Topic: Help needed. Stripped thread cylinder head

[FlipYa4Fake]

I was just reinstalling my cylinder head cover and one bolt just wouldn't tighten down. As I pulled out the bolt the threads came out with it. What are my options at this point? I can tighten enough where I can't loosen with my fingers, but it won't torque to the specs. Is this good enough since it is only one? It is the left bolt of the two in the center of the picture below.

[Flyin900]

That looks like a Heli Coil that has come out with the bolt threads. I won't use them for that reason. I have had the same issue with bikes I restore that someone has used a Heli Coil as a thread repair.

Time Sert is the only repair I will use today on stripped threads. I am fortunate that I own a Kent Moore complete Metric Time Sert kit that makes it easy. A Time Sert is a full steel insert that locks into the repair and will never wind back out like that Heli. The down side for you is a complete Time Sert set will run about $50 to fix that hole.

[Mikal]

If it's the cylinder head cover I wouldn't stress to much about it. I'v ridden for two years with my cb500four -72 with two bolts just like that. A fresh gasket and no leaks. Agreeing with Flyin900 that it's a helicoil that came out. I use a little threadlock when I insert helis.

That being said, and without any knowledge about the 650's internals, you should be careful about shavings ending up inside the engine when stripping bolts. Especially when it comes to the oil canals in the top end, would be a shame to block any of them off.

[70CB750]

It is only valve cover, just helicoil it.

[FlipYa4Fake]

Thanks. I guess I'm not too worried about it since it is only the cover. I will watch it and if it seems to leak or anything then I will get an insert. Thanks for the responses.

[MickB]

Put a new helicoil with some locktite on the out side of the coil.

[MRieck]

That's not a helicoil...it is the aluminum threads that were in the hole. Touch it with a magnet and you'll see.

[przjohn]

That's not a helicoil...it is the aluminum threads that were in the hole. Touch it with a magnet and you'll see.

I'll take even money on that one, put a magnet to that scrap. Is it a Helicoil or threads?

[MCRider]

If there is enough meat left, tap it out to 1/4"-28, and run a 1/4"-28 screw in. No one will ever know.

[chewbacca5000]

Wish I had a  Kent Moore complete Metric Time Sert  kit!  That would be great.  Ez-loc is a nice mid range option a little more than heli, but is a solid insert like time sert.  It does not have a seat like time sert, but if you peen it into place it ain't going anywhere.

[FlipYa4Fake]

I am very confident that this is aluminum and not an old helicoil.

[jonda500]

That's not a helicoil...it is the aluminum threads that were in the hole. Touch it with a magnet and you'll see.

+1 looks like aluminium to me too - I would just put a helicoil in, I have many helicoils in 2 of my 3 bikes and I haven't had one fail yet!

[PeWe]

Helicoil it. If the helicoil will go bad you have a 2:nd chance with Big-Sert.
(Ruined M6 helicoil hole is appr 7.1mm, Big-Sert drill is 7.3mm, easy to drill with a tap tool, then tap it... I used it in my CB750 head, cam studs.)

[70CB750]

Or you could drill it and tap it for bigger thread, kinda crude but I done it for jeep valve covers.

[MRieck]

I'll donate 100% of my winnings to Cal's next project.

[MCRider]

Or you could drill it and tap it for bigger thread, kinda crude but I done it for jeep valve covers.

See reply #9 above. A 1/4" screw with a 28 pitch is slightly larger than a 6mm x 1.