[hr]Hi guys. First off, great forum. I've been trying to find my solution by checking out other threads but I didn't really get anywhere so I decided to join. Now here's the shocker. I don't ride street anymore. I still ride Red, and always will, but I have been forced to stick with 450cc's of dirt chewing bliss (I have a CRF 450). Three years ago my girlfriend, who's now my wife, saw me swap paint with a Toyota Corolla (you can guess who was driving) on the 405 freeway while she was following me home. Amazingly, I stayed on the bike, an F3, and only suffered a sore knee and a cracked fairing. The accident happened at 20MPH but that was still it for riding street according to her. Anyways, what am I doing with a F4 engine you might ask? Well, I'm building my wife a Mini Buggy (think 3/4 scale Class 1). Here's the link for those interested http://www.minibuggy.net/modules.php...pic&t=1112
The power plant is a F4 engine with Ebay purchased parts, which has been another disaster. So here's what going on. I have bypassed the anti theft wire (the pink one at the ignition) with a 9 volt voltage regulator. That took a week to figure out but it gave me spark and fuel. So now it fired but it would only run for 45 seconds at a rough idle and if I gave it any gas it would die. So, I cleaned out the carbs, which were actually really dirty, bolted them back up.....nothing. It still ran the same. So, still figuring it was the carbs, I buy a set off Craig's List from a guy a few blocks away. They were just serviced and synced by Mach 1, the local streetbike gurus, so I thought the problem was over. Guess what...same thing. I drop the bowls and the jets are perfectly clean. It's giving all of the signs of running lean. Rough idle, any gas and it backfires, hard to start, etc. If I spray ether over the velocity stacks it has no effect and the pump is clicking the whole time. So here's the weird part, the plugs are black. So I talk to a few mechanics and now I'm thinking it's electrical. When it stops running, it does just that, just stops, like the ignition has been killed. So I pull the plugs and check for spark.....again. It still has spark so wtf? So after two weeks of this I am working on it for the umpteenth hour and it just stops generating spark. Ignition Pulse Generator? I just pulled the cover and the magnet is fine which is usually the problem, so I'm told. I ordered one today but now I'm thinking CDI. The engine is on a test stand and when I first started messing with it the rectifier got dislodged from the ground I had it hooked to. Think that could cook the CDI or IPG? The other thing is that all of the parts are cobbled together. I got the motor from one guy, wiring harness from another, and CDI from another. I'm not sure if the motor is a '99 or '00 so are there different CDIs for each year? My CDI has the part # MBWA A W73A 9204. I'm taking the CDI to Mission Motorsports tomorrow to test the CDI. The problem with taking the entire engine to a shop, which is what I'd prefer at this point, is that NOBODY want's an engine that isn't in the bike. It makes it a pita to move around the shop if they have to. So what do you guys think? Thanks in advance....Jesse
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To fix your loss of spark check the engine kill switch, the solenoid valve relay, and the fuel cutoff and transfer relays. If any of those are toasted/disconnected you'll lose the tied power for all 4 coils. For the low power/dieing issue it sounds like an ICM issue.

 

my relays were bad in mybike and cause it to shut off and turn the plugs black...so def. check them out