YY250T bogging when hot & starter problem By dannytroy (Read 498 times)

[dannytroy]

Ok, I hope I can get some suggestions to the problems I'm having with my year old YY250T (Helix clone engine), with only a few hundred miles on it.

I've been having problems, where after the scoot gets hot, it stalls and can't be restarted till it cools.  At first I thought the battery was bad, since it was the usual low quality battery that came with the scoot, so I replaced it with a good quality battery.  I had the same problem with the new battery.  It seems like there are multiple problems going on.  After it warms up the engine seems to bog and it sounds like the carb is running rich.   When I turn off the engine it almost doesn't want to turn over.  I actually took it for a 15 minute ride a few night ago and broke down.  It just lost power and anything above idle caused it to stall.  My wife came to my rescue, and brought a spare battery.  I thought that the battery had been drained, but the replacement battery also would not start the scoot, with the same hesitation when trying to start.  To me, it seems as the the compression is too high when the scoot warms up, and the starter isn't powerful enough to crank the engine.

Let me go over what I have done to the scoot so far:
1.  Replace battery
2.  Replace head and taillights with LEDs
3.  Added an on-off switch for the cooling fan, thinking the fan may be draining the battery
4.  Installed a new R/R from Oregon Motorcycle Parts (this solved the low voltage problem at the battery I had been having)
5.  New fuel filter
6.  Iridium spark plug installed
7.  Tonight I took out the wires that feed the starter and will replace them tomorrow with a heavier gauge wire
8.  Adjusted the valves today, thinking they were too tight.  No change.

When disconnecting the wire at the starter tonight I noticed it was very hot.  To hot to touch.  Is this normal?  Is the fact that it doesn't want to turn over the engine when hot a sign that the starter is bad?

I made a little video tonight so you can see exactly what I'm describing.  You will also see the bogging when giving it throttle.  This time it didn't die on it's own, and I was able to restart.  I'm wondering if the fuel filter replacement I did tonight might have helped.

Here's the link:

Hopefully someone can shed some light on these problems.

[beebo]

I watched your video and it sounds to me like you might need to clean or adjust the carb. It seems to be hesitant to rev up when you give it the gas. Does your temp guage read hot? I couldn't see it well in the video. It may be running too hot, making it hard to crank. When mine gets hard to crank, it is usually time to change the oil. When it gets old and thin, mine gets hard to start.

The start and charge systems on these bikes are barely adequate when everything is working good. I noticed you kill and restart about a half dozen times in a few minutes. You need to give it some time to recharge the battery when you start it--at least a few minutes, or take it for a short ride. Idling, with the lights on full time, will probably not charge the battery much, at least not very fast. Your meter showed it to be charging, but likely not very many amps. You need to ride it to get a decent charge.
Looks like you have it set to idle around 1000 rpm. Can't tell too well on my monitor. I would idle it up around 1800 to 1900 rpm or as high as it will go without engaging the clutch. It will help the charge and might help it to crank a little easier, too.

Does yours have the remote start? I kept having battery problems until my dealer told me about the remote start. If you start it with the remote, kill it with the remote, or it will still be "on" and it will drain the battery.

I listened to the video again, and it does sound to me like the bike has a miss at idle, and sputters on rev like it is dirty/running a little lean at idle/off idle. Clean or adjust.

[dannytroy]

Well, I solved most of my problems yesterday.   On a whim, I thought I'd check for a spark, when it died on me again.  Since I had used an Iridium plug, I thought it could never be the plug, and it was.  I put a good old NGK back in (I still had the one it came with) and the scoot came back to life.  I guess the Iridium was crapping out when it got hot.  I took the scoot for a long ride and it was near 100%.  I still get some hesitation, but hopefully adding some Seafoam and fresh gas will help that.

There is still some starter hesitation, and I suspect the starter may be on it's way out.  I also installed a much heavier gauge starter wire yesterday (positive and ground) and the starter is still weak.  The charging is great with the Oregon MP R/R, and my battery is showing good voltage when charged with motor off.   As long as it turns over it will suffice for now.

So, I'm ready for that cross-country ride.  OK, maybe cross-county for now.   I just ordered a gel-pad for the seat modification.   My back aches after only about 1/2 hour ride with this scoot.  I installed gel on two other scooters and was always happy with the results.