Brand New 2005 RM250 Run-In but won't rev

[2005RM250OWNER]

Hi I,m pretty much a novice to motocross but I'm a qualified car mechanic so I should grasp technical stuff ok.

The problem is I've bought a 2005 Suzuki RM250, ran it in for two hours been riding it for a further 3 hours but am not impressed.

The motor just doesn't want to rev out, it's got a really good bottom end pull that comes on power mid-range then it's like the rpm is limited, no matter 1/2 or full throttle the bike won't rev.

I have a Kawasaki KX125 2001 also that is stock and I got my father to ride the RM250 flat-out down a dirt road and I sailed past him on my KX125! That can't be right!!

The RM250 won't go any more than what seems like 40-50 mph. My KX125 will rev forever it just keeps pulling, where the RM250 justs revs to the same speed.

Any help would be most appreciated as the reason I bought the RM250 is to go faster than on my 125, so I'm kinda regretting buying it at the mo, but any help would be most appreciated. The plug porcelain is darkish brown with 20% black spot on. It ticks over fine and upto mid throttle fine maybe a little lumpy of the starting off but good pull to 1/2 throttle then won't go any more, no misfires, just fixed engine note.

Many Thanks Ashley.

 

[kevinmfaust]

I would start with the easy stuff first. Check that when you are at WOT the slide in the carb is full open. New plug. Plug cap is on tight. Clean air filter, not too much oil on it. Pipe has no clogs, muffler has no clogs. Check the timing. Check that trere is no wacked out main jet.......etc. Good luck. let us know.
Kevin

 

[RM_guy]

Make sure the power valve is working properly and the spring tension isn't too tight. If it doen't open it will have no top end at all. All the info you need should be in the manual.

 

[Wilky]

Sounds just like what my CR250 did when the main jet came loose and fell into the bottem of the bowl. Way to rich.

 

[kawamaha]

99% it's the power valve (does not open) or the main jet like the guys told you before... :nod:
http://www.supercross-online.de/e/

 

[Danger]

What jetting are you running? Some bike tests stated the same till they changed the main jet.

 

[2005RM250OWNER]

Hey guys thanks for all the advice so far, I really appreciate all your support, all your replys are helping me get a good understanding of whats going on.

I just whipped out the carb earlier. I'm getting full throttle ok, no sign of the throttle slide through the venturi, and it closes fully aswell.

The air screw was 1 turn out when I removed it (as per manual states as factory), the main jet was #172 (as manual states), the power jet was #55 (as manual states), jet needle was 2.72mm dia (NEDH). and was on the 4th clip (again as manual states).

I also whipped out the reed valve and checked for cracks etc, none found and had 0.008 inch valve clearence (again as per manual).

I soaked and cleaned the air filter couple of days ago and re-oiled it correctly (not too much so its drips but made sure it was fully covered).

The silencer and pipe had no blockages, I ran a hair dryer though each and could feel good air flow at the opposite end.

I'm live in the UK and run it on 95 octane unleaded fuel at 30:1 with a fully synthetic 2-stroke oil. Temps have been averageing 22'C when I've been out on the bike, but it's always been the same, no top-end. hope this makes things clearer?

Is the power valve the carburettor solenoid? sorry just can't find power valve in the book. any info again would be greatly appreciated.

Many Thanks,
Ashley.

22 'C

 

[muddy226]

In the manual they prob. call the power valve the "exhaust valve". If its not opening properly the bike won't rev out as it should. The solenoid on the carb is prob for the power jet, and the manual should say how to test it. Good luck with it. (The only time I had a problem like this was when I'd left the choke out )! It may be worth checking that the timing hasn't slipped or been assembled incorrectly. It should advance fairly regularly up to about 8500 then "kick" back. I'm sure you will find the problem quite quickly, these are more simple than cars.

 

[2005RM250OWNER]

Hi, I checked the powervalve this afternoon. I removed the right hand exhaust valve cover and rotated the valve with it connected and without it connected to the lever that goes down into the crankcase/transmission.

With it disconnected it felt a little notchy, I sprayed some WD40 around it, that helped a bit. I also checked the spring tension, 180' clockwise as per manual states.

So far I haven't seen anything obviously wrong. Tommorrow I'm gonna Change the mainjet from #172 to #168 and change the fuel from 95 octane to 98 octane.

I'm also gonna change the pre-mix of 30:1 as manual states to 32:1 and take it out for a ride and see how it goes? wish me luck!

Regards,
Ashley.

 

[Wilky]

If you can look at the PV while you rev the engine and see if it is moving soothly. Also you plan on leaning out the main (good) but richening by putting less oil in the gas. My advice is pick an oil/gas ratio and jet to it. Do one thing at a time and test. Have you checked the timing yet?

 

[Benny477]

Rm Help

What does it sound like on top end when you ride it,boggy,does it knock,will it rev out cleanly,does it fall on it`s face? That should tell you more than anything. Look and see if there`s something in the airboot between carb and airbox also.

 

[muddy226]

if you're still stuck, talk to the spares man at Taylor Racing, Chippenham, he's very good, and if its been a problem on other RMs he'll know all about it.

 

[2005RM250OWNER]

How do you check the timing on a motocross bike, is it the usual timing light procedure at TDC markings? If so are they under the magneto cover?

I'm gonna stick with a oil:gas ratio of 32:1 as the suzuki hop-up guide recomends this ratio, even though the manual states 30:1. I'll also stick with 98 octane fuel (Shell Optimax).

Also on my engine you have spacers for the powervalve shaft/cam and when you remove one of the exhaust valve side covers the spacers are unsupported, would it be ok to still run the engine to see if the powervalve is opening ok? Maybe I could just hold it in place with my hand while reving the engine as the shaft won't be rotating a high rpm?

Ashley.

 

[muddy226]

Timing check is the normal procedure, the stator plate has a mark on it, and on the RMs you can adjust the timing within two corresponding marks. ( You can on the older ones anyway ). Your petroil mix sounds just right, I use Optimax and TTS usually at 32:1, but sometimes up to 40:1 if it needs to be a bit richer. I know that the motor was changed from 2000 on, but on mine if I want to see the power valve working I take off the right side cover first ( the exhaust needs to be out the way on mine) and look while revving to make sure that the actuating rod is working on the main exhaust valve, and to check the sub valve take off the left side cover as you describe. Although the cover doubles as the bearing retainer the bearing shouldn't be loose enough to fall out. Another thing I've just remembered is that (on mine anyway) the main valve rod is attached to the valve by a piddly little Allen headed screw, and this once fell out. As the sub valves are operated off the main valve the result was that nothing worked. Luckily I noticed a rattle in the pipe when dismantling, and found the little ..... Loctite is good stuff ! To check this the main power valve cover ( at the front ) will need to come off

 

[2005RM250OWNER]

Hey I checked the power valve with the right hand-side cover off. The valve opens fully at high rpm and closes again when the revs slow down. The new jetting dosen't seem to have made any difference and neither does the change in fuel or the new 32:1 premix. I can't see that the static ignition timing will be out as the engine runs fine from idle to mid throttle/rpm. I think it therefore must be one of the following:
1. CDI unit
2. Power Jet
3. Ignition Coils
and maybe but not sure, the throttle position sensor.

It was a bit crisper than before due to the changes in fuel and jetting but no hit top end!!! :fft:

I will be taking the bike back to the dealer on saturday and getting them to sort it. I would carry on further with fault finding but I don't think I should have too, considering it's a brand spanking new bike, that cost me £4000. They'll have to sort it or I'll be looking for a refund. I really enjoy motocross but this has really put a downer on it for me, I just hope this gets sorted soon.

To top things off I just spent £550 on new talon hubs and excel rims cus I ruined my back wheel on a rock landing from a jump and the front was a bit dented anyway. The problem is the new back hub has the wrong diameter axle hole, mines 20mm the new hub is 25mm!!, so no riding for a while again!!! Thanks again for your advice,

Regards, Ashley.

 

[muddy226]

Good luck with it, it would be interesting to know the results.

 

[2005RM250OWNER]

I checked the throttle position sensor resistance earlier at full throttle and closed throttle, the results were not with in the resistance ranges stated in the manual!
So I'll start with replacing that.

I also check the Power Jet/solenoid across a 12V battery and it opens and closes fine. Lets hope the throttle position sensor fixes it. It makes sense if the CDI unit is not sensing full throttle, therefore it won't advance/retard the timing and I presume the power jet won't open unless full throttle is detected?

Oh let's see how easy it is to get a throttle position sensor for a 2005 Suzuki RM250 on a Saturday!!!

Regards,

Ashley.

 

[kart]

what about stator & coil.

 

[2005RM250OWNER]

Hey all, after returning the bike to my dealer, they had the bike for a week and said they had fixed the problem. They said it wasn't running the optimum spark plug, so they replaced it with a BR8EG. I've got the bike back and it still feels exactly the SAME!!!

I don't know, am I expecting too much from a 250? I thought the thing would be an animal. My KX125 in 6th gear pinned will go past the Suzuki in 5th gear also pinned! I thought 250's were a lot quicker than 125's? Any one know of a good pipe/silencer combo to give me more top end and more power?

Cheers, Ashley.

 

[Danger]

Check out this thread for interest re the TPS wiring.

http://www.allthingsmoto.com/forums/showthread.php?t=16709

 

[2005RM250OWNER]

My bike makes that exact same noise coming down to idle, a rev from the motor and just as it settles down it goes bing......bing......bing. I also found the TPS resistance was iffy. Even though I got it back from the dealer and they said it was all fine. I'm running out of ideas of how to remidy this. Like I said I have a KX125 '01 and I love that, but this RM is not quick enough for me and where it stops reving you creep up to the fuel tank just before you change gear, so it makes it very hard to ride. Also with the jumps the bing......bing.......bing does make the rear wheel drop when it doesn't need to so it feels uncomferatable to jump. I'm gonna ring Suzuki GB again and see if I can get more help.

 

[2005RM250OWNER]

Phoned Suzuki, got to return the bike to the dealer again on Friday!!! I hope they can fix it soon!!!

 

[kart]

rm250

if it were me id try a full set of electrics on it.
plug cap, coil, stator & ecu <cdi>.
sometimes even though all of the above test out ok on an ohm meter ,under load they can break down.eg coils stator.
have had this myself with a yz250.surely there is some warrenty with the thing?? :p

 

[2005RM250OWNER]

I was told that MX bikes come with no warranties due to the fact that they are competition bikes. But I'm sure I still have consumer rights if the product is not fit for the purpose that it is intended for. If it drags on anymore I'm gonna give the dealer an ultimatum, new bike or full refund. I wouldn't mind but the bike was brand new and I've put like 12 hours on an engine that have not been enjoyed, so I think a new bike maybe the only option soon.

Regards,

Ashley.

 

[Kawi4life]

Lawl... A KX 125 smoking a RM 250... Should of stuck with a KX. :laugh: