What do you think is wrong?

[Broken Spoke]

I have been given a 95 kx60 by a friend. Of course, something is wrong with it. While he had it, it was running great until he tried to teach his 6 year old son how to ride it. Apparently, his son would not shift out of first gear and he had it hammered down. All of the sudden, it quit and would not start, but it was not locked up. He tore it apart, slapped in a new piston and rings, and fired it up. It never even made it through the warmup. It started knocking and losing power. He took it to a shop and they want to rebuild it from the bottom end up. The bike is not worth that much money, so he gave it to me. My question is, does it really need bottom end work, or will a nice cylinder plating job and a new piston and rings take care of it? What do you think happened to it in the first place?

 

[dante]

cylandar clearances could be off... It also might have spun a main bearing...

 

[Broken Spoke]

I am assuming that that the main bearings are ball bearings. How do you "spin" a ball bearing?

 

[FruDaddy]

Main bearings are most likely not ball bearings, but more like an automotive bearing, a thin piece ot material (not sure what it is) that gets covered with oil, and surrounds the journal. Spinning a bearing means that the bearing has literally moved out of its position and the ends of the halves are not where thay should be. These bearings typically has oils holes in them for automotive use, and if the bearing spins, the oil hole doesn't line up, and the crank journal recieves no lubrication and fails.

 

[Broken Spoke]

Thanks for the replys. I know what spinning a bearing is in your typical car engine, I just didn't think that this engine had those type main bearings.

 

[Broken Spoke]

Maybe I am confused on which bearing y'all are calling the main bearings. I think it is the bearings in the cases that support the crankshaft. I just looked on bike bandit and they showed ball bearings.

 

[FruDaddy]

I could be mistaken about the type of bearing in your bike, but if a needle or even ball bearing were to seize up, it could still spin the bearing race.

 

[ziptiedEXC]

A few years ago my son was riding a 98' KX 60, and the same thing happened to him. Kawasaki sells a replacement kit that was not too much. It included a new crank, bearings, and rod. I think it cost me somewhere around $450 parts and labor.

 

[RMASS]

Ok wait a minute, I have had both a kx 60 and a kx 65 and they both went thru. two young boys who rode them quite hard. I have been into the bottom ends of both of the bikes mentioned above so let me help you out here.

1st I would guess that the connecting rod bearing (which is a needle bearing that is mounted between the crank halves is your problem ) this can be a common problem on the little two stroke bikes because of the rpms that they run at any time you a moving at a decent pace..

the knocking is from the piston hitting on the head due to the wore out bearing

the main bearings are roller type bearings and usually hold up longer than the connecting rod bearings

more than likely if your main ( lets say crank ) bearing siezes up it would spin on the crank before it would in the case half (they are an interference fit on both the crank and in the case half)

hot rods crank kits usaually run somewhere around 139.00 or a complete top and bottom kit for 260.00 if you don't have the tools or experience to split the case you need to have this done as well and this is generally any where from 80-150 $

I would check prices and suggest that if you can get into the bike for less than 550.00 that it would be worth it

the age of the bike and drum brakes hurt it in resale