Damaged And Removed Bolt 765 Rs

That should have helicoilled ok.
I have done this on quite a few bikes from different manufacturers with success but it does need care.
Here's a 675 camchain tensioner top bolt resolved with the engine in the frame, awkward yes but with care and a few tools easily solved.







By the sound of it your assistant was gung ho and has made a bigger problem hence why he's disappeared.

The first issue and question is, what is the current hole size now?
You need to measure it and the easiest way, assuming limited tooling is available, is to use drills. If you haven't the right size then pick the next one down, then add one wrap of insulation tape at a time until a nice snug fit.
With a caliper or micrometer then measure and post the size here?

Alternatively, if you do have some bore gauges, like I do, then measure directly.



As seen above, the wall thickness is very thin and critical to a successful outcome. Can you also measure the available wall thickness around your problem?

 

I'd need to check but the 6mm helicoil drill is something like 6.3mm so you are already far beyond that which is an issue.

M8 tapping drill is 6.8mm but your pushing the case wall thickness there.

 

How deep is the current drilling, not the original hole?
Has all the steel now been removed?

 

Hi I have had problems with helicoils personaly have found them to unwind if fixing is unscrewed a few times if fitted and left alone are fine there are better options out there if a fixing is to be removed on a permanent maintanance schedule

 

Better options being?

If the clearance drill is held true and a new hole created with care, likewise with the helicoil tap, then a sound repair should be the result.
I have helicoiled undamaged holes, yes holes as good as new, especially in magnesium or aluminium off road motorbike components to make them harder wearing, including items that are frequently removed, and not experienced your issue @philip ham

The emphasises here is on " with care".
A sloppy hole is no good to anyone

 

Welcome to the family. spot of bother there. I my self prefer inserts to helicoils alought nothing wrong with them done properly. But like someone said have found they are great for fixed but removing every new and then does weaken them. I have also mended things like this by taping with a 7/16 if the hole is not to over. But do let us know how you get on Joe

 

Hi yes if holes are in good condition but helicoils don’t always utilise the full depth of hole available not a being critical but just saying

 

Wurth timeserts are the dogs but not cheap you get what you pay for

 

I think a stud rather than a bolt would be a good solution for you. With care and accurate measuring to ensure the issue doesn't escalate to scrap crankcases,
I'd be tempted to thread M8 and bond with red threadlock ( strong bond) an M8 stud and drill the clutch bracket to suit.
This would avoid any future removal issues and should give adequate strength.

Are you aware that helicoils do come in different lengths?

The basic sets available don't show this but they are available and I'd guess in my collection, I have x3 different lengths of say M6 for example.

 

Like Eldon says it is fixable, have a look at bikers toolbox website, they do a great range of Helicoil inserts etc.

 

I wouldn't do that

It basically forces its way in, so if wall thickness wasn't an issue then no problem.
If, as in your case, the surrounding metal is thin then it could, quite possibly, just split the casing wide open.

An accurate size of the current hole including it's depth and shape i.e. round or oval as in off the original center?

I was thinking last night about this and I'd be tempted to helicoil to M7 to retain the maximum casing.
I have a lathe, so I'd then machine a stud with M7 one end and M6 the other ( I already have M7 taps/dies but they are easily available). The original bracket would then fit as before and other than it now showing a nut instead of a bolt head, the repair would be sound and invisible.

If you want a ride to Yorkshire, and pay me for my time, I'll sort it for you?

 

I don't know if this is possible on a 765, but my Speed Triple has the clutch cable bracket attached to the clutch cover using 2 of the cover bolts. Is it feasible to abandon the original damaged mounting point and fabricate a bracket to attach to 1 or 2 suitably positioned existing fasteners? Probably not but just a thought.