03 wr450 dieing in the rough.... ideas?

Hey guys I'm having a problem when i'm hitting some whoops or a rough spot my bike will bog or completely die.

It's almost like running out of fuel, I was thinking possibly dirt in the carb getting stirred up?

What do you guy's think?.. am I on the right road?

Thanks in advance :cry:

Todd

I wuold try cleaning the carb with some carb cleaner and see if it still happens.

It may be the floats.

Disconnect the kill button and see if the problem goes away.

This bikes have really crappy designed buttons that after some use, start shorting out by themselves.

Mine is an 03 that also just started flaming out every now and then. Turned out to be the button.

Thanks for the reply's.... I didn't even think about the kill button I'll try that first because that's easier. If that doesn't work i'll rip the carb apart.

Todd:thumbsup:

I have seen both happen. Dirt in the carb plugs the jets. Try draining or removing the bowl - you may have sucked some sand. On the other hand I had a friend who had a bad kill switch. He got a new one from Yamaha and it did the same thing. He goes without now. As others have mentioned, float levels will cause the same to happen. Hope this helps.

Riding with the Choke on will act the same way.

I learned this 2 weeks ago, after getting up too early for a ride and not being awake.

i had the same problem,it usually occured at low rpm under load in technical sections. almost like someone pulled the plug wire, well after some research i found that high compression motors can blow out the spark occasionaly and at the low rpms goin' up a technical hill it just doesn't have enough momentum to carry it through the next stroke. so i started looking at ignition options,(jetting was perfect,valves were in middle of spec) well vortex and such were all around $500,tried a irridium plug;helped a little. then saw the i-cat and figured i've spent $200 on worst things. installed it and it hasn't happened in the 3 months its been on. way better throttle response and better fuel economy. now just about everyone says these things are a bunch of crap,but i've researched the technology behind it and its valid. and everyone who has actually tried one loves it. i'm not saying thats your problem but if the other things don't do it,you might think about one.:cry:

If the drain hole on the side of the cylinder get plugged, water doesn't drain away if it gets in. The when the engine gets hot it can boil and pop your spark plug boot up. You mau not notice until you hit the rough stuff and you get an intermitent spark. Just a thought.

i had the same problem,it usually occured at low rpm under load in technical sections. almost like someone pulled the plug wire, well after some research i found that high compression motors can blow out the spark occasionaly and at the low rpms goin' up a technical hill it just doesn't have enough momentum to carry it through the next stroke. so i started looking at ignition options,(jetting was perfect,valves were in middle of spec) well vortex and such were all around $500,tried a irridium plug;helped a little. then saw the i-cat and figured i've spent $200 on worst things. installed it and it hasn't happened in the 3 months its been on. way better throttle response and better fuel economy. now just about everyone says these things are a bunch of crap,but i've researched the technology behind it and its valid. and everyone who has actually tried one loves it. i'm not saying thats your problem but if the other things don't do it,you might think about one.:cry:

I'm very interested in the research you did on the icat. Can you post it?

posting copies of things still baffles me but i can explain a little. its a potted diode,in reverse phase that acts in a sense as a capacitor;as the charge is sent to it it dams the charge until it reaches a bypass level thereby lengthening the negative spike which in turn lengthens the spark duration. the process does not amplify output(in fact it degrades it slightly) but the benefits outwiegh that. many think its hogwash but everyone who has tried one (that i've seen probly 30 or so diff people) all sing high praise. :cry:

Oh, a zener diode. Must be using a res/cap tank circuit to change the discharge time or pulse width, a diode can't do that by itself. I knew the increased power level was BS without an external source. Increased spark duration I can see.

Thanks for the reply.

Hey guys I'm having a problem when i'm hitting some whoops or a rough spot my bike will bog or completely die.

It's almost like running out of fuel, I was thinking possibly dirt in the carb getting stirred up?

What do you guy's think?.. am I on the right road?

Thanks in advance :cry:

Todd

Todd, is it happening when you hit the throttle quicklyfrom a low rpm? If it is there is quite a few things to check but I found out one area that might effect this problem.

You are right to be looking in the fuel distributing area of course, my problem was in the Accelerator pump area. I did it last year with my mechanic so I am a little foggy as to which return spring/lever we worked on. Anyways open it up so you can see the throttle assembly and accelerater pump levers 1&2 and while you keep an eye on the opening and returning of the accel pump have someone crack open the throttle and release. What you are looking for is any delay upon opening ofthese levers. When I looked at mine it was vident that the lever was not opening quick enough. Therefore the fuel did not dispense when the throttle was needed for a quick burst instead It developed a stutter (stall) because of the poor movement of the Accel pump lever. We fixed mine by tieing it open with a zap strap. But evidently there is a jet now that can change the effect of the accel pump. Sorry I am not sure what it is. I will talk to my YamahMan and get back to you. Unless anyone else has had my situation! :cry::cry: P.S. Don't do it with the bike running!

Maybe a broken wire going to the ignition switch or wher it's soldered onto the switch.Mine used to die when backing off the throttle it took a long while to find as it appeared to be a fuel problem.

Hope this helps Dave

Feedback requested:

You found the problem yet ?

I pulled the carb off and went right through it , it looked good though.

Didn't have a chance to get out for a ride last weekend so I will be going out for a rip this weekend,I'm going to try unplugging the kill switch and see if that works..... I'll let you know. :cry:

Todd

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