WR 450 won't accelerate


22 replies to this topic
  • pilsner

Posted June 29, 2007 - 08:36 AM

#1

My o4 will not accellerate while under load, it just bogs down real bad. While in neutral it will rev up no problem, but as soon as the transmision is engaged it just bogs. I tried new jets from 160 to 180 but no improvement. Tried playing with air/fuel mixture screw, no improvement. Top end was just rebuilt and all valves are perfectly in spec. My lights don't work and battery doesn't charge but this isn't new and my bike worked fine before with these problems. What could it be????? Something electrical???

  • clark4131

Posted June 29, 2007 - 08:41 AM

#2

Worn out clutch maybe?...SC

  • pilsner

Posted June 29, 2007 - 11:09 AM

#3

Worn out clutch maybe?...SC


The engine does not accelerate while under load. If it was the clutch the engine would accelerate but the bike would lack.

  • TajMan

Posted June 29, 2007 - 11:11 AM

#4

Have you checked the plug?
Hmmm I dunno if something with ignition could do that.

  • pilsner

Posted June 29, 2007 - 11:16 AM

#5

Have you checked the plug?
Hmmm I dunno if something with ignition could do that.


Brand new plug, put in with top end rebuild.

  • redhurricane

Posted June 29, 2007 - 11:47 AM

#6

Does it accelerate while NOT under load?

will it accelerate under "light" load? is it relative to how much throttle?

  • waynus

Posted June 29, 2007 - 01:13 PM

#7

Did this start happening all of a sudden or have you had something apart and then it started happening?

Electrical can cause this type of thing but it's more likely to be fuel related. Is the carby slide in the right way?

  • Mutu

Posted June 29, 2007 - 01:25 PM

#8

change the battery.....

  • pilsner

Posted June 29, 2007 - 01:50 PM

#9

Does it accelerate while NOT under load?

will it accelerate under "light" load? is it relative to how much throttle?


The bike will accelerate to a slow/moderate speed by slowly rolling on the throttle to about a quarter turn, anything past that the bike totally bogs down and all acceleration is lost. the further I roll on the throttle the more the bike bogs, also, when letting off the throttle the bike backfires so loud it sounds like someone got a shot gun in my muffler.

  • pilsner

Posted June 29, 2007 - 01:52 PM

#10

Did this start happening all of a sudden or have you had something apart and then it started happening?

Electrical can cause this type of thing but it's more likely to be fuel related. Is the carby slide in the right way?


Yes, this just started happening all of a sudden.

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  • MountainMax

Posted June 29, 2007 - 02:13 PM

#11

did you give the carb a good cleaning? is the flow from the tank good? sounds like it's starving for fuel to me.

  • new2blu

Posted June 29, 2007 - 03:04 PM

#12

Remove, dis-assemble and clean the carb and all passages with carb cleaner. If this dosen't help maybe the cam chain has jumped time and the cam chain will need to be replaced and cams re-timed,but I really sounds like a carb issue to me.

  • pilsner

Posted June 29, 2007 - 03:05 PM

#13

did you give the carb a good cleaning? is the flow from the tank good? sounds like it's starving for fuel to me.


That's gotta be the problem (starving for fuel). I'll give the carb a good cleaning. Would this account for my stock muffler getting so hot as to melt the plastic, while the header pipe does not get overly hot????

  • MountainMax

Posted June 29, 2007 - 03:30 PM

#14

if that don't fix it, check the timing, i know in vehicles if they are off one tooth you can lose major power but it will start and idle fine. Keep us informed

  • pilsner

Posted June 29, 2007 - 04:11 PM

#15

Talked to the local yamy garage, they say it's definitely the stator going on the fritz. Does this make sense?? poor stator performance = poor spark = poor/shitty bike performance = muffler getting so hot as to melt the plastic??

  • MountainMax

Posted June 29, 2007 - 06:52 PM

#16

Again, sounds lean to me......... that will make the exhaust red hot

  • MojaveThumper

Posted June 29, 2007 - 07:42 PM

#17

Again, sounds lean to me......... that will make the exhaust red hot


This has my vote.

As stated, take apart the carb and clean.

As for your lights and charging, that could be your stator. Pretty sure the manual has a procedure for testing that.

  • Matt James

Posted June 29, 2007 - 08:34 PM

#18

Sounds like your pilot jet is plugged. Try running it with the choke on. It will be real rich and get you past the dead spot. If that works you need to pull the carb and pull all the jets and clean everything.

  • Asgeir

Posted July 01, 2007 - 01:20 PM

#19

Check if the muffler is open through, no fiber restricting flow.

The stator could be the problem, measure the voltage, install a battery.

The Ignition control box, does change maps between neutral and "in gear".

Way to lean usually shows on a red header. (helps to check in the dark)

  • pilsner

Posted July 01, 2007 - 07:14 PM

#20

Yeah I thought my muffler may have been plugged to, but when i dropped my flashlight in it, it came out the other side no problem. I'm just waiting for my new stator to come in, does $140 cdn. sound ballpark?




 
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