Topic: Differences in 550 carbs up to 1976, out of curiosity

[seanbarney41]

Come on Hondaman...pure speculation.  Really going to need some evidence for all these claims.

[jonda500]

Why would Honda adhere to a smog law with the 77/78 550K but not with the 77/78 550F (-early F models had exactly the same carbs as the later (77/78) F models)?
John

[grcamna2]

Why would Honda adhere to a smog law with the 77/78 550K but not with the 77/78 550F (-early F models had exactly the same carbs as the later (77/78) F models)?
John

That's a good point John.

[Deltarider]

Just before I was to type, I remembered I have posted on this before: http://forums.sohc4.net/index.php/topic,162944.msg1875707.html#msg1875707

[HondaMan]

Why would Honda adhere to a smog law with the 77/78 550K but not with the 77/78 550F (-early F models had exactly the same carbs as the later (77/78) F models)?
John

That's a good point John.

It was because of "Type Acceptance" rules that were set up at the time. It went like this: if you could make your bike#1 pass emissions law for the 1973 model year, you were given [n] number of years that you could build them just like the first one. If you changed anything involving carbs, pipes, or engine configuration of displacement (or cam), then you had to follow the NEW rules that were set up for the model year in which this new version came out.

So, the 1973-introduced CB500F/550F bikes had the same carbs and pipes all the way thru their run, while the CB500/550K bike, which was changed considerably in 1976, had to follow another set of rules. Then again, the last 2 years, with the improved rocker shaft cam-cover engines, had different pipes again, so they had to follow yet another set of laws.

That's how it all happened, and why there are 5 different carbs in as many years on this bike.

[jonda500]

Whilst I don't own any, I am under the impression that the 087A carbs are in fact also identical to the other early style carbs (627B, 069A, etc.) which means there were in fact only two types of carbs used in the cb500/550 F/K's?
John

[scottly]

Why would Honda adhere to a smog law with the 77/78 550K but not with the 77/78 550F (-early F models had exactly the same carbs as the later (77/78) F models)?
John

Even in California, which had to most stringent smog laws in the country, motorcycles were largely exempt, as were cars with multiple carbs, such as two four-barrel 426 Hemi Mopars, until the 1972 laws took effect which killed the muscle car. If you bought a 1963 or newer car, it had to be inspected for the smog equipment for the year model it came with, but when I bought an '82 Honda Ascot, no inspection was required, and even then the only "smog equipment" was the tube that vented crankcase fumes into the air filter housing, like the later '70s bikes.
As far as Harley and Honda, I do recall in the '80s when HD got our government to slap a tariff on Japanese motorcycles larger than 700ccs, claiming that Honda was dumping bikes on the US market and competing unfairly, even though Honda didn't make anything that would have appealed to the average HD buyer. I remember the price of a then-new Honda 750 Interceptor increased by $1000 overnight.