2003 RM250 jetting

[02'Cr Rider]

Anyone who has a 03 rm 250 please help,I'm running mx2t @32:1 w/race gas in my bike.The jetting is close,but would like it to be better.Current jetting is 162main,42 pilot,stock needle, 2nd clip,48 power jet,A.S. 1 1/2 turns out @2000 ft. Mods are pro circuit pipe and spark arrester,V-force valve.Its running rich somewhere around 3/4-full throttle,I get oil out of silencer just a tad.Main is good according to carbon ring.Should I lower the power jet to a 45,or try diff. needle.I see suzuki has change the 04 rm's needle to a NEJC.Does anyone who owns a 03'rm 250 have this problem.If only I can get that oil to burn. :whiner:

 

[ochster]

My jetting has taken place near sea level, at 70-90 deg. weather. We have been running C-12 straight, 32:1. The rider is a pro, wich definetley accounts for something.

We are using the 01' 250 needle, in the second position. We are using one size leaner pilot and main jet, than you, stock power jet. We have cut the slide 1.5mm, and typically have the air screw near 1.5 turns out in these conditions.

We were not fans of the v-force, and actually like the stock or boysen rad assy. This bike seems to eat reeds, may be something for you to check.

We are running the Wiseco GP piston for a 03' YZ250. The crown is .007in. taller than oem. They are a race piston that requires frequent change.

The squish on these seems to run near .060. We have taken .015 off the head, with good results.

We are using a Vortex ignition, from MT racing. It has proven to be worth the money. We are running the timing slightly retarded.

This naturally does not have a spark arrestor, but may give you something to use a guide. We were able to drop two teeth on the rear, and it pulls hard and clean...no spooge at all.

 

[_j0kA_]

my 04RM250 is completely stock and is tad rich from 1/4 to 3/4, but have very little spooge out of the silencer.. HOWEVER, there is spooge marks (like the ones on the back of a jersey) on my cylinder/carb/etc.. any ideas?!

 

[02'Cr Rider]

ochster,

Thanks for the info.May I ask what needle part # you running?Is it stock? I forgot to mention also running a leaner slide 7.0.The jetting is close to mine except the needle.I tried a n3wk but it doesn't work that good.

 

[ochster]

It is the stock (oem), 01' RM250 needle. They were given to me, and I have to many needle numbers in my head to remember, sorry.

 

[Wind]

You said:"Current jetting is 162main,42 pilot,stock needle, 2nd clip,48 power jet"

This doesn't sound like 2003 RM250 at all. I have one and don't even know what a power jet is. Your settings sound way lean. At 2000 feet in this weather? And you are still rich? I'm running 168 Main, 45 pilot, N2ZH Needle, 2nd clip, stock slide. I get the slightest bit of oil coming out and I feel like I'm doing great. Now that it is colder I may have to go richer.

 

[02'Cr Rider]

Wind,

I mainly trail ride,and the elevation vairies from 2000-4500 ft.But when running near my house I change to a 165 or 168 main.The power jet is the one that has the wire connected to the solinoid on the carb.It has a small tiny jet.

 

[02'Cr Rider]

ochster,

Can you give me more info on milling the head.Since I already run race gas,and would like a little better low to mid.Can I cut the head without reshaping?

Thanks

 

[ochster]

Cr Rider,

Take a piece of solder, and check your squish clearance. We have run these near .050 with oem chamber volume and shape. This will crispen up the bottom to mid, and definatley run race fuel. We have had great results with the Bill's pipe, and cutting the oem muffler down 50-60mm. When cutting the muffler down, you basically go as far down as you can, without jepordizing the top mount. You can sorta cut into it about 1/3 and blend the transition with a nice radius. Check your timing marks on the stator, slightly retarded seems to help with temps and power. We have also been running 03' YZ250 wiseco GP pistons (.007 taller crown). These motors make huge midrange.

 

[02'Cr Rider]

ochster,

I check my squish clearance,Its @.067 inches.should I take off .015 off the head? I've done this before with 02 cr250 and had great results.

Thanks

 

[ochster]

I have been pleased with running between .045-.050 total squish, on the oem design head. Race gas is mandatory in my testing, but I consider this to be conservative.

I would make sure everything is mechanicaly tight and sound, including crank seals, exhaust joints, powervalves, reeds, etc.

We have not had any lower end related issues this year. I have seen the need to stay on top of the stator side crank seal.

 

[02'Cr Rider]

Help,

Anyone who has a 03/04 RM 250 I need your help.I lost my manual,and need the head nut torque specs.

Thanks

 

[_j0kA_]

do you still need them? i got an 04RM250 and have my manual in the garage..


right now my current jetting specs are

168 main
stock needle 2nd from top
48 pilot
air screw 1.75

i have a twin air filter and shorty silencer, it runs perfect.. its an 04RM250

 

[Superbike373]

I have an '04 RM 250. I am running the NEDJ needle, 2nd clip, 162 main. 45 pilot. stock PJ. Seems to run perfect but I am still getting a little spooge. I cant tell where? ---Mike

 

[motocrosskx47]

if youve not solved the problem email me and ill -

if youve not solved the problem with ur o3rm250 email me. i had the exact same problem , and took mine to the dealer , they changed the jet and clip location and i am useing suz. oil/gas as instructed , with the plug theyve instructed... its solved our problem. yes i paid for it ...$230.00 but its solved and my boy isnt having trouble at the gate! if u havent corrected yours id be happy to call the mech. and ask him for the exact settings , etc. they keep a log of all changes in my file. if uve corrected your problem , good luck and safe raceing to you.

motocrosskx47 :ride:

 

[blockpass270]

squish

After trying every darn jetting combo I've thought of, I finally measered the squish on my 03RM250 at the request of an engine builder.... right around .070: kinda large. He machined the head down to .050 and I got it dialed in in a couple hours... and this was after messing with the jetting for several months. The bike is much less fickle with air temp and elevation now as well. Runs fine on pump fuel (CA, 91) and 2R @40:1.

I was so frustrated with the jetting (bought the bike used), I even rebuilt the entire engine with new crank seals and all.

Extremely tough bike to jet, and I've owned two strokes for 20 years.

 

[snb73]

I guess I'm a little late. The 2003 RM250 was a tough bike to jet. I had the same problem as you. I leaned my jetting and used Sunoco Standerd Leaded Race Fuel.

http://www.sunocoinc.com/Site/Consumer/RaceFuels/TraditionalFuels/Standard.htm

here is what worked for me;

Main - 168
Slow - 45
Power - 48
Slide - .65
Needle - N8RH 3rd Clip

 

[jason33]

here's your solution - klotz oil- 40:1-
your bike runs great but had oil build up - try new oil-a leaner ratio check the plug
it should be tan/dark tan
also change the silencer packing- as it is full of oil that didn't burn completely, and will hold in back more pressure
this will eliminate oil drool , and carbon build up,and plug fouling-
if you decide to run race fuel - check the plug again ,as it will burn more completely
but most ppl can't afford 7 dollars a gallon- so 40:1 with high octain pump fuel -