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SOHC.co.uk Forums => CB500/550 => Topic started by: davidrsmith on November 18, 2017, 04:44:57 PM

Title: CB550K3 speed/revs question
Post by: davidrsmith on November 18, 2017, 04:44:57 PM
Hi

I have now fixed the sticking front brake, thanks to all who answered my query especially BryanJ. I took the bike out for a test ride the other day, in top gear it was doing 60mph at just about 5000rpm, can anyone with a K3 tell me if this is about right.
Perhaps its the mists of time or just an age related thing, but as far as I can remember my old K3, back in the late 70s didn't need quite so many revs to stay at 60mph in top gear. But saying that it seems to be running well and I am pleased with it.

Many thanks
Dave
Title: Re: CB550K3 speed/revs question
Post by: hairygit on November 18, 2017, 05:42:32 PM
Different sized sprocket(s) from standard alter the gearing, so what number of teeth f/r should it have, and what are you running. Any deviation from stock will alter the revs to road speed in any gear.

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Title: Re: CB550K3 speed/revs question
Post by: deltarider on November 18, 2017, 06:18:41 PM
Could correspond with the rear sprocket. The CB550K3-ED had 34 teeth, the other markets had 37. cf. p. 62 http://www.honda4fun.com/pdf_parts_list/pdf_spac500-550/CB500-550_K3-K4.pdf
Title: Re: CB550K3 speed/revs question
Post by: Johnwebley on November 18, 2017, 08:09:02 PM
Hi

I have now fixed the sticking front brake, thanks to all who answered my query especially BryanJ. I took the bike out for a test ride the other day, in top gear it was doing 60mph at just about 5000rpm, can anyone with a K3 tell me if this is about right.
Perhaps its the mists of time or just an age related thing, but as far as I can remember my old K3, back in the late 70s didn't need quite so many revs to stay at 60mph in top gear. But saying that it seems to be running well and I am pleased with it.

Many thanks
Dave

 I seem to think my CB500 is about 12mph per 1,000rpm.
but tyre sizes make a difference, such as a 90/90 front,and 100/90 rear.these low profile will lower both the bike and gearing.

 I seem to remember 5,300 approx was mid 60's
Title: Re: CB550K3 speed/revs question
Post by: deltarider on November 19, 2017, 09:11:28 AM
For the CB500 - primary reduction of 2,0:1 - it is simple: in 5th gear 5000 rpm = 100 km/h, 6000 rpm = 120 km/h, 7000 = 140 km/h, 8000 = 160 km/h. Don't you love the metric system?  :)
Title: Re: CB550K3 speed/revs question
Post by: K2-K6 on November 19, 2017, 09:25:09 AM
I do like the metric system, so simple.

All the bikes run imperial wheels though to mess it up  ;D
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