Dealing with a touch of tropical disturbance/rain here on the Texas coast. Kinda stuck inside thought I’d post cause I’ll never figure this one out.
Went to the track last Friday, MX2.0 out east of town. Houston area out I10 before Winnie, Tx. It was ride for free day 4 till dark, I paid anyway cause it costs a lot to run an MX track. I know the owner, got out there early to help out, get tiller hooked up to tractor, help sign people in the normal etc. Typical Southeast Texas weather, mid 90’s, 80 percent humidity.
Got suited up, fired up my 2024 Beta 300 RX. It ran a few seconds and died. Thought well guess I fouled a plug. Did the normal. Dried the plug but wasn’t fouled. Checked for spark it sparked once I could see, figured sun in my eyes and I couldn’t see it. We cranked, tried to bump start nothing, drove an hour to ride and get to drive hour back home.
I get it back home, throw a new plug in it, nothing. Next morning, hit the stater and it fires up run a few seconds and dies. Put my handy dandy Harbor Freight spark tester on it and sparked one time, one little spark then nothing, no spark.
I did the normal, checked fuses, pulled the tank, checked connectors. Pulled coil checked it, primary side read 27 ohms, secondary 42 Ohms but not sure what either should be other than thought secondary should read higher. I cut all the tie wraps, checked wiring. The only thing I found was a little bit of rust on a ground wire that grounded to the frame where coil mounted, wiped it off and reconnected. I’d come to the conclusion CDI went south.
Put it back together so I could take to the dealer. I thought what the heck will try it again. Hit the starter and it fired right up ran like a top. I started it two, three times ran great. I can’t make myself believe it was that ground wire, but might have been. This will bug me forever, I doubt I’ll ever really know unless it does it again.
Thanks Billy.
It sounds like the ground wire was it, you could always try giving it a "bad" ground to see if that mimics the problem. I definitely know the pain of the magical fix that you aren't very confident in.
I thought of the very thing. Once it quits raining where I can open the garage door I plan to pull both wires connected to coil mounting bolt one at a time to see if it does it again. I should have traced both those ground wires last night when I had the tank off to see where they go, but didn’t think about it. With the kill switch being normally open, I tested it. My gut tells me on of those wires is the kill switch. Earlier this morning opened the garage door long enough to see if it would fire and it started and ran like it had good sense. Ya get a problem like this and it always makes you wonder if it will do it again. It’s the two black wires.
Yeah sometimes it is nice for it to work at all but, it makes you doubt it. I'm a huge fan of putting dielectric grease on basically all the connectors you can. It can help a lot with the conditions. I have also stared using an air compressor to blow any water off my bike after I wash it when I can.
I need go back to using dielectric grease. The older I get the less I do lol. I also need to go back to using an air hose instead of cordless blower, air hose does a better job around connectors. I have an air hose reel just as close as a cordless blower.
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Did you remove the lil green thing from the gas tank cap yet? They fall out and cause vapor lock. This almost ruined my friends ride once. It's a common problem with the venting system they used.
Bike started up ran good during warm up. Went to take off and it died. Thought plug fouled. Nope. Electrical nope. This was on his 125 so we kicked the shit outta it. Pushed it nothing.
Was about to give up until I took the gas cap off and we saw the lil green thing floating in the fuel. Removed it and it ran fine all day. He now runs inline vents in the fuel hose like the yz's.
If you do suspect the ground wires , check the factory heat shrink finishes shy of the flange of the bolt so as to make proper contact between the bolt and the ring terminal , hard to see in your pic but have had this issue before on a new bike and the bolt was doing up on the edge of the heat shrink , not making full contact on the terminal .
My green thing fell out on my garage floor. I wasn’t even sure where it came from. Called the dealership, know the owner. He said it came from gas cap and throw it away. He said it’s a Euro thing they have to do to keep gas from spilling if bike falls over.
Good idea to check. The heat shrink goes a good way up on both those ring lugs. I’ll check it tonight when I runaway to the garage to get away from my wife lol!
Post a reply to: Beta 300 RX, no spark, not sure what I did but fixed it. Mystery on what I fixed.