Best Mod For Improving Low End Power

I got my WR250R a few months ago and love it! having a blast after a 15 year hiatus from riding. My only complaint is that the low end power is lacking a bit. The only place it really bothers me is hillclimbs. Was going up a twisty one the other day and the 2nd gear powerband was too fast. Slowed down and it bogged - luckily I got up it in 1st ;-)

Just wondering what is the best mod to help with this? I've read the 12T front sprocket might help, but dont mind putting in the work if a rear sprocket would help more, or a combo of both.

I'd like to not sacrifice too much top end. But, I dont ride street that much and when I do, I hardly ever go above 75 mph, so if it still cruises fine there, Im happy.

Also, what are the best brands for sprockets? Renthal? JT?

If I need a new chain with the rear sprocket, who makes good chains these days?

Sorry for all the questions! Any feedback is much appreciated

Thanks!

I would start with the 12T, it's the cheapest and you'll notice a difference on the bottom without a huge sacrafice on the top. you don't need a new chain to do this and you can decide if you want to go with a larger rear sprocket and new chain once you try just the 12T up front and decide you still want more lower end.

I've got a 12T on mine, it's a JT. I like it much better than the 13. I can tractor up hills a lot better and I also can utilize all the gears much more efficiently. On the tarmac, I still have lots of jam to pass vehicles on the highway easily, so top end isn't an issue. The 12T is much cheaper than replacing the rear sprocket and chain. You can still go up to a 45T on the rear and still use the stock chain if you find the 12 doesn't give you enuf grunt, but after the 45 you'll need the bigger chain.
As for chains, I haven't changed mine out yet. From what I've seen, a lot of riders have gone with the D.I.D chain (either o-ring, or the x-ring).

+1 on the X-Ring. Got mine on the bike but waiting on a clip style master link. Such a perdy gold color. Now I will really be keeping that bike clean so that I can see it.

Thanks for the advice guys. I'm gonna order that JT 12T today!

i had the same complaint as you (the OP), went 12t-45t and it made it livable

did airbox mods, full fmf exhaust, fmf power programmer and it REALLY gave it some low end... or so it feels like it by the seat of the pants

Changing the gearing won't actually change your power band, but it will make the bike more rideable at any speed your likely to be using a WR at. If your bike is new then the 12t is likely the way to go because it's cheapest. When I needed to get a new chain I decided to stay with the 13t and go up to a 47t in the back. I'm running the little X tires still and I can say I wouldn't want any taller of a gear than that.

I don't know of any mods to actually get a better bottom end power. The common programmer, pipe, flapper mod helps mid+.

I have read a few places where people had concerns and experiences with the 12t front wearing on the swingarm, but I havent read that here.

nobody on this forum had this problem?

It's not the sprocket causing that...chain tension is a huge problem if not watched periodically.

Interesting point about swing arm wear. I could see it happening. The thick rubber protector on mine has some major grooves worn in it and I'm running a 13t.

Do you figure it's loose tension that's the issue or tight? I tend to run on the loose side.

So far I'm golden with my 12. Have it on there longer than the 13 and the grooves aren't really much deeper than when I had the 13 in there.

my swing arm guide had groves in it from the factory, like they are meant to be their.

after 1,000 miles of riding with a 12t front i have seen no wear.

Seems the wear indicator gets deep if the chain is run too loose. Too much freeplay I guess and slapping around like that can make it skip and sheer off the top of the teeth. I run mine a little on the tighter side of things.

I agree with everybody on here about the 12t. Just went for my first ride with it yesterday and I am happy. I can slow down to a certain point but still keep it in second and then pick up speed again with just a twist of the throttle where normally I'd be downshifting into first and then back up into second. First gear wheelies are real easy without any clutch also. Hill climbing is much better in second gear also.

I read about the swingarm wear with the 12t front on the big dog adventures website, he has a little article about the mods he did to his bike, and there is a bit in there with some pictures of a worn swingarm. cant remember how many miles it had on it or what the circumstance. but you can see the pictures there

FWIW... I just threw on a 48 on the rear with a new chain and I like the extra torque it generates and also the reduction in weight.

Just my 2 cents.

LacRouge wrote:

I read about the swingarm wear with the 12t front on the big dog adventures website, he has a little article about the mods he did to his bike, and there is a bit in there with some pictures of a worn swingarm. cant remember how many miles it had on it or what the circumstance. but you can see the pictures there

So far he's the only one I've seen have that happen with.

Rodents gnawing on the swingarm maybe?

I had a ground hog sharpen it's teeth on the frame of our bus once. He was a vicious critter that took some fighting off.
Once I had to chase some squires away that were playing 'jungle gym' on the Unimog under carriage.
Another time we had a giant porcupine chew up a large part of the mud flap on the Unimog. (I didn't chase that one away, I honked the horn and stayed inside.)

So, a species of rodent that likes swingarms is totally believable to me.

It's them pesky beavers I say!

Okay,...so how high can I go on the rear sprocket, keeping the stock CS sprocket, before I have to get a different chain? AND does anyone have the gear ratio chart that was posted on ADV? I reaaly don't want to have to wade through that monster thread again. I still may try a 12 on the front, not sure yet. Sure would be nice to crack the throttle and lift the front wheel when needed without using the clutch, not sure if this bike will do that and still keep the top end I need. I'm not thinking i am going to get the programmer, pipe, open the airbox. If I have to go that far for more power I should just buy a bigger bike. That's just my opinion, I know most folks enjoy that part of it almost as much as riding the bike.....I have too many jobs to be wrenching on the thing, barely have enough time to ride!

You can go as high as a 45 before you have to go to the bigger chain. Are you looking for this?



There's this too.

BPG wrote:

REALLY liked the 12/43 combo - both on the highway and on
trail. Kinda cool to do a mod to a D/S bike that makes BOTH those areas
better, instead of one better at the expense of another.

Based
on that experience, I think I'll go with a 47 or 48 rear and usually run
a 13 front for commuting, general trails, etc. When I know I'll be in
some exceptionally steep/rocky/tight terrain, I'll drop to a 12 front.

STOCK:

43/13 = 3.31

43/12 = 3.58 <-- this feels great in most
conditions, still a little steep for aggressively rocky/rooted hills.

110
LINK:
46/12 = 3.83
46/13 = 3.53
46/14 = 3.28

112
LINK:
47/12 = 3.92 <-- ought to be able to walk up a wall w/
that ratio!
47/13 = 3.62
47/14 = 3.36

48/12 = 4
48/13 =
3.7
48/14 = 3.42

Maybe this?

Stock gearing is 13T
Front / 43T Rear sprockets with Trailwing rear tire. The ratio with the
taller D606 rear tire assumes a 5% increase.

Front	Rear	Ratio	Ratio w/D606 Tire
14	46	3.286	3.115
13	43	3.308	3.136
14	47	3.357	3.183
13	44	3.385	3.209
14	48	3.429	3.250
13	45	3.462	3.282
13	46	3.538	3.354
12	43	3.583	3.397
13	47	3.615	3.427
12	44	3.667	3.476
13	48	3.692	3.500
12	45	3.750	3.555
13	49	3.769	3.573
12	46	3.833	3.634
12	47	3.917	3.713
12	48	4.000	3.792

Thanks SW, you rock! The speed chart doesnt agree with my speedo or GPS,.....but the gear ratios are what I was interested in anyway. I might try the 12 cause it's cheap to try. Not that I don't have the money, I'm just a tightwad!

Yeah, that 12 really makes a huge difference. It's not so long legged.

I originally went with a 12 tooth and loved it. It didn't seem to affect my top end much because the bike didn't have the hp to wind out in 6th anyway. I did however just get the 13 back on and put a 45 in the rear (this puts you a little lower then half way between stock and 12 in front). My resons were 3 fold. 1 I got tired of winding the bike so high on the highway and burning all my gass, 2 I was finding the shiftpoint between first and second inconvenient during technical riding (on the track and in gnarly woods) I kept wishing I could use first for more then just starting out. 3 It was difficult to ride wheelies since it seemed to always be time to shift just as the front tire was leaving the ground. The only way to do it was to pull it up in second by jerking back on the handlebars like a 10 year old on a huffy.

oh I forgot to mention, do not try to run a sand paddle with stock gears, the clutch will not hold. also I fount that my paddle didn't clear the swing arm, so a smaller front sprocket kills 2 birds with one stone (at the time though I couldn't get one right away so I just peeled out on the pavement untill the paddles were just a little smaller)