Author Topic: CB250T  (Read 410 times)

Offline blackeagles

  • SOHC Member
  • Posts: 155
    • View Profile
CB250T
« on: February 28, 2024, 10:19:37 AM »
I have not been on the site for a while (cancer) but after 3 odd months of 'nil by mouth' and an operation I have lost a lot of strength and as I cannot manage the 750/650 anymore I thought I try a 250t.

I know most will say they like to rev but it's a bit much to me so I was thinking of changing the gearing a bit.  The stock is 15/40 and 'Gear Commander' says going up to 17/40 will drop the revs by about 250 at 8k (60mph).

Anyone done this or similar??

It seems to me the options are :

1 - stay with 15/40 and put up with it;
2 - go to 17/40;
3 - try 18/40 (not sure it will fit in and I would have to change the chain) or
4 - go 17 but lower the wheel sprocket to say 35 ish (no idea what rev saving this is)


Any comments?

Offline Johnwebley

  • SOHC Jedi
  • Posts: 3232
    • View Profile
Re: CB250T
« Reply #1 on: February 28, 2024, 10:26:09 AM »
Going to such a high gearing will blunt acceleration, and turn top gear into an overdrive,

It would give you relaxed cruising in the 50s, but cut your ability to overtake,

You will also need to drop to lower  gears Going up hills,


My advice is to keep it how it is,

Just ride slower

Sent from my SM-A546E using Tapatalk

lifelong motorcycle rider,and fan

Offline Bryanj

  • Grogu
  • *
  • Posts: 10799
    • View Profile
Re: CB250T
« Reply #2 on: February 28, 2024, 11:58:41 AM »
Dont do it, Honda spent a fortune on r and d to get the best out of the bike in all circumstances

Offline McCabe-Thiele (Ted)

  • Grogu
  • *
  • Posts: 6285
    • View Profile
Re: CB250T
« Reply #3 on: February 28, 2024, 12:32:24 PM »
I've messed with gearing on cars wheel diamteres, tyre profiles, final drive ratios plus gearbox ratios when I was younger - an expensive process with a disappointing outcome for me.
Honda CB500 K1 (new pit dug out ready)
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html

Offline hondarc166

  • SOHC Associate
  • Posts: 98
    • View Profile
Re: CB250T
« Reply #4 on: February 28, 2024, 04:39:19 PM »
go with what john @bryanj says

Offline Rozabikes Tim

  • SOHC Master
  • Posts: 1191
    • View Profile
Re: CB250T
« Reply #5 on: February 28, 2024, 05:26:13 PM »
Done it the other way with a 400 Superdream on 250 gearing on rear wheel. Wheelies yes but also hole in crankcase due to lack of mechanical sympathy..

With what you are thinking as the others say. no. Not a rocketship of an engine to start with and no excess of power / torque to deal with greater load.
One day I'll have the time to restore it, not just talk and dream....

Offline Bryanj

  • Grogu
  • *
  • Posts: 10799
    • View Profile
Re: CB250T
« Reply #6 on: February 28, 2024, 08:58:28 PM »
Is this an old CJ250T?  If so they never had the ump th pull the skin off a rice pudding if it was already detached plus no electric start and cam/head troubles when the owners didnt know to remove clutch case to clean centrifugal filter!

 

SimplePortal 2.3.5 © 2008-2012, SimplePortal