Author Topic: 50cc Mopeds and AutoChokes  (Read 175 times)

Offline Kiwingenuity

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50cc Mopeds and AutoChokes
« on: June 18, 2018, 01:26:29 AM »
Right.. so I got cornered into fixing a 50cc 2 smoker and I thought I would share my findings into Autochokes in case anyone else comes into issues trying to figure it out.. seems to be a fine point missed on the scooter forums.

Scooter in question - 2012 Benelli Pepe 50cc. (Anther GY6 139QMB clone)
Issues - numerous - predominantly hard starting, stalling, dying on takeoff even when left idling, poor idle etc. 

They had quite a bit of work done prior to tracing the fault.. probably needed doing anyway..
  • Replaced roller weights and belt (originals stuffed)
  • Replaced carb (original had been messed with, new jets etc) - all set per factory spec
  • Replaced Autochoke
  • Replaced starter motor
  • Replaced vacuum petcock line
  • Replaced battery (AGM)

The Autochoke has a nominal coil resistance of 330ohms when good.  What I had failed to check was the upstream supply - I didn't have access to a wiring diagram and assumed that a new battery and good charging system would have been a sufficient check...

The autochoke has 12V supplied from a dedicated regulator mounted under the footwell at the front of the frame.  The regulator gets its own dedicated AC supply from the alternator while the engine is running. The regulator then provides 12VDC to the autochoke element which closes the enrichment circuit once it has time to heat up and close the piston on the carb.

The regulator is a QJ 1E40QMB - or one of the many GY6 clone parts that exist out there.  Did i mention it is a PITA to find on the bike???  :technical:  It is also mounted in a location that can get drowned.. and they used a non water proof 4 pin connector.....

You can access the connector to the autochoke and measure for 12V with the engine running - if you get 0V you have a good chance the regulator is stuffed and the carb is running rich 100% of the time.. there are also other posts on how to check the autochokes themselves online.

Anyway, if this saves anyone some time I hope it helps.   :cheers:

Offline Joolstacho

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Re: 50cc Mopeds and AutoChokes
« Reply #1 on: July 01, 2018, 04:38:20 AM »
You need new crank seals, and an exhaust burnout I bet.
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Offline Kiwingenuity

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Re: 50cc Mopeds and AutoChokes
« Reply #2 on: July 01, 2018, 07:37:03 PM »
Had done the exhaust burnout, it's at the shop for a closer look at the crank seals this week..

Seems to be a non-repeatable fault, the worst kind of fault..

Offline yamahonkawazuki

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Re: 50cc Mopeds and AutoChokes
« Reply #3 on: July 02, 2018, 12:10:13 AM »
A clone of a clone lol 110% chinesium. Looking at a gy6 rhats never been titled. Only faults atm are a cracked carb boot. Of questionable rubber compound. And that damn autochoke. Thought if i get it will convert to manual type. Might be an option in your case?
P.s. my voice recognition software on phone recognised chinesium lol
« Last Edit: July 02, 2018, 12:11:34 AM by yamahonkawazuki »
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Offline cbrfxr67

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Re: 50cc Mopeds and AutoChokes
« Reply #4 on: July 02, 2018, 02:44:19 PM »
chinesium! :bowdown: lol
my 125 grom clone is full of that stuff.  Guys think the screws on gs are bad, the screws on this bike strip themselves just screwing them in handtight.  I wonder why they even bother to make them, they're so bad.
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