the end to ensure they don't jump a thread. Most insert tools have a collar which should be set to the correct position to ensure this - easy enough.
But if you've stripped a thread at the bottom of a hole which holds a dowel it gets a bit harder to do properly. I've not seen an insert tool collar small enough to fit in the dowel hole. What I've done is machine a short brass spacer 8mm long and 7.5mm OD to slip onto the insertion tool to ensure that pressure can be applied right to the bottom of the dowel counterbore.
Done plenty of helicoils using this - it works.

 

[2BRacing]

Thanks guys. Luckily all three are on the outside and seem by the eye to be accessible. Can I ask, as a way to learn, why the helicoil process is necessary? I was thinking the holes could just be re-tapped and use a larger bolt, the cover itself would need to have the holes expanded to compensate. What does the number (s) on top of the bolt refer to?

Inserting a helicoil of the same size as the original fastener allows you to use the same size bolt again in the repaired hole, instead of just re-tapping and therefore having to use a larger size bolt. There may not be enough metal left around the holes for the valve cover bolts to use a larger size bolt than original.

The number(s) on top of the bolt refers to the tensile strength of the bolt.

 

[1980GS850]

I had a stripped out center cover bolt and I drilled it out to use a bolt with nut, works well after 8 years.

Thank you, this is what I ended up doing. Helicoil may be in my future after the next valve check