My brother has had this bike for 3 years with no problems and its fully stock. Never been into the motot at all. Its a 1986 model and here is the scoop.

He was out riding today and all of a sudden the engine started making so wierd noise so while he was going he pulled in the clutch and the motor died. It was totally locked up. He has always premixed his own oil at 32:1 and has never had any problems with this bike. Now he let it totally cool off and it will fire right up and run for about 15 min and lock up again. Someone told me years ago that 2 strokes needed to have their rings replaced at least once a year - Is that true? He rides his quad probably 3 times a year for 3 to 4 days at a time. He works alot and never has anytime hardly to get out. I thought I would post this and see what I can find out for him. Also, if he needs this fixed how can he go about it with out making it a race bike, what I mean is, if he needs to bore it out and replace the piston and rings what should he go to to be safe and would he have to rejet his carbs. I would think he would have to rejet but shoot me some ideas people.

 

Could be overheating. Check the water in the radiator. There is no set interval for replacing rings. You replace them when the compression drops enough to effect performance noticeably. If it is a cooling problem than he may need new rings now. If it gets too hot, the rings/piston can get tight in the cylinder and lock up. Sometimes you get lucky and they will free up after they cool down but 90% of the time there will be at least some minor scuffing on the cylinder. He will not need to rejet if he just has it bored to the next size up.

 

Ok, thanks. I will tell him to check the cooling system and he is going to tear it down this week.

Thanks again

 

In my opinion he will more than likely have to bore it. He probably won't have to bore it too much, and it's a fairly easy job. Ask if you need help.

 

ok, what should he go up to that would be safe? What size of piston and such?

Thanks!

 

RaptorOwner,

Is there any way to describe the noise the engine started making other than "weird"? Was the noise coming from the piston/cylinder, water pump, or where approximately? Does it make the noise each time the piston seizes? When the engine has cooled down, how does the compression feel? He's owned the bike for three years so he should have a feel for the kickstarter...does it feel much easier to kick over than it did before?

If the engine runs fine for 15 minutes, it sounds as if your rings are okay (a broken ring could stick the piston, but the engine wouldn't run fine for the first 15). So I'm thinking that the engine is overheating, parts are expanding due to the heat, and finally the piston gets squeezed tight enough inside the bore that it temporarily sticks. In my humble opinion, you need to take a closer look at the cooling system. Do you have enough coolant in the engine? Drain your coolant and pull your water pump cover, how does the impeller look? Can you turn the water pump by hand? If so, you most likely have a broken pump shaft. A full coolant system is worthless if your water pump isn't circulating the coolant to the radiator.

Pull the cylinder head and check to see what you have going on inside the cylinder. Is there quite a bit of carbon in the combustion chamber? It's doubtful that carbon build-up is causing your problem, but it may be a contributing factor if overheating is an issue. Kick the engine over until the piston is at bottom dead center and take a good look at the bore. If there is any wear beyond light scuffs in the bore, you should probably consider rebuilding the top-end. **SUDCO pistons are a quality alternative to the WISECO pistons everyone uses when rebuilding their top-ends, you may want to check these out and save some $$**

I know I'm forgetting something, but I've asked more questions than I probably answered...time for me to shutup.

Good Luck!