Exhaust stubs

hayabusaman0 · Aug 8, 2009

Hi All, went out for a ride today & noticed that the inserts fitted by Cylinder head shop(some years ago) had moved outwards, I drifted them back in but wondered what can be done to stop them moving.

Thanks in return, Paul.

Cookie · Aug 8, 2009

Personally I'd mechanically lock them with a set screw and probably remove the head.

splatt · Aug 8, 2009

I assume the ex flange still pushes up against the head so the nut is acting like a screw jack and pushing the insert out. I have seen a similar insert, they ground four notches in the outer face then tig welded around it and built the weld up over the top of it and filled the notches up to prevent it turning,a tad ugly but it fixed the problem. you could start from scratch remove inserts reweld and tap the holes. I saw FULLAUTOS heads are for sale now ,1380 pound seems like alot money to me.

Cookie · Aug 8, 2009

I was assuming he had the type of repair that is like a screw in insert and it had come unscrewed. One should not assume I suppose.

79x100 · Aug 8, 2009

Cylinder Head Shop usually do the bronze inserts, don't they ? Normally just held by interference.

If they move again, I'd try Loctite first - nothing to lose.

Dr_Hiller · Aug 8, 2009

If they are extracting as you tighten the exhaust nuts, remove them and use Loctite sleeve retaining compound (640, if I recall correctly), then use a drift to peen them into place. The sleeve retaining compound is good for more than a ton of extractive force.

hayabusaman0 · Aug 9, 2009

The bronze sleeve is/was an interferance fit, no pics because I have drifted the sleeve back in. I am going to lockwire it to the head for now as I will be taking it to Beezumph next weekend. I will contact Cylinder head shop Monday & see what he thinks.

I will let you know what happens, Paul.

Seeley920 · Aug 9, 2009

Ah, THAT Cylinder Head Shop!! Send it to Steve Maney or Mick Hemmings instead!! CHS will only farm it out to someone else anyway!

B+Bogus · Aug 9, 2009

My cylinder head was in the same state when I got my bike; alloy inserts had been welded in, but were plain sleeves and one of them was on the move.
My local engineering shop (David Burton Engineering 01253 868111) manufactured screw-in replacements and these are retained in the head with some very high temperature locking compound. Can't remember the name of it, but it was fron the USA, and it wasn't Loctite! He doesn't advise welding the inserts as this destroys the material propertes of the alloy he uses.

He's previously done a similar job on my Ducati cylinder heads, and they're doing great.

Cookie · Aug 9, 2009

The screw in type as Andy mentions are all I have seen. I'm sure locally here the folks have a repair also, but I've been lucky enough not to have had that problem.

kommando · Aug 9, 2009

My bike came with one of these interference inserts, it started move and I drifted it back in but it happened on a more frequent basis and was easier to drift back in each time. I gave up and had Mick Hemmings redo it and it is now like new.

Exhaust stubs

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