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2004 RM65 Suddenly Stopped

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First post guys so take it easy on me.

I just purchased a 2004 RM65 for my son. I took him out to ride and it just suddenly stopped running. In all fairness to him it was his first time riding a bike with a clutch so there was alot of riding in first gear at first. But after about an hour he was taking off like a champ. He started changing gears about an hour and a half into the session. Then he was going and i heard a noise. It didn't sound really bad but it did get my attention. I asked him to stop and checked it out and everything looked fine.

He went down a straightaway and as he was making his turn the bike just stopped running. He tried starting it and it wouldn't kick. I went to him and looked down and saw that the oil in the crankcase window looked white. I knew then not to try to start it again. I did however check the compression. It seems to have great compression but there is a small metallic sound when i hand crank it.

There were some other riders there that insured me that it wasn't a busted piston or ring. I am looking to you guys for some support on this issue.

Let me know what to do and i'll get right on it. I am not going to start it or attempt to start it until i figure out what this is.

The guy that i bought it off of said that it was raced. He said that he had put alot of work into right before he sold it. But it is always my experience that when a dad says they put alot of work into it and that it was raced that it could mean that all the high priced racing parts where changed out with the stock parts so they don't lose their shirts when they sell their bikes. Anyway let me know what you guys think so that i can get this thing back into riding shape. He is fresh off of a CRF50 and ready to rip this RM for everything it is worth.

Thanks in advance.

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I would try to post this in the 2 stroke suzuki sub-forum as well. I can be of no help, but definately sound like you got coolant into your oil. Maybe a head gasket leaking? One good thing about two stroke, super easy and cheap to re-build.

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Pop the case cover off and open it up to the clutch. Hand turn the crank. If there is grinding or binding I would think that it may be a bottom end. I lost the crank in my sons bike. As you would kick it over you would get a small metallic sound. Replaced a nuked crank with hot rods.

Also the impeller on these bikes can wear, so you may want to make sure that there is no problem there. You would notice the water level going down in the radiator.

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if it kicks over smoothly. do a compression test to make sure you did not lose a piston or ring.

if that looks good. replace the plug, they will foul up quick and usually the culprit to a no run condition in the KX/RM.

moisture in the Oil can mean it was pressure washed too close to the seals or a bad seal in the water pump.

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if it kicks over smoothly. do a compression test to make sure you did not lose a piston or ring.

if that looks good. replace the plug, they will foul up quick and usually the culprit to a no run condition in the KX/RM.

moisture in the Oil can mean it was pressure washed too close to the seals or a bad seal in the water pump.

Right, I wouldn't worry too much about the small amount of water in the oil. As long as you are not having to add coolant every ride it's not serious.

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You said that it quit when he was going into a turn, then would not kick. I assume you mean it was siezed? Then after it cooled you tried to hand crank it and it felt like it had compression? I would say it probably blew a head gasket, got coolant in the cylinder and seized. Pull the top end and check for scoring, or a busted Piston Skirt. +1 on the creamy oil, be careful when power washing and use good quality oil. Cheap oil will get milky in those little two smokes. Good luck.... Be sure when you pull off the cylinder you check for up and down play on the crank rod. Side to side play is ok.

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Most likely the milky colored oil has nothing to do with your current problem. Although this is a problem that needs fixed none the less. Pressure washing will have not effect on the water pump seals. Most likely to fix this problem you will need a pump shaft, shaft seals, and bearings.

As far as the no run situation, do a compression test. Minimum for this bike should be about 140 psi. There could be a number of things that have happened to put you in this current situation. We will need more info. to help you diagnose. Things like, fuel in the tank? Spark? Fuel to the cylinder? Air? Compression? If at one point it would not kick, then later it would kick, there is definitely internal engine damage.

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I am going to pull it all apart this weekend. I got busy last weekend and couldn't get to it. I did however check the compression and it was at 135 psi if i did the check right. Would that eliminate any of what i have to check? The metallic sound that i am talking about is just a slight hint of a rubbing when i hand crank it.

A buddy of mine said that when you change the piston and rings in one that it is best to run about 1/2 to 3/4 tank of gas through one while the engine is at idle to insure that the rings seat properly. Is that a fair assessment?

I will tell everyone what i find when i pull it apart this weekend though for sure. And thanks for all the help on this.

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Just an FYI. If you are using the site glass to presume you have water in the tranny oil. That isn't a good method. The site glass is s dual pain and can hold moisture, and it can make it look like water has made it into the Tranny.

That is a KX 65 motor, and they are known to blow cranks. Never run less than 32:1. I've seen those little bikes do the same thing. Then you rock it and it kicks fine. Pull that top end and look for any verticle rod movement. I lost a crank once in my kids old KX65. Spin the crank in both directions. If it even hints at hanging, you are loosing bearings. Not a big deal. These bikes are super easy to work on. Once I got the parts and shoved them in the freezer. I think it took me about 8hrs to strip and put back together. That was mostly done by my 12yr old while I sipped beer and supervised.

For Break in:

I oil everything good with 2st oil during assy. Oil on all teh crank bearings, and then a good coat on the cylinder. Poar a little extra oil in the tank. Add some gas. Then do 2 10 minute heat cycles. I warm it up good and slowly drive it around the neighborhood. Let it cool between each one. Then take it to the track. One slow lap, and then run it like you stole it.

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ok, some kx/rm 65 issues to note...

water in tranny oil can mean two things:

You're pressure washing too close to seals such as the kick starter seal, shifter seal or the filler cap.

The seals from the impeller are done - replace BOTH seals, the bearing AND impeller shaft or it'll just leak again.

Both those issues are VERY common.

Your mild clicking sound could be a ring slightly catching the exhaust port, usually what happens right before your top end blows up - rings float freely, rings in worn pistons jam and stop floating and wear unevenly, eventually catching the ports.

Flat spot on big end bearing - a common issue with these bikes is that owners read their oil can and see that they can run 50:1 or 60:1 without a problem, however the 65's have soft bottom ends and bad oil delivery to them so running anything less than 32:1 is going to shorten the life of the crank dramatically.

If the crank is done, replace it with a hot rods, Hot rods made significant improvements to the crank, it's the only one worth putting into one of these bikes.

Good thing is parts are cheap and the bikes are super simple to work on.

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I am going to pull it all apart this weekend. I got busy last weekend and couldn't get to it. I did however check the compression and it was at 135 psi if i did the check right. Would that eliminate any of what i have to check? The metallic sound that i am talking about is just a slight hint of a rubbing when i hand crank it.

A buddy of mine said that when you change the piston and rings in one that it is best to run about 1/2 to 3/4 tank of gas through one while the engine is at idle to insure that the rings seat properly. Is that a fair assessment?

I will tell everyone what i find when i pull it apart this weekend though for sure. And thanks for all the help on this.

You could borrow another comp. gauge and check it again just to verify if you are concerned that the first test is not accurate. If the 135 psi is correct it means you need to take the top apart at the least and you may find your problem. Remember to throughly check all the crank bearings by feel once the cylinder is off. If there is any question about how long the crank bearings have been in there or any question about the rest of there life span, replace them now and save you and your son the headache.

As far as the break in goes, yes that is a fair assessment but not necessary. Check out this think. This is how I do it.

http://mototuneusa.com/break_in_secrets.htm

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