gearbox helicoil repair

[what have i done]

Hello all.. I usually lurk in the shadows but I am hoping for some advice regarding my gs1150.

A few weeks ago i decided to take a few bits off for cleaning and a maintenance... Well things soon ended in a full dismantle (my garage looks like a haynes manual photo-shoot... a messy one, its now a full restoration..

Problems encountered so far

Corroded/snapped bolts... I am now fully trained up with helicoil inserts and after 3 hours with a Dremel removing a snapped "easy out" I will never use one on a rusty stud again!

The coating inside my tank is coming off in big pieces,, Currently the tank (minus the pump/filter) is filled with a caustic solution to get it all off.

Just when I thought I was ready to drop everything in for blasting (soda for engine, grit for the black bits) the bolt holding the swing arm to the gearbox would not come out... at least not without damaging the threads.. I have sourced a new bolt but cannot find a suitable helicoil.. M27x1.25 anybody know of a supplier?

I am currently investigating having a "top hat" shaped bush made at a local engineering firm to accept the new bolt. but I am open to any suggestions.. obviously changing the box is a last resort!

many thanks in anticipation.

 

[mikeyboy]

Got plenty of casings if you need one swapping

 

[Steptoe]

.. I have sourced a new bolt but cannot find a suitable helicoil.. M27x1.25 anybody know of a supplier?

I don't think the casing is thick/deep enough for a helicoil.

 

[what have i done]

Hello Mikeyboy..
Thanks for the offer let me know how much a casing will cost?.. However today when I asked my engineer friend who came up with the bush idea if he had a rough cost for the bush he said it was made! He just picked up the box and apparently they are going to freeze the bush, heat the box and press it in!.. He is confident it will work... however if it doesn't ... I may need the casing to be honest he has never failed to get me out of the S**t but he no longer has access to a workshop and a friend of his is doing the work I am not counting my chickens..

I will post a picture when i get it back if anybody is interested?

 

[mikeyboy]

Sounds like a reasonable repair,
My only concern would be the lack of "meat" around the mount,just remember that pivot is the only thing holding the swing arm in.
If the casing fails there is every likelyhood that the back of the bike will collapse.not good!
I would consider welding the insert in if it was my bike or some kind of reinforcing around the bush.
JMO of course

 

[what have i done]

I share your concerns.. If the bush hadn't actually been made I would have gone with the casing swap option.. My mate said he wanted the bush to be steel (for strength) but I didn't want it rusting. I probably should have taken his advice but the last thing I want after a nut and bolt rebuild (which was only brought about by cosmetic ... shame) was a rust streak! when I get it back I may well pop it in for welding .. One of my worries is what happens when it has to come off again (hopefully not soon)how will I stop the bush turning!? welding will address this..

I have assured my mate that all this is his fault if he hadn't chased the big money and gone to work on the rigs .. he would be rebuilding my bike in a high tech tool room and getting paid by his previous employer for doing it.. spoilt I was

 

[PaulRS]

Same situation here, a few years back.

We came to the conclusion that a threaded plug would be best.
So we made a plug out of a piece of stainless hex bar, M32 x 1.25 on the outside, M27 x 1.25 on the inside, leaving a few mm of the hex to just get a socket on and fitted that to the rethreaded hole in the gearbox, from the inside.
A drop of Loctite to be sure.

Worked like a treat.

Paul.

 

[what have i done]

Hi PaulRS
Its a relief that I am not the only one to have suffered this..
In hindsight once I had realized that no amount of heat would help the bolt/pin come out I should have cut it off, removed the swing arm and taken the box somewhere to drill it out ..not put a big bar on it! but I am cursed with a "can do" attitude or as it says in my divorce papers "prone to outbursts of irresponsible behavior"

Glad your repair worked I hope mine does. I am itching to start rebuilding I am already into week 3 of the 4 weeks I allowed for the project !!