Bought a JCL 110cc off craigslist for my son. Figured go cheaper with this starter bike and buy him a Honda as his next one when he learns to ride. (all of my other bikes are Honda's and they have been nothing but a pleasure).

The bike I picked up is a 2010 that the guy's kid lost interest in. It sat quite some time and the battery had "died" or as he also said maybe it's the starter. He was not mechanically inclined.

Picked it up relatively cheap knowing it needed a little tlc. He included a new starter he ordered off ebay and never installed. I install the battery and starter, drain the fuel, refill it and go to start it. It starts and then I notice smoking out of the stator cover. I cut it off and open it up to find the stator was blackened and fried looking as were a few of the wires that ran from the stator back to the bike and voltage regulator.

After looking around online I realized the parts were quite cheap so I figured it was the perfect time to freshen it up. I ordered a new carb, all new fuel lines, filters, stator, CDI, voltage regulator, spark plug (ngk), ignition coil... and a bunch of misc parts. Went through the wiring harness while awaiting the parts to be shipped and made A LOT of solder repairs and replaced a few wires that looked questionable with thicker gauge.

Once the parts came and were installed it fired right up and ran fine. I started it up every few days to make sure that it would be perfectly running for my sons birthday.

Last Saturday it ran fine, all day long... he loved every minute of it. Sunday morning I go to warm it up for him and it fires after a little of fiddling with the choke and throttle (it was cold out), it ran for 30-45 seconds and cuts out. I go to restart it up again and the battery is dead enough it wont crank... just my luck. I take the battery off my motorcycle and hook it up to the atv so he can at least play a little. Nothing, it would crank and crank. Fire and sputter and die. Over and over and over. I played with the idle screw on the carb which allowed it to try to kick over a little more so but it would not run at all.

I tested the the coil and spark plug only to find it was getting spark and the spark plug did in fact have unburned fuel on it. I ordered another PZ19 carb offline figuring that was all it could be. Maybe it was flooding out the engine? How, who knows since the other one had maybe 5 hours on it max!

New carb came today and it will still NOT run. I put in a brand new plug and nothing. It tries to kick over but it wont. I don't have a compression gauge that will fit that small a spark plug opening but with my finger over the hole I can see its got compression.

Im completely lost with this. I am very mechanical and have rebuilt plenty of small engines and even car engines. Ive replaced everything on this bike except for the actual engine itself. Ive got more wrapped up in this used chinese junk than it would have cost new... and whats killing me is my son just wants to ride it and he cant. I really just want it to run well enough and long enough for him to learn and me to be sure he's going to stick with it.

Any help would be greatly appreciated. I just dont understand how it could run perfectly fine the day prior, it sits parked in my shed for 12-15 hours and wont run at all the next day. CDI maybe? I think i tossed out the original one when I got the new one.

 

My comments in blue:

Adjust the valves first. This is a periodic maintenance requirement. The valves tighten with wear and tighten further with cold, so the first symptom of valve problems is hard starting when cold, followed eventually by *no* starting when cold. Get this out of the way, so we're not stuck looking for weird esoteric problems while routine maintenance stuff is being ignored.

0.004" clearance (intake ad exhaust) at TDC on the compression stroke with the engine cold.

 

Thanks for the reply and good information. Ill go back through your responses and then later when I get off work I will play around with the atv more.

There is/was no fuse installed. This is how the bike came while yes I should have thought to add one while replacing wiring I just left everything alone when I did it. I can certainly add a 7 amp fuse!

I completely understand your comment about replacing a bunch of stuff at once. I replaced the electrical parts all together because I was worried about what may have been compromised with the destroyed stator, regulator and wiring. The carb, based on the price, I just replaced because I had no idea how long the other one had sat around with old fuel in it. I know I threw out old regulator and stator but will have to look around for the CDI and factory carb.

With regard to starting. The battery seemed sluggish from a few days after I first got the bike up and running...to a point where I considered that it was going to be returned for a new one well before it wouldnt start the bike. I had it on my charger early on and after it was charged kept it on my motorcycles maintainer. When starting that Saturday (that it worked) it was sluggish when the motor was warmed up and he had been riding had no troubles. The next day it was sluggish but yes warm enough for the bike to start up that one first time.

I will make not that the starter does not crank consistently around like my other atvs, motorcycle and lawn mowers. It cranks and then I guess once the motor builds compression kicks/slows a tiny bit and then speeds back up. It does this with both batteries and also anytime the throttle is played with while cranking on it.

I will check the valve adjustment on the motor later. Maybe I just overlooked its importance...just figured it wouldn't be a night and day difference... that it wouldn't run at all the very next day. And for the record last weekend here was really quite warm for fall, both days. So its not like one day was 70's and the next 40's. Ive done valve jobs on Honda cars but most of the motors I have here are actually hydraulic lifter setups. Ill grab my feeler gauges and see whats what.

 

Also wanted to mention that the bike has an alarm/kill. Its a remote with little alarm and control box. Could this be bypassed easily or removed to rule out its not causing it not to start? From what I read this control the CDI... and I am aware that the motor IS getting spark so is it safe to conclude its not the problem at hand?

 

To bypass the remote/alarm simply unplug it. That's it. But there is a small caveat. You won't be able to shut off a running quad with the ignition switch any longer. You'll have to use the left handlebar kill switch instead.

There are ways to restore the ability to shut off the engine ignition with the ignition switch, but let's put that off to later.

If you're getting spark, the remote is almost certainly not the problem.