C15 outer camshaft bush

[Tigerfeet]

The outer camshaft bush is slightly loose in the case on my C15F project. This only came to light when I was checking the camshaft endfloat. I can pop it out of the case with a tiny bit of finger effort. It is a nice fit on the camshaft - and it is pegged (so it hasn't been rotating).

Obviously I could find and fit a new bush, and ream it as required. But could I alternatively use some loctite bearing fit or similar to secure it? Any downsides?

[iansoady]

Loctite should work unless it's a sintered bush which allows oil to soak into it and would be difficult to get the loctite to adhere properly.

[rogerfastlane]

Loctite comes in several flavours so don't use std fastener lock. If this is loose you will need the grade for gap filling (I think they do 2, one for big gaps, one for smaller) Check out their data sheets/website for the correct type.
Degrease the bush and case very well, light oil or grease (vaseline?) the camshaft and once Loctite applied to the bush/case clamp up on the engine with the cam in place to align the bush. If you don't do this the bush will sit wherever it sinks to under gravity and misalign with the camshaft and immediately start wearing.

Personally, I would (and have done in similar circumstances) sent the case off to RTS with the cam and have them make a bush to fit and ream for a perfect long lasting solution that will not fail.
Old Brit bikes get hot, bits move around, radial valve lift forces and accelerations are quite high and these parts are all getting quite old so I don't trust Loctite in the circumstances except in an emergency.

If the bush in keyed how can it have come loose as it could not spin? This suggests the hole may be worn/distorted or a pattern bush was fitted that was never tight, the inner crankcase bush will also now be slightly tapered etc., so check the amount of rock of the cam on the inner bush before doing anything else and measure the inner camshaft journal as well. Hopefully all caught before XS inner bush/journal wear but for the pfaff and cost of a later re-strip/rebuild, if the inner bush and shaft is OK worth sorting the outer bush properly now and this will probably never be a problem in future?
                 

[Tigerfeet]

The same thought had occurred to me - how could the outside diameter of the bush be worn when it is pegged. I went to my favourite US website that give pictures and dimensions for nearly all C15 parts (bsaunitsingles.com) and it informed me that the bush outer diameter should be 0.9155". My bush measures 0.9075" - so I think it has been an undersized pattern part. 
The new bush I have obtained measures 0.9165" - and it certainly is not a push fit in the case.I tried tapping it in after having the bush in the freezer for a couple of hours and heating the case for a few minutes with a hot air gun, and it wasn't having it. So today's question is how much interference should a bush like this have?

[Oval57]

I was just reading through a few posts on the forum and seen yours, sorry to drop in on it but I have attached a chart I use that may help,
Sorry not really being familiar with the engine you are working on but I have always found that when warming a case for press fit type bushes you need some good warmth and a hot air gun doesn't get things hot enough, I usually put cases in my hooded BBQ set at 200 F for a while or play a Butane torch around the area, and sit the bush in the freezer whilst it warms up......you know you will more than likely have to ream the bush once fitted

[Tigerfeet]

Thanks so much for the chart. I will do some measuring and see if my new bush needs reducing a fraction before I go in for round two.