01 suzuki rm125 problems

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foxracing7790

Member

Oct 9, 2008

17

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• Oct 10, 2008

• #1

im posting this on request from my brother. he recently bought a 2001 rm 125 and is having trouble with it running to rich. the previous owner but a bigger jet in it but we dont know what size, the needle is on the 1st clip, he's running a 32:1 ratio mix, and the filter is alil dirty but even when it was new we still had this problem

any suggestions??

-Justin

 

R

rmc_olderthandirt

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Apr 18, 2006

1,533

8

• Oct 10, 2008

• #2

You said "first clip". Would that be the top or bottom position?

If the clip is in the bottom position that would raise the needle, which would make it run rich. Try lowering the needle to lean it out.

If you take the carburetor apart the main jet will probably have the size stamped in it. A repair manual should tell you what the stock jet is or the online parts diagrams will often tell you what stock is.

If the air filter is dirty, clean it! Expect to do this after every ride.

My questions to you is: How do you know the bike is running rich?

Rod

 

F

foxracing7790

Member

Oct 9, 2008

17

0

• Oct 10, 2008

• Thread starter
• #3

the bike is blowing out oil from the pipe and smoking bad. the needle is on the 1st clip from the top. im not sure on the size of the bigger jet yet until we take it apart again

 

H

huskey89

Member

Jul 27, 2008

52

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• Oct 10, 2008

• #4

well it is a two stroke, so oil and smoke are not all bad

 

F

foxracing7790

Member

Oct 9, 2008

17

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• Oct 13, 2008

• Thread starter
• #5

that is true but oil is blowing out while riding it but when done riding oils pours out the silencer.. any suggestions?

-Justin

 

robwbright

Member

Apr 8, 2005

2,283

0

• Oct 13, 2008

• #6

Take the carb apart, clean it, find out what jets are in it, start with the pilot, go to needle and main. . .

The jets are stamped to show you which ones they are.

It's not as difficult as it sounds.

 

F

foxracing7790

Member

Oct 9, 2008

17

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• Oct 13, 2008

• Thread starter
• #7

we checked it today and the main jet is 460 the needle is on the 2nd clip from the top, cleaned the filter, and carb, carbon fiber reeds. run alot better and smokes perfect but oil pours out the pipe after 5min of riding.

suggestions??

-Justin

 

whenfoxforks-ruled

Old MX Racer

~SPONSOR~

Oct 19, 2006

8,129

2

Merrillville,Indiana

• Oct 13, 2008

• #8

Is it premix billowing out of the pipe, or trans fluid and premix?

 

F

foxracing7790

Member

Oct 9, 2008

17

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• Oct 13, 2008

• Thread starter
• #9

not to sure. its real dark and runny

 

whenfoxforks-ruled

Old MX Racer

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Oct 19, 2006

8,129

2

Merrillville,Indiana

• Oct 13, 2008

• #10

Choice a) buy a leak down kit. b) make one. c) take it to someone that has one. You can not jet a bike with issues. Adjusting the premix is foolish at best.

 

C

Chili

Lifetime Sponsor - Photog Moderator

Apr 9, 2002

8,062

17

• Oct 13, 2008

• #11

Pretty sure the 460 is the stock main jet for that bike, RM125's were generally very rich from the factory. Odds are if the rider isn't really screaming that bike you will need to lean it out significantly on all circuits.

 

F

foxracing7790

Member

Oct 9, 2008

17

0

• Oct 13, 2008

• Thread starter
• #12

ok sweet. if we do adjust the premix what should we try?? were mixing 32:1 right now
how much is a leak down kit??

 

F

foxracing7790

Member

Oct 9, 2008

17

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• Oct 13, 2008

• Thread starter
• #13

the previous owner said is changed the jet from stock to the 460 cuz it was running to lean

 

whenfoxforks-ruled

Old MX Racer

~SPONSOR~

Oct 19, 2006

8,129

2

Merrillville,Indiana

• Oct 13, 2008

• #14

Leak down 101, priceless! http://www.motionpro.com/tech/articles/leak_down_tester_101/

 

C

Chili

Lifetime Sponsor - Photog Moderator

Apr 9, 2002

8,062

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• Oct 13, 2008

• #15

Leave your ratio at 32:1 and change the jetting, chasing poor jetting by playing with the mix ratio is a waste of time.

Everything I've found online and from memory that 460 is the stock main jet regardless what the previous owner told you. There isn't an RM125 made since 2001 that needed a richer main jet stock unless it had mechanical issues it was trying to compensate for or hide. In their jetting specs FMF recommends a 450 main for the 01 while PC and Bills recommend a 430 and MXA recommended the stock 460.

 

0

01zuki

Member

Oct 14, 2008

3

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• Oct 14, 2008

• #16

i am the own of the bike that foxracing is talking about. the bike does have the stock 460 main jet in it. carbon reeds mixing 32:1 amsoil domintor. the air screw is at 2 turns out. filter is clean. the biek runs perfect and fast. doesnt smoke hardly at all except when you really get on it. i ride the bike hard constantly. the problem im trying to figure out is why this oil is oozing out the tail down the pipe? i just hate cleaning up the mess it makes on the swing arm. thanks TK

 

J

_JOE_

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May 10, 2007

4,697

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• Oct 14, 2008

• #17

The mess is unburnt fuel. Rich jetting or a leaking crank seal will cause excessive "spooging". The amount of premix you put in the gas has very little to do with this. Most likely you are several steps too rich on the main jet as you say it seems worse on hard acceleration. Your altitude, temp and humitidy, along with fuel type will affect the jetting. Going off what a magazine says might put in the nieghborhood, but I would suggest going to the shop and buying a few smaller main jets. Keep dropping the jet size until the bike quits making more power and the smoke decreases. Then put in a new plug and do a chop test. If you're familiar with that do a search for "plug chop test". This will ensure you aren't too lean and will tell you exactly how it's running.

A leak-down test should be done prior to tuning the carb. If you pull the tank it shouldn't cost much at all to have a shop do it up for you.

 

0

01zuki

Member

Oct 14, 2008

3

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• Oct 14, 2008

• #18

alright thanks. i'll try to make it to get some main jets soon. any idea how far down most people run theirs?

 

J

_JOE_

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May 10, 2007

4,697

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• Oct 14, 2008

• #19

Unless those people are where you are, thier jetting will be different. Usually people end up modifying something by the time a bike is a few years old, so most peoples jetting will be different than stock anyway. Without actually trying a different jet or doing a plug chop there's no way to know if it's right. I would get three smaller jets to start, a 450, 440 and 430. Start with the 440 and ride it for a while. Get a feel for the way the bike pulls in the top end. Once you get used to the feel, swap to the 430. If it continues to rev quicker and pull harder, do a chop test to see what the mixture ring looks like. If it's still thick, go see if you can trade the shop where you got the first three jets, one or two of those for a couple smaller. I would watch the plug closely and chop one with each main change if you get any leaner. Buy a box of plugs while you're at the shop. :cool:

 

0

01zuki

Member

Oct 14, 2008

3

0

• Oct 14, 2008

• #20

sweet, thanks everyone. hopefully i can get it runing better or perfect.

 

M

Matt Fisher

Member

Apr 17, 2002

136

0

• Oct 16, 2008

• #21

Keep in mind that pump fuel will sometimes cause pipe drool. Jet the bike based on what the plug reads, or use the oil line method. Using pump piss and leaning it out until the drool stops may be a recipie for a 1-piece piston and cylinder.