250-500cc Husqvarna wr 250 '04 Bad fuel mileage

Hi,

Well you know what my problem is--> bad fuel mileage.

I'll explain first what jetting and stuff I have on the bike.

Mikuni TMX 38mm Carb:
Main: 390
Pilot:35
Needle: 60 (original)
Clip: Middle
Slide: original


I bought the WR and I noticed that it has a very bad fuel mileage 10l/100km.
Than I checked the carburator and the cilinder for piston wear.

My exhaust pipe also has a few dents in the curve part, and a little hole in it. But the hole is big enough to hear it when the engine is running.

Ok so I checked my carburator and it was fine. The piston was bad. So I put in a new piston, rejetted my carburator. And again my fuel mileage was exactly 10l/100km. I thought with the new piston it would be better, but it wasn't. Now the only thing left that isnt 100% OK, is my exhaust pipe. Now could that be the reason the fuel mileage is so bad? Or are there other reasons?

I already ordered a FMF gnarly because my current exhaust pipe is a bit broken. But will this new pipe improve my fuel mileage?

Greetings from belgium

Nick

Mine did the same thing.

I bet your float level has risen with wear of the needle and seat.

Tilt the bike on it's side and see if gas is coming out of the overflow.

I'd lower the level to 20mm and see what happens.

I went from 15 to 18 mpg with that fix and went to 20mpg with a PWK carb.

But my husqvarna dealer told me that WR's should get 29 mpg to 33mpg on normal terrain so no loose sand terrain or somthing. There are 2 things I didn't try on my wr to increase the mileage, and that is changing the exhaust and checking my ignition. And tomorrow my FMF arrives at the dealer. So than I know if it improves on it or not.

I already want to thank you guys for replying that fast. I really like this forum everybody's so helpfull and friendly. And offcourse it's HUSQVARNA!!!

Greets Nick

Your jetting is the same as mine except I run the 400 main. I seem to get good mileage. I ran out of gas at 77 miles with the stock tank at the GP. Maybe it was a little lean cause of the colder temps that weekend, but my bike runs better with that jetting where I live and wasn't changed for that trip. Same elevation, just the GP was wet and cooler. So saying WR's get bad mileage seems it would be bike to bike, not all bikes.

And what pipe do you have? On what height do you live? And could it be that he will need more fuel when I have a pipe with a few small holes in it (close to the cilinder). And a few dents in the curvee part of the exhaust.

My OM says that i should run a 420 main and a 40 pilot cause I live on a height of 130 ft (40m) with a temperature of 0°C. But if I run those specs it's too rich.

Grtz Nick

I live in Central Oregon. Elevation is 3000' to 5000'. It is dry here due to the high desert. But the terrain varies with each riding spot.

I too have a ding in the left side of the curve coming out of the cylinder. It's about the size of a small ovacado cut in half. Not small. I run an FMF Gnarly and Turbine Core II. My OM says I should run a 380 main and 30 pilot at 0 degrees C, or 32 degrees. But I did a jetting test day (approx 75 degrees) and found that the 380 and 32.5 pilot that I was running, were a little off. I kept going richer until I found something good with no power loss, bog, or spooge. I actually gained power with richer jetting. I could tell cause I would ride the same trail back and forth after rejetting. This helped me realize what was going on with the differences in each jet. I also started with the pilot and air screw. Figured it out. Then moved to the main. I don't believe the book. Find what works for your bike.

Maybe I just got lucky on that GP day. We did do some road miles. That could of helped, but the pipe was singing for a while.

Ok, first I'm goin to try the new pipe. If the mileage is still bad. I'll do a recheck on the jetting, and check if the ignition is right. But I think the new pipe will help. Cause if your pipe doesn't work well, you'll have a powerloss. So the engine has more effort with certain things than it would have with a good pipe.

Spot on,yet the killer factor is how aggressive you ride, where you ride and how flowing as riding on different trails wide and open, short and tight, hilly etc...you can only determine an average unless you can consistently run the same trail at roughly the same speed to get a more accurate picture - an MX track would be the best place to calculate that..
As an example, a place where we regularly go camping, there is a 100km loop (2x long hill climb then about 30kms of fast flowing mountain top trail and then 2x decents) that we always ride (warm track we've named it) and on my 96WR360 (8Lt tank) and mates WR250's and on a good clear day, no wind, flowing speed l would just hit reserve, my mates 250 on reserve so that's 29mpg BUT on a different day where it's muddy and slippery or stop and start l would run out after 75-80kms(23mpg).

Bad jetting, age of the motor or running too rich will affect mileage but running too lean then you risk a seizure and to put this into context, the warm track loop that l am talking about, my friend's completely rebuilt 93WR360 running very rich, ran the same loop and out of fuel within 60kms whilst l made it on a tank. Next day, at roughly the same time and conditions the same with a variation in temperature of 3 degree's (anal about recording jetting), l installed my Keihin in his bike using my jetting as a baseline with the air screw a bit richer....he completed the same loop on reserve.

Moral of the story...ditch the TMX and go Keihin

I must say I ride pretty agressive I think. But mostly when I ride i do like 1/3 of the whole trip on road. But when I'm on the road I ride really relaxed and pretty slow (to save those nobby's).

Like I mentioned I installed an FMF gnarly on it. And I'm right back from the trip. And my mileage is improved a little bit. Not what I thought, I thought it would be so much better with a new exhaust without dents and holes.

But the weird thing is that my carburator is jetted very good. You think that the mikuni is just a bad carbu on the WR? And on which models are the keihins mounted stock on? So maybe I can buy a second hand.

In 1978 3 of us went for a ride on 390 Husky's. When we stopped the 390 auto with a Mikuni was out of gas, the 1977 390 with a Bing had a 1/4 tank left and the 1978 390 with a Lectron carb had 3/4 of a tank left. I have no idea how a Lectron would compare to a Mikuni today but if fuel milage is important you might look into a Lectron.

I have a 2003 WR 250 and a few weekends ago I was trail riding after a lay off of nearly a year.My friend has a 2000 wr and we were riding together on mixed forest trails a few fast road sections and a few miles of tricky moorland.I went onto reserve at 60 mls, and was out before 70.We drained a litre of fuel from his bike twice to get mine home.
My bike has had, in mileage terms, a recent top end rebuild and is in tip top condition.Both bikes are set up the same in terms of carb and jetting.
The only thing I think will account for the difference is he is around 170lbs and I am around 225lbs.Riding style might have a bearing on it, but I've just come to the conclusion that they are thirsty animals.
I did though drain the tank with the bike on a pit stand.When the tank ran dry I tipped it over and managed to sqeeze about a litre from the right hand side of the tank.I now have it in my head to fit a tap to the right side and link the two.It might interfere with the kick start if I do it that way.
Has anyone tried this modification.

Interesting thread. I have a '09 WR 300 with the Keihin and using VP C-12 racefuel. Weekend before last at Hatfield Mccoy I rode 66 miles in the afternoon and it took exactly 1.5 gallons to fill it back up. that works out to 44 mpg. Those trails are super fast, average speed for the day on the Trail Tech was 22 mph. Seems to consistently get around 40 mpg no matter what.

When I first got my 09 WR250 it used fuel like there was a hole in the tank. Now with the correct jetting and even more important the float set correctly the fuel mileage is approx twice as good. I will try to calculate it exactly when I get a chance to ride some entire tanks through and then I will post it on this thread. The float level on the Mikuni is really important not only for mileage if set too high but if set too low will cause erratic performance. My bike seems to like the 380 or 390 main for a harder pulling midrange but it comes at the cost of mileage and a flat top end. (possibly it is just running out of pipe on top)

Best I've ever done on my 02 cr250 w/ pwk is 13km/litre....that was dual sport. On an enduro or trail ride 8 km/litre is about it.

Interesting thread, I don't have too much to offer except to say it's not the first time I've read that fload levels on the TMX can have a big effect on mileage. I've only done 220km on my '10 WR300, using around 25l of fuel (jetted a bit rich for break-in) The first 100km were mixed terrain dirt and hard use at the supermoto track, but in 100km of road riding mostly twisty roads in the hills, but not really giving it heaps it didn't hit reserve (7l/100km approx). So it seems that riding style plays a big part in how much fuel you use.
I guess the best bet is to make sure your float is set right, and if you need to go further between refills, either back off or buy a bigger fuel tank

Float level. That seems to be a big factor on carb problems on the Husky.

Float hieght.I can't say I've checked that.It can't hurt to check, there's no reference to float hieght in my manual. 20mm has been mentioned on this thread, is that the correct hieght.
I'm still of the opinion that the difference in mileage between my 03 and my friends 00 can be accounted for by my extra 55lbs. The best adjustment I could make might well be dietry
I'd still like to get at that last drop of fuel thats hiding in the right side of the tank, without stopping and lying the bike over.

+1 for Float Level. It can make a big difference in jetting and fuel consumption. Float level should always be checked and double checked before any jetting adjustments. When the floats rise to close the needle valve, they should be parallel to the side edge of the carb from my experience. And once set, they should be checked periodically. I don't know how, but on my KTM 250, I have had floats that were set perfectly somehow come out of adjustment over time causing the bike to run lean. When they were reset the jetting was perfect again.