NO power with my RM250, need help!!!!


rodH

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

I bought the bike and after realizing that I am getting use to the bike (I hadn't riden in over 10 years) I realized that it isn't running 100%. I also started to foul plugs every ride after my 4th day. 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 better at idle (starts on 2nd or 3rd kick everytime), 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. 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 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 and runs horrible (impede exhaust flow at greater than 1/2 throttle and under half throttle it sounds OK, but still runs slow) .

Plugs look GREAT, jetting is the exact jetting Bills recommends on thier site for my bike (Main Jet...Stock=175 Bills=165, Slow Jet....Stock=48, Bills=45, Jet Needle=3rd positon).

Called Eric and asked for advice, he gave me some ideas, and sold me on his book (which I immediately bought, buy haven't found the answer to my problem)

I was convinced after reading that that my spring was crisscrossed or the valve was sticking, that that was going to be my problem, but after going home and taking the whole dumb thing apart, that was NOT my problem!!!!!, BUT, BUT, BUT....I look next to the spring at the outer lever and I notice that the valve assembly Rod isn't connected AT ALL to the outer lever, so I connect this ROD, but it feels like it isn't connected to ANYTHING inside the crankcase???? But I put it back together and test it out.......SAME PROBLEM.

As I completely take the crank case apart to see what I find is connected to the other end of this ROD, and it is connected, BUT NOT CONNECTED PROPERLY, at the end where it is supposed to go in the hole of the Actuator, it isn't actually in the hole, it just slides back and forth without actually moving the ACTUATOR!!!! (or the actuator when it moves, would have NO EFFECT on the rod, which means it would move the outer lever/exhaust valve)

My conclusion WAS that this HAS to be my problem. I rush to get new bushings/clips, put it all together. I get the thing started and SAME FREAKING PROBLEM?!?!?!

At full throttle the bike jerks back and forth and has, and if I modulate the throttle just right I can get this to decrease, BUT the bike has absolutely NO power (bottom end, and especially TOP END). On a flat road, it can bearly maintain speed in 3rd gear. It is sort of like a bike when it is flooded, but it is in a more on-and-off feeling, NOT just bogging.

Things I have checked that look fine:

1. Exhaust valve moves freely when I move it by hand and watch it move when I twist throttle
2. Spark plug looks great (put in a new one and no change)
3. Exhaust valve springs both adjusted to stock settings
4. Jetting in Bills Spec
5. Bills pipe was just fixed
6. New premium gas
7. Suzuki premium oil 32:1
8. Silencer repacked 2 rides ago
9. Air filter recently cleaned
10. Reeds inspected and look fine (no crakes, chips or gaps)
11. Gas filter flows properly

Things that concern me that it still maybe the problem:

1. Jetting, it maybe what Bills recommends, but maybe still off??? (since the problem was worse after I fixed the pipe, even though the bike wasn't 100% to start off with?)

2. Top end-was done a few rides ago, BUT what we found on the old piston/rings was the valve rubbing and scrathing the piston, I rode it 2 times since the new top end, but maybe this was enough to screw it up again?

3. problem in crank, lower end, bottom end???

4. Something electrical???

ANY OTHER IDEAS???????? This is driving me crazy. I have a Clymer manual, Erics Manual and decent mechanic skills, but I just don't have any experience or knowledge on how to diagnose what the problem is.

ANYONE????

I am supposed to go riding on Tues with my bro out of town (he is flying out over 1000 miles for a vacation and has been bugging me to teach him how to ride, I took a day off work to do so, and we don't have a bike to ride, no mechanics in the area have the time to do it either).
 

rodH

Member
Aug 17, 2005
369
0
just noticed that my pilot air screw was out 2.25 turns and it is supposed to be only 1.5 turns is that a big difference?? will that matter??
 

sick 96 250

Damn Yankees
Member
Jul 16, 2004
1,207
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what elevation are you at? I had a 96 RM250 and now have a 99 and i believe the jetting was mostly the same within those years. If your near sea level I can give you the specs i had on my 96 and maybe that will help..... and yes if your air screw is out to much it can cause a lean condiditon possibly causing your bike not to run right. I will check the jetting specs after work, i have written down somewhere and maybe that will help ya out. Also check your carb, clean it real good and make sure your floats are at the correct level, i believe it was 16mm for 97 Rm250's
 

steve125

LIFETIME SPONSOR
Oct 19, 2000
1,252
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One possible cause is the high speed coil has gone bad or is going bad on the stator.

When this happens the bike will start and run to 1/2 throttle but then cuts out and misfires after that.

If its a PV problem, like not opening, mid to top power will be weak but it will run smoothly to full throttle.
 

rodH

Member
Aug 17, 2005
369
0
Sick96, yes, I am at sea level. Love to get your specs.

Steve, thanks, is there a way I can test the speed coil???
 

sick 96 250

Damn Yankees
Member
Jul 16, 2004
1,207
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The specs are different between our two years, but I'm guessing you should be somewhere around a 160-165 main jet, 43-45 pilot jet and needle on the 3rd clip with air screw somewhere around 1.5 turns out. Do you know jet sizes that are in there now?
 

rodH

Member
Aug 17, 2005
369
0
these are the stock jets and the Bills recommended jet specs, jetting is the exact jetting Bills recommends on thier site for my bike (Main Jet...Stock=175 Bills=165, Slow Jet....Stock=48, Bills=45, Jet Needle=3rd positon).
 

sick 96 250

Damn Yankees
Member
Jul 16, 2004
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just cause its the bills recommendations doesnt really mean much, did you check your float level to make sure its not raised to much or to low? That happened to a friends 125 and it was causing all sorts of crap till it was situated. Does it seem to run any better if you turn the air screw on the carb out any?
 

rodH

Member
Aug 17, 2005
369
0
sick 96 250 said:
just cause its the bills recommendations doesnt really mean much, did you check your float level to make sure its not raised to much or to low? That happened to a friends 125 and it was causing all sorts of crap till it was situated. Does it seem to run any better if you turn the air screw on the carb out any?

I haven't messed with the air pilot screw yet. It was at 2.25 turns and it is supposed to be at 1.5, I haven't started it since I adjusted that to 1.5 turns, can that make a big difference??

Also, I haven't checked the float levels yet either, I will have to do that as well, any hints??
 

sick 96 250

Damn Yankees
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Jul 16, 2004
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do you have a manual? Thats what i highly recommend, it will tell you everything you need to know, if not i can try to scan a few pages from mine on adjusting the floats and such, maybe tomorrow
 

steve125

LIFETIME SPONSOR
Oct 19, 2000
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rodH said:
Steve, thanks, is there a way I can test the speed coil???

Yes, you need an OHM meter though. Check your manual to see what the spec is, its usually a range the measurement needs to be within.

If your having low power in the mid to top RPM ranges, the air screw will make little to no difference.

The float level is a long shot to solving your problem. If the level is high you would be having a flooding/fouling problem. You would also notice an excess of fuel out of the drain hoses. Power would feel weak throughout the range.

If the level is to low, it would feel like its always running out of fuel. The plug would look very clean and white. The bike would also tend to ping and over heat. Power would feel strong at times but mostly it will surge and feel erratic.
 

rodH

Member
Aug 17, 2005
369
0
sick 96 250 said:
do you have a manual? Thats what i highly recommend, it will tell you everything you need to know, if not i can try to scan a few pages from mine on adjusting the floats and such, maybe tomorrow

Sick, Yes, I have a manual, I just found the section on the float, and will have to try that next. Thanks for being so willing to help. The manual is nice, it just isn't the best at telling you how to trouble shoot the problem(s).
 

sick 96 250

Damn Yankees
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Jul 16, 2004
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steve125 said:
The float level is a long shot to solving your problem. If the level is high you would be having a flooding/fouling problem. You would also notice an excess of fuel out of the drain hoses. Power would feel weak throughout the range.

If the level is to low, it would feel like its always running out of fuel. The plug would look very clean and white. The bike would also tend to ping and over heat. Power would feel strong at times but mostly it will surge and feel erratic.
The level of the floats made a huge difference on my buddies rm125 which use to mine back in the day. It was able to handle the lower RPM's but when he would crack it open it would lose power and constantly give you irratic throttle control making the bike have power then have none, then power, etc. We had no pinging or anything either and the plug actually looked oil fouled. Once that was adjusted to the specs the bike ran great and all of the symtoms were gone. Everyone swore it was the coil or a RH crank seal but it ended up being just a little adjustment.
 

steve125

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Oct 19, 2000
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Im not saying it's impossible, just a long shot. Once the level is properly set unless there is a lot of needle to seat wear, the adjustment/level should never change.

So your old bike may have had excessive needle to seat wear?, or just some dirt that was removed at the time of the adjustment is always possible.

Your symptoms sound like a low float level or very much like dirt plugging the main jet. Any internal wear inside the float bowl would make the level higher not lower.

So unless someone was fooling with the carb, sounds like you had a case with just dirt in the carby.

Once again any internal wear would not lower the float level.
 

rodH

Member
Aug 17, 2005
369
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FREAK!!!!!!

I took my bike to my mechanic today, after I went through all the hassle of trying to figure this thing out, it was a stupid little mistake by me. Within a couple hours he calls and tells me that the packing from my silencer is plugged in my screen/spark arrester. I guess some of the packing I put in there was lose or worked its way lose and found its way to the screen. I can't believe that was it.

I guess it wasn't all for NOT, as I did find the exhaust valve assembly actuator rod was NOT connected, which obviously will me the bike not run right (not opening the exhaust valve), I also think that this is what was causing all the spooge all over my bike, so at least my fixing wasn't a complete waste of time.

Think runs AWESOME now...

I never have had my bike feel this fast!!!!! I rode it at the shop it was fixed at on the street, tire was coming off the ground in all of the 3 gears I was in, the thing felt sooo fast. When I got back, the guy who worked at the shop said that I should be "right there" with straight line speed VS even the NEW YZ, which surprised me when he said that. I asked "so, what has changed on the late 90s bikes compared to todays 2 strokes?" He said that the power is gonna be about the same, but most of the improvements people notice is gonna be in the handling. The wts aren't that much difference (2 pounds??) but it is where the wt is placed and the geometry that makes the new bikes faster on the tracks. I was surprised that he said that the power isn't much different. I can't wait to take my RM out now, I am sooooo happy this thing is moving like it was supposed to. In the course of 1 day I went from thinking that I wanted to save up for a used CRF250, to maybe saving for a used YZ250, to wanting to keep my RM250 and NOT waste my money (I don't race, so the slight advantage I might get with a new yz250 wouldn't be worth the price it would take to get into one for me and my skills and my budget). Thank goodness for a good mechanic!!!!
 

ryan123

Member
Mar 6, 2008
2
0
Thanks this info has been handy. I just fixed my 98 rmx250 with the same sounding problem. Mine was either float height adjustment, moving the main pin in the carb, cleaning out the carb(not that there was any blockages that I know of), cleaning the back of the coil mounts and frame real nice, I did fully stip down the top end looking for stuff gone wrong but changed/fixed nothing. I can't say exactly what fixed it cause I did it all at once. I have a suspicion it was the carb float level it was set to 25mm rather than the correct 16mm for the 98(so I'm told). And I thought it sounded rich, using heaps of fuel, black stuff everywhere. F*cks me.
but it runs sweet. Fangs once again.
 

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