Modern Buddy

My 125 which has not given me any issues until now, cut out and left me coasting while I was cruising the access road. I was going WOT to get my speed up to the flow of traffic and at about 50mph (55 buddy miles) it just died. I stood on the shoulder puzzled and went through the usual quick trouble shoots.

Gas-check
Oil- check
Battery- check

I was just about to start walking home and I gave it another crank and it kicked over. It was a pretty prolonged crank though, and it caught me off guard when it turned over.

My question is, what would you do next? It's still under warranty.

alleycat2332 wrote:My question is, what would you do next? It's still under warranty.

That's a n easy one - take it in for warranty repair.

Is your gas cap vented? I had the same issue a few time on my Buddy 150 until I vented the cap myself. Vaporlock!

It sounds a bit like a phenomenon know (somewhat incorrectly) as "vapor lock" (which is actually something a little different). If your gas cap isn't vented, it can create a partial vacuum in the tank as the fuel drains into your engine, temporarily starving it of fuel. Loosening the cap will immediately equalize the pressure (you'll hear a little whoosh), and let you get back on your way, maybe with a little extra cranking. Otherwise, the pressure will slowly equalize on its own (because the seal isn't perfect) and the scooter will again run, also with extra cranking. The problem then goes away completely... until it returns when the conditions recur.

The long-term solution (if this is the cause) is to make sure your cap is vented. The Buddies sold over the last several years should be, but maybe yours got clogged.

What they said!
I had the same issue. Venting the gas cap was a permanent fix.

Please do check the gas cap thing. If that's not it, and if I correctly understand that it just suddenly quit running, no sputtering or loss of power or other symptoms, then it sounds like an electrical problem. When symptoms like this pop up, I always suspect the stator. An intermittent stator can mimic other problems and then spontaneously start working again. It's maddening to troubleshoot and the only cure is to replace it.

If you're talking to your shop guys and you want to sound knowledgeable, you can tell them that you suspect the ignition pickup coil that's built into the stator assembly. That'll wow 'em. You can also tell them that it's a known weakness of the Genuine Buddy, because it is, sorry to say.

^^^^^With "vaporlock", I did have a sputtering and backfires before the stall. It may well be electrical.

If not vapor-lock:

I had another issue that acted very similarly to it, after a bad tank of gas. After that, any time the tank was less than half full, while at WOT, the scooter would start popping and then stalling. The shop cleaned it out, I got fresh fuel, but the problem kept happening. When I brought it in a second time, it turned out that the spark-plug had to also be replaced.

So, replacing the spark-plug is also a possible fix, if it isn't vapor-lock, which I did deal with before I got a vented cap. BTW, I don't think the 150s were ever sold with a vented cap, because it's technically illegal according to certain state's emissions laws.

jrsjr wrote: When symptoms like this pop up, I always suspect the stator. An intermittent stator can mimic other problems and then spontaneously start working again. It's maddening to troubleshoot and the only cure is to replace it.

I also always suspect the stator. I also recommend going with the NCY stator.

Sometimes you can tell the stator is going bad by check the spark plug, when mine went bad it still sparked but it was a very weak spark.

Same thing happened to my 125 with only 1,000 miles on it. Stalled a few times on a hot day after about 45 minutes on the road, going 40ish. Let it rest a minute or so and it started up with much cranking difficulty, then stalled again as I tried to get back onto the street. Very dangerous situation!

The power also seemed to surge in and out before stalling.(like I was giving it more and then less throttle)(like vroom, slight pause, then vroom again, then another pause, every second or so). Surging diminished when I slowed to 25 mph.

Based on this thread I think my issue could be electrical too.

Has anyone had a POWER SURGING THEN STALLING experience?

Someone mentioned it could be the ignition pick up coil in the stator? I have no idea what these words mean.

Thank you most kindly!

Well hell, I want to believe it's just a fuel vacuum. I did turn my deadlights into running lights by way of LEDs, and I hope that doesn't void my warranty from an electrical standpoint.

I'm not positive, but it may have lost a little power once before it died, it wasnt something I was really thinking about at the time, and I couldn't tell if there was a sound when I opened the gas cap, on the count of the loud as all get out traffic wizzing by.

It was pretty hot today, but not nearly as hot as it has been. I don't know guys. Where might I find a vented gas cap, fingers crossed that keeps this from happening again.

I had the same until it was vented. It reared it's head most if I got hit by a powerful gust of wind, so I'm guessing it just lost air. It would just lose power fairly quickly then die.

After the vented cap, 0 reoccurences.

Welcome aboard!

alleycat2332 wrote:...Where might I find a vented gas cap, fingers crossed that keeps this from happening again.

You can vent your cap easily with a drill and a small drill bit. There's a trick to it, though. For instructions how to do it right, go to this thread, Page 2, read POCPhil's explanation of what to do, then look down four posts to sotied's post that has photos showing what he did.

If you do this mod and your scooter ever does the sudden death thing again, you'll at least know for 100% certain that the problem is not vapor lock.

P.S. IMHO, sotied used too large a drill bit. I'm betting he used whatever was handy. If you have a choice, half that size, maybe a 1/16 ought to be plenty large enough. You just want to vent the cap so gas pressure can equalize is all.

Same thing happened to me several times this hot summer. But it had never happened until I had over 9,000 miles on it. Drilled the gas cap and everything is fine now.

My vote is electrical; start with the stator. I had a stator problem at the same time as a fuel system problem (bad valve at the bottom of the tank, and gunked up filter). I replaced fuel system parts that needed to be replaced, but I still needed to replace the stator.

If I had to do it all over again, I would start with replacing the stator, and cross my fingers that I don't have issues in more than one system.

Well, I drilled the cap, so far no problems. It hasn't been nearly a hot the last few days though, so the real test hasn't happened. I really appreciate all the suggestions guys, hopefully this will be the fix and I'm not gonna have to deal with any electrical BS.

Hoping someone will pick this back up and give me a hand. I've changed the stator, and my spark plug. Battery has been on a tender and is fully charged, and I do have spark. Fresh gas with stabil in it for while I sit.

I thought it was the vapor lock issue. But not only is my evap system off the bike (shhh, our secret) but I've made those handy holes in my stock gas cap.

the3rdleonard wrote:Hoping someone will pick this back up and give me a hand. I've changed the stator, and my spark plug. Battery has been on a tender and is fully charged, and I do have spark. Fresh gas with stabil in it for while I sit.

I thought it was the vapor lock issue. But not only is my evap system off the bike (shhh, our secret) but I've made those handy holes in my stock gas cap.

Start by cleaning your carb, then go from there. Doesn't take much to gum up a float needle.

avescoots1134 wrote:

the3rdleonard wrote:Hoping someone will pick this back up and give me a hand. I've changed the stator, and my spark plug. Battery has been on a tender and is fully charged, and I do have spark. Fresh gas with stabil in it for while I sit.

I thought it was the vapor lock issue. But not only is my evap system off the bike (shhh, our secret) but I've made those handy holes in my stock gas cap.

Start by cleaning your carb, then go from there. Doesn't take much to gum up a float needle.

Sorry, should have included that a carb cleaning has been done as well. Any other ideas?

I had been having similar issues intermittently for a few months until recently (which was always concerning as it would cut out mid-throttle and sometimes have trouble starting back up-not fun on busy roads!). I tried everything I could think of (vented gas cap, carb clean twice, petcock and fuel line replacement).

Finally tried a new stator and whadduyaknow, haven't had a single issue with it since! If your bike is still under warranty I would certainly ask your shop about that. It was covered under mine and a quick fix.

laurfunkle wrote:I had been having similar issues intermittently for a few months until recently (which was always concerning as it would cut out mid-throttle and sometimes have trouble starting back up-not fun on busy roads!). I tried everything I could think of (vented gas cap, carb clean twice, petcock and fuel line replacement).

Finally tried a new stator and whadduyaknow, haven't had a single issue with it since! If your bike is still under warranty I would certainly ask your shop about that. It was covered under mine and a quick fix.

Stator didn't work for me. Still hopong someone has another idea.
Heres whats been done:
Battery charged
Fresh gas
Spark plug changed
Stator changed

the3rdleonard wrote:Stator didn't work for me. Still hopong someone has another idea.
Heres whats been done:
Battery charged
Fresh gas
Spark plug changed
Stator changed

Have you checked the valves? How many miles are on it?

Is it getting gas? I believe a few people on here have had their petcocks go bad.

scootERIK wrote:

the3rdleonard wrote:Stator didn't work for me. Still hopong someone has another idea.
Heres whats been done:
Battery charged
Fresh gas
Spark plug changed
Stator changed

Have you checked the valves? How many miles are on it?

Is it getting gas? I believe a few people on here have had their petcocks go bad.

No on the valves. Would that be for compression? 15k on the miles. I could smell gas pumping through when I checked for spark, unscientific, but it was clearly there.

the3rdleonard wrote:No on the valves. Would that be for compression? 15k on the miles. I could smell gas pumping through when I checked for spark, unscientific, but it was clearly there.

Have the valves ever been checked/adjusted? Because if you have 15k and they haven't been adjusted I could almost guarantee they need to be adjusted. I have to adjust my exhaust valve every 8k(I check it every 4k,) the intake valve needs adjustment much less often. Generally the exhaust valve will close/tighten over time. The valve clearance is supposed to be .08mm, but by 8k mine has been under .04mm.

Someone else will have to comment on what can happen if the valves lash gets too small.

Two guides-
topic8312.html#101937

topic5671.html#65196

Have the valves ever been checked/adjusted? Because if you have 15k and they haven't been adjusted I could almost guarantee they need to be adjusted. I have to adjust my exhaust valve every 8k(I check it every 4k,) the intake valve needs adjustment much less often. Generally the exhaust valve will close/tighten over time. The valve clearance is supposed to be .08mm, but by 8k mine has been under .04mm.


I'm not sure... There was a shop here that took care of my maintenance, unfortunately it closed. I've never done any work of my own so I'm super new to this. I never had any issues of performance over the years, that scoot has literally been twist and go WOT for all 15k. Those don't look terribly complicated so I'll give that a go and see what happens. Thanks again for the idea.

Valves were slammed! Thanks for suggesting the adjustment. That second tutorial was very handy as well.... unfortunately, my scoot still doesn't start. While I was in there, I noticed I should change the oil. Could that keep it from starting?

the3rdleonard wrote:Valves were slammed! Thanks for suggesting the adjustment. That second tutorial was very handy as well.... unfortunately, my scoot still doesn't start. While I was in there, I noticed I should change the oil. Could that keep it from starting?

F that oil get a spark.


When that engine sounds like it is running, climb on. Good luck.



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the3rdleonard wrote:Valves were slammed! Thanks for suggesting the adjustment. That second tutorial was very handy as well.... unfortunately, my scoot still doesn't start. While I was in there, I noticed I should change the oil. Could that keep it from starting?

When you say "slammed", how far out of spec were your clearances?

HowHH wrote:

the3rdleonard wrote:Valves were slammed! Thanks for suggesting the adjustment. That second tutorial was very handy as well.... unfortunately, my scoot still doesn't start. While I was in there, I noticed I should change the oil. Could that keep it from starting?

When you say "slammed", how far out of spec were your clearances?

There was no clearance.

No clearance is bad. It's possible you burned an exhaust valve.