Topic: CB750 Chains and sprockets

[Bankerdanny]

I know there are various threads on this subject, and I did do a search and read a few. But most are a few years old and so I thought I would ask my questions and see if we can consolidate some of the info into a new thread.

I am wrapping up my 750F1 project and it is time to order new sprockets and a chain.

1. Does the 750 have the same clearance issues with 530 o-ring chains as the 550?

2. If I convert to a 520 chain, do I need to do anything with the offset? The 520 front sprocket will be ~1/8" narrower because the inner width of the chain is narrower, which would move the chain slightly to the right towards the engine case. But with the 0-rings on either side, the actual width is likely to be about the same as a conventional 530. Is there a risk that the chain rubs on the side of the engine case?

3. Is there any real benefit to an aluminum rear sprocket on a stock modestly powered 70's street bike? They cost much more than steel and it just doesn't seem worth the extra cost for my application.

Cheers

Danny

[slikwilli420]

Go with the 520 conversion since you are getting everything anyway. I use the DID 520 x-ring chain. I think its always prudent to use an aluminum sprocket. Most are made from 7075 and as strong as steel at half the weight.

[seanbarney41]

no clearance issues with o/x ring chains on a 750...pretty sure aluminum sprocket is plenty strong, but what about durability?  400mile day, half of which in the rain is wayyyy different than 4 lap road races 5 times a season.  On the other hand, the finish/plating on steel sprockets is generally poor and they end up at least "looking" #$%*ty after one season.  520 sprocket is narrower on both the front and the rear, so no alignment issues...but is the difference between 520 and 530 worth it on the street?  Does anybody even sell "over the counter" 520 sprockets for a cb750?

[Bankerdanny]

Devin at Cognito sells one, but it's $78 and the matching aluminum rear is $69. Combined that's roughly double what conventional steel sprockets would run me.

As long as there are no clearance issues I think that I will stick with the 530. I've already spent quite a lot to get this bike ready and I still need throttle cables, brake lines, and brake pads.

[ofreen]

1. I’ve been running RK x-ring chains on my ‘75 750F for at least 25 years. It is fine.

2. Haven’t tried it but have wondered if a 520 would last as long as a comparable 530. I usually get 20-25000 out of the RKs.

3.  I put an aluminum rear sprocket on a CB900F years ago.  Sprocket Specialists as I recall. It was very pretty but it only lasted about 5000 miles.  I’ll never get another one.

[70CB750]

Steel sprockets and Tsubaki O ring chain would be ny choice.

[754]

TSUBAKI QR SERIES ARE PRETTY TOUGH IF YOU ARE WILLING TO LUBE IT, and they are cheap.
 If they no longer make them , you can still get on ebay, I paid around 40 bux for mine.
 Alloy sprockets are fairly tough, keep in mind, lighter..so better acceleration.. sometimes it's a tradeoff.
 520 will cost more , for a slight gain.

[tlbranth]

I have an RK x-ring on my '70 750. Definitely the way to go. No clearance issues. Years ago I tried an aluminum rear sprocket. Wore out quickly. Won't ever buy another. I'm pretty happy with JT sprockets - the steel ones.

[PeWe]

I had nylon rear sprocket in the 80’s.  I have no more memories so it might have been bad.

[slikwilli420]

Not to dog Devin, but $78 for a front sprocket is absurd. I converted to 520 and was able to get 520 front sprockets for mine for under $30 shipped. I used Sprocket Specialists in Utah. They had it on the shelf. Only place I could find since PBI stopped making them.

Rear sprockets are 7075 aluminum which has the strength of mild steel at half the weight. Definitely worth it on a race bike and if hard anodized, should last as long as a steel one on a street bike.

[przjohn]

There is no issue with the 530 O ring chain on that bike. Steel rear sprocket will last longer and is cheaper too. I don't believe anyone can notice the weight savings of an Aluminum vs. Steel rear sprocket for normal street riding. $78 for a Front Sprocket sounds kinda high to me too.

[Bankerdanny]

That was for a 520 sprocket set up to align properly with a 520 rear, I think it has a little bit of offset built in to account for the narrower teeth.

In the end I went with a 530 chain and just spent a little more for a good brand of chain. All together the sprockets and chain cost about what Devin gets for the two 520 sprockets combined.

[ofreen]

Rear sprockets are 7075 aluminum which has the strength of mild steel at half the weight. Definitely worth it on a race bike and if hard anodized, should last as long as a steel one on a street bike.

I don’t know anybody who has had one last any where near as long as a quality steel one. Somebody who buys one thinking it will is going to be disappointed.

[slikwilli420]

Rear sprockets are 7075 aluminum which has the strength of mild steel at half the weight. Definitely worth it on a race bike and if hard anodized, should last as long as a steel one on a street bike.

I don’t know anybody who has had one last any where near as long as a quality steel one. Somebody who buys one thinking it will is going to be disappointed.

Hard anodized or plain aluminum?

[PeWe]

About weight savings on a street bike. Skip the large fast food meals. Skip pasta and pizza as late food too. That will make a bigger difference

[Don R]

 I bought and sold a 750 with a nylon rear sprocket too. The PO loved it and it was old and not worn out. He thought the chain lasted longer also.