cleaning/replacing

[dirteater17]

hi. i recently bought an 2000 Rm125 a step up from my 1979 dt80 :nener: . i was wondering how long people usaully replace the top end. i hear that 2 storkes need to replaced/clean often. i know the prevoius owner cleaned the piston and replaced the gaskets in 04, he also put a new clutch in, and v force reeds and a full FMF excust. i just got done repacking the muffler and cleaning the fatty. so i was wonder if it is time to clean or replace the piston and gaskets, put a new clutch in, do somthing with the reeds, all that stuff.

 

[_JOE_]

Service intervals are listed in the manual. If you didn't get one already, GO BUY ONE. If you're going the pull it apart, you might as well change the piston/rings, clean the power valve, and inspect the rod and crank for play. Also look at the clutch plates(specs are in the manual), and inspect the reeds for any cracks/chips/frayed ends. If the top end hasn't been done since 04 you are long overdue, unless it wasn't ridden for a couple years. Also take the time to clean the carb while you're at it. I'm glad to hear you repacked the silencer! Too many people run around with blown out silencers. Good luck and have fun!

 

[dirteater17]

yea I've got an aftermarket manual but the number seem a little.......................odd? for example; it says to replace the sprocket after 4 hours, replace the piston after 7 hours. piston cost $100 each, Sprockets $75. in 1 ride i usally do 4 hours. if i did everthing this manual says i might as well go and buy a new bike every few months.

 

[MOTO ON RM250]

I had this same bike for about a year before it was stolen. It went through parts like crazy but that was mainly due to the previous owner. The guy who stole it took it when the back tire was flat.

 

[hot125mod]

wtf who would steal a dirt bike if I were in your shoes I would hunt that monkey down. and not stop till I found him also i would beat him with a tire. :yell:

 

[_JOE_]

You should look for a less performance oriented bike. These bikes push the limits of the materials they use. They turn 13,000+ rpms. In 7 hours the rings have wiped the cylinder 5,460,000 times. The piston has been subjected to the same amount of explosions. Have you ever held a 125 piston? They are small and light. If you think about the cicrumstances, 7 hours is a long time. Do I change my piston every 7.5 hours like my manual says, no. I go closer to 30 or 40, but rings every 15 or 20. I also change my oil every other ride or 6 to 8 hours, and clean the air filter every ride. Bikes like the xr's and alike use much heavier pistons that can be used a long time. If you don't want the maintenance, or can't afford it, you would be better off swapping to a bike of that nature.

 

[CHR!S]

if your not sure whether the piston or rings are worn, you can pull it apart and measure the ring end gap, piston diameter, ect and compare to the wear limits in the manual.

things like sprockets and chain depend on how you ride, if you lube your chain every ride, things like that. a visual inspection is usually all thats needed, but you can measure the chain (a certain number of links) and look in the manual for the stretch limit.

 

[dirteater17]

it looks (the manual) and sounds like its a big deal to rip apart the cylinder head. if i was to i might as well clean and replace evrything, right? so if just going to check whether the piston or rings are worn i would have to get new gaskets? cant use the existing ones?

i do all the basic stuff. change the oil and air filter every other ride, oil the chain, check the fluids. this bike is just a big step up from my 1979. i could ripe that bike apart in 10 mins.

 

[dirteater17]

Do I change my piston every 7.5 hours like my manual says, no. I go closer to 30 or 40, but rings every 15 or 20. .

thats what im asking. people (most anyways) dont go by what the manual says (like u :nener: ) i was wondering how long people usally go before switching this stuff out.

 

[mox69]

The average guy just waits until his engine blows up, then replaces the piston and rings :)


Those recommended intervals are for people who are racing the bike. A and B level racers thrash a bike much more than your average trail riding joe.

It's very hard to give a specific number on when to do maintenance. If you putt around on the bike at slow speeds you will get a much longer top end life compared to running it at full throttle all day.


Once you hit 15-20 hours tear the top end off and look at it. Once you've done it a few times it will become pretty cheap and easy. The only part you will need to replace is a few gaskets. Replacing the piston ring while your in there is cheap and easy too.

This will give you a good feel for how hard you are on parts.

 

[_JOE_]

The average guy just waits until his engine blows up, then replaces the piston and rings :)

If they are very lucky. I've seen more bikes crack piston skirts ruining the cylinder plating and dropping chunks into the bottom end :yikes: . Repairing this kind of failure can be very expensive.

 

[snb73]

Service intervals are listed in the manual. If you didn't get one already, GO BUY ONE. If you're going the pull it apart, you might as well change the piston/rings, clean the power valve, and inspect the rod and crank for play. Also look at the clutch plates(specs are in the manual), and inspect the reeds for any cracks/chips/frayed ends. If the top end hasn't been done since 04 you are long overdue, unless it wasn't ridden for a couple years. Also take the time to clean the carb while you're at it. I'm glad to hear you repacked the silencer! Too many people run around with blown out silencers. Good luck and have fun!

This is good advice. If it hasn't had a top end since 2004, it's probably due. A compression check will answer your question for sure.

yea I've got an aftermarket manual but the number seem a little.......................odd? for example; it says to replace the sprocket after 4 hours, replace the piston after 7 hours. piston cost $100 each, Sprockets $75. in 1 ride i usally do 4 hours. if i did everthing this manual says i might as well go and buy a new bike every few months.

These numbers are for Ricky screaming the bike every moto. I would bet you will get a few more hours out of a pistion. Rocky Mountain ATV/MX has some great prices on parts. Unfortunately dealers are a bit more expensive.

Good luck, Steve.

 

[dirteater17]

thxs guys
-nate

 

[dirteater17]

o-yeaaa i dumped my bike today and broke the clutch lever.(not a small brake either :bang: ) any suggustions on a new 1. maybe a one of those break aways?

 

[76GMC1500]

Just get the $7 one, you'll break a lot more in the future.

 

[CHR!S]

o-yeaaa i dumped my bike today and broke the clutch lever.(not a small brake either :bang: ) any suggustions on a new 1. maybe a one of those break aways?

This happens often. Just buy a lever that will fit in the stock perch (assuming thats what you are using). Don't buy and OEM lever, they nail you for those small parts.

You can loosen the bolts on the perch a little so it rotates in a crash.

non-breaking levers, like ASV or ARC levers are great, but expensive. However, you most likely won't be stuck 20 miles from home without a clutch though.

 

[_JOE_]

This is good advice. If it hasn't had a top end since 2004, it's probably due. A compression check will answer your question for sure.

Don't rely on a compression check. A leak down test and tear-down to measure piston clearance, bore size, and ring end gap are the only way to know what condition your engine is in. A completely sacked out piston can still yield good compression as long as the ring/s seal.

 

[snb73]

o-yeaaa i dumped my bike today and broke the clutch lever.(not a small brake either :bang: ) any suggustions on a new 1. maybe a one of those break aways?

I use this clutch lever, it has some great features at a great price.

http://www.rockymountainatv.com/pro...&vehicleType=&pageLinkUri=&prodFamilyId=11631