Cam Chain Shrunk!

Rockitdoc said:
I've got all the mounts attached (loosely).  Is there a sequence, or can I just start tightening stuff up?
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No particular sequence on the rubber-mounted 120? models, just nip it all up.  Pay special attention to the 2 x M8 bolts for both upper rear mounts.  Check these (as you are certain to do anyway... ::) ) after the engine has run a bit.  They are especially difficult to reach and are often neglected.  Paint or powder coating will spread under the load of the bolt torque, the nuts can loosen, resulting in quite harsh vibration.

And yes, the main stand is the first thing to fit to a bare frame, then the side stand on 120's... :D

piet
 
So, I am inclined to put the rear wheel on, then the front so this beast can stand on it's own.  However, I thought I'd better check with the experts, since you WERE SO RIGHT ABOUT THE SIDE STAND!  Way better to have put that sucker on before the engine went in.  That spring is a bugger.  Got it on, though.  Center stand not so bad.  Tip the whole mess forward and the bottom reveals itself.

P1010659_zps6906d104.jpg
 
It looks like you have the two simplex chains, which is what you should have on your standard SFC 1000. Should be good for 15,000kms. Post 96 shows the triplex, which is not your engine! Maybe Andy's finally finished that pint........
 
Laverdian said:
It looks like you have the two simplex chains, which is what you should have on your standard SFC 1000. Should be good for 15,000kms. Post 96 shows the triplex, which is not your engine! Maybe Andy's finally finished that pint........
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I was confused, as usual, not knowing much about these bikes.  Glad to hear confirmation that mine has two simplex chains.
 
I double checked my cam chain tension before buttoning things up.  It's got 1 mm of slack between the cam sprockets on the head.  Too tight, right?  No tensioner tension, original chain, sprockets, head.

I looked at a previous posting regarding cam chain being too tight and saw that sometimes the cam chain can be cattywampus on the crank sprocket.  So, I opened up the inspection port on the bottom to take a look.  Here is what the eye-on-the-end-of-the-stick (EOTEOTS) shows:
P1010661_zps11fe12f1.jpg

another view:
P1010662_zpsa2025391.jpg


without EOTEOTS:
P1010665_zps19e7a63f.jpg


It appears to my untrained eye that the chain is seated properly on the sprocket.  What say those with experience in this matter?

Cam chain shrunk, right?

 
Rockitdoc, it depends what you mean by "slack". 1mm is way too tight with no tensioner, you should have +/- 5mm with the tensioner in. But do remember on the 120 engines there's probably no position where the valves aren't acting on the cams so you will always be fighting against the valve springs. If you press down hard on the chain do you get more travel than the "slack" 1mm?
 
Laverdian said:
Rockitdoc, it depends what you mean by "slack". 1mm is way too tight with no tensioner, you should have +/- 5mm with the tensioner in. But do remember on the 120 engines there's probably no position where the valves aren't acting on the cams so you will always be fighting against the valve springs. If you press down hard on the chain do you get more travel than the "slack" 1mm?
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Good point.  I rotated the motor about five or six revolutions and gained another 1mm of 'slack' (not pushing down hard) when the engine is in it's most 'relaxed' position. Then, I pushed down as hard as I could on the chain and got a little over 5mm.  Sound about right? 
 
It sounds about right, good luck with the rest of the build but try and get your hands on a copy of a RGS workshop manual, if you dont already have one, it will help no end. I've had a look but I haven't got a PDF version to send.
 
Laverdian said:
It sounds about right, good luck with the rest of the build but try and get your hands on a copy of a RGS workshop manual, if you dont already have one, it will help no end. I've had a look but I haven't got a PDF version to send.
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Yeah, I've got it.  It helps, but it could be a little easier to understand. Probably just my rough Italian language skills.
 
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