Clutch bearing collapse

[R-III-R Turbo]

And they are standard thread M6 ISO-C bolts - Which is a 1mm pitch.

Thank you Chris, well spotted, I made a balls of that note. Updated now so as not to spread misinformation. I also had x6 down instead of x5. Must have been smoking crack that day

Don't be fooled into using stainless bolts they are not typically high tensile unless forged and marked Gr8.8 or higher Gr 316 are far better than Gr304 - better to use high tensile carbon steel bolts if you are going to replace them and they will need to be M6 x 1mm ISO std. Gr: 8.8 or better

Thanks John that has me wondering, why would high tensile carbon steel bolts be needed when they're going into a small & fine aluminium thread?

Also what tensile rating are the stock bolts do you know?

 

[ruzzle]

Strikes me that the main requirement is resistance to straight shear... which is what happens when/if the towers are about to give up the ghost. Bin thar, dun that..........

 

[barbagris]

iirc - The stock bolts are SHEAR bolts anyway. The shank is less than the thread major diameter. I cannot remember if the minor diameter is undercut.

The idea (I guess) is that bolts are actually sacrificial. Designed so the heads pop off. This should (in theory) protect the Basket towers. But as Scott so cleverly discovered - this is not the case.

Standard A2-70 will be more than enough. I'd not use 4.8 but I'll bet that close to what the originals are.

 

[ruzzle]

The idea (I guess) is that bolts are actually sacrificial. Designed so the heads pop off. This should (in theory) protect the Basket towers.

Dunno about that Chris. With the stock setup, when the towers break away from the hub, the bolts (which are wholly within the towers) are relatively undamaged... (apart from the grenade effect!) Warp??? Comment??

The longer bolts going deeper than the towers and into the hub should provide some additional shear resistance when load is applied to the towers.

But anyway... the longer bolts seem to cure the problem, even at ridiculous engine outputs.......so far!

 

[barbagris]

Dunno about that Chris. With the stock setup, when the towers break away from the hub, the bolts (which are wholly within the towers) are relatively undamaged...

So I see we still have undying faith in Triumph Designers - I'm afraid the whole detent thing cured me of that.

 

[warp9.9]

Dunno about that Chris. With the stock setup, when the towers break away from the hub, the bolts (which are wholly within the towers) are relatively undamaged... (apart from the grenade effect!) Warp??? Comment??

The longer bolts going deeper than the towers and into the hub should provide some additional shear resistance when load is applied to the towers.

But anyway... the longer bolts seem to cure the problem, even at ridiculous engine outputs.......so far!

I must agree with Ruzz there some of mine where pretty much undamaged but all snapped in the hollow area of the casting fillet radius.

 

[ruzzle]

So I see we still have undying faith in Triumph Designers - I'm afraid the whole detent thing cured me of that.

Not quite undying... but the OEM tower setup survives the OEM engine OK.

Gotta go along with you on t'other tho!!

 

[barbagris]

My point was/is that had the bolt heads actually popped off (as I think they were sort of expected to) then the baskets themselves would remain unscathed - sort of anyway.

Without access to the original designers plans and the final production plans there is no way we'll know what corners may have been cut in the design->production stages. It would not be the first time that "I know, we'll just change this itty bitty part" has not been fully thought through.

 

[Stephen McMullen]

hI IF YOU GO ON YOU TUBE AND SEARCH FITTING ROCKET CLUTCH TERE A VID OF A GUY FITTING A BARNET CLUTCH ON IT AND IT SHOWS THE BEARING CLEALY
HOPE THIS HELPS YOU

 

[R-III-R Turbo]

Thank you Chris, well spotted, I made a balls of that note. Updated now so as not to spread misinformation. I also had x6 down instead of x5. Must have been smoking crack that day

Thanks John that has me wondering, why would high tensile carbon steel bolts be needed when they're going into a small & fine aluminium thread?

Also what tensile rating are the stock bolts do you know?

@John Miller