RGS cam chain replacement

W

woodlawn

New member
Location
CT USA
Hey all,
Couple questions: When removing my cams, I don't believe the half rings were present.  I was carefully following the instructions posted on Laverdamania. It is conceivable they could have fallen into the tunnels, but I was taking care and I don't believe they were present. Has anyone ever seen this before?
Also I also can't seem to get the cam chain correctly positioned to meet between the gears while maintaining #1 cylinder at TDC. Do I need to remove the chain tower and the tensioner blade to get the chain free of the crank? What it the best method? Thanks
 
RGS Cam blocks don't run the 1/2 rings

cam chain does not need to meet in the exact centre, as long as you have the cam marks lined up and the No 1 piston at TDC then it does not matter where the chain meets
 
+1 on what Red said......

I find it easier to get the master link in a new cam chain when the two ends of the chain meet on a sprocket and both ends can engage on gear teeth. The master link position moves around, don't worry about it, just get TDC and timing marks on the cams correct.... and try not to drop an end of the chain down the tunnel or you will have to remove the cam chain guide from under the crank/bottom of the motor and fish it back through.

sounds like you are being very diligent with the instructions, good on you, but where the chain ends ends meet simply does not matter.

and to anticipate your likely next question, yes the bloody new chains are freaking tight when first installed, can be tough to get the master link in, various techniques are advocated as to how to draw the chain ends close enough together to get the master link actually in, I use circlip pliers in the chain ends, myself. Just be sure and stuff rags down the cam chain tunnel to keep anything from falling in if you drop anything.

Paul LeClair
 
If the chains are tight there could be a cure.

If the chain has any grease on then it is likely to be industrial, not
a bad thing depending on make, drop the chain in petrol overnight
to remove all lube. The lube takes up the tolerances in the chain.

Andy

PS iwis chains have just a very light lube and they almost looked worn
out when new.
 
Just a suggestion, this looks like it will do the job efficiently?

http://www.demon-tweeks.co.uk/motorcycle/chain-tools/sealey-motorcycle-chain-puller

17286_0.jpg


 
As per what others have said, RGS cams have thrust faces either side of the centre bearing rather than the half ring.  So nothing to worry about there!
The chain is likely not meeting in the centre because you have presumably rolled the new chain in on the end of the old one so it ends up a bit out.  The easiest way to get it exactly where it was before is to roll in a scrap chain (you could just get any 06B industrial chain from a bearing shop if you don't have an old chain) , connect the new chain to it and roll the scrap chain out backwards.  The new chain is right where the old one was.  I do find it easiest to connect the joining link if it's in the middle or close to it, but it is not critical as long as the timing is correct.  This whole thing is a bit more tricky on 120's because there is no point where the cam is not acting on any of the valves like there is in a 180.
If you have installed the chain any other way, best you remove the inspection cover and confirm it is on the crank sprocket teeth correctly.  Not a bad idea to have the thing off every once in a while to clean out the grunge anyhow.
Oh, and I always remove the tensioner and blade when fitting a chain, it makes joining the ends much easier!
Cheers
SteveB
 
Now there's a coincidence Simon. I just bought one of those exact same chain puller things on Ebay a couple of days ago. Hasn't arrived in my letterbox yet. I haven't done my valve clearances for a while and I thought a new tool might motivate me to do it!

This whole thing is a bit more tricky on 120's because there is no point where the cam is not acting on any of the valves like there is in a 180.
Click to expand...

That's an odd claim to make. So I've just been doing a little thought experiment about it, and I don't believe any Laverda triple or parallel twin has a crank position where no cam lobes are acting on valves. You might be able to find such a spot on a twisted twin, depending on the crank phasing.

Cam
 
If there is then it's not at the timing mark for joining the camchain.
I always have to pull the inlet cam against spring pressure to join the chain. The exhaust sits there ok though.
 
Grant said:
If there is then it's not at the timing mark for joining the camchain.
I always have to pull the inlet cam against spring pressure to join the chain. The exhaust sits there ok though.
Click to expand...

works fine on a 180, exhaust sits still, need to move inlet to join the chain, not so easy on a 120

 
Cam,

You're over-thinking again, I didn't say crank position. :)

On a 180 there is a point (on each CAMSHAFT) where no valves are acting, that's the point you use when removing or installing each camshaft, then you bring it to the correct timing position and join the chain.  On the inlet that point is just slightly retarded from the TDC position, so you just have to advance it a tooth or two against a spring to be timed.  The exhaust is between cylinders, which is both why it stays still on it's own, and also why you have to lower #1&3 pistons away from TDC (to avoid valve to piston clash) and wind the cam about 180 degrees to find the "no valves rocking" point when you uninstall / reinstall it.  Of interest to pedants is that the 180 and 120 run #1 cylinder on the opposite stroke at the timing mark.

With a 120 inlet or exhaust cam, there is no point where a lobe does not touch at least one valve, simple geometry.

cheers
SteveB
 
Well ok guys, thanks so much. I really appreciate eveyone's prompt feedback. I guess I have been overthinking it. Now to go out and get it done.
 
breganzane said:
Cam,

You're over-thinking again, I didn't say crank position.
Click to expand...

OK, fair point.

I've never checked on a Laverda, but I assume it's possible to clash valves. Something to keep in mind if turning the camshafts indepenently, or when bolting down the camshaft bearing caps.
I actually did this on my Kwak 1300 in a moment of inattention. Bolted down the cam bearing caps with the camshafts out of phase. Bent a new valve and cracked a new valve guide, so the head had to come off again half an our after I'd installed it. Couldn't believe I'd made such an elementary blunder.
 
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