So I have a 11/1969 Diecast K0 with a matching 11/69 motor that RC Engineering built into a milder version of their cobra 1000cc mill(Cobra big bore pistons, fully ported heads, modified HD valve train, HD studs, etc. but with a cam milder than the wild RC#327 and retained the electric starter) I'm planning on a stock blue/green tinned and original ducktail seat bike with vintage performance mods. An RC recommended 18x3.5 aluminum rear wheel, a matching 19x2.5 front, RC Engineering 4 into 1 exhaust, an ARD magneto, low rise handlebars similar to the low rise cb400f bars. I am not interested in the fastest bike around, just a very vintage style modified cb750 using somewhat forgotten old school parts and technology for the $hit$ and giggles of it. All those funky performance parts that you rarely see today on a cb750.
The motor should be capable of putting out a reasonable amount of power over a stock K0(not interested in getting bogged down in debating over potential HP numbers) One of the first problems eager cb750 owners had with their new K0s was broken chains (not the primary chains, but the final drive chains to the rear wheel), usually taking out the primary cover and sometimes the lower engine casting along with it. Not fun for either Honda or the disappointed owner. Aftermarket companies soon replied with dual row chains(more is stronger they thought) ...Thoughts on the subject from Hondaman a while back.
Quote from Hondaman back in December 22, 2007 from
http://forums.sohc4.net/index.php?topic=29164.0"They were an aftermarket accessory, expensive and not really needed. They also came in chromed versions. The biggest issue with them was in getting the engine sprockets and wheel sprockets aligned, because these don't always match up in the stock configuration (see the chain notes in the FAQ). The K0 required notching of the chain cover at the engine to make it all fit together; I never installed one on a K1-later, so I don't know if yours is also notched. They appeared first in 1970, due to the reputation of the CB750 being "the $1695.00 chain breaker tool". I always thought of these kits as being like the guy who stuffed a sock into his tight jeans before riding the "strip" for the night....
They are heavy, adding a lot of unspring weight, and between the weight and the extra friction, consume several HP in the process before reaching the wheel.
The 530 chain can transmit over 100 HP continuously, if properly lubed. The 50 chain (and similar O-ring chains) can handle about 70 HP. The difference is in the pins inside the rollers that also connect the links together. Superior quality chains like the Diamond XL series can handle even more HP and torque. I've long used the Diamond XL100 (hard to find!), getting up to 20,000 miles on them, replacing at 1.5% chain stretch. Dyno tests in the 1970s were used to develop these chains for the motorcycle industry, specifically for the CB750 and the Kaw Blue Streak, both notorious chain breakers.
Serious drag racers avoided them for their weight and power loss...chopper 750s seemed to have lots of them!" ...end quote from Hondaman
I have seen bunches of these dual row kits on cb750 choppers, but know of very few on standard frame bikes any more. According to Hondaman's book, Honda went nuts in late 1969 trying to solve this problem, and altering the design of the rear sprocket seemed to be the major change that fixed the problem. The "chain breaker" reputation did not go away overnight of course and a few companies undoubtedly sold a whole bunch of dual row chain sets through the early 70's. Being that my bike is not only a 1969 K0, but with a ported 1000cc RC engineering built K0 motor, it would not be historically unusual to expect the guy who paid for both those sizable expenses to also have purchased a dual row chain kit for a perceived added insurance.
I'm wondering if it would be worth the pure retro style factor(not unlike the ARD magneto I have for it) to run a dual row chain? I am not too concerned with the minimal power loss through the heavier/higher friction chain. I'm not planning on racing anyone! But I am concerned about making sure the chain and sprockets are of a quality manufacture and design to comfortably handle the RC1000's extra power and torque. A thrown dual row chain could do major damage...
My more sensible option, of course, is to convert to a nice 530 chain setup, keep it properly oiled, and never have to worry about it. But shouldn't life be more challenging than that?
George
