See if pushing down on the air box lid helps any at all. I've had to replace air boxes and warped lids because of this when bolts broke and lids would not seal tight enough and it would run lean. Still to be sure I'd check the exhaust lobe. Maximum wear limit on the lobe is 1.2766 inches. Any lower that that could cause the valves not to open enough to allow full power and could cause backfiring through the air box.

 

Well I think I found the problem. I tried to time the engine again, and I noticed that the new crank shaft sprocket I put on (it was broken in half when I bought the bike) was stripped at the key-way and the slit nut was loose. I bought a new sprocket and the actual tool to tighten the slit nut. This time I will put lock-tite on the slit nut and be able to actually get it to the 70 ft-lb or torque needed.

 

Use plenty of loctite! Even though this slotted nut has reverse threads they can back off and cause woodruff keys to split and cause sprockets to crack as you've found out. I've had several do this through the years along with this recent post and video by another member. http://forums.atvconnection.com/pola...ml#post3186503

 

should I jbweld it or something? This is probablly how the old OEM crank sprocket broke

 

No Jb weld! Just red loctite on the threads if you have it, if not,blue will be ok,then since you have the slotted socket,just impact the nut tight.Half the time I didn't bother with the socket! I just loctite the threads and used a punch to stake the nut tight when I rebuilt engines. Just make sure the new sprocket you have hasn't worn down in the key way slot from the loose nut and the wooduff key is ok. After it's tight you shouldn't have anymore problems.

 

Ethanol gas boys. Starts to mold up in 30 days. It's the 10% corn that they put in it. Have your carb cleaned with an ultrasonic cleaner. I fix so many carb problems with small engines. Theses things rock. Dismantle the whole carb and soak it in the ultrasonic cleaner for 15 minutes. Blow out all the passages with compressed air. Run nothing but high octane gasoline in all your small engines.

 

What difference does it make when the high octane gas is also 10% ethanol?

 

No there is no ethanol in high test gas.

 

Found this article below.
I live in Ontario Canada. We don't have ethanol in our high test gas. T.G

There are certain myths floating around about premium gas and what it will and will not do. Myths like you get better gas mileage on premium gas. Or your car lasts longer if you spring for the expensive gas. Is there ethanol in premium gas?

does premium gas have ethanol.There are some people, who swear by premium gas and will put nothing else in their vehicle. We think of those people in the same grouping as the people who swear by changing their oil every 3000 miles on the dot.

There's nothing technically wrong with either of those things. It's just that they may not be getting all the benefits they think they're getting, not to mention throwing money away unnecessarily.

In one of our previous blogs, we were discussing how ethanol requirements actually vary by state. The individual states have a certain amount of freedom to write their own rules for how much ethanol is made available and where you can find it. That doesn't mean there are any states which are ethanol free. The differences are mainly in the labeling laws and whether the states will allow ethanol and ethanol-free gas to be sold alongside each other. Some states like Oregon prohibit that completely while other states like Arkansas allow it much more.

Ethanol in Premium Gas?

There is a difference between states on whether premium gas specifically has ethanol in it or not. Or, more correctly, whether it's required to have it in it. Two states in the Union, Missouri and Montana, have specific exemption to allow ethanol-free premium gasoline. So if you live in one of those two states, you can be thankful.

For the rest of us, we are faced with the unpleasant reality that the refineries are all but tied into putting ethanol in premium gas. This is because they have to use the ethanol to raise the octane level of their gasoline blend in order to satisfy the higher octane requirements of premium. This is one reason why you don't get better gas mileage with premium gas, because an essential part of that blend is a component that has less energy and forces the gas mileage down simply by nature.

So don't get fooled into thinking you can escape ethanol's grasp simply by paying more and getting premium gas.

You May Be Interested In These Other Posts:
Ethanol Additives For Boats
Using Premium Fuel

 

Have plenty of ethanol down here. Just use any good brand of fuel stabilizer that can protect fuel,hoses,engines and keeps gas fresh.Then you wont have fuel related problems.These are just two. Several more out there that are good.
Marine STA-BILŽ Ethanol Treatment & Fuel Stabilizer Star Tron Enzyme Fuel Treatment