hheywire
05-04-2015, 10:00 PM
OK so I have an 87 BW200ES, I noticed that it was running very weak and from multiple hours and days of reading forums I had pretty much traced it down to the cdi. And of course to my discovery that every Bw owner finds out the cdi is stupid expensive due to the rarity of them. Well after more countless hours of forum reading I've heard of people trying a universal chinese cdi but no one ever gives feed back on whether or not someone has successfully accomplished it. Well I did something better than using a chinese cdi, after trying out 4 CDI's I found one that worked. the first one I tried was a 2001 polaris sportsman 500 cdi I had laying around but no success of even getting a spark. Then I tried an 85 bigred cdi I had and the timing was so advanced it would kick back at the starter and even when you would get it to fire up it would run like crap. Then I tried and old cdi from an old chinese kazuma atv and it would run better but not great at all. It would idle funny and give you this pinging noise from the timing advance and then it would feel like it had intermittent spark while driving, so that cdi was also out of the equation. Finally I had one more cdi that I really didn't think would work since it doesn't advance, a 1981 atc 185/200 cdi! hooked it up and the beast fired right up, it does idle a little funny but revs up quick with plenty of power. Now here's what I've discovered over all the testing, the stock cdi is retarded at idle then advances to top dead center when throttling up. The pick up coil is set to top dead center so the stock cdi has to be retarded starting out to have low end power then advances to top dead center for your top end. Since the other cdi's advanced way too much it leads me to believe that most motors have the pickup coil retarded then the cdi advances it to top dead. The reason I know this is because the atc 200 cdi is firing exactly at top dead center with out advance. So you loose a little low end power but with a little bit more rpm than what you would normally putt around at it will climb you anywhere. And the rpm doesn't have to be that high to have a lot of power, you just wont be climbing a hill at idle and you probably wouldn't be doing that anyway. For me it drives normal, the idle is just a little choppy but once you re tune your carb you will be good to go. It actually likes the idle needle really lean with the new spark timing at idle. So yes ya'll it is completely possible to change out the cdi and the honda cdi is definitely better than a china one. But don't hold me to it yet, the only testing I've done is driving around the neighborhood several times. Am planing on hitting the trails this week to see if it holds up. If anyone is wanting a wiring diagram I will include one once I look at it and re figure it out. Or you can look at the wiring diagram for the BW and the atc and figure it out.