RM125 2001 RM 125 problem (only runs good after 1/4 to 1/3 throttle)...carb issue?

B

badseed

Hello everyone....

I need a bit of advice with my son's (new to him) used 2001 RM 125....

I have zero background on the bike.(but I got the bike for next to nothing)

What I have did to the bike:
#1. put a fresh top end on it...
#2. new clutch
#3. new plug
#4. new air filter
#5. cleaned the carb
#6. fresh gas of coarse :silly
(running 32:1 premix)

The bike starts on the first kick (cold or warm engine) with no choke....
in neutral it runs and idle's fine...However, once in gear it runs like crap until about 1/4 to 1/3 throttle....once past the 1/4 to 1/3 throttle position it runs like a bat out of hell....I'm also getting (spooge?) coming out of the silencer...

when I say "runs like crap" it's just all loaded up (I don't want to say it "bogs" it just runs all loaded up until past that 1/4 to 1/3 throttle position) then it clears up and runs like a bat out of hell...once you slow down it does the same thing again until past that 1/4 to 1/3 throttle position....

It won't climb the smallest of hills...It loads up and stalls....(unless it's above that 1/4 to 1/3 throttle position(into the powerband)....

I have a cement slab in my yard that sticks up above my grass about 3 inches...pull the bike up to it and from a stop I can't get the bike up over the slab without revving it like crazy and feathering the clutch and then it's almost next to impossible to even get up over the 3 inch cement slab because the bike "runs like crap at low throttle positions"....

also....The air/fuel mixture screw has zero effect on the engine....If I turn it in all the way it will kill the bike....if I turn in out it has zero effect on the bike no matter how far out I turn it....once the bike is running turn the choke on and the bike will die...

with the way it runs and the spooge coming out of the silencer I'm thinking pilot circuit is running rich???

bike is stock with stock jetting....

what do you all think?

any advice/opinions are greatly appreciated....
 
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PALMER84ONE

PALMER84ONE

I think you still have and obstruction in the pilot circuit of the carb. You say cleaned carb, did you replace jets? Bikerchickltd on eBay sales a great kit for under 30.00 delivered. Has everything you need and seals/o-rings/etc.
also, spooge can be a little of everything, timing, mix, mix type, packing, pipe, etc. used bike so replacing with new everything rules out old stuff.

Air screw may be damaged, can't mash them in to hard and the kit will give you a new one.
 
B

badseed

PALMER84ONE:
I think you still have and obstruction in the pilot circuit of the carb. You say cleaned carb, did you replace jets? Bikerchickltd on eBay sales a great kit for under 30.00 delivered. Has everything you need and seals/o-rings/etc.
also, spooge can be a little of everything, timing, mix, mix type, packing, pipe, etc. used bike so replacing with new everything rules out old stuff.

Air screw may be damaged, can't mash them in to hard and the kit will give you a new one.
Click to expand...


No, I haven't replaced anything in the carb yet....wanted to make sure I was on the right track first....

I took the carb completely apart, soaked it over night, sprayed all passages and jets with carb cleaner(with the little red tube the can came with) and then again with my air compressor, and re-assembled it...and it made no change in the way it ran....had someone tell me go one size smaller on the pilot jet....so before buying the carb kit or a smaller pilot jet I figured I'd pop in here for a 2nd opinion first :wink:

my local bike shop here in Michigan has that same rebuild kit for $28 (in stock)...However, I gave it a real good cleaning and with someone telling me go one size smaller on the pilot jet I wanted that 2nd opinion before I bought the rebuild kit with the same size jets in it....the silencer repacking is already on my list of things to buy was just waiting on the 2nd opinion and I was planning to buy everything at the same time...

for $28 I guess that's my best bet to start with....then I'll go from there.....

Thanks for the reply and the warm welcome to the forum :thumb:
I'm going to go grab the rebuild kit and I'll post the results once It's rebuilt and test ridden.....(if all goes well I'll have an update by tomorrow night)....

Thanks again!!!
 
AdamRides87

AdamRides87

badseed:
No, I haven't replaced anything in the carb yet....wanted to make sure I was on the right track first....

I took the carb completely apart, soaked it over night, sprayed all passages and jets with carb cleaner(with the little red tube the can came with) and then again with my air compressor, and re-assembled it...and it made no change in the way it ran....had someone tell me go one size smaller on the pilot jet....so before buying the carb kit or a smaller pilot jet I figured I'd pop in here for a 2nd opinion first :wink:

my local bike shop here in Michigan has that same rebuild kit for $28 (in stock)...However, I gave it a real good cleaning and with someone telling me go one size smaller on the pilot jet I wanted that 2nd opinion before I bought the rebuild kit with the same size jets in it....the silencer repacking is already on my list of things to buy was just waiting on the 2nd opinion and I was planning to buy everything at the same time...

for $28 I guess that's my best bet to start with....then I'll go from there.....

Thanks for the reply and the warm welcome to the forum :thumb:
I'm going to go grab the rebuild kit and I'll post the results once It's rebuilt and test ridden.....(if all goes well I'll have an update by tomorrow night)....

Thanks again!!!
Click to expand...

I have heard if you can start the bike (cold start) WITHOUT the choke on there is a problem with the pilot circuit. Shouldn't be able to start without the choke on
 
B

badseed

2strokesteve89:
off throttle bog, id also be looking at dropping the needle, one position and recheck.
Click to expand...

Go one size smaller on the pilot jet and raise the needle clip one position was what I was told.....I came here for the 2nd opinion....It appears I got that 2nd opinion now :thumb: going to grab the carb kit and the one size smaller pilot jet along with some new silencer packing in the morning....will for sure post the results tomorrow evening after the test ride....

Thanks for the reply 2strokesteve :thumb:
 
B

badseed

The forums are back up :banana:

Quick update....

got the carb rebuild kit and I rebuilt the carb today... ( but I broke the cardinal rule....and made two changes at once)....I went down one size on the pilot jet and raised the clip one spot on the needle (went from stock 3rd middle clip position and raised it to the 2nd clip position)....The bike runs like a totally different bike....climbs hills now and it wouldn't start cold without using the choke :thumb: my air screw now works but it's not a very noticeable change when adjusting it.....
It was ridden for about a hour tonight and "almost" no spooge out of the silencer :clap: )

My son loves it and says leave it how it is....but me (dad) am not done tuning it yet :ride:......
So, I'm going to pick your brains a bit more if that's ok....


It runs GREAT from idle through 6th gear "if" you stay on the throttle.....

I found this (below) from some internet searching....would you agree with the below statements?

________________________________________________________________________________________

On a 2-stroke - You should be able to ride in 3rd gear, throttle BARELY cracked open, and it should cruise smoothly. If it sputters and crackles, the pilot is too rich. If it bogs, the pilot is too lean.
(The bike runs smoothly)....

________________________________________________________________________________________

Needle Clip:
On a 2-stroke - Riding in 3rd gear, with a warm engine and the throttle BARELY cracked open, roll the throttle to 1/2.
If the bike sputters and crackles, and you feel like you have to keep rolling on the throttle to smooth it out, the needle is too rich. If, on the other hand, you get the dreaded 'buhhhhhhwaaaaa', the needle is too lean.

(the bike gets the dreaded "buhhhhhwaaaa" so I'm thinking I should put the needle clip back to the stock 3rd position??? <-----that cardinal rule I broke making two changes at once).
________________________________________________________________________________________


Main jet:
On a 2-stroke - Riding in 3rd, with the throttle BARELY cracked open and cruising along, whack the throttle wide open. If you end up with a set of handlebars impacting your nose, or you loop out, the main is perfect!
If it crackles, smokes, and won't get 'on the pipe' quickly, then the main is too rich.
If it gives a 'buuuuhhhhwwaaa' sound and feels like it's sucking for air, then the main is too lean.

(the bike gives the "buuuuhhhwwaaa" should I go one size bigger on my main jet?)

________________________________________________________________________________________

again, from idle through 6th gear "if" you stay on the throttle it does run great!!!



also.....The new packing I bought for the silencer...repacking the silencer without cleaning out the pipe is defeating the purpose? How would I clean the pipe to get all that spooge out that I'm sure is still sitting in the pipe?
Or should I just leave it how it is and repack the silencer?

________________________________________________________________________________________

I'd like to thank everyone for getting me this far and I appreciate you letting me pick at your brains a bit more:hail: :hail: :hail: :thumb:
 
B

badseed

Oh....I more thing :devil:

my brand new clutch.....
I adjusted the cable just like my manual told me to....

But, I pull the clutch lever in and put the bike in 1st gear the bike don't start to move until the clutch lever is about 3/4 of the way out...shouldn't the bike start to move once the clutch lever is closer to the handle bars?

I took the side cover off and if I adjust the cable any further the (sorry I'm sure my terminology is wrong) lever inside the cover that the cable is hooked to will start to rise up...therefore pushing the rod and separating my clutch plates....that can't be a good thing to do can it? what would cause that? a stretched out clutch cable? time for a new cable???


Thanks again for letting me pick your brains :thumb:
I'm a car guy....working on these bikes is somewhat new to me.....
 
Nighthawk016

Nighthawk016

badseed:
Oh....I more thing :devil:

my brand new clutch.....
I adjusted the cable just like my manual told me to....

But, I pull the clutch lever in and put the bike in 1st gear the bike don't start to move until the clutch lever is about 3/4 of the way out...shouldn't the bike start to move once the clutch lever is closer to the handle bars?

I took the side cover off and if I adjust the cable any further the (sorry I'm sure my terminology is wrong) lever inside the cover that the cable is hooked to will start to rise up...therefore pushing the rod and separating my clutch plates....that can't be a good thing to do can it? what would cause that? a stretched out clutch cable? time for a new cable???


Thanks again for letting me pick your brains :thumb:
I'm a car guy....working on these bikes is somewhat new to me.....
Click to expand...


This sounds pretty normal, just pay attention to the clutch basket. Suzuki is known for getting heavy notches in the clutch basket causing lurching and all sort of other problems.
this is the notching im speaking of.
grooves.jpg
 
B

badseed

Nighthawk016:
This sounds pretty normal, just pay attention to the clutch basket. Suzuki is known for getting heavy notches in the clutch basket causing lurching and all sort of other problems.
Click to expand...

Ok, thank you for the reply....

It has a brand new basket, inner hub, steels and fibers....

Clutch does work perfect....no lurching, no drag, no slipping...Just thought it should start to move the bike when the lever was closer to the handle bars....

again, Thanks for the reply!
 
Nighthawk016

Nighthawk016

badseed:
Ok, thank you for the reply....

It has a brand new basket, inner hub, steels and fibers....

Clutch does work perfect....no lurching, no drag, no slipping...Just thought it should start to move the bike when the lever was closer to the handle bars....

again, Thanks for the reply!
Click to expand...
my 88 rm and my street bike are exactly the same. About 3/4 out the bike starts to move.
 
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