Kawasaki Quad's & ATV's Quad (Leisure) & ATV (Working) talk within here.

Bayou 250 -- electrical gremlins

Old 03-08-2019, 03:12 PM
Junior Member
Thread Starter
Join Date: Mar 2019
Posts: 1
Default Bayou 250 -- electrical gremlins

I'm at a loss. I have a Bayou 250 I picked up a while back that SHOULD run, but won't. Overall it's in really good shape.

Initially thought it was a carb problem, so we played with the carb, and actually got it running at one point. Started up and idled repeatedly. Took it out of the garage and it had good power, ran strong. But halfway up the driveway, it cut out, and won't start up again. Carb seems to be fine, and it is certainly getting fuel. It won't start even with starting fluid.

Only thing I can think is the spark is too weak, or it's not sparking at the right time. Timing looks good. Valve clearance is good, everything inside looks mint. Changed plug, battery is good (on a charger). Checked ohms on the stator (within specs), the crank sensor (within specs), and the coil (within specs). Actually bought a donor bayou 220, and tried the coil and CDI from that. No change. I read somewhere the harness can get frayed somewhere along the frame, but I don't see anything obvious. Cleaned the main ground. Has good compression, over 140.

One interesting thing. Input from the battery to the CDI is 12v. Output from the CDI to the coil will rise to NEGATIVE 120 or so DC volts (not AC) when cranking, then slowly falls off. It's this way with both CDIs. Is that normal? Is it supposed to be negative voltage? The leads to the coil are different sizes, presumably to prevent reversing polarity, so it seems to be wired properly.

On the CDI wiring harness:
BK -- goes to coil neg
G/W -- goes to coil pos
R/Y -- shows 12v when key is "on"
Bk -- 0v when "on," 10.8v when cranking
Bk/W -- from crank sensor

I'd appreciate any ideas, I really don't know where to go from here.

Last edited by v8unleashed; 03-08-2019 at 05:28 PM.
Old 03-19-2019, 03:41 PM
Junior Member
1st Gear Member
Join Date: Jun 2015
Posts: 13

That sounds like a polluted and / or gelatinized "gas factory" with jets that do not let anything through.
Old 04-28-2019, 02:58 PM
Junior Member
Join Date: Apr 2019
Posts: 6

After changing the plug, what color and how much spark did you have at the plug?
Related Topics
Thread Starter
Last Post
KLX 250S
09-09-2014 05:02 AM
General Tech
04-03-2009 02:13 AM
Kawasaki Quad's & ATV's
09-11-2007 02:44 AM
Kawasaki Quad's & ATV's
07-12-2007 05:09 PM
Kawasaki Quad's & ATV's
02-09-2007 06:11 PM

Thread Tools
Search this Thread
Quick Reply: Bayou 250 -- electrical gremlins

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.