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2004 RM 125 NEED HELP!

By rmwoods,
in Suzuki 2 Stroke

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rmwoods

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I have a 2004 rm 125 that is seriously lacking bottom end power. I want to wheelie but it won't lift without frying the clutch. Is this just a thing with rm 125s? I know that a yz won't have this problem. If anyone can tell me how to improve this it would be highly appreciated. Thanks

Also i just recently blew it up trying to wheelie lol. (Needed a rebuild anyway)

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rmwoods

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You answered your own "question". Read your post and therein lies the answer.

What do you mean? Will a new top end really do that much? I was curious if there's anything else i can do. I have a bigger rear sprocket but it's too big.

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Rising Star

78SuzyQ

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well theres not much to say about this the motor is blown, you said it needed a rebuild anyways means that the compression was down and you couldn't get the power you were looking for you replaced the clutch and rode the clutch til your motor couldn't keep up

 

you could have had tuning problems to begin with and that could have added to the final result

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rmwoods

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well theres not much to say about this the motor is blown, you said it needed a rebuild anyways means that the compression was down and you couldn't get the power you were looking for you replaced the clutch and rode the clutch til your motor couldn't keep up

you could have had tuning problems to begin with and that could have added to the final result

Alright thanks for the help

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Grand Master

KPRacing

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PM me if you want that bike to straight up rip.

For 2004 suzuki redesigned the rm125 engine. All good improvements except for one mistake.

The rod was lengthened by 8mm (not a bad thing) but the crancase volume was not correctly reconfigured. It has too much crancase volume which seriously hurts lower rpm throttle response. Even the lower midrange is a bit weak.

The large crankcase volume is like having a low compression head only it affects crancase pressure as the piston approaches bottom dead center. As the piston opens the transfer ports, this lower pressure hurts port velocity through the transfer ports which results in a lazy powerband until piston speed increases & the exhaust pipe comes into tune. I correct the crankcase volume as well as alter how the air flows through the cases to the transfers (as well as cylinder, head, & intake manifold work). This work results in a tremendous gain in usable power. A true 125 with this work will absolutely pound on a bigbore that doesn't have this work.

An fmf factory fatty (with a shorty silencer) & a radvalve are helpful to "beef up" the torque of this narrow powerband. The pro circuit pipe is a dud on this bike. If you can swing the extra cash, the Italian company "messico racing" makes a really good pipe too.

The rm 125 is a killer bike with handling second to none. It just needs that anemic powerband beefed up.

Edited by KPRacing
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rmwoods

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PM me if you want that bike to straight up rip.

For 2004 suzuki redesigned the rm125 engine. All good improvements except for one mistake.

The rod was lengthened by 8mm (not a bad thing) but the crancase volume was not correctly reconfigured. It has too much crancase volume which seriously hurts lower rpm throttle response. Even the lower midrange is a bit weak.

The large crankcase volume is like having a low compression head only it affects crancase pressure as the piston approaches bottom dead center. As the piston opens the transfer ports, this lower pressure hurts port velocity through the transfer ports which results in a lazy powerband until piston speed increases & the exhaust pipe comes into tune. I correct the crankcase volume as well as alter how the air flows through the cases to the transfers (as well as cylinder, head, & intake manifold work). This work results in a tremendous gain in usable power. A true 125 with this work will absolutely pound on a bigbore that doesn't have this work.

An fmf factory fatty (with a shorty silencer) & a radvalve are helpful to "beef up" the torque of this narrow powerband. The pro circuit pipe is a dud on this bike. If you can swing the extra cash, the Italian company "messico racing" makes a really good pipe too.

The rm 125 is a killer bike with handling second to none. It just needs that anemic powerband beefed up.

So how would i go about getting this work done. It sounds like a very expensive process and I wasn't looking to break the bank.

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Grand Master

crider400

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I have a 04 Rm 125, it felt like it was bogging often more than a 125 should so i re jetted it leaner, it ran cleaner and i got the plug to a brown/ slightly black and it would still boging coming out of corners so i took pv cover off and it was not moving so i did a re-ring on piston/ head o-rings - (check ring end gap) and cleaned pv (lot of chunks in there) and ran 1/1 fuel 107/91 and the bike ran flawless after that! wheelied out of corners and bike was crisp! ran 32:1 with vp. Put 10 hrs on track with stock pipe then put a PC header on and rode the bike and noticed a huge improvement with the mid-range and top end. Remember on 125's, you have to keep the momentum up!   :banana:

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Grand Master

KPRacing

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Lol hopefully not!

The factory fatty makes more torque (broader powerband) than the pc.

A messico racing pipe makes good torque & pulls good in the overerev but they are pricey. They are an Italian company.

Edited by KPRacing
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dbrunski125

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Lol hopefully not!

The factory fatty makes more torque (broader powerband) than the pc.

A messico racing pipe makes good torque & pulls good in the overerev but they are pricey. They are an Italian company.

You sound like you really know motor work. Specifically latest generation rm 125 motor. Would you say the boyesen rad valve is better then the v force reed cage. Specifically for the 04 rm 125?

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