05 RM250 Jetting

[evsuper]

hey guys, just wanted to talk about jetting a bit, i'm going to work on my jetting a bunch on sunday. i just got an 05 RM250 and it seems to be running rich, especially on 1/2 throttle and below. i have the keihin PWK38S carb, PC works pipe, FMF shorty, and i'm at sea level.

right now i have a 50 pilot and 170 main in, not sure what needle is in there or what clip its at, gotta open 'er up on sunday.

i was hoping to find out what everyone else is running in their carb, if anyone has a similar set up and elevation as me.

thanks ?

[mihylo33]

hey guys, just wanted to talk about jetting a bit, i'm going to work on my jetting a bunch on sunday. i just got an 05 RM250 and it seems to be running rich, especially on 1/2 throttle and below. i have the keihin PWK38S carb, PC works pipe, FMF shorty, and i'm at sea level.

right now i have a 50 pilot and 170 main in, not sure what needle is in there or what clip its at, gotta open 'er up on sunday.

i was hoping to find out what everyone else is running in their carb, if anyone has a similar set up and elevation as me.

thanks ?

You are in the ball park with those settings. (I have the same carb) Now remember no 2 bikes jet exactly the same.

Drop your main down to a 168, your pilot down to a 48 and your clip should be 2 down from the top to clean it up a bit. To further educate you in jetting go to the sticky titled Suzuki FAQ's at the top of this forum page. Ckick on the jetting link in the very 1st post and read it. It is by far the best write up I ever read on proper jetting. Follow it to the letter and before you know it you will be re jetting bikes in 10 -20 mins.

Good luck:thumbsup:

[evsuper]

yeah that FAQ is awesome! that's how i originally learned how to jet

i'll get everything sorted this weekend hopefully. i just picked up a service manual today so i know what all the stock settings are at least too.

just was curious as to what other people were running, good to know i'm not too far out already.

i'll let you know how it goes ?

[Dangeroo0]

What temp? I'm at sea level with an '05 and have mine running mint. We have high humidity here and I can dig my specs out later (its 3.09am here and I need to get my specs from the work shop).

[evsuper]

right now the temperature is pretty low: 8 - 12 degrees C, 45 - 55 degrees F, something like that... but it should be warming up and be 20C (70F) or more soon.

let me know what you have in there and what the temps are like over there too.

i haven't been able to mess with my carb at all cause my friend has all the jets and he's been out of town.. hopefully this weekend i'll get a chance to get in there!

[Dangeroo0]

Ok I spent a season playing around with the JD needles and the bike was always to lean somewhere with those so I went back to using the stock needles, note a different needle depending on season. Most of the year I run my winter settings, the RM is not very tolerant of cooler weather with my summer settings, it starts to get lean. I also use 98 octane fuel, Motul and 50-1 and we usually have high humidity, I run a Bills pipe and stock silencer (the shorty took away too much top end for me) and have retarded the timing a penny width so bare those factors in mind. We run in sand which is hard on a bike if its too lean on the main.

Summer 20 degrees - 28 degrees

Main 168

Needle NEDH3

Pilot 45

Air screw 7/8 in cooler (18 degrees things start getting lean) to 1 1/4 depending on the days temp and humidity

Winter

Generally 12 degrees is as cold as it gets, but have used this jetting in 7 degrees further south (cooler and drier), this works well up to about 20 degrees but once we start getting those temps I switch to the summer jetting. Bike is more tolerant of warmer conditions with the winter jetting than it is with cooler temps with summer jetting.

Main 170

Needle NECH4 (different but still a stock needle included in spares kit)

Pilot 48

Air Screw 1 3/4 for cooler (7 degrees) up to 2 1/8 in warmer weather

Pretty happy with these settings and don't need to experiement anymore but as the temps here even in winter can reach 18 degrees or more the crossover between summer and winter can result in tweaking the air screw some days. Most summer days are over 22 degrees. Once we get into autumn and the days get cooler around 18 degrees I have to run my winter jetting or it starts getting lean. Other bikes like my KTM have a different crossover temp which works better ie the temp where things start to get rich or lean depending on jetting is lower, about 14 degrees.

[evsuper]

thanks dangeroo, that's some good info! it'll be good to compare with my settings, i'll let you know what i end up with.

one question: you found changing the clip on the needle didn't work as well as just putting another needle in? did you have any luck changing the clip position, or was it no good?

[Dangeroo0]

I've adjusted the needle clip as well, thats the clip position listed after the needle ie NECH4 and NEDH3. These settings are what I've found to work best for me, that included changing the needle for the season. I've tried just changing the clip position, it was not as good as the change of needle as well. I think the needle change is worth a half clip position but its been a few seasons now since I went through the exercise and while I continue to fine tune with more time on the bike and monitor its performance each ride its been a few seasons now and these settings are practically written in stone for me now. If your summer and winter temps have a larger range than what mine do, the same needle might work fine with the clip change. I know my KTM works with a clip change and the same needle, but I'm not using a stock needle in that bike or even a similar one.

The same needle probably would work ok in most situations with a clip change, but over a period of time and fine tuning I just found what worked best for me. Over time and if you keep good records you will eventually find what works optimal for your bike and conditions. My settings might guide you but might not be correct for you.

Good luck and let us know how you get on.

[evsuper]

hey guys, i got my needle out over the weekend and i realized that the collar and the spring that is supposed to be inbetween the throttle cable holder and the jet needle is not there, so my needle was able to move around and up and down slightly, so i have to order those little parts!

anyways, i was looking at TT OEM store for them and they want to charge $50 for shipping to Vancouver up here in Canada, or $98 if i want them express.. so it's not really a good option for 4 dollars worth of parts.. ?

does anyone else know of another good option for OEM parts? i had a look at Sudco, but for some reason i couldn't find those 2 parts..

[Dangeroo0]

Wow thats strange that someone left those parts out. I'm surprised the bike even ran!

Can't help you much with this, sorry.

[evsuper]

yeah, it's pretty crazy... definitely noticed it on the low end, it wasn't as noticeable high up though..

i was looking at diagrams for some of the other PWK carbs and it looks like some of them don't have that little spring and collar, so maybe the previous owner was looking at an older manual or something.. looks like the 2001 - 2004 RM250 carbs didn't have them at least.

?

anyways, anyone have input on good online OEM stores? gotta order those parts up soon! i'll see what my local dealers can do for me tomorrow.. hopefully they can get some parts in asap!

[Not-So-Fast]

In Canada you need to buy the part from someone in Canada or else you will incur major shipping taxes due to US/Canada trade regs which kick in over $25 dollars I believe.

Good luck on your jetting. I strongly suggest you look at the jetting specs on FMF, Pro Circuit and Bills Pipes websites. They give you a good starting point. Also, if you aren't exactly sure then err on the right side.

[evsuper]

yeah, i ended up just getting a local shop to bring in the parts for me.. just have to wait a week and a half now for them to come in

luckily i have a YZ with the same carb so i'm going to take those parts from there and see how it runs today! i had a look at bills pipes for jetting and it looks like they recommend some learner settings than i have in there, so i'll have to spend some time and get 'er jet just right ?

[evsuper]

So I ended up with a 45 pilot and a 168 main, and my NECH needle on the 2nd clip.

It was running pretty nice, but could have been a bit better in the 1/4 - 3/4 throttle area. I got a ton of top end power just from that new main though!

After riding for a few hours I had a little crash, and then my bike got all screwed up and died - turns out the needle broke in half at the 5th clip position!! ***??? I was way out in the dunes and managed to get it back to the truck with the choke out..

Anyways, my friend happened to have a hugely fat needle from a CR that I put in it just so I could keep riding. But it definitely took away from my mid-throttle area, didn't have the punch that it had before and bogged a bit when I'd need it on hill climbs. So I'm going to order a couple needles and get it all running good again.

I was hoping to get some input on the needles because I haven't really figured out what all the letters and numbers mean:

Does anyone have a good place to check out the differences between the needles? I just want to see the profiles and see and compare the tapers and stuff..

My NECH was alright, but I wouldn't mind putting something a little leaner in there instead.

Any help is appreciated!

Thanks guys

[mihylo33]

I'll have to get a Sudco catolog and then mic my JD needles and see what I can find that is close and post it.

I have never heard of a needle breaking before. YIKES!

[evsuper]

Yeah man, I was blown away to find my needle broken in half when I opened up the carb. I was expecting to find a piece of sand or something jammed in the main or the pilot, but instead I found the tip of the needle poking through the bottom of the main! ?

Maybe I accidently weakened it when I was changing the clip the day before or something..

Dangeroo, is that NEDH needle that you run thicker than the NECH? I'm still trying to get my head around all the letters for the needles. And do they change from make to make? My YZ has a N3EJ or something like that in it, which I don't see for the Zook anywhere..

[Dangeroo0]

No the NEDH is slightly richer although the same outside diameter. According to the Suzuki manual the next leaner to the NECH (2.725 0.D) is a NEDW (2.735 0.D), this has a slightly larger outside diameter. You might want to try a NECW (2.735), which is the next leaner needle again but the same outside diameter as the NEDW.

You sure you didn't just need to tweak your airscrew?

[evsuper]

Thanks Dangeroo, I think I'll order a few different needles and try them out. I'll probably get the NECH again, and maybe one of the NEDW or NECWs

It could be the air screw, but I was noticing a lack in pull mainly around 1/2 - 3/4 throttle or so. I'll still have to really refine my jetting, but so far the new pilot and main have helped a bunch. I figured since I broke my needle and need to get a new one I might as well get a few and see how they change everything.

I'll let you know how it goes once I get them in.

?

[08suzook]

Dangeroo,

I'm also using the NEDH and NECH needles. What size powerjet are you running with your settings?

Cheers

[Dangeroo0]

The stock power jet which is a #55 in the 2005 RM250. Never thought about changing that for any reason and not sure if other years run a different size?