auto. cam chain tensioner (2007)

comnoz · Feb 28, 2013

I would use the Kelly Cork unit.
I would not use the RMA unit. Jim

madass140 · Feb 28, 2013

I used the Kelly Cork unit years ago without issue, not sure if I'd bother to fit one again,

JimC · Feb 28, 2013

Looks like this thread has pretty well spelled the death knell for the RMA tensioner. I've yet to see any objections such as I saw from criticism about other Norton specialists who have produced subpar products or subpar work.

madass140 · Feb 28, 2013

I've never seen a used Norton cam chain that doesnt have a tight spot, if not renewing the chain then wind the engine over when adjusting the chain to check the tension, I think replacing the chain more often is probably the best option

ashman · Feb 28, 2013

I have been running a Kelly cork one for over 15 years now without any problems, but you still have to check on chain wear as nomal, its just nomal maintenance that has to be done, all chains after some time running will get tight spots or wear, but this auto chain ajuster means less times pulling the timing case off to ajust lose cam chain as you can hear them when they are lose, as well the chain seems to run more smoother, but thats my opion

Ashley

swooshdave · Feb 28, 2013

Can you even get a Kelly Cork tensioner anymore?

comnoz · Feb 28, 2013

The Cork unit has a ratchet that will leave a little play in the chain.

The RMA tensioner will remove all the play at the loosest point of the chain. Then when the chain gets to a tight place something has to give. In my experience it is usually the bracket that flexes slightly every revolution until it breaks off. Jim

ashman · Feb 28, 2013

I'm not sure if mine is kelly cork brand but is the same design, I brought mine from Pioneer Cycles at Caloundra in Qweensland Australia, this was Aussie made at the time from a local man in Brisbane, but that was about 20 years ago, Pioneer Cycles I think are still in bussiness, but it has been a few years sinse I have been up that way, so not sure if they are still making them, but mine is still working fine and have clocked up over 90,000 miles with it installed, I have replaced the Cam chain on every rebuild ( 2 engine rebuilds and once to replace crank cases), I am still running the same sprockets sinse new in 1976 when I brought my 850 Norton.

Ashley

johnm · Feb 28, 2013

Mr Slim slider has put up a good set of photos of the Kelly Cork unit.

This is exactly what I used in my race bike for 10 years. You can see the plus's and minus's clearly in the photos.

The issue which eventually showed up in my bike is the mounting plate compromise. The plate is mounted by two countersunk screws and the unit is then attached to the plate by a single bolt and a roll pin.

If you think about it there is a fair bit of torque on that mounting system from the chain. After 10 years of racing this fretted some elongation into the mounting screws and they allowed the unit to twist sideways.

The best fix would be a three point mounting sytem into the cases. Preferably with at least two of the studs going all the way through from the cases to the outside of the tensioner body. The stud alignment would be better parallel to the chain run and not at right angles. This would give a very good solution.

Chain over tightening has never been an issue with the Cork system in my experience.

marinatlas · Jan 14, 2017

Hi, I had dismantled one of my spare engine (built 20 years ago by Pete Lovell !!), and barely used , and found inside a Kelly Cork , as said they are not made anymore, so where could I find a notice ( had lost mine , if I had any !!) and had no idea what kind of key it was to move the ratchet , is there someone who could give me a help ...??

kommando · Jan 14, 2017

Its just a plain rod that fits in the hole and locks the ratchet. This pic is from earlier in the thread and shows it with the dog leg bend.

Correction, the plain rod just locks the ratchet so the plunger will not extend outwards, to release the ratchet you rotate the chainlink which moves the ratchet off the teeth on the plunger and allows it to be pressed back in, once in you insert the pin and keep the pin in place until you want the plunger to extend eg once the chain is in place.

marinatlas · Jan 14, 2017

Hi Kommando, thank you for your help......now I know!!

ashman · Jan 14, 2017

Yes its just a pin that you push in to hold the ratchet in place, I have had mine on my Norton for over 20 years maybe even longer now with no problems at all. I have the full instruction somewhere in my shed, I will have a look for it and post it up if I find it, the cam chain runs smoother and no noise at all when running.

Ashley

andychain · Jan 15, 2017

The cam is very short at 38 links and should not need a tensioner.

The main problem is the lack of automotive product with most on the market
being budget industrial.

Andy

madass140 · Jan 15, 2017

ok Andy, how much is your cam chain? and is it endless?
Don

andychain · Jan 17, 2017

Do 2 types 1 is standard automotive as used by BMW, Mercedes etc etc etc
and 1 is big pin as used by Comstock. I dont like putting prices on the site
but e-mail me and perhaps ring Jim to get his views.

Andy

madass140 · Jan 17, 2017

Andy, is the big pin chain physically much bigger?

andychain · Jan 17, 2017

A little but no probs fitting.

It has a 4.41 pin instead of a 3.31 and no rollers to fail.

Andy

Ian James · Aug 31, 2020

Thank you all for the replies . I am going to go with it after shortening the spring by one coil and squaring up the end for slightly less tension wish me luck Cheers Ian

kommando · Aug 31, 2020

Ian James said:
Thank you all for the replies . I am going to go with it after shortening the spring by one coil and squaring up the end for slightly less tension wish me luck Cheers Ian

You do realise that shortening a spring by removing coils actually increases the spring rate. You reduce the preload but once this extra play is used up the spring is stronger not weaker. You could end up making the situation worse. Better option would be the same number of coils and length with a thinner wire size, plenty of custom coil makers around or make your own.

Cutting Coil Springs - EATON Detroit Spring

Under certain circumstances, you can cut coil springs. Read on to find out how, why, and when to cut your coils.

www.eatondetroitspring.com

.

The first thing you need to know is that cutting a coil spring will not only lower the vehicle, but it will also stiffen the spring making the ride and handling a bit firmer. But this is a good thing because lowering a vehicle reduces the amount of suspension travel. A stiffer spring will help reduce bottoming out.

auto. cam chain tensioner (2007)

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