I went out riding on a long stretch of road. I had it about 3/4 throttle, the back wheels locked up and that was it, i couldn't kick it or anything.

Got home, I stood on the kick starter jumped and it broke lose. I got it started by dragging it behind the truck for about a mile.

It started, sounded like it was running dry(chugging like) and it was clunking. Sounded like an egg timer, just louder.

So i dumped some premix in it. Didn't run any better.

I took off the motor, pulled the head, and my piston is all scared up.

The side where the 2 squart holes are it is scratched on either side of them. Then on the opposite side it is scarred all the way up and down.

The top of the piston is like brass colored with a silver and black streak across it. I don't know if this is how it should run or not since this is my first time tearing down a 2 stroke.

The bottom end of the motor appears fine.

The cylinder it's self is pretty scratched. None really deep by my standards. I hope it won't have to be resleeved or anything. if it does i will just wait and get a 240 kit done on it.

Tomorrow i will hopefully have some pictures of the piston. 4th period i will hopefully have a chance to use the digital camera at school.

now does anyone know what happened? Did my oil pump go out? Jetting wrong? my plug was a nice brown..

And Who does good work on this sorta thing. And i would also like to get it ported. I was thinking of the www.macdizzy.com person.

Thanks all.

 

While I make no claim to crystal ball diagnosis, your last question is probably a good place to look. It's one reason many people with oil injection convert to premix..when it fails to lubricate it's cause you're out of gas & the motor stops
What about your jetting? If you were running very lean it could result in a seized engine also. Did you possibly break a ring? that could mess up your piston & cyl. walls, & if any of it went down in to the lower end, bad news!

 

the first thing you should do after the new rebuild is take that oil injector off and premix. I just done trust them. Also check your crank breaings upper and lower. If the bike locks up never try to restart the bike. You could cause further damage and have to spend more money

 

I got the pictures of the piston


http://www2.1st.net/ar15/pistontopside.gif

http://www2.1st.net/ar15/pistonside.gif


The pictures are kinda big.

 

Bore your jug and get an over-sized piston, blank off the oil injection and run the best oil& gas you can afford.

 

First of all you got some good advice from the other posters.
1. NEVER TRY TO FORCE YOUR KICK STARTER IF IT DOES NOT WANT TO MOVE.
2. TRASH YOUR INJECTOR THEY SUCK. IT'S BETTER TO MIX THE GAS YOURSELF. (THAT WAY YOU KNOW YOU HAVE OIL IN YOUR CYLINDER)
3. IT LOOKS FROM YOUR PISTONS THAT YOU ONLY NEED TO BORE YOUR CYLINDER. (CHECK WITH YOUR LOCAL DEALER) YOUR DEALER SHOULD BE ABLE TO BORE IT.
4. AS FOR YOUR BOTTOM END. THE WAY TO CLEAN IT OUT IS, PUT SOME PREMIX IN YOUR BOTTOM END. SWASH IT AROUND TURN IT OVER. DO THIS SEVERAL TIMES UNTIL ALL PIECES ARE REMOVED. (TRUST ME I USE TO RACE PROFESSIONAL MOTOCROSS BACK IN THE EARLY 80'S)IT'S THE QUICKEST AND EASIEST WAY.
5. CHECK YOUR SPARK PLUG ALL THE TIME TO MAKE SURE YOU HAVE THE RIGHT JETTING/PREMIX OR EVEN CARB ADJUSTMENTS CORRECT.
6. CHANGING YOUR PISTON AT THE BEGINNING OF THE RIDING SEASON EVERY YEAR SHOULD KEEP THAT RUNNING THROUGH OUT THE SEASON. (we use to change ours every 6 times we would go riding obviously you don't need to do that but changing it is very important to a 2 stroke engine)
7. WHILE YOU HAVE YOUR TOP END OFF IT'S NOT A BAD IDEA TO CHECK YOUR ROD AND ROD BEARINGS.
8. YOUR ROD WILL HAVE SLACK IN IT FROM SIDE TO SIDE (NOT MUCH) BUT IT SHOULD NOT MOVE VERTICALLY ONCE IT'S AT TOP OF ROTATION. IF IT DOES TIME TO REPLACE IT OR YOUR TOP END WILL KEEP SEIZING.
94DGblaster,
Good luck with your rebuild if you have any questions on your 2 stroke motor email me at rdyami@aol.com I'd be glad to help you.

Quadcrazy
98 warrior
durablue axle
dunlop skins all the way around
dg skid plate

 

maybe you can help me out.
I'm stupid when it comes to computers.
How do you put a picture on the messages.
that way you can see my high flying act on my warrior.

 

Well, i found out what happened, my oil injector got dirt in it(somehow!) and it clogged up.

I took the oil injector off, My friend who has done many rebuilds honed it for me(there were no deep marks in it now or any slight ones now) It has already been bored. .20 over. I ordered a new pistons they sent me the wrong one! a stock one. When i said exactly what i wanted.

Magic Racing, never again!

Tomorrow night, i am going to pick up a new piston at a yamaha shop

The reason i kicked it over was, mainly..How can this damn thing be locked up? It has had a top end done no more than 3 months ago.

And i was 5 miles from home. Long walk when it's 90 out!

 

Do one more thing while your at it... check your air filter. It looks to me like some dirt and sand might have gotten past it and that added to your injector failing caused you to sease.

 

I have a new Uni filter.