205 AJS digita 50cc headache please help

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205 AJS digita 50cc headache please help

Postby Miae6 » Mon Dec 25, 2017 9:06 pm

I recently bought a 2015 AJS digita with what the owner claimed to be a carb issue (its not) and I replaced the spark plug with the same that was in it a cr6hsa or somthing like that turns out AJS recomenda a cr7hsa is that a problem? However I go to accelerate and the bike stays at idle speed but it breaks up almost like a rev limiter at low rpms there’s wires that go no where and there’s one that when I touch the head cover the rpms go up to the point the wheel spins please help me thank you

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Re: 205 AJS digita 50cc headache please help

Postby robcurrie » Tue Dec 26, 2017 1:59 am

Seems like you have a bad earth connection. First check your battery connection, the negative battery cable should be connected to the frame at some point, clean that connection and give it a try again.

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Re: 205 AJS digita 50cc headache please help

Postby SPRIDDLER » Tue Dec 26, 2017 2:27 pm

Miae6 wrote: I replaced the spark plug with the same that was in it a cr6hsa or somthing like that turns out AJS recomenda a cr7hsa is that a problem?

It's unlikely to be the problem as the numbers 6 and 7 refer to the plug's heat range and one number different wouldn't cause your problem. However, even new spark plugs have been found to be faulty.

......with what the owner claimed to be a carb issue (its not)

How do you know it's not a carb issue? A blocked jet could produce similar symptoms.

''...there’s wires that go no where and there’s one that when I touch the head cover the rpms go up to the point the wheel spins

You need to be a bit more specific. Where are the ends of these 'going nowhere'' wires? How many wires? Colour? Where do they come from? Do the ends of the wires that 'go nowhere' have connectors on them (if so what type of connectors?) or are they just bare ends? A photo of them would help.

there’s one that when I touch the head cover the rpms go up to the point the wheel spins

Do you mean that when you touch one of the wires on the cylinder head the engine runs o.k. and so if you fixed the wire to the head you would be able to use the bike? What colour is the wire?

As Rob has said, it could be just a bad earth connection. Until very recently Chinese bikes have been notorious for the poor quality of their electrical wiring, fittings and connectors.

LATER...........
The Digita has a centre and side stand. If your stand has an electrical cut-out it could be that the switch is faulty so that when the engine revs increase the vibration causes the cut-out switch to cut out the ignition intermittently.
Some wires are cut by owners to derestrict their 50cc scooters. That could why you have wires going nowhere. Have a look at this video:
https://www.youtube.com/watch?v=eTcTUOJaWhc
I poke badgers with spoons.

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Re: 205 AJS digita 50cc headache please help

Postby Miae6 » Tue Dec 26, 2017 7:56 pm

It’s a black wire wire where the conection snapped off I’ve replaced the carb so there is slim chance if that being bad too I’ll have a look at the video ASAP thank you I’ll get back soon and the lean on stand has snapped off and is just under the door compartment don’t onow if that changes anything?

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Re: 205 AJS digita 50cc headache please help

Postby Miae6 » Tue Dec 26, 2017 8:06 pm

I can’t seem to post a video I have of how the bike runs

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Re: 205 AJS digita 50cc headache please help

Postby SPRIDDLER » Tue Dec 26, 2017 9:07 pm

Miae6 wrote:It’s a black wire wire where the conection snapped off I’ve replaced the carb so there is slim chance if that being bad too I’ll have a look at the video ASAP thank you I’ll get back soon and the lean on stand has snapped off and is just under the door compartment don’t onow if that changes anything?

Generally, the black wires on Chinese 50cc scooters are Earth wires. Search on Google for 50cc Chinese scooter wiring diagram and you'll find hits like this which you can zoom in on:
Chinese 50cc scooter wiring diagram (640x413).jpg


The 'lean on' side stand will probably have a kill switch to prevent the engine starting until the stand is 'up'. The switch will be adjacent to the stand leg such that when the stand is up it will depress a plunger and connect/disconnect the circuit internally. Since your stand has been damaged/broken it may be causing ing intermittent activity of the switch due to vibration when the engine is revved so it would be worth checking the switch for damage. If you want you can bypass the stand switch by taking off its (probably) two wires (one will usually be black 'Earth') and joining them together electrically. Be aware that if you fit a new side stand this disabling function will be inoperative.

Has the scooter ever run properly?

In your first post you said:
when I touch the head cover the rpms go up to the point the wheel spins

I assume you are aware that since it's a Twist 'n' Go scooter the rear wheel is supposed to turn when the revs increase.

Make sure you know where the fuses are located and that you have some spare fuses available.

A Haynes workshop manual for these bikes is available from AJS.
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Re: 205 AJS digita 50cc headache please help

Postby Miae6 » Tue Dec 26, 2017 9:12 pm

It was a grounding issue thank you so much

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Re: 205 AJS digita 50cc headache please help

Postby SPRIDDLER » Tue Dec 26, 2017 9:16 pm

Excellent! Well done.
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