I just bought a used trail boss 250 i believe it to be a 1988 res. I am planning on rebuilding it. I want to try to do this as cheap as possible i have ran into a few items that i need. I am new to this forum and thought that there might be some people on here that might be able to help me out. found out the recoil spring on the pull start is broken and the started just click could be the brushes need cleaned or the solenoids busted. i do not know if the atv runs but i do know the piston moves freely in the cylinder. the one exhaust mount is broken along with the upper engine mount and every cable and hose needs replacing. i am new and if this is posted incorrectly. but i could use help this is my first time rebuilding an atv.

 

You can try running battery voltage directly to the starter to bypass the solonoid, that will tell you if it is the starter or the solonoid. If the starter is not working, you might get by cleaning it, brush kits can be bought pretty reasonable on ebay. The cables and most parts are usually available on there too. I'd be careful not to wrap too much cash up in it unless you are in love with the machine as there is not alot of value to them anymore. If you can get it to turn over with the starter, check your compression, needs to be at least 100 psi to run right. You will also likely need to clean the carburetor or rebuild it, check your transmission oil as well, I got one of those awhile back that had the motor out, I made the mistake of putting the engine together and getting it running before I checked the oil in the trans....when I noticed it was empty, I added fluid...it ran out on the bench through the big hole in the bottom of the trans which someone had tried to weld with no luck....I junked the quad right there on the spot.

 

I got the atv for 50 bucks i am not to worried about compression i am planning on rebuild the whole thing i got it tore down to just needing the primary clutch removed and the lower motor motor mount unbolted to remove the whole motor. i plan on re ringing it and all new bearings and crank seals. i got a carb rebuild kit for 24 bucks. i am not to concerned about putting to much money into this because the parts are dirt cheap its just time and a little elbow grease. i am wondering should i bore it or leave it bone stock what about primary clutch springs??? where am i going to find any easy ponys???? i know these things aren't know for there racing but i would like it perform good. any help or thought appreciated i may post photos. i am also looking for a good working pull start for this atv???

 

welcome to the forum. if the pull start is good except for spring, just find a nw spring and you'll be all set to crank it over even if you don't get the starter fixed right off. as far as boring it out if it needs it i would go just .20 over if that will true it up as there really isn't any power to be gained in boring it out. clutching,exhaust and air filter is the best power gains w/ the 2 stroke being the easiest to gain w/out spending any mods on the eninge. you need to get a clucth puller or make one for the primary to get it off. the thread is a 3/4" fine thread for the puller.

 

I'd recommend boring it to get the bore round again, I've honed several bores and they always end up smoking, gave up and have been taking them to the shop for reboring. I don't have a set of inside mic's, but I figured the cylinders being out of round was my problem. I haven't had any trouble since I started having them rebored.

 

GOOD ADVICE! Just honing cylinders normally just enlarges the bore and if you just stick a stock piston and rings back in the seal is never too good! Don't think I hardly ever saw a used engine where the original piston was still within tolerance! Plus you almost never have a good straight cylinder top to bottom! On my old Bore Master boring machine I would first take out about .002-.003 to "clean up and square up" to get the egg shape out of the cylinder,then bore to the size of the new oversize piston,then hone to final clearance. It was old when I got it back in 1987 and was still going strong when I retired in 2010! Should have brought it home with me to bore a few cylinders to keep me busy. Still have the bore gauges and micrometers OPT