stripped threads on cam bearing covers

[robsGS850]

Was adjusting my valves and noticed two bolts on the exhaust cam bearing caps were poking up, and totally floating loose! The threads had been stripped by the PO, I guess.

It's one bolt per side, the other three on each side are fine, as are all the bolts on the intake side. Can I keep riding it like this or is it a fatal blow? Can these be retapped? Will i have to drill out the cap as well for the newer, bigger bolt? I know there's something called a Helicoil (or something)...

any advice greatly appreciated, thanks

[Billyboy]

You can heli-coil them. Depending on where the bolts are you might have to pull the head off.

Quick search will tell you. I've never used them myself.

[triffecpa]

The engine will run fine with three of the original four bolts holding the cam covers in place. Long term solution is to heli-coil as Billy mentioned. You can buy a Heli-Coil kit at any good bolt store. They come with the correct drill size, correct tap and a selection of different length inserts and the tool to put the insert in place. The only other thing that I would recommend is some aluminum cutting fluid (green stuff) to help cut smoother threads. The kits cost $35 or so (or did the last time I bought one). A kit is designed for one size of bolt and pitch (ie 6mm x 1.0mm threads)

TR

[Don-lo]

A 1/4-20 SAE bolt, slightly shorter, will self-tap in nicely and probably last forever. There will be more drag on the threads, so forget the torque wrench for that one and snug by hand.

Before reinstalling any new bolt, run a Q-tip down the hole to make sure it is not filled with oil! Hydraulic lock is often the reason for the destroyed threads.