G: Gearbox (Twin) Final Drive Chain

[stevierob]

Pushing along slowly with the Black Shadow build and have removed the home made breather chamber (previous post). Having a nightmare now fitting the final drive chain. When the drive sprocket nut is tight the chain is locked up against the engine case. Should a spacer be installed engine side of the sprocket or would that cause the boss on the sprocket to not reach the oil seal. The chain is a 530 with appropriate sprockets. would a 520 setup improve the clearance between sprocket and engine case. One of the photos shows the damage on the casing. Anyone experienced this?Glad of any help
Steve

 

[A Nut]

An O ring or X ring chain is too wide to fit the standard setup. I think that you will need a narrower engine sprocket (thinner on the gearbox side) narrow rear sprocket and a 1/4" chain. I have never fitted one but maybe someone who has will confirm this.
Brian

 

[Michael Vane-Hunt]

If an o or x ring chain is being used you need thinned down sprockets and a 1/4 520 chain.

 

[vibrac]

Nothing wrong with a 1/4" chain anyway our racer runs a 5/8" X 1/4"

 

[stumpy lord]

An O ring or X ring chain is too wide to fit the standard setup. I think that you will need a narrower engine sprocket (thinner on the gearbox side) narrow rear sprocket and a 1/4" chain. I have never fitted one but maybe someone who has will confirm this.
Brian

That is correct, as far as I know the thin sprockets are available from the spares company. I have found in the past that gearbox sprockets have bee provided with the depth of spigot at the back of the sprocket to be of different lengths, this dictates the clearance of the rear chain on the gear box housing as the said boss buts up to the gearbox bearing, the greater the depth, of the boss the more the sprocket move out along the drive shaft. giving greater clearance for the chain. On measuring one of my old sprockets I find the depth of the boss to measure 0.2995" where as according to your sketch yours is 0.25". could this be your problem ?

Hope this helps.
stumpy lord

 

[LoneStar]

My sprocket, used successfully with a non-O-ring chain, measures .594" overall width - same as yours. But my crankcase has a shallow groove carved in it by the pins of various chains used over the years, which helps with clearance.

I believe the original Renold 530 chains are narrower than the Japanese non-O-ring ones; it shouldn't be necessary to switch to 520 sprockets and chain unless you want to use an O-ring version.

 

[Monkeypants]

A new 530x ring fit just fine on my Rapide. The new sealed chains are narrower than older sealed chain.
The chain is a DID vx 530.
There is also a narrower yet 530x ring available from RK. That chain is intended for owners who would like to convert an older machine to sealed chain but would prefer to use standard 530 sprockets.

 

[rapide049]

530 EK NON O Ring chain is the narrowest chain you will get
Best solution 520 O ring chain with 1/4inch sprockets

 

[LoneStar]

There is also a narrower yet 530x ring available from RK

That looks to be the RK 530UWV chain (https://rk-europe.com/chain/uwv-chains/), 22.6mm wide vs. 21.7 - 21.9mm for their non-sealed chains (M530 & 530KS). It's expensive, though possibly not if you compare with a 520 chain and new sprockets, and seems not to be distributed in north America.

 

[stevierob]

That looks to be the RK 530UWV chain (https://rk-europe.com/chain/uwv-chains/), 22.6mm wide vs. 21.7 - 21.9mm for their non-sealed chains (M530 & 530KS). It's expensive, though possibly not if you compare with a 520 chain and new sprockets, and seems not to be distributed in north America.