|
|
Post by steve on Sept 2, 2015 17:50:46 GMT -5
So, my scoot is having some problems. It idles fine, and runs perfectly normal until it gets up to almost exactly 40mph. Then, it will start skipping and sputtering badly. It also does it when taking off, when the RPM get really high while the clutch is engaging. Seems to happen right at 6300 rpm. It also will go for a while without doing it, then skip badly for stretches. The RPM guage will fall 1000+ RPM when it starts doing it. I'll tell you what I've done.
Checked the boot. I have one of those good metal boots. It's not the boot.
Changed the CDI.
Changed the head.
Changed the sparkplug
Checked the connections coming out of the stator.
I'm thinking the pickup coil, maybe? The little magnet on the flywheel?
What the heck could it be?
UPDATE: The pickup coil on the stator had separated from the bracket, and cracked. It was leaning at an angle, and would lean even more at high RPM. I ended up hearing it rub the flywheel.
|
|
|
|
Post by JoeyBee on Sept 2, 2015 18:00:07 GMT -5
Have you done any carburet tuning. Specifically, what size engine do you have? And what are your jet sizes?
|
|
|
|
Post by lain on Sept 2, 2015 18:11:42 GMT -5
Checked your variator?
|
|
|
|
Post by steve on Sept 2, 2015 18:58:16 GMT -5
I installed a 50mm big bore, like 5 months ago. I think I'm running a  jet. It has been running perfect on this jet setup, and carb for months. Got a new carb a couple of days ago, but it didn't work right, so put the old one back on. The carb is cleaned, and in very good condition. I will add it to the list to check out, though. How could the variator cause missing and skipping? I will check it, but I'm curious as to how it could cause this seemingly misfiring condition. |
|
|
|
Post by steve on Sept 2, 2015 19:00:06 GMT -5
It will also almost stop the skipping and sputtering when I'm going uphill. I forgot to add that. It is worse on straightaways, and even worse going downhill. Uphill, it almost completely stops.
|
|
|
|
Post by steve on Sept 2, 2015 19:02:51 GMT -5
Actually, I'm running a 100 jet. 50mm big bore.
|
|
|
|
Post by lain on Sept 2, 2015 19:04:52 GMT -5
I hadf a similar issue over the weekend. I went on a very long trip and during the trip it started acting exactly the way you are describing your issues symptoms. It turned out for me that a very tiny rock made it's way past the joke of a "filter" cap of the cvt case and found it's way into my variator and obliterated my weights and variator, though suprisingly I still made it about 150-200 miles on it with the issues. Good to have a kevlar belt that's for sure haha.
Though if you feel it may be jet related, then do not hesitate to experiment, but it's still always good to check what you can. Better to know it's something in the CVT or not, and always a good thing to check your weights periodically for wear and flat spots.
|
|
|
|
Post by steve on Sept 2, 2015 19:14:22 GMT -5
Thanks. I will add that to the list.
Tomorrow:
Check Carb. Perhaps put a smaller jet in, and see if issues subside.
Thoroughly check variator.
This should keep me busy. If anybody else has a suggestion. I'm all ears.
|
|
|
|
Post by steve on Sept 3, 2015 8:25:30 GMT -5
Let me ask y'all something: Is a 100 jet too large for a 50cc with 50mm BBK? I was hung up that it was something electrical, but it makes sense that at high RPM, the vacuum gets higher, and it would suck the most fuel. I want to run it a little rich, but is a 100 pushing it too far? The plug doesn't look too bad, but I don't really trust that method anyways. Anybody with a 50mm piston, free flow filter, and 20mm carb? If so, what size jet? I'm going to put a  in there today and see what happens. |
|
|
|
Post by lain on Sept 3, 2015 11:46:01 GMT -5
Vacuum is lowest at highest revs
|
|
|
|
Post by steve on Sept 3, 2015 16:33:32 GMT -5
Damn. OK, I tried smaller jets. It decreased the power significantly. Would only go like 30mph. I checked the CVT, all is good.
Let me ask ya'll something: the other day when I was messing with the carb, I took out the main jet, and a small brass piece fell out from under the whole main jet apparatus. I dropped it back in, and I thought it looked right. Could that be the cause? I'll take it back apart and look.
The only thing I haven't checked is the stator. Anybody got any suggestions? It's got to be the carb, right? Still sputtering badly, and the top speed has decreased from about 52, to 40. Sputters so badly at times I think it's going to die.
|
|
|
|
Post by pistonguy on Sept 3, 2015 16:39:08 GMT -5
It will also almost stop the skipping and sputtering when I'm going uphill. I forgot to add that. It is worse on straightaways, and even worse going downhill. Uphill, it almost completely stops. Engine Load The More the Load the Worse it gets. ?? hmm? |
|
|
|
Post by cyborg on Sept 3, 2015 16:53:42 GMT -5
bad coil,,,,or terminals loose and its losing ground or positive ,,,,or the plug wire isn't either in the coil correctly or loose on the plug
|
|
|
|
Post by steve on Sept 3, 2015 21:23:08 GMT -5
It will also almost stop the skipping and sputtering when I'm going uphill. I forgot to add that. It is worse on straightaways, and even worse going downhill. Uphill, it almost completely stops. Engine Load The More the Load the Worse it gets. ?? hmm? What I wrote came out wrong. The engine runs better going uphill. I sanded the diaphram shaft on that new junk carb I bought, and put it on. It ran a lot better for a short run. We shall see if it is fixed. |
|
|
|
Post by pistonguy on Sept 4, 2015 19:29:44 GMT -5
My bad
|
|
jet. It has been running perfect on this jet setup, and carb for months. Got a new carb a couple of days ago, but it didn't work right, so put the old one back on. The carb is cleaned, and in very good condition. I will add it to the list to check out, though.
in there today and see what happens.