Author Topic: C15 Max Speed  (Read 540 times)

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scarle34

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C15 Max Speed
« on: 01 June, 2017, 14:10:20 »
Just got a 1961 C15 which runs Ok but max speed is only 50mph.
I have no experience of bike maintenance and would welcome any ideas on how to improve the speed.

JulianS

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Re: C15 Max Speed
« Reply #1 on: 02 June, 2017, 11:31:30 »
Read up and become fully aquainted with the workings of your bike. There is a lot of literature out there you could do worse than get the "Rupert Ratio" Unit singles manuals.

The engine and cycle parts need to be in good condition and properly adjusted.

Be realistic in what you expect from it, the bike is 56 years old and when new was claimed to produce a modest 15 BHP for the standard "Star" and a bit more if you have the SS80.

Most riders are a bit bigger than those who rode them back then.

The easiest way to more speed is a bigger bike.






scarle34

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Re: C15 Max Speed
« Reply #2 on: 02 June, 2017, 15:37:00 »
I agree in general but expected to cruise at 50 with 60 max and I will look into the Rupert ratio manuals. You are right about being bigger (I was 9 stone wet through in 1961 when i got my first bike) and as I don't now want a bigger bike I may have to accept the lower speeds.

Thanks for your comments Julian.

MICKREEVES

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Re: C15 Max Speed
« Reply #3 on: 14 June, 2017, 07:27:22 »
I dont think that riders weight affects the top speed. It is only the acceleration which will be slightly less with heavier rider, although I doubt it would be noticeable without checking by stop watch.
What does affect top speed is air resistance. Crouching down will increase the top speed.
Of course gradient and wind speed/direction has a big effect.
My C15 ss now reaches 60 mph, then slowly creeps up to 70, no more.
Mick

JulianS

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Re: C15 Max Speed
« Reply #4 on: 14 June, 2017, 09:01:16 »
Sorry I dont agree about weight.

Experiment by carrying a pillion passenger.

MICKREEVES

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Re: C15 Max Speed
« Reply #5 on: 21 September, 2017, 18:43:02 »
My wife absolutely refuses!!
Mick