Big Problem!!!

[ryanbranscum]

So I have a huge problem on my RM250....I was doing some maintenance on my bike, greased the axle, tightened the chain, repacked my silencer and replaced the rubber boot that goes around the joint from the pipe to the silencer......after I got all done I started it to hear the difference after packing the silencer.....it ran for like 20 seconds and made a terrible noise and stalled! You could hear chunks in the cylinder! I tore the top end off and found that the piston had grenaded!! It was literally in a thousand pieces! I just bought the bike too! I changed the oil in the bike last week and notice the color of the oil was gray...the lighting in my garage isnt great but today out at my dads I drained the oil and it looked the same as it did last week but in better light you could see all metal shavings!! GrEaT!!! Any advice or input would be appreciated....where do I start....there are gouges in the cylinder, by the way...My friend is taking the cylinder to a speed shop to see if it can be saved, I have to work all weekend.....are there any reliability issues with boring the cylinder? Thanks

 

[76GMC1500]

You ride a 2-stroke, the oil you drained is in the transmission and is completely seperate from the rest of the engine. A fine metal powder in the transmission oil is standard. The aluminum clutch plates shed metal into the oil, it's perfectly normal. Change it frequently. New cylinders can be bought from a dealer for around $300. Replating can repair some gouges for $200. Deep gouges can only be repaired with an iron liner. When a piston breaks, it often binds up as it goes. This can damage crankshaft bearings. Rotate the crank and move the connecting rod around and feel for any excessive play or unevenness in the rotation.

 

[2smokers]

Dam that sucks, it happened to me when I bought my 96 rm125. Well first you can send the cylinder to be welded and replated, it cost me 350 CAD. It's safe to bore it to a 265 but you might need to send the hole motor for other case mods they might have to do. Then you have to worry about any metal chunks that went down into the crankcase. You can do it the easy way and pull the motor and flush it out really good or you can do it the proper way and split the cases and really clean it out and replace any thing eles that this guy hasn't replaced in a long time.

 

[ryanbranscum]

The crank still feels real smooth and even , there are no grinding noises or any sloop as the crank rotates. This really sucks! I think I might just buy a new cylinder...

 

[76GMC1500]

Too bad there is no Service Honda for Suzuki, you can get cylinders through them for a little over $200. You'll probably be out $300-$325 through a dealer.

 

[Chili]

Contact Eric Gorr ( http://www.forwardmotion.com.mx ) He'll be able to help you either with fixing your cylinder or if you want another last I saw he had a 265 Big Bore Cylinder for your bike on his site ready to go.

 

[snb73]

Replating can repair some gouges for $200. Deep gouges can only be repaired with an iron liner.

This used to be true when it was more cost effective to install sleeve over replating. Sleeveing may have issues with port height if not matched correctly. This may effect the power characteristics. Not to mention, heat transfer will be effected.

Now it is more cost effective to replate. I have the 265 kit on my 2003 RM250, ported for more top end. Let me tell you it is awsome. I used to get walked in the straights and uphills by the 450's, now I am right there with them. I can actually run a gear higher than normal for each given obstical.

Contact Eric Gorr ( http://www.forwardmotion.com.mx ) He'll be able to help you either with fixing your cylinder or if you want another last I saw he had a 265 Big Bore Cylinder for your bike on his site ready to go.

U.S Chrome will strip your plating, weld the gouges, bore, then replate. They can fix cylinders that were prevoiusly considered junk.

http://www.forwardmotion.com.mx/nicomcylinder.html

Good luck, Steve.

 

[Red Ryder]

What would cause a piston to just bust into pieces like that?

 

[RM_guy]

What would cause a piston to just bust into pieces like that?

If it was left in too long it can do that. It is very important to replace a cast piston (all stock, OEM pistons are cast) after 30 t0 40 hours of use even if it measure within spec. I always use a forged Weisco pistion because the life can be greatly extended.

 

[TWRT]

Whenever you buy a used 2-stroke, a new top end is a good idea. You could check compression, ring clearence, etc... to tell if you need a new top end. I just spend the $100 or so to replace the piston, rings, gaskets, etc so I know I am starting fresh. I had a bike destroy the piston and it was due to piston slap cracking and breaking the piston skirt.

 

[flattie]

i'm gonna stay that greasing the rear axle was the cause of ur piston failure..... :) jk, u need to split the cases. all those little pices of alum will be in ur crankshaft bearings and oiling holes, wont hurt to do main bearings and seals anyway. no since it spending 350$ on part just to have more problems ahead.

 

[ryanbranscum]

The piston head is cracked all the way across the top, there is no skirt and the wrist pin and bearing were pulled out of the piston......I have never seen or heard anything like that in my life! How tough is it to split the cases?

 

[76GMC1500]

It's easy if you have an impact wrench and a case splitter. It can be done without the splitter, but the impact is still a must.

 

[ryanbranscum]

Let me ask you guys this (Thank you for the input so far) If it were your bike what would you do? & How much am I gonna spend to do this right?

 

[snb73]

If it were me, I'd remove the engine from the frame and send it to Eric for a complete rebuild. It's nice to know you're starting with a fresh engine.

http://www.forwardmotion.com.mx/mxenginerebuilding.html

 

[Red Ryder]

I have been working with motorcycles for less than a year now and have split several cases myself, it is sooo easy. I don't even own a case splitter, I just use a heavy leather/wood mallet and bang on the flywheel shaft. It will slowly just split appart. It's just as easy to put it back together, you just bang on the other side. You really do want a repair manual.

 

[whenfoxforks-ruled]

I just use a heavy leather/wood mallet and bang on the flywheel shaft. Have you ever checked the crank for true after that onslaught,does your bike vibrate with the rpm? A case splitter is a good investment or could be made for cheap! Try prosource for suzuki parts,oem head should not be too bad on price. Talk to Eric like they said. Anybody beating on crankshafts with hammers should be welding the pins on the journals,alignment changes on a pressfit ruins the fit,you just made it easier to spin back,in my opinion.