Motorcycle Repair

Automotive
#1

It’s been giving me trouble all summer and I thought I had it fixed but here we go again…

I’ve done a few procedures already (valve adjustment, rewired some poor connections, new spark plug, new battery, carb clean) with significant improvements in performance but the spark plug isn’t getting consistent power. Bike is a 2013 Cleveland Cyclewerks Ace Standard 250cc.

The battery is getting good charge and all lights and gauges are functional while riding so I don’t think it’s the regulator/rectifier or stator. I don’t have manufacturers specs to test the coil with. Anyone want to lend an opinion?

#2

Have you tried replacing the ignition coil?

#3

That is the next thing I planned to do. There was a poor connection coming out of the coil, which I repaired and the problem seemed to be solved or at least greatly improved (coughing and sputtering while under throttle. Idle is ok most of the time). Maybe damage has already been done to the coil due to the bad connection?

#4

I’m by no means an expert, I’m just a shade tree throwing parts at a problem. It’s possible it got damaged, but it’s also possible something is up with the carb. I’m having similar issues with my ninja 250, carbs are “fun”.

#5

I have a spare carb I bought for the gasket a few months ago. Maybe changing the jets out for the new ones? The spare carb isn’t equipped with the same throttle connection that I need so I haven’t switched it outright. I’m confident that the carb is clean.

I’m also fairly confident the problem is electric. While troubleshooting I narrowed it down to getting no spark at the end of the spark plug. I know the plug is good and when I’d turn off the bike and adjust the coil ground (I think it’s the ground) wire connection it would spark again.

#6

Yeah, I’d change the ignition coil next instead of messing with the carb.

#7

Happens when the bike gets warm. After a couple miles. It’s air cooled engine. Doesn’t seem to be overheating but the intermittent firing is much worse when it’s warm.

#8

It is either compression, air/fuel or spark. You can get an inline spark tester at harbor freight and see if you have a strong spark and then I would check compression if those are ok, it has to be the carb.Depending on the way it is built you might do a leakdown test on the crankcase but that’s all I can think of. When you fix that I have got a RM250 2 stroke that needs an expert touch.

#9

Cleveland carb clean video

#10

It’s getting at least enough compression to run. Feels great too. It’s not a super bike or anything but it feels like it’s getting enough power when it chooses to operate. I’ve never done a compression test but I’m leaning towards something else as the culprit.

My spark plug test consists of me pulling the plug and grounding it while I watch the spark. I haven’t taken any numerical readings but the spark is blue and bright enough to see easily in the sunlight. That is, when it decides to fire. This problem has been especially hard to diagnose since the bike runs fine at some times then totally not fine at other times with the same conditions. I’m missing something obviously.

My money is on the coil. Happens to be a pretty cheap part so I may roll the dice and just swap it out and see what happens.

As for the RM250, bring it on.

#11

Don’t mess with the carb until you’ve gotten the spark issue solved. Carb isn’t going to be affected by the bike warming up. Either it’s going to run smooth or it’s not with a carb issue. At worst, if the bike has a TPS, that could affect how smooth the throttle is but you can easily test that by disconnecting the TPS and riding without it. Based on what you’ve said I would wager electrical is the issue. Especially if you fixed a connection and it’s better. I would also check all your grounds and scuff/clean them up

#12

Carb sync? It’s a more advanced project but they float out of sync depending on the model of bike. When I rode I took my bike to elmer in corinth once a year just to sync the carbs.