2003 suzuki RM125. More Power Needed

[Jonny Whyte]

Hi all. im looking for some way to get more middle to top end power. I have been looking about and I seem to be getting the idea that the pro circuit works pipe is the way to go or is there any other way to get this power apart from exhausts. What do you's think is the best option?
Thanks

 

[marcusgunby]

Some aftermarket pipes do work on the 03 rm125, i would advise against a v force as they are hard to jet right.A 2004 top end would work the best but that would be alot of work(including new crank)

 

[flyinzuki]

oops!

 

[KDXman_88]

send the cylinder to eric gorr and have him port it to more mid to top and get a fmf rev pipe that and a power core II.. all of that should do the trick

 

[sodflyer]

Althoug my bike was....still is not jetted right ( working on it) when I installed the PC pipe I gained on the low end and then I installed the new Vforce 3 reeds and I gained again on the low end... I have to say it's got more now than it did down there....now to get this jetted right to gain even more :) good luck! Jeff.

 

[highflyernick]

If you wanna race, bore it out to 134, get new pistons while your at it. PC pipe and silencer, V-force reeds.....other stuff you could do too, thats just main stuff....

 

[Chili]

My son raced an 03 RM 125 this season so I'll offer what we have gone through so far. The first thing you need to do if you haven't done so is work on the jetting with that bike. Based on your stated location you would have received a bike with "Rest of the World" jetting specs instead of the USA specs. Stock is a 560 main and 40 pilot for RoW specs and is so fat that bike runs terrible. I would never tell you to change to my jetting since we are in different parts of the world, diff fuels etc but to give you an idea how far off the jetting was for us I am now at a 460 main, 35 pilot and 1 up on the clip.
As far as pipes go the only 2 we have run is stock and an FMF SST with a shorty silencer. Every person who rode the bike back to back with stock felt the SST combo gave the bike a bit more mid to top with a lot more overrev. We had a bit of detonation going on with this combo and have since upped the octane level for the bike.
The only other change we made to the bike was gearing and are now running 12/51 (12/49 stock).
We've never felt this bike was lacking in mid to top so I'll ask if everything is kept fresh (piston, rings etc) The only short coming I felt on this bike performance wise was on the bottom but that is pretty much any 125 2 stroke.

 

[Jonny Whyte]

How big of a difference did the pipes make? We are thinking that we would need to get the barrell reported and everything to get the proper effectiveness of the pipe. What positions was your son getting in the races he was doing or in other words was the difference in speed noticable from watching him ride? So far as jetting goes we havn't had a problem with it at all but as you say its due to the different areas we are in.

 

[marcusgunby]

Heres a pipes dyno for a KTM-its not the rm but it gives a idea of the differences a pipe can make.

 

[Chili]

My son was running near the top of his class but it was essentialy the C class level. To be perfectly honest I don't feel the pipes would have gained or lost him any positions but it did help some when he got too lazy to get that last shift in on a straight. The biggest difference was getting the jetting spot on and gearing.

 

[Jonny Whyte]

Ok thanks for the info. We might actually try the different gearing because I'm only 15 and still learning about all these things and I dont know how different gearing setting will feel.

 

[Chili]

Stock was 12/49 we tried 12/50 and 12/51 and my son preferred the 12/51 as it made it easier for him to keep it on the pipe through corners and to get a decent drive for jumps right out of corners.

 

[tony250]

sorry to be blunt but buy a 250

 

[Chili]

So he's 15 and looking for a little performance boost on his 125 and the blunt answer is get a 250? You have no knowledge of his size, riding experience etc but your certain he needs a 250? :think:

 

[Shig]

Ok thanks for the info. We might actually try the different gearing because I'm only 15 and still learning about all these things and I dont know how different gearing setting will feel.

You can trust Chili. A different rear sprocket is the most economical way to dramatically change your bike's performance. The best part is that it is easily reversible. You could spend hundreds doing irreversible changes like porting and head mods, only to find out that your lap times were faster when the bike was stock. I'm not saying that motor mods won't make a good bike even better. Its just that until you know exactly what you need its better to take baby steps with respect to modifications.

 

[bclapham]

So he's 15 and looking for a little performance boost on his 125 and the blunt answer is get a 250? You have no knowledge of his size, riding experience etc but your certain he needs a 250? :think:

i think he is sorry for being blunt, since he is not the sharpest knife in the draw! :eek: :eek: :rotfl: :rotfl: