1955 18CS Drivetrain Rattle

keje · Post by **keje** » Sat Sep 09, 2006 10:33 pm

Hi Folks!
Ive just put my bike together with the engine totally restored, except the cams.
The drivetrain rattles like ....
Tryed with a new pinion gear from the club but it only reduced the noise some.
What to do?
Getting new cams from the club? (expensive try if it doesnt work)
Dont know if anyone of you have tryed them, are they quiet compared to the original cams (there is some miles on my old ones but they seems OK)? - a mystery it is!!!
Although! The bike leaks no oil, even the old primary tin-covers are tight and dry!
Keje,Sweden, 1955 18CS with SH-cams

Don Madden · Post by **Don Madden** » Sat Sep 09, 2006 11:25 pm

There was a factory bulletin, mentioned in some of the books, about fitting high lift cams in earlier engines. It covered removing some material inside the timing chest to prevent interfence.

I don't have my hands on the bulletin right now & it may only apply to pre-55 engines, which should originally have "H" cams.

remove the cover & inspect for scuffing of the interior. Alternatively, put in the original cams to see if the noise goes away.

Or, wear industrial strength ear plugs, or better yet an IPod.

Cheers, Don.

Biscuit · Post by **Biscuit** » Sun Sep 10, 2006 12:29 am

What do you mean by 'drive train', this usually means the transmission from engine sprocket to back wheel and all in between, yet you are talkimg valve gear. Your not hearing a rattling clutch by any chance?.

Dick Hobart · Post by **Dick Hobart** » Sun Sep 10, 2006 12:41 am

I thought the same as you Alan. I know it's a CS and not everyone bothers with the dynamo on these models, but if it does have one and it's been refitted maybe it's "bedded in", as it were, and there's now play in the dynamo chain. That can make a disturbing racket echoed by the pressed steel cases. If you're sure it's the cam box, Keje, have you checked the followers. I know AMC followers are not noted for wearing, but on most British bikes if there's noise in that area it's more usually the followers than the cams themselves.

itma · Post by **itma** » Sun Sep 10, 2006 11:23 am

With the glorious exhaust note produced by SH cams, surprised you can hear anything....
Have you checked the exhaust cam follower/ valve lifter set up? if theres not enough slack in the valve lifter cable a lot of noise can result, especially if the lift arm is in constant contact with the tappet collar

Biscuit · Post by **Biscuit** » Sun Sep 10, 2006 8:47 pm

I'm surprised you thought to replace the halftime pinion, but not the cams/gears. If the pinion was worn, surely the cams must be also, if they are they will make short work of your new pinion. My advice would be to put the old pinion back until you decide whether to get new cams. Apart from backlash, you can check for wear by feeling for a raised burr on the side of the teeth.

keje · Post by **keje** » Mon Sep 11, 2006 9:24 pm

Biscuit,
I beleive you have a point!
The old Pinion had a bit of wear on it why I changed to the new one, but the cams wear is nothing to be alarmed about. So what to do? I already got the new pinion in and that did not make any major difference to the rattle.
The bike have been running as a MX-bike for some years before I bought it, so who knows what has been done to the engine thru the years.

Im curious about if a change to new cams would cure the problem though.

Will check for the raised burr on the gear teeth.
Thanks!
Keje.
Straight pipe could be an option!

itma!
cam follower/ valve lifter set up is OK.

Dick!
I ment the cam side , the drivetrain is OK, both drivechain and gen. drive all new.

Don!
Dont know if the cams are the original ones, but there is no scuffing of the interior.
Although, Ive got both an Ipod and some really nice sounding Sennheisers to go with it..

RogerNorman · Post by **RogerNorman** » Mon Sep 11, 2006 10:32 pm

Is it a rattle or metalic clonk? My 16C engine makes a right clattering noise when its warm - surpised Busicuit didnt mention it earlier - he's had to put up with the row often enough. Its because there is too much end float on the camshaft. The bush in the case needs knocking back into place a bit but I'm lazy and the bike still goes extremely well (for a 350) and no I do not treat it too kindly - never have done in the 35 years I have thrashed it. Its biggest issue is that I don't ride it often enough nowadays. If you know the engine well enough and the noise was there before I'd be inclined to leave it. Mines been noisy for nearly 20 years but it still performs and hasn't missed a beat in years

itma · Post by **itma** » Mon Sep 11, 2006 10:39 pm

quite right, the rattly ones are often the fast ones

Merlin · Post by **Merlin** » Mon Sep 11, 2006 11:02 pm

Bit like some women I have met