UPDATE: Hesitation at 30mph (when NOT accelerating)

Discussion of the Genuine Buddy, Hooligan, Black Jack and other topics, both scooter related and not

Moderator: Modern Buddy Staff

Post Reply
User avatar
ChuckyD
Member
Posts: 29
Joined: Sun Jun 25, 2017 1:00 pm

UPDATE: Hesitation at 30mph (when NOT accelerating)

Post by ChuckyD »

Symptom: At steady 30mph, she briefly and constantly hesitates (1-1.5 seconds), then recovers. I have no issues when accelerating... only when pinning her at 30mph on level ground.

Things I've done in the first month of ownership:
. Replaced gear oil
. Replaced/bled brake fluid
. Replaced fuel filter
. Replaced air filter
. Replaced sliders with 11g Dr Pulley
. Replaced drive belt
. Replaced spark plug
. Replaced battery
. Re-covered (with plastic loom) the wire to starter
. Adjusted valves to 0.08mm (they were tight)
. Rebuilt carb (one jet clogged, white residue on rubber diaphragm)
. Cleaned/lubed caliper pins, etc.
. Added Seafoam to gas
. Checked fuel & vacuum hoses for cracks - none found

meh! Thanks! Chuck
Last edited by ChuckyD on Thu Aug 31, 2017 6:07 pm, edited 2 times in total.
User avatar
az_slynch
Member
Posts: 1806
Joined: Wed Sep 12, 2012 4:56 pm
Location: Tucson, AZ

Post by az_slynch »

Chuck,

That's a comprehensive list of work there! That Buddy got lucky to wind up with such an attentive owner.

Now, assuming all else is well now, I'd check your spark plug wire and the spark plug cap. Firstly, check that the cap clicks securely onto the spark plug when seated. Unclip the cap from the plug, slide back the boot from the cap to the wire, hold the wire and try giving the cap a clockwise twist. If it turns easily, continue to twist clockwise until it snugs up on the wire. Try the same procedure on the other end of the wire, where it enters the ignition coil. Once that it all good, check the two spade terminals on the back of the coil to ensure that the wires are securely connected.

Test ride and see if you still have the hesitation.

If so, check the connections to the CDI box. Make sure they're clean and secure. If they're OK, there's a possibility that your stator has a poor or broken winding it it. A friend's 4T Stella would behave as you describe. It would intermittently cut out for a second or so, then go on again as if all was well. Stumped us for a bit until it flat-out died on a mountain ride. I hope that's not your issue, but keep that in your back pocket if all else fails.

Folks here often recommend replacing the OE stator with one from NCY. I believe this is the part?

https://www.scooterworks.com/NCY-Stator ... -P491.aspx

Keep us posted with what you find.


1700!
At what point does a hobby become an addiction? I'm uncertain, but after the twelfth scooter, it sorta feels like the latter...

Seriously...I've lost count...

Seven mopeds ...that's still manageable...
sc00ter
Member
Posts: 1140
Joined: Sun Mar 30, 2008 9:17 pm
Location: Norfolk VA

Post by sc00ter »

What year Buddy? How many miles? The plug boot and wire check is a good suggestion. I have had the cap on the coil go bad before. If you have to replace it, put some dielectric grease on the plug end and in the cap. Stators have a mind of their own and can fail within the first month or run for many trouble free years. Nothing else to check is popping in my head at the moment. Let us know what you find!
User avatar
ChuckyD
Member
Posts: 29
Joined: Sun Jun 25, 2017 1:00 pm

Post by ChuckyD »

She's a 2007 Buddy 125, with 10K.

Today I:
. Checked both ends of the spark plug wiring - looked good. Even took apart the cap: spring & resistor.
. OK, I'm an idiot... I though I was inspecting/cleaning the CDI (but it was the starter relay). Can someone steer me to the CDI location? UPDATE: Found it! Under the beep-beep.
. Inside the stator wiring connection/plug I found some sticky, yellow crud around the contacts. Cleaned it up. It would be nice if that's what's causing the 29-30mph lagging!

I'll road test tomorrow after the lunar/solar event!
Thanks a ton, guys!
Chuck
User avatar
ChuckyD
Member
Posts: 29
Joined: Sun Jun 25, 2017 1:00 pm

Update: report

Post by ChuckyD »

Performed
. Cleaned/checked both ends of the spark plug wiring - looked good.
. Cleaned/checked CDI & connections - looked good.
. Inside the stator wiring connection/plug I found some sticky, yellow crud around the contacts. Cleaned it up.
. Used compressed air to blow out most of the vacuum lines.

Result
Still getting that weird 1-second lag at 29-30mph! Strangely, I think it was actually worse today.

Questions
. Would it be worth it to order/install new spark plug wiring, CDI, & stator? It would bum me out if these didn't solve the issue (but everything is 10 years old).
. From what I read, I prefer NCY (though I don't need performance, just replacements). Thanks for your purchase recommendations!

Guys, thanks!
Chuck
BMW_Art
Member
Posts: 48
Joined: Mon Jul 24, 2017 8:40 pm
Location: Coachella Valley

Post by BMW_Art »

Just curious but is the stumble random or cyclical? Meaning does the stumble happen at the same number of seconds each time? If it is random, I could see it being a failing electrical part. If not, then I could see it potentially being a mechanical issue.

I thought of a fuel issue, but since you are going WOT I could only see that as a fuel starvation period and I'm not sure that would really explain it.
User avatar
ChuckyD
Member
Posts: 29
Joined: Sun Jun 25, 2017 1:00 pm

Post by ChuckyD »

It occurs:
. between 29 & 30 mph
. every 7 seconds or so
. for about 1 second duration
. every time

Note: I'm not WOT... 29 is pretty low revs. WOT is about 64 mph.
HanShan
Member
Posts: 148
Joined: Thu Apr 13, 2017 1:24 pm

Post by HanShan »

I suggest speeding through 29-30 MPH and settling in at 31MPH.

:)

Maybe the piston cylinder has an imperfection at that RPM? IS that even possible? I don't know, I just love these random issues.
User avatar
Mileslord
Member
Posts: 46
Joined: Thu May 26, 2016 3:14 am
Location: Fridley, MN

Post by Mileslord »

Sounds like a transition from the idle jet to a main jet by the speed you are describing, did you change the jets to a different size?
User avatar
ChuckyD
Member
Posts: 29
Joined: Sun Jun 25, 2017 1:00 pm

Post by ChuckyD »

Mileslord,
Thanks!
I've not changed the jets... but I bought the bike 2nd hand. It has the stock exhaust. (My slow is a 38, I noticed that.)

Question for all: What are the stock jet sizes for the Buddy 125?
I think I'll just order a new set, try those out.

Good tip - thank you!
Chuck
User avatar
Mileslord
Member
Posts: 46
Joined: Thu May 26, 2016 3:14 am
Location: Fridley, MN

Post by Mileslord »

If you are going to replace the jets, I would also replace the slide diaphragm, just because if that does not seal correctly when you reinstall it can cause some issues (mostly not being able to go above 30 mph) but I would replace it just to cover you ass!!!
BMW_Art
Member
Posts: 48
Joined: Mon Jul 24, 2017 8:40 pm
Location: Coachella Valley

Post by BMW_Art »

As I am planning to rebuild my wife's carburetor shortly, I have to ask ... how did you clean the carburetor?

My usual method is to:

1) Buy a can of carburetor cleaner at the auto-parts store with a removable shelf. This is not a pressurized container. It's like a paint can with a removable shelf.

2) As I remove the rubber/replaceable parts the metal components go into the can on top of the shelf to soak.

3) After a few hours - generally overnight or the next day - I'll remove the metal components, hit all of the various ports with carburetor cleaner and an air hose to make sure each port is clear. In real nasty situations I'll run a carburetor pick/brush through the ports.

After that, it's reassembly time with new replaceable components. Usually that means - for me - new float, new float needle, all new rubber components, new springs, etc. I generally keep the jets unless they are worn and needing replacement.

Any jet that is worn larger than the associated needle will not flow fuel properly. Any clogged jet/port will cause issues as well.

It's also really imperative that any new seals be installed correctly or you'll get an air leak. Any seal by a port needs particular attention to make sure you don't block a port.

So, how did you rebuild yours?
User avatar
Mileslord
Member
Posts: 46
Joined: Thu May 26, 2016 3:14 am
Location: Fridley, MN

Post by Mileslord »

ChuckyD wrote:Mileslord,

Question for all: What are the stock jet sizes for the Buddy 125?
I think I'll just order a new set, try those out.

Good tip - thank you!
Chuck


looks like my notes said mine was a #38 and #92 on my 07 buddy 125
User avatar
Mileslord
Member
Posts: 46
Joined: Thu May 26, 2016 3:14 am
Location: Fridley, MN

Post by Mileslord »

BMW_Art wrote:As I am planning to rebuild my wife's carburetor shortly, I have to ask ... how did you clean the carburetor?

My usual method is to:

1) Buy a can of carburetor cleaner at the auto-parts store with a removable shelf. This is not a pressurized container. It's like a paint can with a removable shelf.

2) As I remove the rubber/replaceable parts the metal components go into the can on top of the shelf to soak.

3) After a few hours - generally overnight or the next day - I'll remove the metal components, hit all of the various ports with carburetor cleaner and an air hose to make sure each port is clear. In real nasty situations I'll run a carburetor pick/brush through the ports.

After that, it's reassembly time with new replaceable components. Usually that means - for me - new float, new float needle, all new rubber components, new springs, etc. I generally keep the jets unless they are worn and needing replacement.

Any jet that is worn larger than the associated needle will not flow fuel properly. Any clogged jet/port will cause issues as well.

It's also really imperative that any new seals be installed correctly or you'll get an air leak. Any seal by a port needs particular attention to make sure you don't block a port.

So, how did you rebuild yours?
I use kerosene as a carb soak, work just as good if not better than the "new" carb cleaner stuff, plus its cheap.
I always replace anything rubber or you just end up doing it again, but that's just me and my OCD kicking in
User avatar
ChuckyD
Member
Posts: 29
Joined: Sun Jun 25, 2017 1:00 pm

UPDATE: 30mph hesitation

Post by ChuckyD »

Recap
2007 Buddy 125 hesitates/drops out when cruising (not accelerating) at 30mph. (See original post to view previous attempted fixes.)

New Stator
Today, I replaced the stator with a new NCY from Scooterworks. The old one was totally caked wth dirt.
During test ride, it runs smoother at all speeds... but still does that pesky hesitation/dropout.
NO JOY!

What's Next?
. New jets?
. Regulator? (If so, is this the guy: https://www.scooterworks.com/Regulator- ... P1033.aspx)

Thanks for the hand! Chuck

UPDATE: Oh, brother.
So, I'd been hitting this gas station that offers non-ethanol fuel. Today, I filled up with 92 unleaded from Costco. And she felt like a new bike. "At least my new stator is a new stator," he assured himself.

#badgas #storyofmylife
Post Reply