Off Road tranny ratio

Reading the cycle world Husqvarna '77-'84 book. They say the desert racers used cr bikes which in the open areas were ok but in the rough rocky areas the cr first gear wasn't low enough. In the open the wr tranny they couldn't wind them out to shift. The "OR" tranny with the first three gears being WR and the last three gears being CR was the hot ticket for desert racing. You have the low end grunt and the rpms stayed up in the meat of the power band in the last three gears being CR. my 78 250 OR was a perfect example of that. With that said I wonder why Husqvarna didn't continue the OR tranny into the evolution milk truck bikes?
Was the XC model it's replacement? But that was a WR tranny.

seems like when they went to the primary kick engines, they figured out good ratios to use in each application. apparently it wasnt needed to mix and match. you can still mix and match if you like with them though.

OR became the XC and no...XC trans ratios not same as WR

Funny they list the wr the same as the XC in the data specs. I'll have to look closer and check what's the difference between the wr and the XC. I wonder if the XC has cr porting? I know there is a slight hesitation when we short shift the 250wr without winding it up. The or tranny eliminated this. We really have to wind up each gear then shift the wr when we're flying. Third through 6th gear.

I have a 87 xc and a 85 wrx , both 250's with the same sprockets and the xc don't like close quarters at all but the wrx is fine and dandy in the woods. There's definitely a difference between the two.

Bigbill, I know you know your stuff, so I'll chalk it up to clerical error, but I think you've got CR and WR swapped in your original post. Doesn't CR stand for "Close Ratio" and WR for "Wide Ratio" with the CR being the MX bike (lots of turns, accelerating and braking), and the WR being the traditional Enduro bike (more open, fewer tight corners)?

I admittedly haven't gotten out on my WRX much, but am looking forward to the mix of CR and WR gearing. My WR is a beast on two-track and wide trails, but technical single-tracks are challenging, and even in first I find my hand on the clutch more than I like in the tight corners, and it's usually not worth it to run up a gear for the brief straight shots on narrow trails.

I think the wrx is built for the tighter stuff , keep in mind you have a 400 it will probably want to lug more at lower 1st gear speeds and if you do alot of this riding you may want to change sprocket size.
CR is close ratio meaning close gear ratio's to correspond with each other (sports car) lots of shifting to keep good rpm's consistent.
WR is wide ratio meaning gears that have farther spaced ratio's (a jump between each gear ratio) longer periods between shifts.rpm's start low and have to travel through a broad range to achieve the next gear selection.
Kinda hard to put into words , hope I got right .

There are differences depending on the displacement. We all can look at the parts sheet. In the displacements I have pretty sure it is just gears 1, 2, and three that differ for a six speed. The one year they made a wr 500 I am pretty sure that gear box was the same as an xc 500 of any year. First gear is built into the shaft the clutch is on.

It matters a lot to where your jetting it to as far as throttle response. If it's close to being jetting right the throttle will feel crisp and clean response wise. If it's too rich it will be sluggish when you down shift or lug it.

I didn't ride my '86 400wrx as much as I should have. I rode the 78 390cr more? I had a few 390's a '77cr, a 78cr, a79cr and the 80cr. The close ratio allows you to stay in the meat of the powerband between up shifting. The wr you need to wind it up more. On my 81/250cr I ran a 11t front sprocket with a 53t rear but the engine was heavily ported. She was in the gangster buster mode all the time. But the smaller front sprocket winds up quicker but also takes you up one gear most of the time. If you spent more time in third gear with the 12t you were in fourth more with the 11t. But she was ballastic when you wicked it. That's with extreme porting and the UFO installed. The 77, 78, 79 390's were stock. The 80/390 had the ports cleaned up and the 40mm carb. I dropped the needle jet down two sizes and installed the UFO also.

When I got the 84/250wr husky I noticed a big difference in throttle reponce. It felt like a cr with a wr tranny. I wonder why husky didn't do that sooner using a cr cylinder on a wr bike.

I'm no different than anyone else here I'm still learning too.

Using a CR cylinder on a WR makes sense if you ride in a region that requires it. Even when Dirt Bike tested the 84 250WR in a shootout with the other offerings at the time, they made a point of saying it was not as suitable for real enduro as the 1982 and 1983 250WR were.

It works if you are running ISDE qualifiers but some factory riders chose to detune the mx powerband for the sake of making the engine last for six days

CR :Cross, ie mx.
Primary drives were 30/79 for 4,5 and 6spds. Together with internal rotor ignition, heavy clutch ring gear it made for rapid throttle response and accelleration.

WR: Enduro, ie Euro woods racing. 6spd
33/76 primary with heavier external flywheel and somewhat less clutch ring gear mass.

XC: Cross country, Off Road, ie desert type racing. 6spd.
39/70 primary, light clutch basket and ring gear, much higher gearbox rotational speed and external flywheel.

After this comes a variety of barrels, head squishes, pipes etc.

The above counts for the evo 2t engines.

I just seem a guy selling a 83/250 XC cylinder it's got the extra cr porting. This in a wr tranny is two different worlds between both bikes XC and wr. I had two 83/250wr that were not close to my 84.