Rear Chain on a 350?

[mhsilverw]

Whilst fiddling with the clutch (well trying too) I couldnt help notice the rear chain could be past its best....so as I struggle to get the bike ship-shape for the riding season (and a visit to watch at Cadwell); What size should I be looking for?

I cant find a reference in the manual other than a Morini part number of 29.01.05 Catena/Chain.

When browsing on internet 428/530/520 o ring / x ring / non-o-ring / split / non-splt all jumped out at me....I dont recall this being this confusing before. That will teach me to have had a "boxer beemer" in the recent past which didnt need such things; so a bit 'rusty' (like the clutch spring nuts it seems ) with all the modern-day stuff.

One site suggests a DID chain....350 STRADA 80-86 DID 50NZ x 96 / 350 K2 CLASSIC 84-86 DID 50NZ x 96 --- so that seems to add '50' to the numbers above [I am assuming 96 is the length or number of links] -- all in all quite confused.

...so more numbers I dont understand

( a bit like modern tyre sizes...I knew where I was with tyres like 4.00x17 but firing numbers like 130/80-17 65H just seems confusing).

Its ok I did cope with the change from shillings and theepenny bits, so I am ok with decimal currency - but had a while to get used to that.....but chains have me stumped.

[Paul the Destroyer]

The 50 is possibly the pitch (the distance between rollers). As you can see the chain is the same for both models.

I'm sure a more experienced member will be along to shot me down in a while

[George 350]

Hi Mark,
Firstly the size: the 5 in the number is the pitch,(the distance from roller to roller)1/8" increments, ie = 5/8". The 3 refers to the width, so is 3/8" between the plates.
What you want is a '530' chain, 96 pitches long. Whether you want to go o-ring, x-ring etc depends on how much money you want to spend and how much mileage you intend to do. O-ring/x-ring chains do last longer, but still need regular spraying with grease. The o-ring ones absorb a bit more power compared to a non O-ring chain, the x-ring ones are near to a standard chain for power loss. M&P direct list an 'RK 530x98 standard' chain on offer at £12.10. http://www.mandp.co.uk/productinfo.aspx ... l=Standard
Ok, it is 2 rollers too long, so a few minutes with a chain splitter (or an angle grinder and pin punch for the brutal ones) will soon have you a correct size and length chain at a decent price. You don't need heavy duty chain on a Morini unless you are complete abuser of the bike(a standard one is only 35hp at best). RK is an OEM chain supplier for many Jap bikes.
A heavy duty chain is also listed at £27.50, still not a bank breaker price. As with all chain, decent lubrication is the key to survival. If you intend to do a lot of miles, buy a scottoiler.

Cheers,
George.

[MickeyMoto]

Give 'Andy the Chain Man' a call.

http://www.the-chain-man.co.uk/

I bought the primary, cam and final drive chains from him for my Laverda, very reasonably priced, quick delivery etc.

Mike.

[MickeyMoto]

oh yes, forgot...

O-Ring chain does not allegedly need lubing, although the plates can rust...

I have a scottoiler, although the chain lasts ages, the cleaning is a pain as the lube goes everywhere.

I think it all depends on how the bike is used. Lots of trips etc go o-ring - occassional Sunday trip out, non O-Ring, cleaning and lubing....

My thoughts...

Mike.

[72degrees]

I tend to go for Heavy Duty non O ring chain though it's probably over engineered even on my tuned 375. In fact, a 520 conversion is worth considering, though it's not that easy to get suitable sprockets for a standard 350 straight off the shelf. I used to run 520 on the hill climb Morini with custom rear sprockets and a Kanguro? front . The 604 Nordwest which was dyno tested at 55 BHP was fine on HD 520 chain. Then there is the vexed question of 'soft link' or 'split link'. Personally I wouldn't hesitate to use a split link on anthing up to 500 cc (well perhaps not a race RG500) others would. A spare split link clipped around the clutch cable up by the lever gives me a sense of security.

[EVguru]

A chain number like 420, 428, 520, 530 etc. are made up as follows.

The first digit is the pitch in multiples of 1/8th of an inch, so a 428 chain will have a pitch of 4/8th or to simplify 1/2".

The last two digits are the width in multiples of 1/80th of an inch, so a 520 chain is 20/80th or 1/4".

If you would like to run an O-ring chain, then you really do need to go down to a 520 to gain enough clearance to the crankcase.
Front sprockets are no problem at all, the Dart, Excalibur and Kanguro all ran a 350 engine with 520 chain. Both NLM and Sprockets Unlimited usually have them in stock.

520 rear sprockets are more of a problem. It usually means having one made from an Aluminium 'blank' or plate wheel (just teeth and a small centre hole). I think NLM keep a few in stock and you can also get them from Sprockets Unlimited. They tend to be a bit expensive to buy ready machined, but are pretty cheap as blanks if you know someone who can machine them for you (It's not difficult).

O-ring chains should be lubricated to stop the outside of the rings deteriorating. An O-ring chain and a Scottoiler is a very long lived combination.

[George 350]

just to add further info. O ring chains still need lubricating otherwise the rollers and sprockets wear at an increased rate. Failure to do this leads to a perfectly good chain without several rollers on it and dreadful drive noise when on holiday in Austria. The rollers on the links (the bit that actually touches the sprocket) crack up and break off. Can't think as to why I know this, but it was with the first o-ring chain I had ever used...
O-ring chain + Scottoiler meant adjusting the chain once in 26,000 miles when I had a Yamaha Thundercat, and the chain and sprockets were still as good as new.

George.