Alright, I'm new to this site so sorry in advance if something isn't right. Anyway ill get to it. I have a 91 king quad that i have owned for about 10 years. Ever since the day i got it it has burned oil. This last summer i decided to rebuild the top end since i was only getting around 90 psi of compression. All the way up to the point that i took the motor apart it had incredible low end torque and i could motor up most any hill at 20 mph without any bog down. Since i have rebuilt it i have had non stop problems. I raised compression to 150 psi, and i have had to go through all kinds of parts in the carb including the slide diaphragm. But even with the huge increase in compression i just cant get anywhere near the low end torque and when i try to run up to a decent cruising speed it just seems like it wont spool up and it wont hold a hill, and it shows on the plug that it is rich but i have had it jetted for my altitude. I am in desperate need of help since i use this day in and day out to plow driveways around the neighborhood and i really need the power back . If you would like more info let me know.

 

When you do a top end rebuild you only move two things that affect power, the valve timing and (possibly) the valve clearances if you ground the valves in. Check these are right. You can also damage the inlet manifold when removing the carb so check for air leaks. Regarding running rich, someone in the past may have compensated for a partially blocked jet by adjusting the mixture, or your choke may be sticking.

 

So, from my understanding if these machines were off by just one tooth on the timing they wouldn't start at all. Is that true? I also checked the valve clearances after the first 100 miles of break in and the were fine (im setting them at in .08mm ex. .10mm). As far as i can tell if i pull the top cover from the carb, the choke looks to be closing all the way and moving freely. I will have to look into the intake leak at the head this weekend. That also might explain why it seems to go through the rpm range slower and smoother but if you give it all it wants it will cough and sputter.

 

Provided one of the valves doesn't hit the piston, the engine will run with the timing out by one tooth, in fact a tuning mod on the old A series engine fitted to MG Midgets/Sprites was to set the timing a tooth out.

 

Alright. I'll take a look at it hopefully this weekend and I will let you know what happens

 

Well I was extremely disappointed to find that when I took the valve cover off the timing was dead on. So i am going to look at the possibility of an intake leak and if that doesn't turn up anything I'm not really sure where to go from there.

 

Im going to have to take that back. After i went back out i noticed that the chain was really loose even with the tenioner and if i rotated the cam so that the top of the chain had tension on it and it was off a tooth. I put it back together and it runs great. Im just left wondering if i should have retarded it one more tooth but i think i will leave it where it is at.

 

You need a new cam chain. With the tensioner fitted and adjusted, there should be no slop in the chain.

 

I was thinking the same thing. And I have a feeling that explains the abnormal engine noise. However I looked in my manual and in order to replace that it looks like I have to take the transmission pretty far apart and I don't know if I'm up to that challenge.