Final drive chain

[Sprunghub]

Sorry to monopolise the q's & a's....but the bikes running well enough & getting some miles on her now.

I've got a very good 'local' chain / sprocket supplier, & as the chain on the bike is as cruddy as hell & I'm a bit 'critical' about chains & tyres, I decided to get a new socket set & chain.  I'm not sure the old ones have done that much.....just been horribly "greased".

I rang up & they were a bit cautious about supplying an 'O' ring chain.  The 'man' thought it might be a bit heavy for the clearances in the sprocket 'case' at the front end - mainly due to width.

He advised me to pop over & see him to pick up the sprockets & let him weigh up the 'width' to see if an 'O'  ring would fit.

When I turned up he pointed out that underneath the grease........was an 'O' ring chain....so it would inevitably fit.  Chain duly supplied, so far, so good.

Tonight as a prelim to an intended fit tomorrow, I've removed the sprocket cover just to make sure there will be no 'gremlins' tomorrow when I propose to fit it.  On removing the small case which covers the sprocket, I found that there was fairly substantial "chaffing" to the triangular rubber/plastic cover which protects the top alloy "blade" which sits just below the top run of the chain........& more remarkably, fairly deep scoring of the reinforcing bead which forms part of the tube the fixing bolt goes through & should be about an inch from (above) the chain as it comes of the bottom of the sprocket.  So.....what do you reckon......is it down to the 'O' ring chain being too big......a period when the bike has been run with a seriously slack chain, a knackered chain ?? (she runs loose then tight for no obvious reason) ....or "none of the above" ??  The angle off the sprocket is about 45 degrees, so how the heck that scoring has happened there, I just can't see.   

[matthewmosse]

Is the damage fresh(ish) or well covered in grease and grunge? Always possible a chain broke in the past, hence 'upgrade' to O ring chain, I've had a chain or 2 break over the years and now tend to use O ring chains as a matter of course - on a cb500 though so not a garuntee of compatability. I'd hazard a geuss that poor adjustment or braekage would be the cause............

[Seamus]

It seems that chain breakage was quite common on the early 750's Many of them resulted in a hole in the back of the gearbox, so I would'nt be surprised if there was some scaring in this area. (Mine had a 2 inch square hole hiding under JB weld).
I believe that O ring chains are fine as long as you have the correct width (530). The chain will be a bit wider than standard as it has O rings between the side plates. Also you will probably have a soft link in place of a split link for completing the chain.
Cheers

Seamus

[Bryanj]

750  is OK with the 530 "O" ring chain, which should be oiled with gear oil not lubed with aerosol chain grease as the propellant attacks the "O" rings.

Its the 500/550 that cant take the "O" ring as the sprocket is set too far in towards the crankcase and the chain will eat the cases

[Sprunghub]

Cheers all.....instinct told me it was a slackness thing......but.....the pre-formed 'groove' isn't wide enough for an 'O' ring chain, in all honesty....but it shouldn't be contacting with it if set up properly, so hopefully will be ok.

[Sprunghub]

All fitted, 1/2 cwt of accumulated gunge all cleaned back to nice bright alloy, new sprockets, nice Regina chain in shiny gold, rear wheel assy all cleaned up.....looks A1 & rides as sweet as a nut.  Very pleased, chrers again all.

[Yoshi823]

The CB750F2 OEM chain is a 630 'O' ring.This is the same as fitted to the GS1000.

I had a Regina chain on my 750F2...once. It lasted 1800 miles and had so many tight spots at the end of that time that I vowed never to buy or recommend the brand  to anyone asking.