Should I change my Alloy Large Idler Gear?

Shadowman

Well Known and Active Forum User
VOC Member
My Rapide has an aluminium large idler gear and although it looks okay and is not unduly noisy I notice that a steel one is available. Should I change?

I'm trying to do preventative maintenance before I set off on a 5000 mile trip from southern UK to the Arctic Circle in June.
 

petermb998

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Non-VOC Member
Yes I would although it might look OK now the law of averages may be against it lasting 5000 miles.
I would also consider Changing your rear chain and sprockets and put on a 1/4 inch O ring chain. With a automatic chain oil-er such as the Scot oil-er.
Once the initial stretching has taken place the chain will out last the 5/8 inch chain.
I wish you good luck with your trip I wish I could come with you.
What an experience that is going to be.
regards Peter Bromberg
 

nkt267

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VOC Member
My Rapide has an aluminium large idler gear and although it looks okay and is not unduly noisy I notice that a steel one is available. Should I change?
Everything maybe ok now.Talk to JohnSD in the suffolk section.He arrived at a meet ok and then could not leave.I'm pretty certain that his large idler stripped 1 or 2 teeth.If you want some spare alloy ones with no teeth I can supply some:D.
Don't forget that you will need to lock all the other gears inplace unless you want to totally retime your engine when you replace the idler.John
 

Tom Gaynor

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VOC Member
Alloy idler

I decided to keep mine, being persuaded by the argument that once it had run itself in, it wouldn't fill the motor with flakes of ally unless I moved it. Later, after fitting a Grosset distributor, the bike wouldn't run properly. Timing was perfect on the rear pot. I checked the front pot. Gosh! I have a 50 degree vee-twin with sparks (easy to detect with Francois's distributor) 57 degrees apart...... Francois provided me with new parts although we neither of us could see why the spruiter should be at fault. It still wasn't right so I dismantled the timing gear for a look-see. Only when I took the large idler out could I see that it had broken the inboard 3/4 of one (critically positioned) tooth.
When I dumped the alloy idler into the box of Comet bits I had, I found that I was well on the way to cornering the world market in ally idlers with one tooth missing. I have five.
So yes, change it.........
 

BlackLightning998

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VOC Member
Iwis Megalife is the proverbial dogs.....

I fitted an Iwis Megalife which has impregnated bushes and is said not to require lubrication (although I do). I've run it 500 miles now and it had not needed any attention, so not long enough to give you a 5000 mile advisory note, but lots of people rave about these chains. Much more expensive that the standard, about £85 from memory, but fits to standard sprockets no problem - straight exchange. I got mine from Sprockets Unlimited - highly recommended in my view.


"I would also consider Changing your rear chain and sprockets and put on a 1/4 inch O ring chain." Peter Bromberg
 

Tom Gaynor

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VOC Member
Final Drive Chains

Rather than faff about thinning sprockets (a modern 520 - 5/8" x 1/4" - chain will fit in the space available for the 5/8" x 3/8" original), I decided to keep the Renolds chain, skinny sideplates and all, but fit a Scott-oiler. One was fitted to my Ducati and once i realised what this device tucked neatly away under the seat was, have needed to adjust the chain once in four years and 10,000 miles. I'm a complete convert.
The only mod I needed to make to the Vin (apart from drilling and tapping a 4 mm hole for the suction lead into the front inlet tract) was to add an extension to the rear chainguard a la Eddie Stevens' in KTB to keep the back of the bike clean.
I've adjusted the chain once or twice in 4000 miles. Making a long story short, if i was to choose between a modern chain and a Scott-oiler, I'd buy the Scott-oiler first, and decide on a chain later. Unsurprisingly, chain saw-oil works very well in it.
 
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Robert Watson

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VOC Member
A good quality O ring chain - about Can$80 and good sprockets (8620 case hardened on the drive end) and a little spray on lube periodically (if riding a lot in the rain) and no extension required for the chain guard as there is nothing flinging off the chain, and 15,000 miles without adjustment.

Robert
 

Shadowman

Well Known and Active Forum User
VOC Member
The day before I posted the question about the large idler I fitted a DID530 'Professional' 5/8 x 3/8 heavy duty chain. I noticed it is 2.5mm wider than the normal chain I removed leaving only 1mm gap either side at the drive sprocket end. I wonder if I'm making a mistake?
Thanks for the replies on the large idler. I will change it for a steel one.
 
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