hi i am about to tear down the top end of this and rebuild it looking for any advice on what all to do and any info on where to get parts. it has 1900 some miles on it and has sat for 5 years i did have it running but it is very hard to start. runs good after warm up.cold it only has about 60 lbs compression add oil goes up to 90. after running and warmed up it had 115. so i am kinda ruling out just a valve problem and more like some cylinder problems too.i am going to check the valve adjustment before i take it down but would like some info because i don't feel its just valves. i would like to know if there is a reasonable replacement jug out there i want to keep stock size if i can rather then have it bored. or has anyone ever done piston and rings with out having to bore?do they sell replacement heads or remaned heads? are they expensive? thats all for now thanks

 

If it's not smoking I wouldn't do what you're thinking of doing. Yes parts are expensive.
I would adjust valves, pull carb and clean it real good and adjust the Air/Fuel mixture screw out around one full turn past the factory setting, clean the air filter, change the oil to Amsoil 10W40 motorcycle oil, and change the spark plug and then see where I'm at. good luck and keep asking questions and wait for an answer!

 

i have had the carb rebiult new plug and had it running but very very hard to start.do you thing the valves out of adjustment could drop the compression that low? i did the oil thing and it did increase from 60 to 90 lbs. i am going to try the valve adjustment and the carb setting it would be nice if that fixes it got my fingers crossed

 

If it was not taken care then yes I would think about rebuilting the top end but forsure do a valve adjustment first. I think it's .007 on the intake and .013 on the exhaust. If you want it to spin and a little faster open them up to .008 and .014...this also gives a little more land time so the valves run a little cooler but the valves will tap a little more.BTW a lttle tapping is better then no tapping of the valves.

 

I think this atv has an rope start on it? If so check compression both ways......Electric and rope start to see if compression is the same cold!!! Sometimes starter or starter clutch bearing could be slipping when use electric start which would make engine turn slower...If the compression is the same both ways then values adjustment could be the place to start....Than get back with us here when you get that done....

 

well i didn't think i could have that kind of luck but it was the valves. i wasnt thinking that they could be too tight but thats exactly what it was. there was no clearance on the intake and too much on the exhaust there for the intake wasn't fully closing thus the loss of compression. my clymers book said .001 -.003 for intake and .003-.005 for exhaust. does this sound incorrect? other people thought it sounded too little.i set them at .003 intake and .004 exhaust. i started it first pull with the pull start!!! couldn't believe it. the temp in the shop was about 58. i would like to get the accurate specs to set them if any one knows for sure i would be thankfull

 

The clearance sounds about right. You should recheck the clearance after you run it a bit.

 

18 degrees out today and she started instantly no choke or throttle I'm happy! Going to order some parts gaskets and oil filter got some brake stuff on the way. Going to go over it and give it the lil bit of tlc it needs hope it last me for a good while longer

 

Mine is a 1998 model and my settings were what I told you .007 and .013 your's could be different. Great news about your machine, you're going to love it ,mine tripped 6,000 miles this passed hunting season!

 

well got a chance to do some plowing today ran great but i think its running rich will have to check that out after work on Monday. after plowing for an hour it started to not want to idle as well as it was. i am thinking that maybe with it running rich it is starting to foul the plug. any ideas? going to check plug and adjust carb and also re check the valves. i saw some one in a post mention if the intake valve looses gap it needs replaced any thoughts on this and if so would it be advisable to just do a head or valve job with out doing the piston and rings?