I've got an 85 Lt250r and this is my first 4-wheeler, bought it from a kid who said he'd had a new clutch and a recent top, none of which were true, I'm now in the process of tearing it down. I've done a lot of work on my buddies wheelers so this is not all new to me , but I've never been inside the engine or tranny, anyway, how do I know if the clutch basket is bad? My brother seems to think it is and if it is i would like to go ahead and replace it, but I am curious about what I have heard about people filing them. My only other question is the stamp on the piston, I'm assuming it means .30 over it is as reads... B00F3 not absolutely sure that the f is an f due to deposits on the piston.... Thanks in advance for any help.

 

also, how do I know if I need to do the bottom end?

 

When you look at the clutch basket see if it has grooves were the friction plate ears come in contact, if they are small (less than a 1/16 or so) you can file the basket so grooves disappear, if the grooves are big you need to replace the basket. As for the clutch plates buy a compete set of fiction and metal ones and springs. The factory seem to last longer than aftermarket ones. Remember to soak all the plates in tranny fluid before installing. As for the piston size there should be a stamping in the center of the piston that reads one of the following:

STD (stock)
0.25 (10 over)
0.50 (20 over)
0.75 (30 over)
1.00 (40 over)
1.25 (50 over)
1.50 (60 over)

Stock piston diameter is 70mm and increases in 0.25mm per over bore as chart above shows.

Check the cylinder walls for scares if none then take 600+ gritt sand paper and do across sand on the walls to remove the film coating that was biult up by the rings. If the piston looks good just replace the rings.

 

Just wanted to add one more thing to look for in the clutch basket only cuz mine went bad this way,the rivets that hold the gear onto the basket loosened up on mine,I could hold it in my hand's and move the gear.

 

About 3 months ago i to bought my first four wheeler from a guy that said it had a newer top and and good clutch. Well I rode it for one day and it went down. If the clutch basket is worn, be sure to replace it. That basket is probably original (17 years old). On my first ride my clutch basket ripped apart causing all kinds of damage on the right side of the motor. At that point I decided I better tear this whole motor apart and see what else might be wrong. Piston was a mess and starting to come apart. Parts of it had already come off and fell into the bottom end. Sure glad I decided to rebuild the whole motor.

Here is my sudjestion. You already go the clutch apart and the top on off, why not just take the time to crack the case and clean and check the bottom end. You can replace the oil seals and check out your gears to be sure they are all shifting smooth and not worn or broken. You should be able to find a local engine builder who can get your head bore to the next size up and get your compression back to new for about $60 and $100 for a new piston which you most likely need anyway. They can also measure it to see how much it has been bored. They may be able to just clean it up for you if you seller was at all truthfull about it being a newer top end. If it really was a newer top end and your getting that much carbon on the piston, also make sure you spend some time getting your carb adjusted.

It is all really easy if you get a good manual, ask these guys at ATV Connection a lot of question, and read the manual before you do something, not after you mess it up. I was lucky in that I had two motors to pull parts from when I messed up. All of my mistakes could have been avoided if I would have gone a little slower. This was a great learning experience for me. Worst case is if you get over your head, just pack up the motor in a box.....and walk into your local shop with a shy smick and say "Please put this back together...it just fell apart"

P.S. I have gotten great answers for every question I needed answered......

 

Thanks for all the help guys, I am going to check these things out as soon as I get off of here. As far as the carbon goes, I would assume it would be because one of my reeds was braoken in half... [img]i/expressions/face-icon-small-sad.gif[/img] I would assume that this would make it burn a little strange [img]i/expressions/face-icon-small-smile.gif[/img] anyway, I am going to open the case and do all of the seals and gaskets anyway, any more suggestions are welcome. One more thing, I like the looks of a polished engine, has anyone here done their own?

 

allright, im back from the shop for the moment. the piston reads 534M07200 and what I head written before....

 

Yeh when I rebuilt mine I removed all the paint. I didn't like the blue paint on a the motor especially when it gets old and worn. Well I removed the paint from both my cases. One I did the hard way and the other a much easier way. The first one I used a dremal and a wire brush and it took forever. I mean forever!!! When I got my second motor and tore it apart I decided to try some paint stripper that was for metal. The paint came off in a matter of seconds in the small area I tested it on. Do little three or four inch sections at a time. You have to be very careful because you don't want this stuff all over the place. It will melt seals and gaskets like crazy. Mine turned out great and it only took a few hours. I wouldn't sudjest doing it this way unless you are going to tear apart the motor and replace all the gaskets and seals like you said you would. Also me careful to block all holes in the motor. I removed the top end and piston to make it easier to get into the tight places. Be sure to ripe down your engine with a cleaner as soon as you are done with the stripper to remove this nasty chem. I'm sure somebody will come on and tell you this stuff is bad for the case.....but mine looks really cool. After the paint comes off it is all nice and shinny. You can leave it this way or take a dremal with a fine wire brush and give it the brushed look. That is also a clean look. Be carefull, go slow and don't let this stuff in your case and you should be fine.

 

Sorry...just thought about it...your 85 doesn't have the blue motor. I would sudjest a dremal and a few fine wire bits to clean up your motor. You can also buy a polishing compound and a polishing bit for the dremals. Sorry I wasted all your time with the paint removal talk.

 

thats ok, maybe it didn't have a blue engine to begin with, but it does now, I just spent 1 1/2 hours on the bench grinders wire brush, sand paper and a polishing wheel just to get the head done, but it looks SWEEEEET! Thanks for the info, if nobody has any objections I will try this in the next day or two