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Yfz 450 Cutting Out At Half Throttle....

14832 Views 43 Replies 14 Participants Last post by  alexsis.rodriguez13
I'm posting for a friend that has a sick 450. At HALF THROTTLE, it cuts out. After a new spark plug, new fuel on/off switch, it still cuts out. We've tried cleaning the air filter, and still no dice. This bike would run side by side with my Raptor, and now gets left in the dust. Any help on this subject would be greatly appreciated.

Thanks-
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Try turning the lights on as it's doing it......trust me on this one. :smile:

Read this---->CLICK HERE
if it ran side by side with a raptor somthing was wrong with it to begin with
Originally posted by 2fast4uracingxc@Nov 7 2005, 03:21 PM
if it ran side by side with a raptor somthing was wrong with it to begin with
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Side by side through the first three gears. In a short distance it was side by side with the Raptor. The Raptor was the winner in three out of three and not by much!. In a long distance the Raptor was two and a half bike lengths.

After I jetted the bike, and added the full Yoshi exhaust the Raptor jumped out of the hole and was pulling away in third gear.

My buddy removed the baffle out of the YFZ 450, helped a bit, but not as much as jetting and exhaust system would. The 450 is an awesome bike for it's size class, just not the right bike for me. I'd like to see how the new Suzuki 450 will compare.

Take care-Don't break anything!
Originally posted by YFZ450alterego@Nov 7 2005, 03:14 PM
Try turning the lights on as it's doing it......trust me on this one. :smile:

Read this---->CLICK HERE
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Thanks for the info....We'll give it a try!

Take care-
Originally posted by Flynbyu@Nov 7 2005, 04:37 PM
Thanks for the info....We'll give it a try!

Take care-
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Tried the lights, and it's still cutting out really bad. Anyone know anything about the gas cap or fuel venting properly causing the bike to run funny or anything?
Try running it on reserve and see if that helps.
Originally posted by yfzster@Nov 12 2005, 02:31 PM
Try running it on reserve and see if that helps.
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We have ran the bike on reserve, and that is only a temporary fix.

It continues to cut out within a matter of minutes. I'm thinking there may be a problem with the e-brake sticking, or something. My Raptor cuts out the same way if the e-brake is applied. The previous owner had a nasty spill on the 450, and bent the handlebars.
Originally posted by Flynbyu@Nov 7 2005, 10:38 AM
I'm posting for a friend that has a sick 450. At HALF THROTTLE, it cuts out. After a new spark plug, new fuel on/off switch, it still cuts out. We've tried cleaning the air filter, and still no dice. This bike would run side by side with my Raptor, and now gets left in the dust. Any help on this subject would be greatly appreciated.

Thanks-
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is it stock???
Originally posted by oohrah06YFZ450@Nov 14 2005, 11:36 PM
is it stock???
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Yes, it's stock.
Try rejetting it since it is colder out side now? Is it only happening at half throttle?
I had a problem kinda like that. If you dont push in the cap really tight onto the spark plug, it will wear the spark plug down around the threads, and you wont get full spark.
Originally posted by tersejr@Nov 15 2005, 11:56 AM
Try rejetting it since it is colder out side now? Is it only happening at half throttle?
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I don't think rejetting is the issue, the temperatures until 14 November 2005 have been in the upper 70's low 80's here in Southeastern Oklahoma. Bike has been cutting out while it's mild, low humidity.
Originally posted by hokes@Nov 16 2005, 09:05 AM
I had a problem kinda like that. If you dont push in the cap really tight onto the spark plug, it will wear the spark plug down around the threads, and you wont get full spark.
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It has a new spark plug, and it has occured before and after changing the spark plug.


Thanks!
Not sure about his but mine is an 05 and came with a gas cap with no vent tube. Mine would start cutting out and by loosening the gas cap it would clear up.
Originally posted by rtusnake@Nov 16 2005, 02:29 PM
Not sure about his but mine is an 05 and came with a gas cap with no vent tube. Mine would start cutting out and by loosening the gas cap it would clear up.
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One of my riding partners has a KX250 and he had the same problem, so we'll give it a try.

Thanks!
Mine cuts at full throttle, ive done all the usuals to try and fix this. Im wondering abut the spark plug though. Ive changed it already but i know i tightened it but didnt really wrench it down as i figured would not be good. U think im not getting all the spark. Im good unless try all out full throttle then it cuts out (really sucks!). I feel you pain man !
Originally posted by Flynbyu@Nov 12 2005, 04:50 PM
We have ran the bike on reserve, and that is only a temporary fix.

It continues to cut out within a matter of minutes. I'm thinking there may be a problem with the e-brake sticking, or something. My Raptor cuts out the same way if the e-brake is applied. The previous owner had a nasty spill on the 450, and bent the handlebars.
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If it fixes it temporary then you may have isolated the problem, have you tried running with the choke on or partially on? you might just have trash in the tank filter. its just a thought
Originally posted by Flynbyu@Nov 7 2005, 03:27 PM
Side by side through the first three gears. In a short distance it was side by side with the Raptor.  The Raptor was the winner in three out of three and not by much!.  In a long distance the Raptor was two and a half bike lengths.

After I jetted the bike, and added the full Yoshi exhaust the Raptor jumped out of the hole and was pulling away in third gear.

My buddy removed the baffle out of the YFZ 450, helped a bit, but not as much as jetting and exhaust system would. The 450 is an awesome bike for it's size class, just not the right bike for me. I'd like to see how the new Suzuki 450 will compare.

Take care-Don't break anything!
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yes there is something seriously wrong with the yfz if a raptor can keep up with it. saying the yfz is ok for its size. sorry there fatser then a raptro 660 or 700.
Originally posted by bansheeman@Nov 17 2005, 04:23 PM
yes there is something seriously wrong with the yfz if a raptor can keep up with it. saying the yfz is ok for its size. sorry there fatser then a raptro 660 or 700.
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Bull-butter.

Not trying to start up a pissing match, maybe I've just got a good Raptor, but I haven't been beat by a YFZ450, BANSHEE, DS 650, or a Predator in a drag race. It gets a little old, everyone and their brother coming up and asking you "Is that thing fast?". Two weeks ago I had some guy approach me on a 86' Honda 250R THREE WHEELER and wanted to run for $20 bucks! I told him "I would feel bad taking his riding money for next week." I ran him anyway. He didn't even stop back by and visit with our little riding group after I smoked him like a Thanksgiving turkey.

There is no replacement for displacement, other than spending HUGE amount of money on technology to make a bike perform better. 95% is the rider, the other 5% is the equipment. Given, if I were to buy a bike to race, it would be the YFZ 450 hands down. It's got a sweet suspension, and it's easily tuned. Lots of gizmos out there in the marketplace that are totally trick. To trail ride, or to hit the dunes, I'm sticking to my Raptor.

It's not about going the fastest, it's about getting some seat time in and having fun.

The best bike that I have ran has been a YFZ 450. It had been as modified as much my Raptor, and it's the one that's a bit sick now.
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