2003 rm 125 tuning/jetting, who knows a lot about

[trialsmasta]

Does anyone know any race shops that deal a lot with RM 125’s? I need some hop up tips. But right now I need help with the following.

JETTING
I have a bone stock 2003 rm 125, and live in Austin TX which is at about 700 feet, and the temperature right now is about 95deg. I run Maxima super M oil @ 32:1 with pump gas and run the following jetting
Main: 440 Stock 460
Clip: 2nd Stock 3rd
Pilot 37.5 Stock 40

And I still have black oil coming out my silencer. The bike sounds crisp and I’m not sure where to go leaner. My friends told me I could run 40:1 but Maxima says to run 32:1. Does anyone have any jetting for my altitude and weather?

SUSPENSION
I weigh 170lbs without gear and I’m at about a novice level rider. The rear of the bike seems to ride really low in the travel. I have 95mm sag, 1 1/4 turns out on HS compression, 8-9 out for LS compression. The bike seems to bottom out, but there aren’t any tire marks under my fender, so I’m a little weary about going in on the compression. I’m told for my weight the stock 4.8 or 4.9 (can’t remember) should be fine, so how do I get rid of that mushy feel?

GEARING
I hear that people have been adding a tooth to the rear, if you have done this what chain length did you run?

 

[endurohero]

unfortunatly 03 rm 125 has a tad high compression to run pump gas even if you use 94-96oct pump gas re-check you jetting spec after useing race gas min 104ron.you might find your in the ballpark.

 

[Jman271]

www.bills-pipe.com They know RM's up and down,,,

 

[Luft]

I run the same jetting and am convinced the pilot is still too rich.

Try setting the race sag to 100 mm and measure the free sag. I use the rule of thumb to go heavier on the spring if the free sag is less than 30 mm.

I noticed the the front end was too soft and rode too low so I run heavier springs. I'm still experimenting so I've run all the clickers all the way out to see what everything feels like and will be dialing in my setup.

One tooth larger on the rear is also on my list after the stock chain and sprockets are finished because I really need to feather the clutch to get going.

Watch your spokes (I invested in a Fasstco spoke torque wrench) especially the ones on the front and make certain your wheels stay true. I also run a twin air filter.

 

[marcusgunby]

I would try a 35 pilot.As for the rear riding low-on the one i rode it rode high in the stroke-maybe a service is needed to ensure its working correctly.

 

[bigred455]

You will notice that when Bills or fmf or pro circuit give jetting specs ,it is usually stock or not a very big change. You see they are protecting themselves because they know that their are too many things too consider. So they will not venture off to far from stock when giving jetting specs.Find out for yourself.

 

[trialsmasta]

Originally posted by Luft
I run the same jetting and am convinced the pilot is still too rich.

Try setting the race sag to 100 mm and measure the free sag. I use the rule of thumb to go heavier on the spring if the free sag is less than 30 mm.

I noticed the the front end was too soft and rode too low so I run heavier springs. I'm still experimenting so I've run all the clickers all the way out to see what everything feels like and will be dialing in my setup.

One tooth larger on the rear is also on my list after the stock chain and sprockets are finished because I really need to feather the clutch to get going.

Watch your spokes (I invested in a Fasstco spoke torque wrench) especially the ones on the front and make certain your wheels stay true. I also run a twin air filter.

Hey Luft, how much do you weigh and what level rider are you? I’m about 170 and novice level and the front feels sweet. I just went up one click on the compression. The rear on the other hand is still a battle. I was actually thinking of going to one turn out on the HS compression and maybe a click or two more in on the LS compression. I called Factory connection and they thought the stock rate should be fine.
I was wondering about the pilot but I don’t know too much about jetting so I’m going to try running 40:1 (Pro- Circuit) recommendation instead. Are you plagued by the oily drool out the silencer too? What altitude and temperature are you at. If you try that 35 pilot out let me know how it works.
I’m running a mutli-air filter and I don’t think it’s a good as the OEM one, but for $11 I can’t complain. Stay away from the acerbis airbox cover it’s a piece of ****e. If your are gonna buy one get the twin air one. Makes washing out the airbox a breeze.

I still need to know what chain length to run if I add a tooth to the rear sprocket.

Does anyone know of race shops that deal a lot with Suzuki’s?

 

[Luft]

Try RG3 for spring rates and settings. They will probably tell you to run heavier springs. I'm 6'5' weigh 235 and run .46 front and 5.5 rear. I was running .46 and 5.8 but the front would stink bug or ride too low, this solved the problem for me.

Where are your forks set in the clamps? If they are all the way down in the clamps you might try putting them in the middle position and remeasuring your race sag. Less weight will be on the shock when you do this so it should feel a little more firm. Measure the race sag and free sag as I suggested before moving the forks and afterwards.

I'll order the 35 pilot tomorrow and have it in a week or so. I'm in Florida at sea level with major humidity. It can be 95 degrees, rain, and then be 77 degrees.

 

[Luft]

I replace the chain and sprockets as a set. After installing the sprockets I set the wheel where I want it to be and wrap the chain around the sprockets to determine where it needs to be cut.

Changing the premix ratio from 32:1 to 40:1 will actually create a richer air fuel ratio in the carb. All the oil is not being burned off probably due to the rich pilot circuit. I've been running 1-1/2 turns out on the pilot and it really blubbers. I will try 2, 2-1/2, 3, and 3-1/2 turns out and test with 1/8 to 1/4 throttle turns. If I keep turning the airscrew out and eventually the pilot circuit will clean up. I'll do this before installing the 35 pilot. You canexperiment with the pilot like this to see if the 37.5 pilot will clean up.

 

[bclapham]

go with the 35 pilot, these suzukis run real rich on the pilot. i friend with the stock 02 went from 32.5 (stock) to 27.5.

on my 02 i am trying a 22.5 and a 20 pilot today and hopefully a leaner needle at the weekend. but my 02 is no normal 02!:p I am wondering if these bikes need a leaner slide?

 

[Luft]

I've got 4 turns out on the 37.5 airscrew. So I've ordered the 35 and 30 and will continue testing. There seems to be some hesitation between 1/4 to 1/2 throttle and another 1/2 step leaner on the slide may improve the response. I usually just wind the rpms and feather the clutch, but with proper tuning I may be able to roll on the throttle and save the clutch. Obviously many of the magazines have missed thw whole point of tuning these bikes properly. Some of the best bikes I've ridden were well tuned and adjusted stock bikes.

 

[trialsmasta]

Well I spoke to the boys over at WMR racing www.wmr1.com I think is their website. The guy I spoke to said they are running 430 main, clip in 2nd, and a 40 pilot. Florida and 95 deg, I told him about my 37.5 and he said they only run that for the more novice level rider i.e. me. He said with there testing the 37.5 was too lean. I guess if there fast guys can get away with a 430 main I might try the same.

 

[Luft]

Today the temp was 80 degrees F and 84% humidity. 2-1/4 turns out on the airscrew (37.5 pilot) worked good. The engine was very responsive off the bottom. Still got drool out the back so I ordered the 430 main cause I know it's too fat on the top. There is a very good article at Transworld MX in the how to archives "Race Shop: All Bogged Out" where Randy Lawrence shows how to tune the pilot circuit.

 

[bclapham]

just out of interest, can you guys tell me what the stock needle and slide cut out is for the 03rm125?

thanks

 

[Luft]

03 RM 125 Standard carb settings

Main jet: #460
Jet needle: 6BGY27-77-3rd
Pilot jet: #40
Air screw: 1-1/2 turns out

 

[bclapham]

Luft: its the slide # i am interested in. The stock 02 came with a 32.5 pilot that ran really rich on a #5 slide. so i am trying to understand what was changed to enable them to run a 40 stock pilot in 03??? I wonder if it was the modifications to the airbox and side panels that some of the mags were talking about???

thanks
BC

 

[Jawsrm134]

Had some problems jetting my sons 03 RM 125 and My 03 RM250. Race Gas fixed them both. If you have it close with pump gas try race gas. 110 octane.

 

[Luft]

bclapham you might double check the 01 spec
01 slide 5.75 mm
03 slide 5.00 mm according to the manual
my jets arrived today.

 

[bclapham]

hmmmm, thanks Luft.: so why does the 03 start off with a bigger pilot? i see the needle is the same, maybe they changed the nossle?????

btw- the smallest pilot jet for this model carb i have found is 25- i got a 20 and a 22.5 you can identify them since they dont have the band machined in- the only difference i could see with the jet is that the tube with the lateral holes drilled in is 0.5mm narrower- i wonder how this affects carburation.

btw- when i took the slide from my 02 it just had #5 stamped on it, which i assumed was 5mm, anyone care to correct me on this?

 

[bclapham]

here is something i just comiled- its interesting that Bills ran a richer pilot with a different needle- i understand these are just guides, but its interesting to see the trends.

RM 125 (01)

P M Needle Slide A/S
STOCK 27.5 460 6DGY23-75 3RD 5.75 none 1.5
FMF 27.5 450 6DGY23-75 2ND 5.75 none 1.5
Bills 32.5 430 6BGY-24-76 2ND

RM125 (02)
STOCK 32.5 460 6BGY27-77 3 Not listed 1-1/2
FMF 27.5 430 6BGY27-77 2 1-1/2
Bills 30 450 6BGY27-77 2

RM125 (03)

FMF 37.5 440 STOCK 3RD 1.5

 

[Luft]

I had forgotten I was running a 430 main already.
My specs at 86 degrees with 64% humidity:

430 main
stock needle 2nd clip
35 pilot jet
2 turns on airscrew

It felt a tad lean on the bottom but would probably be different with a touch more heat and humidity. And perhaps another 1/2 turn in on the airscrew would help and/or running the clip in the 3rd position. Will get race fuel this weekend. It's usually always at least 90% humidity here and now that I decide to do some tuning the humidity is messing with me.

 

[trialsmasta]

Hey has anyone tried a v-force on their bike yet? Was it worth the money?

My set up from last weekend, no oily drool out the pipe at all. It was a sandy hilly track, WFO most of the time 97 deg, not sure what the humidity was.

Maxima super M oil, 32:1, Pump gas with PJ1 octane booster, 1 oz, per gallon
440 main,
Clip in 2nd
37.5 pilot 1.5 turns out.

Plug color, burnt orange/clay color might be a smidge rich, but I like to play it safe.

I'm definitly droping a tooth in the rear sprocket when this POS stock chain is dead.

 

[Luft]

Revised jetting with C-12 fuel and Motul 800T 40:1
430 main
clip 3rd position
air screw 1-3/4 turns
37.5 pilot

The 35 pilot was too lean and bogged on the bottom. The 37.5 is perfect with no bog or hesitation.

 

[Chili]

I can't wait until I have some time this week to actually break in Troy's new 03. He's been at the cottage with his grandparents so we haven't even kicked it over yet :think: After reading this thread and then reading the manual for our new 03 I was shocked to find out that our bike comes setup for "rest of the world" and not the USA setup, what's the difference you ask? We get a 560 main :scream: a 40 pilot and the next richer needle in the second clip position :think:. In the parts kit we get a 460, 490, 520 and a 600 main jet. Most of the guys I have talked to here with the 03's said they were running a 500 main with a few guys using race gas and a 480 main.

 

[bclapham]

chilli: remember the mains come in 10's, so be carefull since you can make some big changes with the jets supplied. I think the pilot willl need some attention also, so stock up on brass!:)

enjoy this bike....it rips!