BannedCR500Riders.com

Finally got a chance to take my bike out for a run... it's got some major problems in the engine department....


Left me stranded today, had to walk 4km back to the car..

Seems to run fine cold, once the temp increases anything above half throttle it feels like it's misfiring...

EDIT i mean engine temps not ambient air temps.

it feels like it's electrical, never felt jetting that bad so cant tell if it is

The changes, my engine was running nice before the build. Saying that i have put a new stock standard cylinder on the bike. My previous cylinder was opened up a little "standard port hieghts" but nothing major. I am still running my 40mm PJ carb , i am also running for the first time the coil from the 125 instead of the 500 coil.....

exact same jetting i've always run... it used to be perfect starting cold

NOW, it's a bitch to start cold I came out of a creek bed and it misfired badly 1/2 to full throttle and died under load.

It will not start again, i've tried new plugs, air screw etc. NO GO. I've got spark. The plug i pulled when it stopped was a tad rich but NOT wet..

I'm stumped.

sounds like the coil?
bad luck about the walk man.

just because it sparks in the atmosphere doesnt mean it sparks under compression.

If you have spare parts or a parts bike, id say its time to start swapping parts.

i've gone over the electrical system, checked ohms readings for everything. I have NOT checked peak voltage. I dont know how. Dont have an adaptor.

The coils from both 125 and 500 give same readings...

It may even be fuel, i'll double check.. My bike was similar once before about 8 years ago. I turned out to be choke assembly collapased. I've checked it. It's not that.

Surely the jetting wouldnt be that far out just from swapping the cylinder over

main jet hasnt come loose and fallen out mate

OK, swapped the coil " Bang " started first kick. Still not understanding why the other coil failed though.

Primary and secondary winding had the same values. Maybe something more sinister going on in there.

when switching ignitions, they are ment to be run together as complete units.
running parts from different ignitions does not always give good results. there was a ignition dyno post that gave results for mixing and matching ignitions. and using different coils gave mixed results.