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Triplex Primary Chains

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Triplex Primary Chains

Posted by richard_payne at October 07. 2017

What are people generally using now on Commandos ? I've read various things about the quality of the current Renold items but are they usable or are there easily available better options ?

The chain on my Mk3 has out-run the ability of the tensioners to keep it away from the chaincase so I need to replace. If the gearbox were adjustable, it would only be half worn, so I suppose that means that a Mk3 is not likely to be pushing a chain to the extremes of its fatigue life.

Re: Triplex Primary Chains

Posted by john_holmes at October 07. 2017

Go to Andy the Chainman and get his Duplex chain for the Commando, its a high quality IWIS chain developed for Mercedes timing chains and then used for years on Laverda's as a primary chain by Andy before he started to use it on Commandos. You just put it on the 2 inner lines of teeth and the 3rd outer is left unused.

Re: Triplex Primary Chains

Posted by richard_payne at October 07. 2017

I understand his recommendation, but just how bad are the Renolds nowadays ? What sort of failure risk is there ?

I'm a little concerned on the Mk3 850 that there may be a problem in applying pressure unequally off the centre line on the hydraulic tensioner pads ? The thing becomes useless if it jams due to a side thrust on the pistons.

Re: Triplex Primary Chains

Posted by john_holmes at October 07. 2017

There is enough doubt about reynolds for it to be an issue, even if it was only a problem with counterfeits and not reynolds own quality how do you know what you are getting is genuine.  If you need a Triplex of known good quality then I have an NOS Iwis triplex chain surplus as I went duplex to be able to fit my own electric start before I got round to fit it, it was bought in 1988 before the Chinese were making much of anything but Chow Mein. Alternatively give Andy a ring and see what he says about the tensioner.

Re: Triplex Primary Chains

Posted by Neil Wyatt at October 07. 2017

About 5 years ago my 76 Mk 3 primary drive area developed a knocking noise when blipped from tick over. I called the Corner Garage help line, was asked how many miles were on the clock, I answered 30,000 and the answer came back: 'Primary chain is knackered.'

I ordered a new Renold triplex chain, fitted it and knocking noise gone to this day. I use ATF in my Commando primary case.

Here's to the next 30,000 miles, if I live that long?

I still can't understand why anyone would spend all that cash on a belt kit?

Re: Triplex Primary Chains

Posted by Andrew Heathwood at October 08. 2017

Richard

I've recently purchased and fitted a new primary chain from Andover Norton. It is made by CZ.

Joe Seifert rates this chain as better than Renold.

See http://www.accessnorton.com/primary-chain-t7712.html#p80561

I considered the IWIS duplex but in this case did not want to leave a non-standard fitment for a future owner.

Andy

Re: Triplex Primary Chains

Posted by richard_payne at October 08. 2017

Thanks Andy, I hadn't searched far enough back on Access Norton (I left there in a huff some time back).

Re: Triplex Primary Chains

Posted by robert_tuck at October 08. 2017

I don't blame you Richard ,they have a serious troll problem there.

Re: Triplex Primary Chains

Posted by Bruce Mitchell at October 10. 2017

Previously john_holmes wrote:

Go to Andy the Chainman and get his Duplex chain for the Commando, its a high quality IWIS chain developed for Mercedes timing chains and then used for years on Laverda's as a primary chain by Andy before he started to use it on Commandos. You just put it on the 2 inner lines of teeth and the 3rd outer is left unused.

 

I contacted Andy and asked about Renolds chain, he wasn't very helpful other than stating again that there are better chains and I only need to "look at them" to see ... not sure what I was to see as I'm not a chain man but will take his advice.

Re: Triplex Primary Chains

Posted by Neil Wyatt at October 10. 2017

Sounds to me that the 'Chainman' isn't getting a big enough discount from Renold? Just my opinion.

When ever I order a new chain from RGM (For a restoration as I don't seem to wear them out) they are always Renold. I doubt Roger would knowingly stock inferior kit.

I'll let you know if my Commando Renold chain fails or starts the knocking within 30,000 miles. Don't hold your breath.

 

Re: Triplex Primary Chains

Posted by francis_vidril at October 10. 2017

I do not think that the ATF is a good thing for the chain tensioners of triplex, probably the cause of the noise and only 30 000 miles. On my 850 MK3 I was 60 000 miles with triplex and some oil SAE 30 but not motor oil also.

Re: Triplex Primary Chains

Posted by david_evans at October 11. 2017

It's interesting that a triplex chain that is probably massively stronger than is needed for this task and running in an oil bath should only last for say 60,000 miles. Whilst it is not the same situation, one rotary owner whose final drive chain also runs in an oil bath reported 180,000 miles. My own IP2 had a perfect chain and that probably had about 50,000 miles on it. I would be tempted to go for the Andy chain duplex option only to reduce the weight of the chain and bring that weight inboard. The clutch with bronze plates is a hell of a mass and we all know that the bending gearbox main shaft is the weak link when the going gets tough.  When I had a bronze clutch I removed a serious amount of steel from the inner diameter of the steel plates because it was not doing anything friction wise.

Re: Triplex Primary Chains

Posted by richard_payne at October 11. 2017

Mk 3 850s get through a lot of primary chains as the centres are fixed and the tensioner is not able to extend very far before the chain contacts the case, added to which that there is no oil sealing in the tensioner and only a small oil reservoir so it will quickly drain down (the more so if ATF is used).

Running with no oil in the tensioner (before the chain has picked up enough to fill the reservoir again) probably isn't very good for chain life but there is no external means of priming it.

I've thought several times that I ought to drill and tap a hole in the outer cover so that a Wesco could be inserted, but it would gradually raise the chaincase oil level.

I'm not sure that the power pulses of a Commando are quite as gentle on a chain as a rotary, nor that theyquite encourage the same sort of riding style.

Re: Triplex Primary Chains

Posted by david_evans at October 11. 2017

I think the primary tensioner on the rotary is the same as the Mk3 but as you say it doesn't have the power pulses.

Re: Triplex Primary Chains

Posted by christopher_winsby at October 11. 2017

I fitted an o ring to the bottom chain tensioner to stop the oil draining down (not my idear I might add).

Boyer of Bromley used Duplex chains in their racing Tridents, reving to 9000 rpm. A Commando is more about Torque.

Re: Triplex Primary Chains

Posted by francis_vidril at October 16. 2017

Peharps also change the plungers after 30 000 miles ?

Mine J changed them is 60 000 miles only

https://andover-norton.co.uk/en/shop-details/16496/p-chain-tensioner-plunger-69-0622-2-per-bike-

Re: Triplex Primary Chains

Posted by David Cooper at Tuesday 13:59

All sorts of rumours about Renolds, aren't there?

I had some Renold technical (industrial) catalogues years ago.  I remember a few things:

1) they said that people looked at heavy side plates and thought they were looking at a better chain (Andy is reported as saying "you only have to look at them to see").  But side plates neither stretch nor snap - wear takes place in the bushes, and saving weight is the objective to reduce forces on the system.  Thick side plates = heavier chain = faster wear everywhere.

2) rolled bushes (i.e. with joints rolled from plates rather than bored from solid bar) are used on some chains.  They might not look as good - but they can be made more accurately so the drive is smoother so they suit some applications

3) I think they pulled out of motorcycle market because it was a) so competitive that they made better money out of Industrial applications, and b) all motorcycle chains are so grossly overloaded and underlubricated that they can never perform as well as customers want them too...

But who really knows the truth?  Most products become worse with time when the customers select entirely by price.

 

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