stripped thread on front engine cover

[rossi46]

as the title says, i have just stripped the thread on one of the engine front cover bolts (even used a torque wrench). when i say bolt, the bolt threads are fine, its the female thread which is stripped. some threads are still there so i have put plenty of thread lock on and tightened the bolt as much as i dare.
question is will this do or do i need to re-cut the thread, if so how do i repair this ?
thanks

 

[rossi46]

just found "loctite form-a-thread".
anyone used it, any thoughts ?

 

[(RIP) Arkwright]

To do it properly you need to drill it, tap it and helicoil it, it's not difficult with the correct size helicoil kit. Anyone who has an Airhead will probably know all about it! DAMHIK - previous owners!

 

[rossi46]

but wouldn't i need to remove the front engine cover ?

 

[(RIP) Arkwright]

Not necessarily, as long as you can get something like a small air drill in straight, do you have a picture?

 

[Timolgra]

Push some plastic metal in the hole, lightly grease the bolt and wind it in.

 

[rossi46]

thanks for the reply's. tried timolgra's idea, didn't work i'm afraid.
how easy would it be to helicoil with the front engine cover in place ? i feel it might be quite awkward as the engine cover is quite thick and if it goes wrong i think i might be buggered !!
any advice on the best way to approach this

 

[twig]

you might be struggling ime afraid with the cover in place. the helicoil tap may well be a larger diameter than the clearance hole in the cover. if you let me know what thread size the bolts are and the clearance hole is i will measure a helicoil tap for you tomorrow. you could drill the clearance hole bigger though.
would be easy with the cover removed, i take it that is not straightforward

 

[rossi46]

It's an m6 bolt, to use an m6 helicoil I believe you use a 6.2mm drill.
The hole in the engine cover is more 7 - 8 mm, so it's close but doable in theory !!!

 

[twig]

yes if its larger than 7mm you probably would get the tap through, thats bigger than i thought it would be. tomorrow i will give you a diameter of the tap anyway, hope you go on ok

 

[twig]

6mm helicoil tap is 7.5mm diameter. measured it today.
6.2mm is the correct size drill. i would be tempted to use a 6mm as you would do well to get an accurate sized hole with a hand drill.
hope this helps

 

[cookie]

good place to buy helicoil* kits

http://www.uni-thread.com/

ordered one yesterday, came today. not the first time i've used them with the same service either

*strictly speaking, they're not branded helicoils, but they are good stuff

 

[Timolgra]

Try a slightly longer bolt, there may be some decent thread left if you measure how deep it is

 

[rossi46]

your right timolgra, the bolts are 30mm but the thread depth is 35mm. so off i went today to the engineer's supplies on my works industrial estate. i was going to get 1 x 35mm stainless bolt and the rest in 30mm to match. they had the 30mm but no 35mm. so i bit the bullet & rang adventure bike warehouse 18 miles away from me expecting the worst, £15ish to repair, its now booked in for tomorrow morning for a re-thread operation (like helicoil but not helicoil ???)
apparently the hole in the front engine casing will need to be drilled about 1mm larger diameter but the bolt & washer will cover that.
fingers crossed all is well, thanks for all your help / advise

 

[rossi46]

Sorted by adventure bike warehouse, thanks lads

 

[thosoneill]

just buy a new bike

 

[twig]

Sorted by adventure bike warehouse, thanks lads

thats good to hear
how did they repair it then?

 

[rossi46]

thread insert, i pressume similar idea to helicoil