Topic: 1978 CB750 Chain and sprockets direct replacement.

[crousos]

I know that this is a topic that has been talked about in the past but I am looking for some advice from fellows that did this for the same reasons that I am looking to do it.

Simply both chain and sprockets need to be replaced and I am looking for the best options for a direct replacement.

What are the best options out there for me?

any advice and suggestions are welcomed!!

Constantine

[PeWe]

which model?
The F2 had 630 chain and different sprockets not compatible with the older K models.
Drive chains are improved the last years. Racing guys do not use O/X-ring chains that steal power. Touring guys driving in rain need the O/X-ring chains for better lubrication, keep lube longer. And keep dirt as well, guys running off-road have a reason to stay away from the O/X-ring chains.

Next is riveted link or clip. 
Solid link PITY to rivet. You must have a very powerful tool such as WHALE chain cutter/rivet tool. I know....
I never had any issues with clips back in the days. Usually DID 50HDS O-Ring 530 chain on my CB750 K6-76

[750K]

Go to JT sprockets website, if you are staying with the stock 630 setup for your bike just match the tooth sizes and pick a quality chain (DID, EK, RK are all good) and you're good to go.

If you are going to a 530 chain and sprocket JT has a gearing ratio chart, find the stock ratio of your stock set up and match it as close as you can get. If you want more jam off the line drop a tooth in the front or if you want lower highway rpms go up a tooth in the front. Pick a chain and instal, fairly straight forward. JT is good quality and will be a direct bolt on replacement.

[flybox1]

I switched to an RK 530 HD standard chain and JT sprockets(17/48)
$85 total.

[lucky]

Please listen to this:
You do not need or want that big heavy #630 chain.
It has caused damage to many engine cases .
The more modern chains are stronger.
Use the #530 chain instead.
Some racing bikes even use #520 chain and sprockets.
The #530 chain is more that strong enough at half of the weight.
And that weight is moving weight.

If you use regular chain no special tools are needed.
The Diamond XL chain has bronze inserts in each roller.

[750K]

Lucky, if you think a 630 chain will break you have rocks in your head. Honda went up to a 630 because the old 530's were breaking cases when they failed for whatever reason they were failing. Use your brain for once...

Nothing wrong with using a 630 if the OP decides to go stock, if the bike is being ridden on the street I bet the difference in the rotating mass of a 530 set up might not be really noticeable to most people.

[TwoTired]

Please listen to this:
You do not need or want that big heavy #630 chain.
It has caused damage to many engine cases .

Please do NOT listen to this.  It is pure scare tactics with absolutely no basis in reality and certainly no actual data to back up such an imaginary tale.

My bikes with 630s on them are still original!  They last a very long time if given the routine lube they deserve.  If and when they do wear out, I'll replace with 630, as the "weight savings" means little to me.  I'm not going to be racing these on a track where seconds count.

It takes way more force to break a 630 chain than a 530, even if battery acid does get onto it.  (Check the battery drain tube routing).

While I don't have anything against modern 530s.  The quality certainly varies among the offerings.  And, Honda's sprockets are machined for quiet and smooth operation.

[Mr Freeze]

Sunstar makes everything you need for the 1978 CB750. Going to 530 chain size is a good move because there's more available in terms of sprockets if you want to switch up ratios in the future. I went with a 17 tooth front and a 48 rear sprocket and X ring chain. You'll have to shorten the chain for your bike (it comes with 110 links) and I'd also recommend a clip style master link (it comes with a rivet style link)

Since putting it on, I've gone 1500 miles and haven't had to make any adjustments since the initial one when I installed it.

[crousos]

I have been looking around and I dont see anything available on the 630 chain and sprockets can you please point me to the
right direction? also on the 530 route is something like this ok? are 102 links enough?
      
17 tooth front sprocket
48 tooth rear sprocket
102 link 50VX heavy duty x-ring drive chain

From DID

[crousos]

Sorry for the confusion, it is a CB750K I believe that will be K7.

[750K]

http://www.jtsprockets.com/catalogue/model/4856

Lucky is the only one that's confused lol, here's a link to the 630 set JT offers.

[Airborne 82nd]

Also DSS has all three parts. Scroll down.

http://www.davidsilverspares.com/CB750K-FOUR-1978-USA/

[BobbyR]

Please listen to this:
You do not need or want that big heavy #630 chain.
It has caused damage to many engine cases .

Please do NOT listen to this.  It is pure scare tactics with absolutely no basis in reality and certainly no actual data to back up such an imaginary tale.

My bikes with 630s on them are still original!  They last a very long time if given the routine lube they deserve.  If and when they do wear out, I'll replace with 630, as the "weight savings" means little to me.  I'm not going to be racing these on a track where seconds count.

It takes way more force to break a 630 chain than a 530, even if battery acid does get onto it.  (Check the battery drain tube routing).

While I don't have anything against modern 530s.  The quality certainly varies among the offerings.  And, Honda's sprockets are machined for quiet and smooth operation.

I agree. 630 chains are easy to get and since the 78Ks came set up for 630, replacing a chain and sprocket is very easy with no adapters.

If I follow the logic of a earlier very dire post. A 630 made of the same modern alloys is one strong chain!

[bjbuchanan]

The post was a little over the top but he was just trying to say he doesn't "need" a 630 chain. They are super strong, damn near invincible on our bikes but they are slightly heavier and less options are available.

You don't have to depart from stock, 630 is just fine. Just get sprockets for 630 chain size in the ratio you want. If you want to go lighter (and usually cheaper) you can go for the 530 chain and sprocket combo.

No special magic, just buy the sprockets that they say fit the bike lol. Most of us 530 guys run 17/48 sprockets. Given the longer swingarm I think you will need atleast 102 links, gonna need someone else to verify that as I have only dealt with the earlier k6 and below.

[crousos]

Thanks for all the good info guys! but I have a couple of  more questions:

Will I need an adapter to go with the 530 17/48 sprockets kit.

And do you think 102 links will be enough for my bike?

as always thank you very much in advance!

Constantine

[Airborne 82nd]

Thanks for all the good info guys! but I have a couple of  more questions:

Will I need an adapter to go with the 530 17/48 sprockets kit.

And do you think 102 links will be enough for my bike?

as always thank you very much in advance!

Constantine

Not if you get the correct sprocket. The 77-78 has only one bolt & large washer in the center of the small drive sprocket. Other bikes have two bolts side by side. When you put it on it will move a couple of mm in and out on the shaft sort of a self centering to line up with the rear.

[BobbyR]

I kept the 630 chain since it is really easy to replace and it looks good. I personally kept the stock gearing since it works well in the area I ride in.  Nice low end grunt around Town and balls on the Highway. As PJ can attest to around here you are either going up or down a steep hill. If it were flatter I may play with the ratios. 

[Airborne 82nd]

I stayed with the 630 too it is not like I'm trying to get every 1/10 of a second out of the bike it is just a cruiser for me. Stayed with the stock gearing also like BobbyR said good all around like Honda wanted it to be. I did need and want it and it is gold someones favorite color.

[750K]

I ended up with a 520 sprocket and chain for cheap so I'll be switching over to the lighter setup, I'm trying to put my 77 750k on a diet this year without cutting anything off the old tank. I've got a sprocket combo that puts me as float to stock ratios which are fine for the city and highway I do on my commute, otherwise I would have stuck to my current 630 setup.

[Mr Freeze]

The only reason I suggested going to 530 chain is because it more commonly used nowadays. You don't need any special adapters, it's a bolt up and go operation. I believe my chain was 110 links and I had to shorten it to 104, 102 links will be too short because the 1978 K swingarm is longer than the 69-76 bikes.

So if you're doing sprockets anyway, a conversion to 530 chain and sprockets isn't a big deal. 17/48 ratio is almost exactly the same as the stock 630 setup these bikes had.

[lrutt]

I kept the 630 on my K8 but I pull a sidecar. My K6 has 530. Just pick the highest tensile strength 530 you can and you'll be fine. These motors are pretty pathetic for power compared to what the new bikes put chains through.

I've never used anything but clip type links. Just do them right. and get a spare...JIC.

[Airborne 82nd]

I switched to an RK 530 HD standard chain and JT sprockets(17/48)
$85 total.

Fly how many links did you need for that 530 chain with the sprockets (17/48)?

[lucky]

Lucky, if you think a 630 chain will break you have rocks in your head. Honda went up to a 630 because the old 530's were breaking cases when they failed for whatever reason they were failing. Use your brain for once...

Nothing wrong with using a 630 if the OP decides to go stock, if the bike is being ridden on the street I bet the difference in the rotating mass of a 530 set up might not be really noticeable to most people.

IF you hold a #630 chain in one hand and a #530 chain in the other hand,
Your mind will be made up. That #630 chain is ridiculously heavy for that bike.

[flybox1]

I switched to an RK 530 HD standard chain and JT sprockets(17/48)
$85 total.

Fly how many links did you need for that 530 chain with the sprockets (17/48)?

I cant remember exactly, I'd have to look at the leftover section I have in a baggie, but I bought a 110 and cut 5+/- off.
I mounted my rear wheel near the front 1/3rd mark area of the chain stretch marks, and then cut the chain to fit here.

[750K]

Lucky, if you think a 630 chain will break you have rocks in your head. Honda went up to a 630 because the old 530's were breaking cases when they failed for whatever reason they were failing. Use your brain for once...

Nothing wrong with using a 630 if the OP decides to go stock, if the bike is being ridden on the street I bet the difference in the rotating mass of a 530 set up might not be really noticeable to most people.

IF you hold a #630 chain in one hand and a #530 chain in the other hand,
Your mind will be made up. That #630 chain is ridiculously heavy for that bike.

There is nothing wrong with a 630 chain Lucky, yes it's heavier than a 530 but it works just fine in street applications. Quit trying to scare people into believing its going to break, it's plenty strong. Just because you don't like it doesn't mean there's anything wrong with it.

For the record I'm actually switching over too a 520 setup, not because there's anything wrong with my 630. I got a set locally for cheap as well as a 520 chain, otherwise I'd happily stick to my 630 setup. I'm trying to lighten up the old bike without hacking things off of it. 520 setup, aluminum wheels, drilled rotor, billet motor mounts from 745.