2000 RM125 is it the piston rings?


27 replies to this topic
  • IRIDEKTM

Posted 18 February 2009 - 09:15 AM

#1

Got a 2000 RM 125 and it is losing a little power. The bike smokes a little more then usual. I know it aint the piston itself since it starts easily and runs.

Does this sound like it needs a set of rings to yall? Or could it be muffler packing or what?

Thanks :lol:

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  • Uncle Alpo

Posted 18 February 2009 - 09:27 AM

#2

What makes you think it's losing power?

Did you just buy the bike? A fresh top end is always a good thing to do after getting a used bike.

  • IRIDEKTM

Posted 18 February 2009 - 09:50 AM

#3

My buddy just bought it and is some what clueless about the hole operation.

I dont think it needs a hole new top end just yet, plus he cant afford that overhaul. Just wondering if it would most likely be the rings or a gummy carb or something along that line before I go diving into it for him.

  • Uncle Alpo

Posted 18 February 2009 - 09:57 AM

#4

I trust very few used dirt bikes, regardless of what the PO says they did to maintain it.

Rings are a wear item and need to be replaced on a regular basis. Pulling the cylinder only costs a couple of gaskets. New rings are inexpensive if they're needed. At the very least pull the cylinder head and look at the bore - that can tell you a lot.

The exhaust valves need to be cleaned on a regular basis, too. Doing that won't cost more than a gasket or two and a little time.

If it's been sitting a while it's a good idea to pull the carb and clean the jets/passages; they could be gummed up.

Excess smoking could be caused by a number of things: too much oil in the gas, or a smokey oil used are common causes. It could be the packing in the silencer needs to be replaced; it gets saturated over time.

  • IRIDEKTM

Posted 18 February 2009 - 10:02 AM

#5

Im going to re pack the silencer today, it hasnt been since 2000. Soak the carb, blow the passages and if I get around to it I may pull the head off and look at the piston etc.

Im going to start with the repacking and carb cleaning since it only costs $6 for packing, opposed to $40 in gaskets. If that doesnt solve it Ill tell em to go ahead and get a top end, easier then doing just rings then having the hole top end go to the wall a couple rides from then.

Thanks for the help

  • Uncle Alpo

Posted 18 February 2009 - 10:26 AM

#6

You're welcome.

With the carb, remove the float bowl, remove the jets, clean the jets and their passages (carb cleaner works pretty well). I usually take the whole thing apart and clean everything really well. All you'll need are a couple of screwdrivers and a small wrench.

Repacking is easy, but messy. Wear a pair of disposable gloves. :lol:

If you're somewhat mechanically included a top end is pretty easy to do. Doing it yourself will save you some money, too.

  • IRIDEKTM

Posted 18 February 2009 - 10:54 AM

#7

I'm fairly good mechanic. Taken many carbs apart n such.

Thanks for the help again I will post back the results tonight hopefully.

I usually soak my carbs for a day or two, do you just spray the passages or soak yours?

  • Uncle Alpo

Posted 18 February 2009 - 11:39 AM

#8

I don't soak them unless they're really bad. I usually just clean the outside with mineral spirits, clean the jets, spray the passages, and sometimes chase them with a guitar string to make sure they're clear.

  • shrubitup

Posted 18 February 2009 - 01:54 PM

#9

B-12 Chemtool but wear gloves or you will loose a layer of dermis in the process.

The last time I changed my packing it was not very dirty/oily. Repacking it made no noise reduction. It was in fact - repacked too early. :lol:

  • Uncle Alpo

Posted 18 February 2009 - 02:05 PM

#10

Well, I use my packing until it's good to the last drop. If it's not Poot!ing forth streams of goo, well, you get the picture.... :lol:

  • mihylo33

Posted 18 February 2009 - 03:21 PM

#11

I haven't cleaned the carb on my KX in 8 years. The 80 I don't even think I touched the air screw not to mention even think of cleaning it. I must say that bike is a tank. 18 yrs old and only ever had a leaky fork seal.

  • Uncle Alpo

Posted 18 February 2009 - 03:27 PM

#12

I should have taken pictures of that PWK when I first took it apart. From a 2005 bike and all gummed up inside. Figure that out.

  • IRIDEKTM

Posted 18 February 2009 - 06:35 PM

#13

Alright, got the carb disassembled and soaking, hole bike disassembled, going to do a top end and hopefully call it good. I took the muffler off and the packing out, and it was seriously dripping in oil. Nasty stuff.

Hopefully have it all done by friday or saturday so we can ride sunday. Bike was a mess when we took it apart and the carb was definitly in need of cleaning, airfilter was covered. I should of taken a before picture so yall coulda seen how messy it was.

Thanks for all the help!

  • shrubitup

Posted 18 February 2009 - 07:00 PM

#14

Alright, got the carb disassembled and soaking, hole bike disassembled, going to do a top end and hopefully call it good. I took the muffler off and the packing out, and it was seriously dripping in oil. Nasty stuff.

Hopefully have it all done by friday or saturday so we can ride sunday. Bike was a mess when we took it apart and the carb was definitly in need of cleaning, airfilter was covered. I should of taken a before picture so yall coulda seen how messy it was.

Thanks for all the help!

That would've been fun to see. There's too many photos on this site of bikes where people polish every metal surface including the footpegs. :lol:

  • IRIDEKTM

Posted 18 February 2009 - 08:02 PM

#15

Haha it was a sight!

Do you happen to know if the 01- up plastics will fit this bike. Atleast the rear and front fenders?

  • IRIDEKTM

Posted 19 February 2009 - 05:39 PM

#16

Put the carb back on after cleaning and the bike actually idles. The powerband is present now as well, which it wasnt before the cleaning.


Question: when I pull the choke up if the bike is idling it kills the bike. Dont quite understand that. And on the choke plunger it says adjust idle and you can spin the top....does that actually adjust the idle, since there is another idle screw, or is that black plastic one at the top the air screw and the brass one at the bottom something else?

Long badly worded question, my apologies :lol:

Also the bike only roll starts when cold and wont kick over. My buddy is short on cash and we were going to just get rings since I think that is the problem, it is blowing white smoke still. I was wondering if the roll start when cold is a sympton of needing a new top end soon...

Thanks for the help!

I'm not a RM wiz...

  • mihylo33

Posted 19 February 2009 - 06:06 PM

#17

Put the carb back on after cleaning and the bike actually idles. The powerband is present now as well, which it wasnt before the cleaning.


Question: when I pull the choke up if the bike is idling it kills the bike. Dont quite understand that. And on the choke plunger it says adjust idle and you can spin the top....does that actually adjust the idle, since there is another idle screw, or is that black plastic one at the top the air screw and the brass one at the bottom something else?

Long badly worded question, my apologies :lol:

Also the bike only roll starts when cold and wont kick over. My buddy is short on cash and we were going to just get rings since I think that is the problem, it is blowing white smoke still. I was wondering if the roll start when cold is a sympton of needing a new top end soon...

Thanks for the help!

I'm not a RM wiz...


It only roll starts when cold and it will kickstart afterwards means the top end is shot for sure maybe more. White smoke with a grey tint or white smoke with a blue tint? if it's grey pull the plug and see if it looks funky. If it is Funky looking then you have antifreeze burning up in the cylinder. The plug doesn't always look funky when it's an inner coolant leak though. If it is blue tint then either the rings are worn or you have a crankseal leaking.

  • shrubitup

Posted 19 February 2009 - 06:47 PM

#18

It only roll starts when cold and it will kickstart afterwards means the top end is shot for sure maybe more. White smoke with a grey tint or white smoke with a blue tint? if it's grey pull the plug and see if it looks funky. If it is Funky looking then you have antifreeze burning up in the cylinder. The plug doesn't always look funky when it's an inner coolant leak though. If it is blue tint then either the rings are worn or you have a crankseal leaking.

Like he said, it's F'd up. :lol:

New top end for sure. I wouldn't push your luck for you may end up damaging the cylinder and maybe worse the crank bearing once the piston shatters.

  • Uncle Alpo

Posted 19 February 2009 - 06:49 PM

#19

Put the carb back on after cleaning and the bike actually idles. The powerband is present now as well, which it wasnt before the cleaning.

Excellent!

Question: when I pull the choke up if the bike is idling it kills the bike. Dont quite understand that. And on the choke plunger it says adjust idle and you can spin the top....does that actually adjust the idle, since there is another idle screw, or is that black plastic one at the top the air screw and the brass one at the bottom something else?

Pulling up the choke should kill the engine once the engine is warmed up.

If you have the stock carb (this is a 2000, right?) there should be two screws on the left side. The one with a big head (could be that black plastic one) controls the idle; the one with the small head is the pilot air screw.

Also the bike only roll starts when cold and wont kick over. My buddy is short on cash and we were going to just get rings since I think that is the problem, it is blowing white smoke still. I was wondering if the roll start when cold is a sympton of needing a new top end soon...

As above, it sounds like you're due for at least rings. You need to find the source of that white smoke: is it coolant or oil?

  • IRIDEKTM

Posted 19 February 2009 - 07:03 PM

#20

took the top end off heres what it looks like. Im almost positive the reason it wont cold start is the plug. I sanded down one of my old 8's cuz it was running a 9 and tried it. It kicks over when warm, and kicked over cold the first time we went to look at it only once.

Definitly needs a top end. How am I able to tell if coolant is leaking into the cylinder? For some odd reason I feel like that may be it, but again that might of been left over in the line after draining it....

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And again sorry for my ignorance, first top end I have ever done or taken apart, my KTM 125 never needed one :lol:




 
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