Mine did again yesterday evening. I'll bet that my carbs have blew off at least 10 times, and after installing 27.5 pilots, once again it happens. When the machine was completely stock, the carbs still blew off! I have removed the snorkle, baffle, and rejetted to 145/150 on the mains. Also, the pilots are presently set on 1 turn out for the left side and 1.25 turns out for the right side. When examining the carbs yesterday, it appeared that the right carb came out first. I must admit that the 27.5's helped a lot, but still no fix. Anyone have this problem? The cure? Please only constructive posts. Replies are much appreciated.

 

Is this due to engine vibration?

I saw the same thing happen to a Warrior two weeks ago.

 

What are you doing when they blow off.

Just from your info it sounds like the idle mixture screws are a little lean. Maybe try setting them to 2 to 3 turns out.

 

Only happens at low speed operation....lugging around....hit the throttle...pop! With the stock pilots, when the # of turns out on the pilots was less, the tendency for the carbs blowing off was less......so this is why I used 1 & 1.25 for the 27.5's. Thanks for the replies so far guys.

 

Loosen up your airbox and slide it the hole way forward and take spacers out of carb boot clamps that should fix your problem plus make sure your not lean. You shouldnt have to run 27.5 pilots even with snorkel off I would go back down because this is prob causing you to run rich down low and your not getting totall throttle response which can cause bike to cough and bp will blow carbs off. Loosen up airbox and make sure its as far forward as it can go.

 

I have already moved the air box up and took the spacers out. Throttle response is the same as it was completely stock and it seems to lug down a little farther before stalling. I'll have to check the plug this evening to check for a rich or lean condition. Thanks.

 

Mine did the same thing only it happend when I cranked mine up. It did it 10 or 15 times until I took it to my Yamaha shop and they fixed it. Mine was in the Carbs to lean and the valves off to. Take it to em and see if they can help you out they did mine.

BoOgIeMaN

 

no, your not the only one. i was riding last weekend when i saw a raptor sitting off to the side, and that guy just blew his off. He said he could handle it, so i went on riding and didnt stay to ask any questions.

 

Don't worry about what others think your carbs should be jetted at, give your engine what it wants, and a backfire thru the carbs upon acceleration is a lean condition.

Try some fatter pilot jets, what do you have to lose. Pumper carb(s) would probably be the ultimate fix.

 

The 2 friends that ride with me both have blown off there carbs also. They took the parking brake off and this stopped the problem. I think that it has something to do with the rev limiter kicking in from the emergency brake. Someone might know more about this, but this fixed there problem.