HOME and how to join Forum Open Area General Scott topics Mag Chain size on 29Flyer Re: Re: Mag Chain size on 29Flyer

Roger Moss

Chains have always been a fairly critical item on Scotts if you need the bike to be capable of fairly long reliable journeys. As far as I know, there are no longer ant makers of quality chain in the UK and so most you will be offered are re badged products from the far east. In extracting significantly more torque out of my racer engine, you can understand that I will be taxing the chains considerably more than is normal and so, years ago, failures were common.
I met a man who trades as “The Chain Man” who advised me to try the German IWIS chain, (but, of course, they tell this story to all the girls) Nothing ventured, nothing gained, I thought, so I tried it. I have to report that this chain was by a good margin, the best chain I have used in 46 years racing. I should point out that I arranged a little lubrication by a small aluminium pedestal inside the case bolted to the case outer wall. In this is screwed a “Brush oiler” which, as it’s name implies, is a small round brush with an oil feed, It is positioned to be just above the bottom run of the primary chain with the brush bristles about 1/4″ vertically downwards above the chain. I arrange a slow drip feed from a machine tool dripper I modified. It was originally a four way dripper and I cut off one section to leave three drippers in a neat block. One each for the main bearings and one for the primary chain brush oiler. Feeds are by using Norgren 4mm push in nylon tube and fittings. Very simple and convenient. That takes care of the primary chain.
As for the mag chain, well, years ago, I got fed up with the bicycle chain getting Rigour Mortis like a long dead snake and converted the mag drive to belt with a cover over it to preserve the digestion of those with a passion for authenticity.
However much later “The Chain Man” suggested I recommend a 3/16″ wide chain by IWIS that was intended for use on the final drive of a 125cc Honda racer. He assured me that it would work fine and the extra width would give no problems in operation. I have recommended it to customers over a few years now and nobody has come back and said that this does not work. I can only pass on this information in good faith, as I have not used a mag chain for over 30 years, but believe this is very likely to be a quantum advance on rebadged Chinese bicycle chain. (I have never seem a bicycle with pedals revolving at 4500 rpm or more)
So to information
The Chain Man
Andy Forsdick
11 Gloucester Way
Worcs. DY12 1QF

tel 01299 403688
Mob 07860 577919

For engines with 22T flywheel primary sprocket
Primary drive chain (1/2″ x 5/16″)
1 off IWIS type L85SL chain x 71 links
1 off spare connecting link to suit type L85SL chain

Magneto chain (1/2″ x 3/16″)
1 off IWIS type P83Y x 68 links
1 off spare connecting link to suit type P83Y chain

Rear final drive chain for Flyers etc 5/8″” x 3/8″
1 off The rear chain should be 5/8 x 3/8 iwis ref M106SL. x 94 links (price £36 at 16-03-2013)

Please Note
As I easily unlock some of the untapped torque potential of the Scott and so, on average, raise the BHP figure of a standard 600cc in good condition from 18 bhp to 28 bhp or more, then I fit a 22T sprocket on the flywheel like fitting an overdrive. So if you have a standard engine, you will have a 20 tooth primary sprocket so I suggest you ask Andy for a chain to suit the 20T not the 22T flywheel drive sprocket
Kind Regards to all