OzVMX Forum

Clubroom => Tech Talk => Topic started by: TheDamo on June 10, 2013, 04:42:55 pm

Title: smooth out an 87 CR250
Post by: TheDamo on June 10, 2013, 04:42:55 pm

Hi Guys,
Has anyone had experience with smoothing out the power on an 87 CR250?
Some more bottom end and transition to mid range would be nice.
Cheers

Title: Re: smooth out an 87 CR250
Post by: Lozza on June 10, 2013, 05:07:31 pm

Do you want the easy or the hard way?

Title: Re: smooth out an 87 CR250
Post by: Paul552 on June 10, 2013, 06:41:59 pm

http://www.g2ergo.com/dirt-bike-g2-ergonomics-products.html

http://www.ebay.com.au/itm/G2-Ergonomics-Throttle-Cam-System-2-Stroke-Honda-CR-125-250-89-07-500-89-01-NEW-/380641312734?pt=Motorcycles_Parts_Accessories&hash=item589ffd7fde&_uhb=1

Maybe it might help tame it?

Title: Re: smooth out an 87 CR250
Post by: TheDamo on June 10, 2013, 07:50:31 pm

Quote from: Paul552 on June 10, 2013, 06:41:59 pm

http://www.g2ergo.com/dirt-bike-g2-ergonomics-products.html

http://www.ebay.com.au/itm/G2-Ergonomics-Throttle-Cam-System-2-Stroke-Honda-CR-125-250-89-07-500-89-01-NEW-/380641312734?pt=Motorcycles_Parts_Accessories&hash=item589ffd7fde&_uhb=1

Maybe it might help tame it?

Interesting thanks for the link

Title: Re: smooth out an 87 CR250
Post by: TheDamo on June 10, 2013, 07:51:31 pm

Quote from: Lozza on June 10, 2013, 05:07:31 pm

Do you want the easy or the hard way?

Gimme both thanks

Title: Re: smooth out an 87 CR250
Post by: Damo on June 10, 2013, 08:47:33 pm

Boyesen Rad Valve and Keihin 38mm Airstriker

Title: Re: smooth out an 87 CR250
Post by: Lozza on June 10, 2013, 11:11:53 pm

Quote from: TheDamo on June 10, 2013, 07:51:31 pm

Quote from: Lozza on June 10, 2013, 05:07:31 pm

Do you want the easy or the hard way?

Gimme both thanks

We'll start with the easy way. Machine a 50mm spacer  minimum 2mm LARGER ID than the exhaust duct outlet, Then fit that between the pipe and the cylinder. Test. Measure stinger/tailpipe ID(usualy 27mm).

Title: Re: smooth out an 87 CR250
Post by: whitey 43 on June 11, 2013, 08:28:04 am

From what ive heard, you can buy a flywheel weight which screws into the puller thread...It works really well on the late 80s cr 250s, & would smooth your hit out & make the power more useable.

Title: Re: smooth out an 87 CR250
Post by: 80-85 husky on June 11, 2013, 08:31:12 am

How is the needle jetting? if its rich it will give a harder hit as it transitions than if its spot on?

got blubbering and drag at 1/4 to 1/2 throttle ???