Squeeely cam chain

[Whoa Nelly]

Hullo all, been off the radar for a while..
I fitted some APE ccts about a year ago - set them a bit tight and got a wee squeal once the motor warmed up, backed them off a bit and all has been well since. The other day I was idly wondering whether they needed checking (and wondering what to check for, exactly), and today on startup there it was - a very brief but definite squeaky squeal, which immediately went away. Presumably if the ccts are going to do anything its loosen, not tighten up, surely? I often carry a piglet in my tankbag but not today so some other explanation - what say the FireStorm massive?

[benny hedges]

just back them off a turn one at a time until it goes.
if theyre too tight it will wear the guides and stretch the chain, and cause too much pressure on the bearing surface - as well as be down on power.

[Twinpotter]

If you go back to the installation TDC positions, turn the bolt in finger tight (no tools), brace the bolt head with a ring spanner (otherwise the bolts tend to turn in further when locking) pop a spot of thread lock on the base of the bolt and lock. If you're inclined and very careful, you can do them one at a time with the engine idling and feel you're way in towards that sweet spot.

And here's a tip - cut two 60-70mm lengths off some 15mm pipesnap or rubber tubing (marker pen on each the mileage at which you have adjusted them if you like) and snap/slip them over the bolts to keep them nice and clean.

[Whoa Nelly]

Thanks guys - particularly like the tubing tip TP. But any ideas why they should have tightened up now, after a year of running fine?

[tony.mon]

Low oil?
It's only the oil pressure that keeps the cam off the journal bearing surface.

You can run them tight, but it saps power- I'd advise setting them by loosening until you hear a tiny rattle, then turning in one flat at a time until the rattle goes away.

A lot of people say finger tight, but I think that what most people say would be finger tight is too tight, leaving no slack and pulling the camshaft down into the bearing surface.
Not enough to squeal, but asking a lot of the oil film keeping them apart.
And sapping power as well.

To see what I mean about finger tight, try setting it finger tight, then pop the rear cam cover off and see if you can find any slack in the chain run between the cams....

(Rear one, just because it's easier to get to)

[Whoa Nelly]

Cheers Tony, much appreciated. More twiddling, listening & frowning it is then.