Yesterday evening I met some people while riding the Matfield Mccoy trail and had to immediatly lock-up the rear brakes killing the engine. When this happened..the engine backfired. So I think, no problem...I'll coast off to the side of the trail, let the people pass, refire and be on my way. Big problem...the Raptor won't start...won't even hit...I've killed the plug? I dismount and look at the new woods ornament just sitting there. As I start to pull the plug, I notice that the carbs have blew off. Now how did a simple backfire blow the damn carbs loose? Apparantly, that's a lot of pressure coming back through the carbs! No problem...I'll slide the carbs back into the boots and be on my way. Another problem, this is no phillips or straight head bolt, it required an allen head wrench! No allen wrench on board...I'm outta luck! So I push it in the weeds telling my brother that it's insured and we take off on his Banshee. I stop by the trailhead to see if anyone had an allen wrench. Ha!...my lucks back! A guy working there loans me some and I take back off to drag the Raptor back into the road so I can work on it. Now it's dark (9:30pm) and I am trying to work on the carb boots with absolutely no room around the carbs! My brother is shining his headlights so I can see what I am doing. So what happens now...the Banshee starts to overheat! So he shuts it off and we scratch our heads in the dark. I think hmmmmmmm, detachable headlights huh? So I turn the ignition on, take the headlight off and turned around so I could see. Finally! I got boots back on and tightened up. I look at my watch....damn!....it's 11:30pm!...we mount up and ride hard about 20 miles back to the trucks! What an evening! I'll bet I have an allen wrench on board next time I go riding (hopefully I won't need them!) Later!

 

Gary are you still running the Raptor stock? If so have you taken out your Spark Arrestor? How about did you cut the snorkel intake plastic off?

Also after your break in did you take the bike in to have the valves adjusted?

Blake
2001 Yamaha Sand Raptor 660R

Please visit www.glamisonline.org for everything you want to know about Glamis.

 

This same thing just happened to me a day or so ago except it was before I ever got it into the truck. Is your climate changing? Is it a little cooler than it has been? My guess is that the cool air is causing them to run even leaner than what they were. I believe Yamaha let them go from the factory really lean so that they would pass all emmision laws. We need to contact Yamaha, because this seems to be a very common thing from reading the board today.

 

I have removed the rubber flaps in the intake passageway and the spark arrester is still installed. I opened up the idle circuit a half turn and raised the needles one notch previously. The plug looks good.

 

I just called Yamaha customer service. They said they they don't show any recalls, and that if it is actually a technical problem, the dealer will have to call the Yamaha tech line. We all need to urge our dealers to do this so that we can get some straight answers on what is causing this.

 

hi bash
i dont think it is running lean .
when a motor backfire through the carb (carb blown off) it is because one or more of the intake valves are not fully closed when the motor fires. i think the valves are too tight. it needs to be adjusted.
ps .. so far my bike runs like a dream.
paul

 

Paul....I believe you may be correct. I have'nt had my valves adjusted yet this could easily be the problem.

 

Bash...have you had your valves adjusted yet?

 

hey paulb do you have more info on Kitima? do they have a web site or dealers in the U.S.? Is their exhuast made just for the raptor?

 

hi yamaraptor
the kitima pipe is a slip-on like the ones you get for the superbikes. it is a local pipe (South Africa) and it is based on the r6 pipe.
i will post some pics off the pipe as soon as i get my photos developed.
paul