NEED help with 97 RM250 Exhaust/power valve!!

rodH

Member
Aug 17, 2005
369
0
I recently bought a 1997 RM250 used. The last owner mentioned that I might want to run it 50:1 to avoid all the oil coming out the exhaust, etc....

I bought the bike and after realizing that I am getting use to the bike (I hadn't riden in over 10 years) and it isn't running 100%. I also started to foul plugs every ride. I took it to my mechanic and he said I need a new top end. He takes it apart and says that the piston is scuffed from the exhaust valve sliding into the piston and hitting it. He said he would do the top end, grind down the valve a bit (He use to have a 97 RM250 as well and I guess this is common practice??) and clean it. After he put it back together he said it wasn't running as fast as it should (like I experienced earlier) and he needed more time with it. He calls back and said he got it to run pretty well by adjusting the Valve springs, but it still isn't 100% because I have a HUGE crease/dent in my header pipe (Bills pipe) just exiting the cylinder. I ride it for a few rides and agree, better but not 100%.

I send my pipe out to get fixed and decarbonized and reinstall it. now the bike sounds at better at idle, MUCH more poppy and fresh, only problem is, when I go past 1/2 throttle the bike jerks back and forth like it is misfiring (even though I know that is NOT the case). The ONLY change I made was fixing the pipe, I am still getting a TON of black oil coming out of the pipe/header. I have talked to a few mechanics at the local Suzuki shops and they didn't even know you could adjust the valves :coocoo: so they just recommended cleaning the assembly (my mechanic is out of town and I need this to be fixed in a week, arrghhh). I adjusted the valve springs to the stock settings (1/2 turn) and it seems to run better, but still seems to cut out in a alternating fashion (impede exhaust flow at greater than 1/2 throttle and under half throttle it sounds OK, but still runs slow) .

Any ideas on what to do at this point????

I have searched and gotten 1 result, but he never said what his fix was,

ANY HELP I would sure be greatful!!!!
 

rodH

Member
Aug 17, 2005
369
0
btw, I read Eric Gorrs articles on the subject (great stuff!!!!!), but haven't found the solution to my problem in his information published on the web.
 

sick 96 250

Damn Yankees
Member
Jul 16, 2004
1,207
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did you rejet or anything? Sounds like you just need to mess with you pilot and main jet to get it dialed in more. I always ran 40:1 with my RM's using a good synthetic 2 stroke oil. Mobile MX2t or now called Mobile 2T racing. Get it from your local autozone
 

Rog

Member
Oct 21, 2004
31
0
What plug is in it? if it's too cold it has the symptoms you are explaining. Mine did the same thing after a rebuild. The spark was breaking down under load and misfiring and farting around etc. Put in 1 range hotter and it made a huge difference. Mucked around with jetting after that to get it going even better. Of course this may not be the problem though if you already have the right plug, just throwing ideas around.
 

rodH

Member
Aug 17, 2005
369
0
I didn't mess with the jetting, I checked it and it is slightly modified per Bills specs for thier pipe and that year/bike.

I am using a BR8EG (or is it an ES??), something like that. What would I go to next??
 

rodH

Member
Aug 17, 2005
369
0
Just realized that it seems like the exhaust is running backwards, when I give it more throttle, there is hardly ANY exhaust coming out the pipe, when I decrease the throttle or completely release it, it puts out more exhaust.

After reading more of Eric's info, I wonder if this could be it??

"2. Crisscrossed spring. A centering spring on the right side of the cylinder, located on the rod, actuates the valves. This spring is commonly installed wrong. The spring tabs should be parallel when coupled to the lever and rod. If the spring tabs are crisscrossed, the valve travel will be limited and won't open fully"

He doesn't talk about this is the 1997 section of the article, but could this happen on a 1997 as well??

http://www.ericgorr.com/techarticles/twotopweb.html#Suzuki ATEV
 

flyinzuki

Member
Jan 27, 2001
161
0
If the spring is installed correctly try this.
If the exhaust valve spring was turned away from stock this may be the problem.
He may have adjusted it to work with the dented pipe.
The dent could have tuned the pipe either way.
Now with the repaired pipe you may have either too much cyl pressure and are detonating, or not enough and are bogging.
Try taking a little preload out of your PV spring see if that helps.
 

rodH

Member
Aug 17, 2005
369
0
flyinzuki said:
If the spring is installed correctly try this.
If the exhaust valve spring was turned away from stock this may be the problem.
He may have adjusted it to work with the dented pipe.
The dent could have tuned the pipe either way.
Now with the repaired pipe you may have either too much cyl pressure and are detonating, or not enough and are bogging.
Try taking a little preload out of your PV spring see if that helps.

I have it now set at the stock settings (1/2 turn) and I still hve the problem figuring that the bike is no longer stock, I will try your advice and see what happens. I really think you are on to something when you say that he had it tuned a certain way to compensate for the dented, aftermarket pipe, I just have to figure out with that is.
 
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