New Inner Chaincase Touches Swingarm

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marshg246

marshg246

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I installed a new inner chaincase from AN on the 74 850 I'm rebuilding and carefully got the center stud shimming right. While doing the oil hoses and horn, I noticed that the swingarm appeared to be touching the chaincase. A piece of paper will fit between them except in one spot. Of course, I have the entire primary done.

It would be easy to relieve a little from the chaincase before installing. So, if you're installing a new one it would be good to check before finishing the primary.
 
i have seen witness marks on old ones also and they were properly shimmed.
 
I have also seen polished inner chaincases where the swingarm outer cover has rubbed on the cover. Not much clearance there and with all the tolerance build ups over long distances surprised it does not come up more often. Try 2 gaskets on the crankcase joint and reshim to suit.
 
I've seen marks on probably 90% of the 20+ Nortons I've rebuilt, gouges on about 25% of them, and 3 or 4 with serious cracking from improper shimming.
 
Did a little investigating. My unrestored 74 MKIIa has almost no clearance - maybe .005". The 72 I recently rebuilt has a noticeable gap. I thought it was the new chaincase, but I guess it is something about the 850. Since there should be little to no movement side to side there, it would probably be OK, but I'm going to take it back apart and relieve that area on the back of the chainchase slightly. While harder to do than adding a second gasket, it seems like a better fix to me.
 
concours said:
Iso install sequence is all good, adjusted, bolt tightened?
Click to expand...

Engine attaches to swing arm through the rear engine cradle. ISO's not involved.
Run with loose engine bolts?
Engine pulls itself toward rear on chain side! Chain case (attached to engine) gets pulled/swings into collision with first item....swing arm. Limited only by central post.
Old used cradle with damaged holes? Holes worn bigger on left?
Cradle bent?
powder coat yielding?

NEW AN primary?
Did you check if enough clearance possible prior to assembly. Measure, verify, then use.
 
Last edited:
I finally got back to working on this. To make sure the engine wasn't somehow twisted in the cradle, I loosened the engine mounting bolts and tried to pull the inner chaincase away from the swingarm. That accomplished nothing. So, as several have suggested, I'll put it back together with two gaskets. The gaskets I have from AN are .021" thick - that will certainly fix the swingarm clearance problem (red oval).

While investigating this problem, I noticed the master link is hitting the seal plates (blue oval).

Originally, I thought that relieving the cover where it meets the swingarm was all that was needed, but the master link problem is much bigger. I don't know if two gaskets will fix the master link problem but installing it from the outside in will if not. Yes, it is a standard chain, not o-ring and not heavy duty

New Inner Chaincase Touches Swingarm
 
I installed two gaskets and rechecked everything. The swingarm clearance is resolved and the chain itself was fine, but the master link, when installed normally was very close to hitting the seal plates and with any deflection while riding, it would hit. So, I searched and found some 10B-1 chain (British Standard).

Until I started researching this I didn't realize that British Standard chain is also called Metric Chain. Nominally, 10B-1 and ANSI 530 are the same, but 10B-1 is not as wide and the master link is a good bit narrower. Of course this is nothing new to many on this forum. Once I started searching by Metric Chain, I found plenty of suppliers and ordered from one. The overall width of the ANSI chain master link was .870" and the 10B-1 is .824" so problem solved.

So my research isn't wasted and because plenty of others are asking similar questions, I've started documenting chains and what I found here: http://www.gregmarsh.com/MC/Chains.aspx - I'm clearly not an expert on this subject so if you find something wrong or have something to add, please let me know.

BTW, I bought 50' of the 10B-1 chain and I have a supply of half links and master links so if you're fighting this problem, PM or email me.
 
Edit: Link works now.

marshg246 said:
Until I started researching this I didn't realize that British Standard chain is also called Metric Chain. Nominally, 10B-1 and ANSI 530 are the same,
Click to expand...

Not exactly the same, as it is ANSI 50 or 10A-1. Not only is the side plate thickness and overall width different but also the inside width.

https://www.renold.com/media/228840/renold-brand-chain-tables.pdf

"European (BS) Standard - Simplex
10B1,10B-1, 0.625,15.875, 9.65, 10.16, 14.60, 1.55, 1.55, 5.08, 18.8, 2.5

ANSI Standard - Simplex
50A1, 50-1, 0.625,15.875, 9.40,10.16, 14.60, 2.04, 2.04, 5.08, 20.4, 2.7
"
https://www.chainsupply.co.uk/wp-content/uploads/2016/08/Roller-Chain-Comparison.pdf
 
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gortnipper said:
Just call you Greg "the Chain Man 2". :D
Click to expand...
Bad idea! After 50+ years owning and working on British motorcycles, I know almost nothing about chain specifications - I just want the darned things to do their job and not bang into other parts of the bike! :( Hopefully, by doing a little documentation, I can relieve others from having the chain pain I've been having lately!
 
Hi All. Just came across this thread & encouraged to see others taking a healthy interest in chains. There are too many so called anecdotal "facts" being peddled around so it's always refreshing to see someone taking the time to do some proper research.

I work for Renold having started as an apprentice in 1983 & am regarded as the motorcycle chains guru here. I don't know everything but if I can help with anyone's chain related issues, especially regarding Renold, I'm happy to help where I can. I have access to just about all the motorcycle chain records from the year dot & do actually know what's made & where. I can't go into detail on future plans right now but will be happy to provide any information on historical bike chains.
 
Hi CCG,
Is Renold chain & in particular the motorcycle chain still made in England. Also, are there any plans to start making O ring chain again?

Martyn.
 
Hi Martyn,
Apologies for not responding sooner. I can confirm that Renold at present manufacture all their smaller chains, inclusive of motorcycle chain at their Einbeck factory in Germany. Before people decry this situation, I know for a fact that the equipment is the very same that was formerly used to make the same chain in Manchester.

I know it's always a shame when a product made for a long time in the same place goes to another country but business is business. The old factory was a vast behemoth of a place that played a major part in tightning of financial belts as just about all companies have had to do. We were there at the very start of motorcycles, still here now & will still be here for a long time to come!

I can't state anything right now as to the future of Renold & motorcycling so let's just say my outlook is certainly positive. Otherwise, watch this space so to speak.
 
ClassicChainsGuru said:
Hi Martyn,
Apologies for not responding sooner. I can confirm that Renold at present manufacture all their smaller chains, inclusive of motorcycle chain at their Einbeck factory in Germany. Before people decry this situation, I know for a fact that the equipment is the very same that was formerly used to make the same chain in Manchester.

I know it's always a shame when a product made for a long time in the same place goes to another country but business is business. The old factory was a vast behemoth of a place that played a major part in tightning of financial belts as just about all companies have had to do. We were there at the very start of motorcycles, still here now & will still be here for a long time to come!

I can't state anything right now as to the future of Renold & motorcycling so let's just say my outlook is certainly positive. Otherwise, watch this space so to speak.
Click to expand...
Are there any plans to re introduce the 7/16" duplex primary chain for triumph Trident t160 owners?
Cheers
 
Witness marks from swingarm and chain contact:

New Inner Chaincase Touches Swingarm


Root cause: Incorrect shimming. That led to elongated crankcase holes. One was cracked:

New Inner Chaincase Touches Swingarm


Fix: Mill the case and insert brass sleeves:

New Inner Chaincase Touches Swingarm


Then shim correctly and reassemble.
 
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