ontario400ex
11-22-2006, 07:24 PM
Bought a 2000 400ex, all stock.
I've been through the search feature, one by one, and I've checked/fixed/replaced things based on those suggestions. I'm an auto-mechanic by trade, and I've had 2 stroke bikes and jetski's throughout my younger years.
Anyhoo...
Bike ran fine when I demo'd it before buying, but when I got it off the back of my pickup truck, it would barely start, and then it wouldn't idle without playing with the choke, and then it would backfire through the carb. It backfired so badly that it blew the boot apart that bolts to the cylinder head.
None the less, I replaced that, thinking maybe it had been loose and allowing air in (leaning it out), no different. Still backfires and won't idle.
I took the float bowl off of the bottom of the carb and blew carb cleaner and air through each of the jets. I took the jets out next and made sure they were clean. My pilot jet read something like 138, and the main was 148. I'm not 100% on those numbers, more like 98%. Jets were clean so I reassembled the carb. No difference. It still sputters, backfires, and won't idle unless I play with the choke, and even then it will still die after 2 or 3 seconds.
Pulled the sparkplug.... CAKED with black powdery carbon, and looks like had been in there since... well, quite a long time. I replaced the plug and gapped it to .035 (as per the NGK catalog), Still sputters, coughs, backfires, etc.
I removed the plug again to check the spark. It looks faint compared to what I'm used to, but it sparks consistantly. The end of the spark plug after 30seconds of sputtery running is slightly black and runny looking. i.e. severely rich)
I then unscrewed the sparkplug cap from the coil wire, and snipped off 3/8" so that I could see fresh core wires. I held the wire a 1/2" away from the cylinder head, and it would jump that gap. The spark was by no means super strong bright blue, but it was blue and I could see it jump the gap. I screwed the cap back onto the wire, reinstalled the plug, hooked it all back up, its still coughing, sputtering, etc.
I was going to test the compression while it was still slightly warm, but I don't have an adapter for the goofy tiny plug thread on these engines. I managed to get my thumb down the plug well and it very easily blew my thumb off with hot-compressed air.
I'm very wary on ignition timing or valve timing on these engines, because of past bad experiences.
If there's anyone who can direct me on this forum, or if anyone is in my area (Hamilton ontario/canada) please help me out...
I just want to ride this thing, even if it's around the parking lot at work..
Much thanks in advance for ANY useful replies,
-Scotty
I've been through the search feature, one by one, and I've checked/fixed/replaced things based on those suggestions. I'm an auto-mechanic by trade, and I've had 2 stroke bikes and jetski's throughout my younger years.
Anyhoo...
Bike ran fine when I demo'd it before buying, but when I got it off the back of my pickup truck, it would barely start, and then it wouldn't idle without playing with the choke, and then it would backfire through the carb. It backfired so badly that it blew the boot apart that bolts to the cylinder head.
None the less, I replaced that, thinking maybe it had been loose and allowing air in (leaning it out), no different. Still backfires and won't idle.
I took the float bowl off of the bottom of the carb and blew carb cleaner and air through each of the jets. I took the jets out next and made sure they were clean. My pilot jet read something like 138, and the main was 148. I'm not 100% on those numbers, more like 98%. Jets were clean so I reassembled the carb. No difference. It still sputters, backfires, and won't idle unless I play with the choke, and even then it will still die after 2 or 3 seconds.
Pulled the sparkplug.... CAKED with black powdery carbon, and looks like had been in there since... well, quite a long time. I replaced the plug and gapped it to .035 (as per the NGK catalog), Still sputters, coughs, backfires, etc.
I removed the plug again to check the spark. It looks faint compared to what I'm used to, but it sparks consistantly. The end of the spark plug after 30seconds of sputtery running is slightly black and runny looking. i.e. severely rich)
I then unscrewed the sparkplug cap from the coil wire, and snipped off 3/8" so that I could see fresh core wires. I held the wire a 1/2" away from the cylinder head, and it would jump that gap. The spark was by no means super strong bright blue, but it was blue and I could see it jump the gap. I screwed the cap back onto the wire, reinstalled the plug, hooked it all back up, its still coughing, sputtering, etc.
I was going to test the compression while it was still slightly warm, but I don't have an adapter for the goofy tiny plug thread on these engines. I managed to get my thumb down the plug well and it very easily blew my thumb off with hot-compressed air.
I'm very wary on ignition timing or valve timing on these engines, because of past bad experiences.
If there's anyone who can direct me on this forum, or if anyone is in my area (Hamilton ontario/canada) please help me out...
I just want to ride this thing, even if it's around the parking lot at work..
Much thanks in advance for ANY useful replies,
-Scotty