Topic: 750 K8 630 Chain Replacement

[bhassell]

Looking to replace my worn drive chainand sprockets on 750 K8, How many of my K8 brethren have personal Pros/Cons as to convert to 530 from 630, Stick with 630, O-ring/Xring/No Ring, Who has best price selection etc. 

Appreciate all information,as I need to make a move on this soon, before I tear something up.

[bwaller]

These are great bikes to be sure, but you'll never need more than a good 530 o-ring chain. Check out the superbikes at your lcoal race track, they all run 520's. It's costing you valuable hp to turn that behemeth 630!

[bhassell]

Can't argue that,  but 77 and 78 came stock with 630.  Would need conversion sprockets to accomplish change.  In any event both sprockets and chain will be replaced so no big deal there.   Bob

[bwaller]

Right, if you've got to replace, I'd make the switch to 530.

[Quail "Owner of the comfortable k8"]

I kept the 630 chain but I did not have to replace the sprockets eather.  I will convert to the 520 o-ring chain next time because the sprockets are cheaper, the chain is cheaper, you have all the ratio options you could want,and you will have even more room for that fat oring chain.  I never understood why the bike with the least power (69-78) had the largest chain.  in any case never use a worn out chain, that hole the old chain makes  in the case when it comes apart is a sad sight.  I almost forgot  K8's rule this forum.

[bhassell]

Can you recommend a gould source for either 520 or 530 sprocket and chain combos? 

[bhassell]

Forget recommend source, How many links of 530 to equal length of original 630 which I believe was 88 links?

[bwaller]

With stock gearing, 18T front & 48T rear....100 links.

[dusterdude]

I kept the 630 chain but I did not have to replace the sprockets eather.  I will convert to the 520 o-ring chain next time because the sprockets are cheaper, the chain is cheaper, you have all the ratio options you could want,and you will have even more room for that fat oring chain.  I never understood why the bike with the least power (69-78) had the largest chain.  in any case never use a worn out chain, that hole the old chain makes  in the case when it comes apart is a sad sight.  I almost forgot  K8's rule this forum.

quail,you sniffing glue again?

[bhassell]

Thanks...my stock sprockets are 15 and 41 tooth, ordered 110 links of 530 and will cut down.  Was really concerned i may order too short and have no extra links.  

If it is helpful to anyone else, I will post number of links needed of 530 with my Ratio for FAQ purposes

[Quail "Owner of the comfortable k8"]

I kept the 630 chain but I did not have to replace the sprockets eather.  I will convert to the 520 o-ring chain next time because the sprockets are cheaper, the chain is cheaper, you have all the ratio options you could want,and you will have even more room for that fat oring chain.  I never understood why the bike with the least power (69-78) had the largest chain.  in any case never use a worn out chain, that hole the old chain makes  in the case when it comes apart is a sad sight.  I almost forgot  K8's rule this forum.

quail,you sniffing glue again?

I gave up glue after I passed out with my head stuck in the bag.

[dusterdude]

 

[eldar]

I kinda like the size of the 630 chain. Everyone must remember that when these bikes were made, chains were not as strong as they are now. So 630 was a better choice then but I think I will do a 530 unless I do an 836. Then I will check with others who have done the 836 and see if the 530 has worked fine for them.

As for rockets using 520s, they weigh much less than any cb750.

[bhassell]

Isn't that the truth!!! My son just bought new 600RR.  Thing is so much lighter and thus unbeliveably responsive.  It is amazing the technology that has been applied to our simple SOHC4 building block.  Quiet as a sewing machine, fantastic brakes, and very quick.
But...Aint no way I can see me or anyone else riding one far with their butt damn near higher than their head without passing out!  Besides, with my physique I need the top of the tank pounded in more than the sides...Thanks to all for the advice on chains...

[bhassell]

Wish I would have paid closer attention to what Bwaller was trying to tell me far as 18t fr, 48t r. 

I Ordered 530X Ring Chain and what I thought was right conversions off of a Rocky Mountain Chart.  Very confusing ...Wound up with correct Chain but OE 630 Sprockets again Arghhh...

Have to call in am to arrange return and replace with right stuff.  If I have it right this time, should be JT Sprockets 24-9247 Front, 249404 Rear off of early model 750 Automatic.  Someone please correct me if I have this wrong again.  Thanks..

Was really surprised how sloppy my old chain was when I got it off.  Probably best that bike is now out of commission before tragedy strikes.

[Terry in Australia]

I was surprised to discover that there is no need for a special "conversion" sprocket to change my F2 from a 630 to a 530 chain, I bought a new 530 front sprocket for my K1, and it slid straight on to the F2's splines! Of course there's a couple of redundant holes for the K1's securing plate, but that doesn't matter, as the F2 has the bolt and washer to hold the sprocket on.

Over here in Oz there aren't many sources for 630 chain and sprockets anyway, (the old GS/GSX Suzukis were the last bikes to use 'em, and they finished production 20 years ago) so apart from the advantages of a lighter stronger chain, availability will be a bigger priority. Just make sure you buy a quality 530 chain, there are some cheap 530's coming out of China and Malaysia that are really cheap, but they're rubbish, and they'll snap and plow a furrow through your cases (and maybe your leg too) quicker than your tired old 630 chain ever would. Better safe, than dead................ Cheers, Terry.

[bhassell]

All the Shaft specs look to be correct for the Splines on the Front, and Bolt Pattern looks identical on the Rear when looking at the JT-Sprockets website.  The front sprocket is also thicker.  Comparison is from CB750 K7/8 (77/78) to CB75A (76).  I also see the extra holes in front sprocket you referred to also.

Original Front 24-9230 (JTF-331) for 630 15t
New Front    24-9247 (JTF-288) for 530  Would be for 18t

Original Rear 24-9428 (JTF-333) for 630 41t
New Rear    24-9404 (JTF-284) for 530   Would be for 48t

New Ratio will change from 2.73 to 2.67, hopefully drop highway RPM without sacrificing too much low end torque.

My only concerns are for clearances in the front sprocket area...That is, going too small and chain contacting splined shaft, or too large and perhaps case contact.  Neither would be good.  Hopefully I can get the Parts guy to make some measurements for me.  If I was dealing with a Local Parts source I might feel more comfortable. 

Thanks Terry!

[MRieck]

I kinda like the size of the 630 chain. Everyone must remember that when these bikes were made, chains were not as strong as they are now. So 630 was a better choice then but I think I will do a 530 unless I do an 836. Then I will check with others who have done the 836 and see if the 530 has worked fine for them.

As for rockets using 520s, they weigh much less than any cb750.

Eldar...my Hayabusa puts 186HP to the rear wheel, weighs more than any cb750 and uses a 530 chain. It is more chain-unless someone reallycheaps out- than any CB needs. But, on the other hand you do have a K8 ......

[HondaMan]

The advantage of the 630 chain system is "wear faces". They are slightly wider, supposedly lasting longer. Where this goes wrong is with the O-ring chain, which has much higher rotating friction. The 530 puts more HP on the ground, if both are O-ring types, but the O-ring costs about 1/2 HP and wears sprockets faster - unless you lube it like it wasn't an O-ring type...I'm a big fan of non-O-ring Diamond chains. Reynolds are real good, too. Both have more lateral play and hardened-through rollers, not just case-hardenend.

And, they cost like it...

[bhassell]

The advantage of the 630 chain system is "wear faces". They are slightly wider, supposedly lasting longer. Where this goes wrong is with the O-ring chain, which has much higher rotating friction. The 530 puts more HP on the ground, if both are O-ring types, but the O-ring costs about 1/2 HP and wears sprockets faster - unless you lube it like it wasn't an O-ring type...I'm a big fan of non-O-ring Diamond chains. Reynolds are real good, too. Both have more lateral play and hardened-through rollers, not just case-hardenend.

And, they cost like it...

Should I have any issues with the sprocket set i indicated above?  I don't see anything wrong, but fat fingered one order incorrectly already.  thx

[Terry in Australia]

You'll be fine mate, if anything, the K8's output shaft should be slightly longer, so you won't have any case clearance problems with a 530 "O" ring chain, and the 18T front sprocket was honda's "first response" solution to chain breakage way back when they upped it from 17T.

You've now got the standard 18/48 gearing, ala the earlier K's, so you should have a slight drop in engine revs at highway speed, combined with a slight decrease in fuel consumption without sacrificing accelleration terribly. Good choice mate, I'm gonna do the same on my F2 when  I rebuild it. (dammit!)

Hondaman's point re: non O ring chains is quite valid too, (IMLTHO) people tend to treat O ring chains like they're not there, and wonder why they crap out after only a couple of years of abuse. I prefer to buy chain from a local industrial chain supplier, he only sells quality Japanese non O ring chain in 10 foot lengths, and I have no issue with occasionally oiling my chain. Cheers, Terry.

[HondaMan]

You'll be fine mate, if anything, the K8's output shaft should be slightly longer, so you won't have any case clearance problems with a 530 "O" ring chain, and the 18T front sprocket was honda's "first response" solution to chain breakage way back when they upped it from 17T.

You've now got the standard 18/48 gearing, ala the earlier K's, so you should have a slight drop in engine revs at highway speed, combined with a slight decrease in fuel consumption without sacrificing accelleration terribly. Good choice mate, I'm gonna do the same on my F2 when  I rebuild it. (dammit!)

Hondaman's point re: non O ring chains is quite valid too, (IMLTHO) people tend to treat O ring chains like they're not there, and wonder why they crap out after only a couple of years of abuse. I prefer to buy chain from a local industrial chain supplier, he only sells quality Japanese non O ring chain in 10 foot lengths, and I have no issue with occasionally oiling my chain. Cheers, Terry.

Hey, Terry;

Did the K0/K1 "down under" start out with the 17T counters and 48T rears? Up here, they started with 16T counters and 45T rears until the K1, then Honda recalled all of them and fitted 17T/48T kits with no master links (%$#*!) - had to remove the swingarm to install 'em...The quickest CB750s 0-90MPH were the K0 or K1 dressed in 16T counters...

Just wondering...   

[Terry in Australia]

I'm not sure HM, I'll have to check my parts manual, but you're right, a lot of the extra "oomph" that the K0/K1 was credited with over the later K2-K6 models was all to do with the lower gearing due to the smaller front sprocket.

I've never seen a 16T front on a CB750 here in Oz, (Clyde will probably know) but I'm sure that you're right for US models. Cheers, Terry.     

[dpen]

I replaced sprockets & chain on my K7 about 10,00 Ks ago.

530 "x" ring chain went straight on, no clearance problems etc.

[eldar]

The K8 came with an oring chain from the factory. The K7 may have too.
Clearance is not an issue.

Terry or HM, What was the standard f/r for the K1? How about K2 - K6? Also, as far as I can tell, the distance from spline to axle did not change on the K models, what length of 530 chain would I need?  I dont really care to have to cut it down.

While I do like the style of the K8, chain selection and sprocket is rather slim as terry well knows.