Topic: 17 or 18t on a 9/70 K1 750?

[kck3]

I am looking to purchase new chain and sprockets for my K1 and have searched and have seen both listed.  Which one was factory?  The 17 or 18?  As for the chain will I be ok with a 530 100 link O ring?  Is 100 link what I need?

[Kevin D]

My 11/70 came with 18f/48r. 100L is the right length.

I tried an o-ring chain with clip type master link and found that the extra wide master link tapped the inner chainguard brace. I might have been OK if I had a narrower riveted masterlink or fudged the chainguard this way or that. I went back to the standard chain, but later found that the inner chainguard brace was broken. I lost it the brace entirely on my Godzilla escort ride this past summer.         
Your experience may differ - I'm pretty sure there are others here running o-ring chains on K1's.

I'd choose the sprocket size based on riding style: stoplight to stoplight 17T, 70mph cruising 18T .

Also following this thread:
http://forums.sohc4.net/index.php?topic=74459.0

[Gordon]

We may have to ask Hondaman about this one.  I've seen it written both ways, too.  My K1 came to me with a 17 tooth sprocket, but that doesn't mean it was that way from the factory.  I've kept it that way, and it's been great for both city and long-distance highway riding. 

[Hinomaru]

The Honda publications that I have show the 18T sprocket was fitted beginning with engine number: CB750E-10448069

[andy750]

I use a 17t for both my CB750s. Cruising on the highway is just fine with a 17t and not a whole lot of difference in rpms (not buzzy by any means and better for passing). I have used an RK, EK and TSUBAKI o-ring chains and never had an issue with clearance.

So 17t gets my vote

[Imago]

I just purchased and am awaiting a new chain and sprockets for my 1976 CB750K.

At Bike Bandit, they assured me the sizes were as follows:

18 Front and 48 Rear, 530 non-o-ring chain with 104 links.

After reading this thread I'm concerned that 104 is too many links... did Honda change the length during K1 to K6?

[Don R]

I prefer the 17 for an in town bike 18 for cruising, less noise and slightly less RPM. The longer chain can be used to allow the rear wheel to move back to slightly lengthen the wheelbase which will give the bike a slightly bigger feel.

[bjatwood]

I removed my sprockets and chain and found that the front sprocket was a 17T, I ride this baby 32 miles to work one way. So, with that kind of Highway riding in mind I went with a new 18T front and a 48T rear and a X-ring chain. With a 17T front sprocket I was crusing at 65 to 70MPH and the engine was purring at 5K. The engine did feel like that was it's sweet spot. When you pass a vehicle at 5K, you really don't even need to downshift to get it rolling good, twist and shout!