Modern Buddy

I have a Roughhouse R50, 2015, 7500 miles, stock except rollers and clutch springs, de-restricted.

I've been getting this problem since last week, when I cruise,sometimes the engine seems to lose all power suddenly, it goes down to near idle and it will not rev when I give it gas, the sound changes, and I slow down to a crawl.
It is not the classic vapor/vacuum lock because I ran it with the gas cap half on and it still happened.
It's not predictable, last night it happened once on a 35 mile cruise.

And when it happens, I shut her off, fire it up right again and I can take off with normal full power as normal as if nothing is wrong.

Things I have done so far after this started to happen:
removed airbox and inspected air filter
new fuel filter
Checked for blockage in fuel lines, applied vacuum to the petcock and fuel flow is fine.
cleaned carb twice(wasn't dirty)
checked all wiring
removed and inspected exhaust and cleaned off some carbon
Cleaned and sanded all grounds, electrical connections
Inspected reed valves, no cracking or warping, good condition.
replaced spark plug

Still getting it sometimes. I use the scooter everyday so it's not old gas.

Any idea what this could be??
The scooter has no trouble starting/idling.
Video proof of the symptoms:
Here is it, running bad during a ride, literally crawled to a stop and filmed.
I'm giving it full throttle there, and that's as far as it will rev.
https://www.youtube.com/watch?v=EL078Al ... e=youtu.be
https://www.youtube.com/watch?v=3fwpjRq ... e=youtu.be


And here is is, after I shut it down, then fire it back up immediately:
https://www.youtube.com/watch?v=oK08hFL ... e=youtu.be

as you can see, running and revving happily, running perfectly afterwards.

Sometimes it fixes itself when I back off the throttle and roll back into it, or if it idles for 20-30 sec. Sometimes i have to shut it down.

The fact that I can shut it down, fire it back up immediately and it's fine makes it very confusing to troubleshoot.

Any help is appreciated

The stator might be going bad.

After some more reading on the possible culprit, I decided to order a new Stator.
Hopefully it fixes the issue. I'll update this thread as soon as I get it installed and tested.

OK, replaced the stator with a brand new unit. Turns out it wasn't that.
Scooter still did the same thing just now, lost power, wouldn't rev past a
certain rpm and wasn't running right, just like in the videos above.
Shut her off, fire it back up again, and it's fine.

What else can it be besides the stator?
I'm open to suggestions. Coil/spark plug lead wire maybe? CDI?

Does it have a chance to cool, before restarting? - could be the pickup coil or cdi...

Ootscoot wrote:Does it have a chance to cool, before restarting? - could be the pickup coil or cdi...

Nope, I can literally start it up immediately after and it runs fine and I can drive off again like nothing happened. Starts right up, doesn't even crank more than 1 sec.

Lately i've been just cruising at 1/2 to 5/8 throttle and it never happened to me yet. Its mostly while at wot or rolling into the throttle to wot.

Lately it's gotten harder to start when cold(using starter), like first start in the morning or after few hours somewhere. It cranks but wont start after 5 sec of cranking. Then I kickstart and it starts right up, first or second kick everytime. Dunno if that is related tho since it's not 1000 degrees here in florida anymore.

Milo_R50 wrote:I have a Roughhouse R50, 2015, 7500 miles, stock except rollers and clutch springs, de-restricted.

I've been getting this problem since last week, when I cruise,sometimes the engine seems to lose all power suddenly, it goes down to near idle and it will not rev when I give it gas, the sound changes, and I slow down to a crawl.
It is not the classic vapor/vacuum lock because I ran it with the gas cap half on and it still happened.
It's not predictable, last night it happened once on a 35 mile cruise.

And when it happens, I shut her off, fire it up right again and I can take off with normal full power as normal as if nothing is wrong.

Things I have done so far after this started to happen:
removed airbox and inspected air filter
new fuel filter
Checked for blockage in fuel lines, applied vacuum to the petcock and fuel flow is fine.
cleaned carb twice(wasn't dirty)
checked all wiring
removed and inspected exhaust and cleaned off some carbon
Cleaned and sanded all grounds, electrical connections
Inspected reed valves, no cracking or warping, good condition.
replaced spark plug

Still getting it sometimes. I use the scooter everyday so it's not old gas.

Any idea what this could be??
The scooter has no trouble starting/idling.
Video proof of the symptoms:
Here is it, running bad during a ride, literally crawled to a stop and filmed.
I'm giving it full throttle there, and that's as far as it will rev.
https://www.youtube.com/watch?v=EL078Al ... e=youtu.be
https://www.youtube.com/watch?v=3fwpjRq ... e=youtu.be


And here is is, after I shut it down, then fire it back up immediately:
https://www.youtube.com/watch?v=oK08hFL ... e=youtu.be

as you can see, running and revving happily, running perfectly afterwards.

Sometimes it fixes itself when I back off the throttle and roll back into it, or if it idles for 20-30 sec. Sometimes i have to shut it down.

The fact that I can shut it down, fire it back up immediately and it's fine makes it very confusing to troubleshoot.

Any help is appreciated

Whew, you have already been so thorough in your first post combined with swapping out the stator, that it pretty much leaves us with 2-stroke problems. I think you need to talk to our 2-stroke experts about this. The Stella folks, is who I mean. Since you've done such a thorough job of eliminating everything else, I have to guess that you are experiencing what the 2-stroke folks call a "soft seize" caused by extremely lean jetting or a lubrication issue (or maybe both).

I do suspect it may be a fueling issue. It sounds like it is not getting enough fuel, then shuts down. When you stop, the draw on the engine is reduced, and then the float bowl fills up again. Just my .02 cents.

jrsjr wrote:

Milo_R50 wrote:I have a Roughhouse R50, 2015, 7500 miles, stock except rollers and clutch springs, de-restricted.

I've been getting this problem since last week, when I cruise,sometimes the engine seems to lose all power suddenly, it goes down to near idle and it will not rev when I give it gas, the sound changes, and I slow down to a crawl.
It is not the classic vapor/vacuum lock because I ran it with the gas cap half on and it still happened.
It's not predictable, last night it happened once on a 35 mile cruise.

And when it happens, I shut her off, fire it up right again and I can take off with normal full power as normal as if nothing is wrong.

Things I have done so far after this started to happen:
removed airbox and inspected air filter
new fuel filter
Checked for blockage in fuel lines, applied vacuum to the petcock and fuel flow is fine.
cleaned carb twice(wasn't dirty)
checked all wiring
removed and inspected exhaust and cleaned off some carbon
Cleaned and sanded all grounds, electrical connections
Inspected reed valves, no cracking or warping, good condition.
replaced spark plug

Still getting it sometimes. I use the scooter everyday so it's not old gas.

Any idea what this could be??
The scooter has no trouble starting/idling.
Video proof of the symptoms:
Here is it, running bad during a ride, literally crawled to a stop and filmed.
I'm giving it full throttle there, and that's as far as it will rev.
https://www.youtube.com/watch?v=EL078Al ... e=youtu.be
https://www.youtube.com/watch?v=3fwpjRq ... e=youtu.be


And here is is, after I shut it down, then fire it back up immediately:
https://www.youtube.com/watch?v=oK08hFL ... e=youtu.be

as you can see, running and revving happily, running perfectly afterwards.

Sometimes it fixes itself when I back off the throttle and roll back into it, or if it idles for 20-30 sec. Sometimes i have to shut it down.

The fact that I can shut it down, fire it back up immediately and it's fine makes it very confusing to troubleshoot.

Any help is appreciated

Whew, you have already been so thorough in your first post combined with swapping out the stator, that it pretty much leaves us with 2-stroke problems. I think you need to talk to our 2-stroke experts about this. The Stella folks, is who I mean. Since you've done such a thorough job of eliminating everything else, I have to guess that you are experiencing what the 2-stroke folks call a "soft seize" caused by extremely lean jetting or a lubrication issue (or maybe both).

You might also want to check the separate RH 50 forum. It's all Roughhouse and 2 stroke.

Bill in Seattle (former RH 50 owner)
'12 170i Buddy Oxford Green
'14 170i Hooligan Matte Green

If you had a 4 stroke I would perhaps suggest checking the compression...could relate to had starting...I don't know if this applies to 2t engines...it is about the only thing left to check.

RoaringTodd wrote:I do suspect it may be a fueling issue. It sounds like it is not getting enough fuel, then shuts down. When you stop, the draw on the engine is reduced, and then the float bowl fills up again. Just my .02 cents.

When I apply vacuum to the petcock, the fuel flows fine through to hose to the carb.
I wouldn't know what else I could troubleshoot fuel wise since that's the only part of the fuel system that provides fuel for the carb.
The carb float bowl sits level as it should when I flip the carb over.

skipper20 wrote:You might also want to check the separate RH 50 forum. It's all Roughhouse and 2 stroke.

I posted it there, but haven't gotten a response

Ootscoot wrote:If you had a 4 stroke I would perhaps suggest checking the compression...could relate to had starting...I don't know if this applies to 2t engines...it is about the only thing left to check.

I'm sure it applies, but I doubt that it's the problem since the hard starting is only when using the starter, on the kickstart it always starts right up. And does not show other signs of having low compression.
Again, it runs fine when using 1/2 up to 3/4 throttle.

I'm thinking electrical since it goes away immediately after shutdown/restart. But I don't feel like replacing every single part chasing this down.

Allright so Quick Update:

I replaced the CDI and Coil and plug wire. Didn't help with the symptom unfortunately.

SO I took off the cooling covers and noticed some oil and sludge on the bottom right corner of the cylinder head.
It's on the bottom right cylinder head stud/nut and around the spark plug area.
The headgasket and the crankcase gasket don't look to be leaking since it's clean and not soaked in oil/gas anything.

I made a video, here's the link.
www.youtube.com/watch?v=OKTfWluBHu8&feature=youtu.be

I'm thinking this is definitely the issue now. But what could be causing the leakage? and from where? head stud?
They're all tight to spec.
BTW, no signs of any leak anywhere else on the engine, just this small corner.
Thoughts?