Wr250x

[yanlapanic]

Originally Posted by jpoole

I too have an '09 wr250x and my FE jumped from 62mpg to 72mpg when I started running without the airbox side cover! I had no other changes made and the bike was totally stock. I thought it was just 'cause it was new and breaking in so I put the cover back on and to my surprise the mileage went back down around 62. I went to a 48t rear sprocket for some low end grunt but the mileage dropped to 57ish. I put a 14t up front (with the 48t still on back) which should be a ratio somewhere between stock and where I am now and if it doesn't get much better, I'm going back to the stock 42t rear.

with a 48t sprocket if it was 42 stock youre not right to lower the rpm at cruising speed ..

you need a smaller one at the rear . or bigger one in front

[jpoole]

Originally Posted by yanlapanic

with a 48t sprocket if it was 42 stock youre not right to lower the rpm at cruising speed ..

you need a smaller one at the rear . or bigger one in front

If my sole purpose was to "lower the rpm at cruising speed", then you are correct. That was not my goal at all. The bike in stock form is geared notoriously tall-so tall in fact that 6th gear feels pretty much useless. I'm just trying to find a good balance in the gearing. The 14t up front and 48t out back are working great! I'm getting right at 70mpg and it wheelies a little easier(than stock) and low speed turns are better.

[yanlapanic]

Originally Posted by jpoole

If my sole purpose was to "lower the rpm at cruising speed", then you are correct. That was not my goal at all. The bike in stock form is geared notoriously tall-so tall in fact that 6th gear feels pretty much useless. I'm just trying to find a good balance in the gearing. The 14t up front and 48t out back are working great! I'm getting right at 70mpg and it wheelies a little easier(than stock) and low speed turns are better.

its ok , I never drive this bike .
mine is a klr 250 1997 with 6 gear and when there is a hill at 100 kmh , i need to put it in 5th gear to keep my speed at 100 kmh

these engine are perfect for city driving , mine is very pleasant to drive but it seem to rev too much high at 100 kmh ...

at 90 kmh , my rpm is 6000 .... Pretty high so i think i will buy a drz 400 next summer . more tork , more hp , lower rpm and more fun!

[twday]

The X already has 17" wheels, so that's not going to be a great place for modification. I guess there are two ways to work on improving mileage, too. Highway mileage is interesting, but around town mileage would be really interesting for a bike like this. I just bought a used WR250X and it seems like the perfect urban commuter if mileage could be improved. For the last few years, I've commuted on a Kawasaki KL250 Super Sherpa, but that bike is all but worthless in the cold months because the carb just refuses to work in cold weather. The injection on the WR is the cure for cold weather starting.



Tuners seem to be clueless about improving efficiency performance. I also ride a 650 V-Strom and I've never found a tuner who knows where to begin in improving that bike's mileage. They have all sorts of ideas for getting more power, but mileage is completely beyond their scope.

Tom

[redyaris]

Originally Posted by derangedhermit

First post, glad to be here.

I have a Yamaha WR250X - factory pics here.2009 Yamaha WR250X Gallery

It has a water cooled fuel injected 250cc engine. 6-speed manual transmission.

It gets around 60 mpg stock. I would like it to get 100 mpg when cruising in 6th. It seems to me the main area to address is CdA. I was thinking of:
- lowering it by reducing the suspension travel and ground clearance from 10" to 7" or so
- putting on a fairing, something like the Can-Am 125cc fairing at LANDSPEED, LAND SPEED RACING, SALT RACER, BONNEVILLE, EL MIRAGE, FAIRING, SEAT, FENDER, SCTA, but with lights, and with mirrors behind the fairing
- doing some fuel tuning with a Power Commander (although I doubt there is much to be gained)

The exhaust has a catalytic convertor, but no lambda sensor.

I'm not sure what changes are most effective on motorcycles. (I have been to Vetter's web site). Maybe:
- Cover the rear (laced spoke) wheel with dish covers
- Make sure there is no brake drag
- Bearing grease and engine/transmission oil - how much difference can this make?
- Gearing - it is easy to change the final drive ratio by changing sprockets. What would I shoot for?
- What else?

EDIT: What I would really like for the fairing is to make it out of a stretch fabric, like BMW did on one of their concept cars.

To start with I have a WR250R with the bigger wheels 21' front and 18' rear. The R is undderpowered in top gear and therefore a good candidate for aeromodding. I have a 14T front sprocket but have not put it on yet because until the aero is better ther is no point yet. I started by making a long skid plate from only 2" behind the front wheel too 2" infront of the rear wheel. This winter I am making aluminium cargo boxes to fit close behind the riders legs and making a front fairing that is better than stock. I believe this type of bike can be made more aero but is not the best choise for that type of project. I still want to ride this bike in the dirt and on the gravel roads. The fuel tank is so small 7.5L that better fuel economy would be real benificial.

[twday]

There are some big tanks available for the WR, but better mileage would be ideal. I don't even close to have the inseam for the R model. Hell, I barely can get on the X. I use soft bags and a tailbag for luggage. I'm thinking about trying one of Acerbis' bolt on windshields for aero and wind/rain protection.

[redyaris]

Originally Posted by twday

There are some big tanks available for the WR, but better mileage would be ideal. I don't even close to have the inseam for the R model. Hell, I barely can get on the X. I use soft bags and a tailbag for luggage. I'm thinking about trying one of Acerbis' bolt on windshields for aero and wind/rain protection.

I have one of those big tanks but have not instaled it. As for the "inseam challanged" I am at 30", amung them too. I have instaled a lowering link at the back end and slid the fork tubs up in the triple clamp so the seat is about 2" lower. Even after the lowering I have to be paying attention when coming to a stop. stoping on uneven ground is always interesting.

[twday]

I live in Minnesota. I just got the bike last week, so I haven't had a chance to test my bike or my inseam, yet. It's about as tall, now, as my V-Strom, so I should be ok. I'll let you know if/when/how I'm wrong.

[redyaris]

Direct from my 2008 - 2009 Yamaha service manual the seat height for the WR250X is 35.2" the WR250R is 36.6" you may want to look into the lowering link for the rear suspension just in case...

[twday]

Been there, done that. I'm also installing the "step seat" for another inch. Dropped the stock shock setting to its lowest position and lowered the forks 13mm (max recommended is 18mm). Wish it would quit snowing so I could try it out.