250-500cc WR 250 2002 ~ Is this normal?

G'day from Northern NSW, Australia. This is my first real post, so hope it's in the right place... I think so anyway, sorry if not. Picked up my WR250 '02 model last Thursday and rode it yesterday for the first time off road. My mate has a fantastic natural terrain MX track (built for VMX) in his front garden (30 acres) so took it there for its first run. Had already noticed that it was geared down from the standard 13/48 to 12/50 so took that into account and after having read on this forum it suggested that the bike had a great lineal power curve and plenty of grunt that it could be geared up. So have ordered a 14 tooth for it and that will take it back to just above standard gearing with the 50 tooth on the back. It came fitted with a FMF Gold Series Gnarly pipe which looks brand new. The rest of the bike looks original and very stock, you coulod say its in a very pristine condition considering the age of the bike. it only has 1400km on the clock and judgeing by things like gear lever tip, kickstarter, footpegs etc it hasn't had much use. The real problem seems to be it has a massive hit in the up top and not alot down low or in the mid range. I was wondering if that could be because of the pipe although after reading FMF's website it says that the Gnarly pipe is for more bottom and mid range, not top end so I'm none the wiser there. I've also chatted to a couple of mates and we came up with the theory that maybe the power valve was stuck open which might affect the amount of low and mid range and perhaps explain the big hit up top? There also seemed to be alot more than I'm used to (run 3 other vintage 2 strokes) excess oil coming out of the exhaust making me think that the previous owner was running his fuel mix with way too much oil in the premix thus clogging up the power valve. Anyway I was just after some other trains of thought on the matter. Bought a new piston and rings with the bike so will be changing that in a couple of weeks and can look at the power valve then. Or maybe it is possible to look at it without taking off the barrel? Apart from that I loved the bike, would just like to mellow it out a bit as I imagine it would be a bit of handful on a snotty hill (have bought it to go into the bush with my mates not to MX it) with the power hit it has at the moment. Sorry about the essay length post but like to give plenty of detail so you guys can make a more informed reply. Cheers Husky 430

Welcome.

Your bike should have lots of bottom end and pull out to a very strong top. It can be a hand full when the PV opens, but it's very capable of handling a "short shift" style where you can stay under the massive top end and be smooth.

You can check the power valve by pulling the left side cover off and checking the linkage. You should be able to tell if it's operating smoothly from there. You can disconnect the link at the top ball joint and move the valve through their cycle.

The closed stop is on the other side, but you'll have to pull the pipe to remove that cover and work in there. It could be the stop is set wrong and the valve aren't being allowed to fully close.

If you pull the head you can see full operation of the valves and set the main to it's proper height.

If you haven't dumped the gas and started fresh, it might be a good idea.

Then you might look into the carb and see what jets are in there and make sure the float is working OK. There's a "jetting database" thread you can use to see where you jetting is compared to others.

Thanks for the prompt reply Motorhead, just the sort of info needed to pull it apart. It dosen't seem to have the low end power that was mentioned in other threads about the '02 WR250 I've read on Cafe Husky. And with it having the Gnarly pipe I would imagine you should be able to almost trials ride this bike, but no way at the moment.
I don't have a workshop manual so I was wondering if anyone has the relevant technical info of the power valve settings/measurments? I will pull the carbie apart and check the jetting, but apart from the pipe the bike looks so stock that I'm starting to think that maybe the previous owner put the pipe on because he had these similar problems of no bottom end and was t5rying to get around it with the pipe. Anyway can't be much to it and I'm sure I'll get to the bottom of it and it will be a fantastic bush bike. Thanks again, Motorhead, and by the way I take it you put a 6 speed into your 07 WR250. When was the last model with the wide ration 6 speed gearbox, I'm thinking I just missed out on it in mine, the ad even said it had a 6 speed box but unfortunately for me I didn't check it out until I had purchased it and it was at home. D'oh! Cheers Husky 430

Me again, have just checked out the jetting database but the closest thing to a 2002 WR250 is an 1999 and a 2000 WR360 both of which use the same carby(?) as mine a 38mm Mikuni(?). Though mine seems to have a flat slide carby so have no idea what the standard jetting shoud be. Can anyone give me information on the original jetting so I can tell if it has been played with. Thanks in advance, Husky 430

That motor action sounds alot like my 02 CR250 ... but even it had plenty of mid range power.... Guys were using the WR ignition and FWs to calm the CRs down back in this time frame so UR engine should be the opposite of what U are describing ...

Jetting from a 360 should be lean for a 250, but you should have similar jetting to a newer 250.

Wallybean is the "transmission historian" around here. I'm not sure what year they stopped putting them in the 250's.

Hey Mate, Where in northern nsw are you? I'm in Brunswick heads. Got an 01 wr250 thats dead stock and it strong right through the range. From what I have read the best smooth bottom end comes from stock expansion chamber and especially stock long tailpipe.

My jetting is

400main
2nd clip
32.5 pilot
17mm float

Hope that helps

Thanks Kiethy, I'm out in the hills halfway between Kyogle and Nimbin, work in Lismore. It still has the long alloy silencer and supposedly the FMF pipe gives it even more bottom and mid range so I'm thinking it must be something with the power valve. I will check the carby out, is that the 2nd clip from the bottom or the top of the needle? I've found a bit of a write up in the owners manual on the power valve but it is not very clearly written but I'm sure it will be pretty clear if it's gummed up or not.
Where abouts do you ride around Brunswick? I've only had the bike a week so apart from having a blast around my mates front paddock I'm yet to get out into the bush. Mybe we could hook up for a ride, is your bike rego'd? Mines not yet but will get a mate to rego it in QLD with that single seater rego they've got up there, more than half the price of NSW rego

i bet you're running rich on the pilot circuit and that's stealing your power. i've been trying to sort out the jetting on my '08 and with a very rich pilot/needle it definately takes away the low end grunt

Small world, I'm regoed and ride most of the forests around here. Woodenbong would be your closest. There is a rctb ride this sunday at boonah which is just past beaudesert, no rego needed cost $25 http://www.rtcb.net/rides-a-events.html I'll PM you the rest

How about dropping the needle a notch or 2? A.K.A. raise the clip up on the needle ...

that would def. help lean it out in the low/mid area.
i've had so much trouble KEEPING mine jetted correctly that i just gave up and bought the pwk. hopefully i'll get to install tomorrow and ride next week.