Jump to content
Sign in to follow this  

04 RM 250 hanging up top

Recommended Posts

my 04 seems to be hanging up top, fiddled with the main last week, going from a 165 to a 180, which made it burble, brought it down to a 175 and its running the same as it did when the 165 was in. with the 165 in the plug was perfectly brown maybe a little dark and i only fattened it up because of the cold weather. should i try going leaner than a 165?

also, the idle hangs a little, reeds are sealed, left side crank seal is good and base gasket is not leaking. thinking i should go up 1 or 2 sizes on my pilot(currently a 45)

any help is greatly appreciated.

thanks.

Share this post


Link to post
Share on other sites

Maybe the throttle cable is in a bind ??? Cable getting frayed ????

Have you ever taken out the choke from the carb ???? Sometimes they get corroded over time.

I run 42 or 45 sj ...here at sea level. The main jet...is pretty close to yours also....I have an 05, stock exhaust. Needle jet is stock....pretty close to middle notch on clip.

Can't say much else......I have a 03 crf....that I have been finagling with for a while......sometimes when things go awry.on older equipment...you have keep trying different things.

I also had an 03 rm 250....( sold it with 150 hours on it )....and it needed a new r/s crank seal at 130 hours. ( of course , you would probably know if yours was bad. )

out

Share this post


Link to post
Share on other sites

are u messing with ur air/fuel screw when ur running ur bike? thats a big jump in main jet try a 168 and if not go to a 170 i run mine at a 168 with a 48 pilot and the clip the second down from the top and im in wichita kansas ....

Share this post


Link to post
Share on other sites
my 04 seems to be hanging up top, fiddled with the main last week, going from a 165 to a 180, which made it burble, brought it down to a 175 and its running the same as it did when the 165 was in. with the 165 in the plug was perfectly brown maybe a little dark and i only fattened it up because of the cold weather. should i try going leaner than a 165?

also, the idle hangs a little, reeds are sealed, left side crank seal is good and base gasket is not leaking. thinking i should go up 1 or 2 sizes on my pilot(currently a 45)

any help is greatly appreciated.

thanks.

When You say (hanging up top),, what exactly do You mean,,,, is the throttle sticking open when You let off,,, if that's the case,,,, All Us Guy's can help figure out what the hell is going on.........Dr.D..

Share this post


Link to post
Share on other sites

I ran 172/42 jetting for like 3 years until this year when I pulled my bike apart and the top ring was stuck on the exhaust side and the piston showed signs of detonation. Maybe something in the pump gas changed? The bike always ran great. I rebuilt it and am running 100LL now. Had to lean it a bit, I think I have a 168 main in there right now.

Share this post


Link to post
Share on other sites
I ran 172/42 jetting for like 3 years until this year when I pulled my bike apart and the top ring was stuck on the exhaust side and the piston showed signs of detonation. Maybe something in the pump gas changed? The bike always ran great. I rebuilt it and am running 100LL now. Had to lean it a bit, I think I have a 168 main in there right now.

you ride #700 right? ive sen you all the time out at speedworld, this is my first big two stroke so maybe what im calling hanging(not revving as far as it should) is normal? if youre the ryan(or ryne) im thinking of, do you think we could meet and i could switch bikes with you for a few laps so i can get a feel for proper jetting? im running 25%pump gas with 75%100LL from DV airport. cylinder is ported/polished,RAD valve, head milled.

Share this post


Link to post
Share on other sites
you ride #700 right? ive sen you all the time out at speedworld, this is my first big two stroke so maybe what im calling hanging(not revving as far as it should) is normal? if youre the ryan(or ryne) im thinking of, do you think we could meet and i could switch bikes with you for a few laps so i can get a feel for proper jetting? im running 25%pump gas with 75%100LL from DV airport. cylinder is ported/polished,RAD valve, head milled.

Whoa yeah my number is 700 ha. Just curious how do you know who I am?

I haven't even started my bike since July. I rebuilt it and rode it once then started school and haven't touched it since. Jetting was a tad rich over the summer so maybe now that it's 50 degrees cooler it will be good but I'll mess with that next time I go riding. I may go ride next week. The only motor mods I have done to mine are Boyesen reeds and a single ring YZ250 piston.

As far as what you're calling hanging, not sure what you mean. My bike revs out super clean with no garble or anything. Who did the porting? If it wasn't ported right that could definitely screw up your over rev.

Share this post


Link to post
Share on other sites
Whoa yeah my number is 700 ha. Just curious how do you know who I am?

I haven't even started my bike since July. I rebuilt it and rode it once then started school and haven't touched it since. Jetting was a tad rich over the summer so maybe now that it's 50 degrees cooler it will be good but I'll mess with that next time I go riding. I may go ride next week. The only motor mods I have done to mine are Boyesen reeds and a single ring YZ250 piston.

As far as what you're calling hanging, not sure what you mean. My bike revs out super clean with no garble or anything. Who did the porting? If it wasn't ported right that could definitely screw up your over rev.

Im friends with bill macmaster, and was wrenching for him all the way up until he decided to join the army. I ported my bike the same as i have done many, many RM's, so im sure its not my porting. not to mention i didnt do anything too extreme, just cleaned it up really. also have the YZ single ring, RAD valve as well. i might try going leaner than a 165 and see how it goes. PM me your number and we'll get together and ride.

Share this post


Link to post
Share on other sites

Are you sure you don't have an air leak? Certainly sounds like it.

Freshly built motor right? Retorqued your cylinder, reed and case bolts?

Share this post


Link to post
Share on other sites

Haven't rebuilt yet. But definitely wanna get the jetting figured out before then. No air leaks with carb clean test and soapy water. I'm thinking a 162 main and see how it goes.

Share this post


Link to post
Share on other sites

I would think it needs a leaner main. I find when 2t wont rev out it is rich. if it was running too good is when you need to watch the plug closely to make sure you dont melt down. just a guess though.

Share this post


Link to post
Share on other sites

welp, broke my kickstarter off yesterday, waiting on parts then ill try the 162 main and 48 pilot.

Share this post


Link to post
Share on other sites
welp, broke my kickstarter off yesterday, waiting on parts then ill try the 162 main and 48 pilot.

Sounds like that problem is going around right now. Took over a week for Suzuki to get one in for me.....

Share this post


Link to post
Share on other sites

yeah i guess it had a pretty big groove in it from hitting the peg and it started hitting the stopper in the case so it stressed the knuckle and SNAP! bent my brake pedal up really bad so im getting a new kicker, new rear brake pedal and the two seals for the pedal bolt. comes out to 230 bucks. damn new parts lol.

Share this post


Link to post
Share on other sites

just had a lightbulb moment, considering im running at 40:1, my jetting would technically be richer than someone with the same jetting running 32:1? am i right? so considering alot of guys are running 172/48, @32:1, theyre getting less gas in the same amount of gas/oil mix, meaning my mix is richer, thusly explaining my rich running on top! let me know if you think that my thinking is in line!

Share this post


Link to post
Share on other sites

Two bike with the same jetting, you are correct.

Large bore two strokes are not that finicky between 32:1 and 40:1, but if your on the border line of running to lean it could make a differance. However, smaller bores such as the mighty RM85 it does make a differance in running 32:1 verses 28:1 or 24:1. 28:1 or 24:1 will help bring the jetting around to where it can be fine turned and not bogg on the line or in the corners.

I do just what your talking about. Summer, I run 32:1, late fall I run 40:1. Both my RM250s run 48/168 jetting. One has a PC/304 and the other has FMF SST/factory II. Both run strong, but I just swithed over to 40:1 two weeks ago. Or I can switch to a 170 main and stay with 32:1 and solve the same problem.

You can try the 162/48, but my bikes won't run on that jetting. At least not for WFO MX. Clatters like a Texas girl on vacation in the cold Canadian winter.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×