Question to those with the 351 kit
 

If you are running the stock gearing what RPM are you doing at 110km (70 MPH) in top gear? I would assume it would be lower than a stock 250 as there is more power in each revolution?

I haven't ridden her in a while (winter here) and I run 13/42... I seem to recall at 115km/hr I was up around 6k-ish? I'll try to get it out today to double check

Ok, so the 13 is one lower than stock on the front. 6K -ish at that speed is fine for me. I'm just trying to weigh up if I upgrade to 351 kit or get a DR650. Now I have got better response with the jetting, I'm happy with how much grunt it has in the 4 to 6K rpm range. If get the 351 kit and keep the same low down grunt with going to a 13 tooth front sprocket but lower the highway revs to around 6K I would be happy with that.

Well, the DR will be considerably heavier, but better on the highway...

The 351 with a pumper carb is nuts off-road. The 13 is actually a little too low for some stuff off road for me... It is night and day between stock 250 and the 351. I sold my KLR650 and couldn't be happier...I can go all day and not feel beaten up on the trails.

Anyways, I'll try to get out and verify that RPM today..

All good, don't go to any special effort. I'm trying to avoid going to one of the 650's due to the weight factor.

Haha, I'm getting confused with my gearing, going to a 13 tooth front wouls make the gearing shorter not taller.....my bad. So I could go a 15/42 combo to lower highway revs.

My 2011 stock ran 100km indicated @ 6000rpm with stock gearing, closer to 91kph GPS. with 13 tooth now runs closer to 6800rpm @ same speed. I agree with Dash8, 13tooth is probably too low for the 351, I will be going back to stock when I dig her out of the shed in a few weeks.

Stock gearing will be the exact same RPM at a certain speed no mater what HP increase you have.

^ cmott speaks the truth!


The 13T is not too low for the 351. Right now I'm running 13/51 and for the trails we've been riding, it's perfect. I'm geared just about the same as the WR250F, XR250, and XCW300 I was riding with last week.

If I were doing highway, 15/39 may be perfect. It all depends on the rider and the ride. One size does not fit all.

This is correct. Only gearing will change the speed with same rpm. 6,000 rpm will spin the rear wheel at the same speed as a 250cc or 351cc or 650cc or 1,000cc, period. Only gear ratio changes this.

Hey, Bluezr7 lives in a world where mopowah lowers RPM, so deal with it - yall see his WAAY cool "Sport Adventure'd" KLX?..

https://scontent-syd1-1.xx.fbcdn.net...42200542_o.jpg