1972 Norton Commando Chain
- Thread starter SM2045
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knocking Commando
Hi SM, "knocking" is a term that can cover a wide spectrum of sounds, when you stripped the bike how far did you go?, have you replaced the Isolastics?.After a long period of standing without maintenance the Iso's. may well be " shot" worn or perished / disintegrated Iso. rubbers will cause weird noises that can be interpreted as engine / transmission sounds. Try to move the engine assembly in the frame, noting how much movement you can detect at the front and rear mountings, also the head steady .No doubt you will receive many suggestions from "brothers and sisters" on this sitel, check 'em all out. Good luck. James.
Hi SM, "knocking" is a term that can cover a wide spectrum of sounds, when you stripped the bike how far did you go?, have you replaced the Isolastics?.After a long period of standing without maintenance the Iso's. may well be " shot" worn or perished / disintegrated Iso. rubbers will cause weird noises that can be interpreted as engine / transmission sounds. Try to move the engine assembly in the frame, noting how much movement you can detect at the front and rear mountings, also the head steady .No doubt you will receive many suggestions from "brothers and sisters" on this sitel, check 'em all out. Good luck. James.
when looking at the isolastics is the only thing I should be worried about is the rubber? I did not replace the isolastics I kept those in place when I went through the bike, another way to explain the knocking is that it sounds similar to Chain slappage.
I have tried to move the engine, but I do not get any movement from it, I made sure all the bolts were tight before I started it.
I appreciate the help, is there any suggestions on the best way to check the Iso's?
I have tried to move the engine, but I do not get any movement from it, I made sure all the bolts were tight before I started it.
I appreciate the help, is there any suggestions on the best way to check the Iso's?
Ron L
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If there is no perceptible movement in the rear wheel it is not likely to be the iso's.
Since it sounds like a chain slap, have you checked both primary and final drive chain tension? While your at it, don't forget to check both chains for a bad or rusty link and tight spots in the chain. The primary chain should not be overly tight, but should not be able to hit the chaincase either.
Since it sounds like a chain slap, have you checked both primary and final drive chain tension? While your at it, don't forget to check both chains for a bad or rusty link and tight spots in the chain. The primary chain should not be overly tight, but should not be able to hit the chaincase either.
Ron,
I have checked the primary chain, it is not too loose nor tight, the regular chain is old, and I am waiting for a new chain, I had ordered one, but it was too thick. The thing that puzzles me, is the knocking gets worse when you add weight. Any more ideas would be helpful, hopefully the new chain will take care of it, but the chain on it is not in bad shape.
Please let me know if you have any more ideas.
I have checked the primary chain, it is not too loose nor tight, the regular chain is old, and I am waiting for a new chain, I had ordered one, but it was too thick. The thing that puzzles me, is the knocking gets worse when you add weight. Any more ideas would be helpful, hopefully the new chain will take care of it, but the chain on it is not in bad shape.
Please let me know if you have any more ideas.
Re: Knocking Norton
Just how old is the chain??? Is it rusty? It might have some stiff links in it. The hint there is the more weight on the bike the worse it is. More weight levels out the swingarm more putting more tension on the drive chain agrivating a problem if it is rusty and has stiff links. This could make the sound you are looking at. Before tearing much more apare, put a new chain on and test again.
SM2045 said:
Just how old is the chain??? Is it rusty? It might have some stiff links in it. The hint there is the more weight on the bike the worse it is. More weight levels out the swingarm more putting more tension on the drive chain agrivating a problem if it is rusty and has stiff links. This could make the sound you are looking at. Before tearing much more apare, put a new chain on and test again.
Windy, Bill,
Yes it does change with road speed, while in the lower end of 1st, 2nd or 3rd, if you let off the gas quickly it will knock. I have felt around the gear box and there is no real vibrations, there is a little vibration around the primary chain case. I will keep my eye on it, I have been riding it daily, and it seems to go away and come back, I am hoping it is just my chain.
Yes it does change with road speed, while in the lower end of 1st, 2nd or 3rd, if you let off the gas quickly it will knock. I have felt around the gear box and there is no real vibrations, there is a little vibration around the primary chain case. I will keep my eye on it, I have been riding it daily, and it seems to go away and come back, I am hoping it is just my chain.
Irutt,
I have ordered a new chain, and I am just waiting for it, I had one come in last week, but it was too thick.
The chain is very old, but does not seem real stiff, I have cleaned it, but have not checked every link. I also think I need new rear shocks, and hopefully those two things will help.
I have ordered a new chain, and I am just waiting for it, I had one come in last week, but it was too thick.
The chain is very old, but does not seem real stiff, I have cleaned it, but have not checked every link. I also think I need new rear shocks, and hopefully those two things will help.
I would be going into the gearbox NOW you could very well have a tooth off the 4th gear on the lay shaft if as you stated it only does it in 1st 2nd 3rd and NOT in 4th. 4th lay shaft is one of the problem gears in the box as it is a small diameter gear and is in play in all three of the lower gears. if that is in fact the problem and continue to ride it you can cause a lot more trouble like a busted main case. don't mean to scare you but maintenance or looking is cheaper than a major repair 
windy
windy
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