1994 rm 125 top end rebuild

[jrswerkz]

I have a 1994 rm 125 and will be doing a top end rebuild and would like to know if there is a special plating to these?In the wiseco guide it says to overbore you need some scem composite cylinder sleeving.The bike is hard to kick so im going to rebuild topend.Can i just rering or do i need to bore again or mayybe get away with just a hone and rering?

 

[76GMC1500]

Hard to kick is a good sign, easy means its time to rebuild. Did you mean to say it's hard to start?

Most modern bikes are plated. They generally don't need to be bored. Plated cylinders wear very little compared to pistons and rings. Generally, you can just drop a new piston in. It is wise to measure the piston to wall clearance. If it's too wide, the cylinder will need to be replated or sleeved.

2-strokes generally do not need to be honed as it just wears into this plated coating. Oil consumption isn't exactly an issue with a 2-stroke.

 

[jrswerkz]

I meant the stroke of the kick is like slower(resistance).

 

[cr85rb_rider]

if you have alot of resistence that means there alot of compression...

whats your compression anyway

 

[jrswerkz]

i am not sure as i dont have a checker but is too much compression bad if it is that?

 

[jrswerkz]

Well i removed the plug and its still hard to kick(barely moves).Well i took off the pipe and found a bottle cap in it bocking the hole.I dont know how in the world that got in there so i think the engine is siezed.Can the cap in the pipe caused the motor to sieze?

 

[cr85rb_rider]

The expansion camber pipe or the silencer pipe? Cuz i think the expansion camber is to thick right?

The cap might have blocked the exaust, making it hard to kick because it can suck air in but not expell it out, u know.

Did u kick it with the cap out of the pipe yet?

 

[jrswerkz]

I just took the top eng off and seems like the piston is ok but the rod is stuck(the part closest to the crank).The crank rotates ok until it hits the rod.Might it need a rod kit rebuild?About how much is it for a rod replacement?

 

[2strokerfun]

The crank rotates ok until it hits the rod.

The crank shouldn't "hit" your rod. Can you explain a little better??

Crank kits can be $149 on up if you need one, but I've never found one I need at the low price. You'll also need gaskets, main bearings etc.

 

[jrswerkz]

Just put it this way,crank rotates but the rod doesnt.So, does it need the rod rebuild kit?The price i know i have to split cases but im not going to do that so has anyone had the job done?

 

[rm_racer]

I have the same bike. Cylinder is Nikasil. Sounds like the big end bearing is gone. Probabaly looking at a couple hundred bucks to get it done.