dudeman114

Member
Dec 18, 2010
4
0
Hi everyone, im new to the site and just bought an 03 rm 250. I have a few questions/ problems im dealing with. Ive been checking into everything on it and going it over it so itll be ready for when im ready to ride. My 2 main concerns are exhaust leak and there is way to much spooge on the rear fender. I started looking into part numbers and the number on the side of the carbuerator matches the number for an 04. Am i looking at the correct numbers? and i also pulled the jets out and they match the jettting for an 04, but the VIN on the bike reads 3 in the tenth spot. anyway the bike has an FMF fatty and shorty silencer (i dont really like the shorty). I bought a new spring and o ring kit from fmf and it seemed to help the leak a little bit. I was looking through parts manual the other day as well and noticed there is supposed to be a washer between the cylinder and pipe? is this correct? and if so does it make it seal better?? And as far as the excess spooge what should i be looking at doing? the plug is too black and oily, should i start playing with the jetting and clip position? I put in fresh gas with suzuki premix(thinking about trying race gas), new filter and plug and it still ran very rich. any help would be greatly appreciated! thank you!
 

whenfoxforks-ruled

Old MX Racer
~SPONSOR~
Oct 19, 2006
8,129
2
Merrillville,Indiana
The only way you will know, is take the top end off and inspect it. Minimum rering and gaskets, but you need to know what is in there before ordering parts. Spooge is from, a poorly maintained engine, poorly tuned, or poorly used. Have the bore checked for true, check the ring end gap, piston skirt clearance, and check the crank tolerances. Then you rule out a big issue, you know its fresh. Chances are good race gas will not solve spooge either. You definitely need all the parts to help seal the exhaust! Trying to tune a worn engine/related parts, is a circle jerk. Check for coolant leaks, they are really good for drippy spooge. Replacing the float valve is over looked(by the book replace yearly), as much as backward engineering the oil premix ratio. Engine with in specs, fresh gas and the recommended premix ratio, jet it, and ride it like you stole it. No spooge to speak of. If you went long on a rering, skipped the jetting, erroneously inspected parts, then spooge can start. Get the shop manual, and follow it as close as your wallet will allow? I run mine purposely rich, not to the point of bogging or blowing smoke like a cold diesel. Just because I enjoy a violent hit when the throttle is cracked. How long I can keep that up is another story. Everything on that bike has an expected life, and that is it. You may not need to rering, or a top end in it every 7~10 hours, but it sure would not hurt! Most, myself included, wait too long. But when that black stuff starts hitting the swingarm, I know what is going on and why. Vintage Bob
 

Chili

Lifetime Sponsor - Photog Moderator
Apr 9, 2002
8,060
11
Yes there is supposed to be a very thin metal washer between the pipe and the cylinder. The 03 if I recall was jetted pretty rich from the factory and was a bit on the finicky side to get right.
 

dudeman114

Member
Dec 18, 2010
4
0
ok, ive went and bought the exhaust washer. I checked the transmission fluid and it pretty low compared to when i bought it so that means that its burning it up pretty fast being ive only rode it maybe 30 min tops. so ive started to remove the cylinder and see what it looks like inside. I took the exhaust side valve cover off and noticed there is oil in there, not a ton but some is in there. Is there supposed to be or is that supposed to be pretty dry??? And i have also purchased a serivce manual (downloaded type) and it does help a ton! thank you for your help Bob!. also ive been looking into gasket kits since i will need new ones, are Cometic or Pro X gaskets a good brand besides OEM?
 

dudeman114

Member
Dec 18, 2010
4
0
update: I removed the cylinder, the walls and head look like they are in great shape, i dont feel any marring or anything on the cylinder walls. I do believe i have found my problem though. I noticed the exhaust main valve was just flopping in the cylinder. I removed the cover and found the main valve retainer and screws along with all three shaft arm bolts just lying in the bottom of the space. I dont know how it didnt eat the end of the valve up, good thing i didnt run it for long. but inside the valve area, there was once again, a good bit of black oily stuff. this shouldnt be in there should it? and if not, where would it be getting in at? bad gaskets and seals or just the exhaust valve not being attatched to anything and just flopping around?
 

dudeman114

Member
Dec 18, 2010
4
0
thats kind of what i was thinking after i did some more research online... are there any tale tale signs that i should look for once i get to the seal or is it something i will notice is bad right away? and i guess that would also be a good cause of excess spooge.
 

2-Strokes 4-ever

~SPONSOR~
Feb 9, 2005
1,842
4
Missouri
We have an '03, and yes they're a nightmare to jet.

Finally dialed ours in though...

We change the jets 3 times a year depending on temps.

Woods ridden (probably leaner than an MXer would want)-
70-90 degrees-
500-1500 elevation-
Yamalube/93 octane @ 40:1-

7.0 slide
42 pilot
YZ250 needle euro-spec slot 2 (1/2 clip richer than USA spec)
168 main

50-70 degrees-
45 pilot
needle same
170 main

30-50 degrees-
48 pilot
needle same
main same

The OEM needle is the problem... it goes from rich-to-lean too quickly and no combo of pilot & main remedies it. We still have a slight knock in the midrange when under a load, but it's easy to work around it.

*We put RTV silicone on pipe's o-rings before install.
 
Top Bottom