wr450f very hard starting, no spark?

[aussieklx]

Ok fellas my 05 has become a bitch, i started it fine the other day road down the road to my mates house switched it off talked shit for about an hour went back to start, nothing, had to roll start to get it going. Has started off the button or kick since, put new plug into today, nothing, checked for spark by putting plug end on head bolt and cranking, nothing. So i have no spark. Where do i go from here to diagnose the problem, checked the fuses under the seat near batt, all good are these the only fuses. Its just weird cos its been fine for ages started fine hot or cold. Any help appreciated

Cheers

[tweav]

I'd try unhooking your kill button , and see if your spark gets brighter. after that I'd search for pinched wires.

[MaxPower]

my starter wire was grounding right where it came out of the button against the front brake perch

[BIGMatt]

check your valve clearances too... but that does't explain the no spark.

[flyer05]

Dead coil ? Check as per the manual.

[c9buff]

Flyer's post may have really helped me.

My 05 would start first kick, I'd do 5 laps around the house and the bike would die. It would not restart.

I pulled the coil and put a multimeter on it. Totally out of whack. After the coil would cool, the bike would fire on first kick like nothing happened.

buff

[aussieklx]

ok thanks for that guys, ive checked switched looms fuses couples etc all looks to be in order, disconnected kill button, no change in spark result, so im heading in the direction of the coil, just got to get my hands on amultimeter now and measure the resistance, hmmm. is the coil teh same as an 04 wr250f ive got one of those too

[Fullbore4]

At this point I would now do the electrical check as outlined in the manual. The manual is available on line. Also you can check part numbers on the following site

http://www.crotchrocket.com/pages/parts/viewbybrand/2/Yamaha.aspx

[kskyles]

Flyer's post may have really helped me.

My 05 would start first kick, I'd do 5 laps around the house and the bike would die. It would not restart.

I pulled the coil and put a multimeter on it. Totally out of whack. After the coil would cool, the bike would fire on first kick like nothing happened.

buff

when you talk about the coil, are you referring to the stator?

[c9buff]

The ignition coil on the WR is that big plastic black boot that fits over the spark plug.

buff

[flyer05]

No, the lead from the boot to the thingy that attaches to the frame. That is the coil ( on the frame)

[aussieklx]

the ignition coil is combined with the plug cap on my of, a long black thing which plubs into a lead at the top.

Ive tested the coil on my dads 250f and it works fine sparks up no worries so where should i start looking now. If i want to check the wiring involved, where do i start and head to? With key on i have power up to the speedo, ignition light is on.

Cheers

[rubberband-man]

check the stator. I rewound mine for Dual sport kit, and had the same problem. I could push start it, but that is it. Puled stator and had grounded wires (pinched against body of stator. Haven't had a problem since, but had to replace my battery cuz that drained it out.

[aussieklx]

well you wouldn't ****ing read about it, the plug that comes from the CDI with the grey wire in it was loose, not off jsut a little loose, refitted bobs your uncle, running sweet as, still doesn't explain why it roll started. Now just got to get my jetting sorted....