Honda-SOHC

SOHC.co.uk Forums => SOHC Singles & Twins => Topic started by: scifi on July 19, 2026, 09:38:11 PM

Title: CB250 and Welsh Hills.
Post by: scifi on July 19, 2026, 09:38:11 PM

I was at a Vintage Machinery Show near Corwen, and thought I would take my CB250 up the nearby Berwyn Mountain track.
All went OK for the first few miles, but as the road surface became more rocky I had to slow down to navigate a good line.
As soon as the revs dropped below 5000 rpm the bike just died and stalled out.
This is the sort of track that I have ridden on an old British 4 stroke single, and thought no more about it.

 I now have a list of hills to avoid in the N Wales area, on this type of bike....  It's just got the wrong type of power.

Title: Re: CB250 and Welsh Hills.
Post by: Johnwebley on July 19, 2026, 09:42:46 PM

Check the tickover


Should pull as low as 3k

My little 200 twin will pull that low

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Title: Re: CB250 and Welsh Hills.
Post by: Bryanj on July 19, 2026, 09:43:32 PM

Nonheavy flywheels for bottom end grunt

Title: Re: CB250 and Welsh Hills.
Post by: TrickyMicky on July 19, 2026, 11:23:27 PM

Quote from: Johnwebley on July 19, 2026, 09:42:46 PM

Check the tickover


Should pull as low as 3k

My little 200 twin will pull that low

Sent from my SM-A546E using Tapatalk

   If my memory serves me correctly, the 200 is a 360 degree twin, whereas the 250 is a 180 degree. I think back many years to my 175  twin with the 360 crank, and it would run to reasonably low revs, but my 250 needed to be kept spinning over quite quickly.

Title: Re: CB250 and Welsh Hills.
Post by: Oddjob on July 20, 2026, 12:40:22 AM

You’ve got to rev these small engines to get them to pull hard. Keep around 7k and use the gearbox is my advice.

Title: Re: CB250 and Welsh Hills.
Post by: florence on July 20, 2026, 10:00:13 AM

is this a 250k?

Title: Re: CB250 and Welsh Hills.
Post by: scifi on July 22, 2026, 09:52:50 AM

quote...   is this a 250k?    No it is marked as a CB250 G  .. ( Superdream.?)

My list of hills to avoid now includes any with...  Mud,  Stones,  Hairpins,  or greater than 1:5 gradient.

Title: Re: CB250 and Welsh Hills.
Post by: florence on July 22, 2026, 12:58:56 PM

I am surprised you cannot go up steep hills.  Is your final drive gearing correct? Something doesn't sound right.  Is it running on both cylinders? etc
I used to have a cb250k (similar to the G) years ago and it plodded up hills very well.

Title: Re: CB250 and Welsh Hills.
Post by: Oddjob on July 22, 2026, 03:55:35 PM

The superdream was the cb250n. You may have the cb250g5, which tbh was the worst of the 250s from that era.

Title: Re: CB250 and Welsh Hills.
Post by: SteveD CB500K0 on July 22, 2026, 06:47:02 PM

A photo would nail it.


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