Cr250

[timmersam]

I can get a front brake resivoir and lever off a 2003 cr250r for cheap. Does anybody know if this wil work?
Thanks

[blasterandy]

dont' c y not. I would try and use the stock cable.

[250r4life]

if i recall my msr "raptor easy pull lever" is for a cr 250...

[timmersam]

My only concern is if it will clear the thumb throttle? Any one no how long they are??

[GPracer2500]

I'd guess it will be close enough that it will work ok. They are not the same though. The thing to be aware of is the master cylinder piston diameter and the lever pivot ratio.

The piston diameter will be cast into the body (front) of the master cylinder. The 250r has a 1/2" (12.7mm) master cylinder. The CR250 has an 11mm master cylinder.

The ratio of master cylinder piston area and brake caliper piston area matters. This ratio helps determine lever travel and "firmness" of the brakes. The 250r front brakes have four 25.3mm diameter pistons for a total area of ~2013mm3. A 1/2" master cylinder has an area of 126.6mm3 for a ratio of 15.9:1. Going to an 11mm master cylinder would be 2013/95 = ratio of 21.2:1.

The lower the ratio number the less lever travel there will be and the "firmer" the brakes will feel (all else being equal--line flex, caliper flex, etc). In extreme cases, too small a ratio and the brake lever will have hardly any travel before they just lock up. Too large a ratio and the lever will go all the way back to the bars before maximum braking force is reached.

But then there's the lever ratio as well. This is the location of the pivot point of the lever relative to the master cylinder. I believe on the 250r it's about 22mm (not sure on that though). On the CR250 it's about 16mm. The farther away the pivot point is the less leverage and the more travel acting upon the master cylinder piston. This is a similar to what increasing the size of the master cylinder does.

If you add all that up, I think it will mean that the CR250 master cylinder will need more lever travel to get the same braking action that the 250r master cyl needed. Maybe it won't be enough to notice though [shrug]. I bet just getting fresh fluid and freshly bled brake lines can make up for a fair amount of difference in perceived performance. Then again, the CR250 master cyl was only meant to push about half as much brake caliper piston area.

Try it and let us know.

[250r4life]

for some reason i was thinking clutch lever... my bad... but hey the brake levor may work also ;)

[deathman53]

I tried a cr250r front master on my atc250r, it won't clear the thumb throttle. Its the same at 86-89 trx250r's.

[timmersam]

I am building my 250r from the ground up and thats the reason I want to use one. Thanks for all the replies, I guess I will go with a 250r or 450r lever.
Thanks alot.