Topic: '72 CB500 Shifting RPM

[MikeM]

Hello Everyone,

First off, I'm new here and I already need to thank you. I purchased my '72 CB500 2 weeks ago and if it weren't for this forum, I'd have already been lost. I've had several bikes before but never one of this vintage and in the past 20+ years I've only had a 1500 V-twin.

My question is since I'm not used to running these higher RPMs, what is a good shift point RPM and what would be a maximum HP RPM? When I'm cruising around town I'm typically running around 3000 rpm in 4th gear but is that good? I don't know that either. Does it matter that much?

Thanks again and I'm sure you'll be seeing more of me. I'll post pictures soon, I have already done a lot to the bike to make it my own and I'm loving it!

Thanks
Mike

[Deltarider]

My question is since I'm not used to running these higher RPMs, what is a good shift point RPM and what would be a maximum HP RPM? When I'm cruising around town I'm typically running around 3000 rpm in 4th gear but is that good?

Cruising around town is not ideal for a 500cc motorcycle that weighs almost 185 kg. When I started riding in the 70s a 450cc Black Bomber or a 500cc Four was considered a big bike.
The higher the rpm the better a CB500 Four shifts. From 1 to 2 you can upshift pretty soon. For the rest I advice to shift at least above 5000 rpm. 7000 would be fine too.
If you must cruise @ 3000 rpm (I advise not), you should know that from there your right wrist 'd better not demand more throttle. To accelerate you should downshift one or two gears. Accelerating from 3000 rpm is lugging the engine. You can cruise @ 6500-7000 for hours on end no prob. It will clean your combustion chambers and spark plugs. At 3000 rpm I fear the sparkplugs will blacken soon.

[MikeM]

Thanks Deltarider, I appreciate the info. I'll have to get used to those higher rpms. The bike sure sounds awesome at 7K so I'm sure I'll like it just fine. 

[Rgconner]

Real issue with 3K rpm and slide carburetors is if you grab for too much throttle too quick... bike will lose vacuum then bog and stall. There are no acceleration pumps, so you have to have vacuum to move fuel out of the bowls.

4.5K is ideal for cruising, you are right at the bottom of the power band.

[flatlander]

deltarider's info is good.
i would only add, in terms of shift point: these engines are built for high revs, you can easily go into the red area on your tach, then shift - just don't stay in there constantly.
pushing it like this probably takes some getting used to after your previous bike.

[robvangulik]

We Dutchies should ride together some time, I'd love to compare my old 400 with your bigger cc bikes, I can lug along in sixth at 3k and without hesitation zoom to 10 k, and in low revs my plugs stay clean for hours on end.....