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subxero · July 23rd, 2013, 05:50 PM

^

pretty much this, the tear down is easy. Get a piston kit but do some research first and make sure that the common aftermarket top end kit is plug and play for this bike. Most often the case but not always (example my 03 yz250 needs OEM piston stamped to match cylinder stamp) Make sure you stuff some clean rags in the bottom end whole so you don't lose any clips or anything down into it when tearing apart or putting back together. Make sure you wiggle the rod around while you have access to it and feel for anything that doesn't feel right, to much play, grinding, gritty feel ect... If so you might want to get a second opinion on the bottom end before going any further.

If the cylinder is still in spec get someone to hone your old cylinder for cheap or buy a kit to do it yourself, don't put a new piston rings in with out honing. Don't be afraid to clean your cylinder good once off, get in there with some brake blaster, tooth brush soap and water, but make sure you rinse it clean and dry it super dry, i generally use a blow dryer, don't put it back on until it is 100% dry.

It is easy just put everything back together the way it came apart but with new gaskets ect... Other things you should do, check air filter, prob needs replaced, or cleaned and sprayed for sure. Obviously change the crankcase oil in it, these are dirty bikes oil needs changed every so many hours of ride time, i generally do mine every 6hrs at least. Not sure if that bike has a sight glass, if so great, if not, find out how much goes in and measure it and put in that exact amount after a full drain. Find out what the factory recommends for your fuel mix. Generally 32:1 is fairly standard for 2stroke mx type bikes, People will tell you to thin out your mix if you are running "rich" This is false information, you do not lean out your bike by leaning out your fuel/oil mixture. Just like the ninja250's you lean out or richen your bike by adjusting the air fuel ratio by adjusting the carburetor. If your bike is jetted properly and you run it hard and hot like it is meant to be run 32:1 fuel oil mixture is generally great. Lots of racers run 28:1 but they really ring the necks of those bikes too. The problem generally occurs when someone leans out the fuel/oil mix lets say 42:1 or even 50:1 because they just putt around on their two stroke which they can get away with until that one day they ring it out and then seize the engine.

Thats a healthy start.

have fun, I would tear it apart and check out top end, bottom end and clutch, if any two of those are shot in the *** i would not waste my time fixing it up. top end is quick and easy, bottom end kit is closer to $300 maybe more but will probably need a shop to do some of the bearing work if they need pressed, and a whole clutch rebuild can cost up to $600- or higher if you buy premium parts. Just not worth it IMO.

July 23rd, 2013, 05:50 PM	#27
subxero dirty boy Name: Joe Location: Johnstown, PA Join Date: Sep 2012 Motorcycle(s): I don't even know anymore?? Posts: A lot. MOTM - Apr '14	^ pretty much this, the tear down is easy. Get a piston kit but do some research first and make sure that the common aftermarket top end kit is plug and play for this bike. Most often the case but not always (example my 03 yz250 needs OEM piston stamped to match cylinder stamp) Make sure you stuff some clean rags in the bottom end whole so you don't lose any clips or anything down into it when tearing apart or putting back together. Make sure you wiggle the rod around while you have access to it and feel for anything that doesn't feel right, to much play, grinding, gritty feel ect... If so you might want to get a second opinion on the bottom end before going any further. If the cylinder is still in spec get someone to hone your old cylinder for cheap or buy a kit to do it yourself, don't put a new piston rings in with out honing. Don't be afraid to clean your cylinder good once off, get in there with some brake blaster, tooth brush soap and water, but make sure you rinse it clean and dry it super dry, i generally use a blow dryer, don't put it back on until it is 100% dry. It is easy just put everything back together the way it came apart but with new gaskets ect... Other things you should do, check air filter, prob needs replaced, or cleaned and sprayed for sure. Obviously change the crankcase oil in it, these are dirty bikes oil needs changed every so many hours of ride time, i generally do mine every 6hrs at least. Not sure if that bike has a sight glass, if so great, if not, find out how much goes in and measure it and put in that exact amount after a full drain. Find out what the factory recommends for your fuel mix. Generally 32:1 is fairly standard for 2stroke mx type bikes, People will tell you to thin out your mix if you are running "rich" This is false information, you do not lean out your bike by leaning out your fuel/oil mixture. Just like the ninja250's you lean out or richen your bike by adjusting the air fuel ratio by adjusting the carburetor. If your bike is jetted properly and you run it hard and hot like it is meant to be run 32:1 fuel oil mixture is generally great. Lots of racers run 28:1 but they really ring the necks of those bikes too. The problem generally occurs when someone leans out the fuel/oil mix lets say 42:1 or even 50:1 because they just putt around on their two stroke which they can get away with until that one day they ring it out and then seize the engine. Thats a healthy start. have fun, I would tear it apart and check out top end, bottom end and clutch, if any two of those are shot in the *** i would not waste my time fixing it up. top end is quick and easy, bottom end kit is closer to $300 maybe more but will probably need a shop to do some of the bearing work if they need pressed, and a whole clutch rebuild can cost up to $600- or higher if you buy premium parts. Just not worth it IMO.