74 xs650 advance spring question

[Ben10]

Hey guys Im new to this forum and the xs650. I recently acquired a 74 xs650 chopper and when i got it it had no kickback or backfiring when kickstarting and ran great but now it does that almost every time. I know it could be the timing so I checked the advance and there are no springs at all. Im confused and would like some direction on what i can do from here thank you!!

 

[toglhot]

You mean it has no advance unit. I'm guessing it has electronic ignition, correct?

If so, most electronic ignitions handle the advance. Take note of the name of the unit and Google their website.

 

[Ben10]

You mean it has no advance unit. I'm guessing it has electronic ignition, correct?

If so, most electronic ignitions handle the advance. Take note of the name of the unit and Google their website.

Nope kickstart only it has a capacitor

 

[toglhot]

Yes, but what's behind the points cover? Points or electronic pickup?

 

[Ben10]

Oh shit I honestly do not know what Im looking at ive only read the service manual and through these forums about points

 

[toglhot]

Remove the points cover and take a pic. Kickstart means the starter motor has been removed. Capacitor means the battery has been replaced, neither have anything to do with advance unit.

 

[Ben10]

Remove the points cover and take a pic. Kickstart means the starter motor has been removed. Capacitor means the battery has been replaced, neither have anything to do with advance unit.

 

[toglhot]

Being as the PO removed, or disabled, the electric start amd replaced the battery with a capacitor, the next obvious simplification would be an electronic ignition system. So I'm guessing that's what you have.
There are only a couple of electronic ignition systems that retain the mechanical auto advance unit, but they are a rarity. Only a peek behind the points cover will tell you what you have.

 

[WideAWAKE]

Looks like a Hugh’s CDI.

https://www.hughshandbuilt.com/product/complete-xs650-cdi-system/

 

[Ben10]

Thank you gents appreciate it I’ll be looking into it and ill try to figure out whats wrong

 

[toglhot]

Well before you look into it and try to figure out what's wrong you probably need to know the picture you posted is not the points or where the points go, it's the PMA alternator!

 

[Ben10]

Well before you look into it and try to figure out what's wrong you probably need to know the picture you posted is not the points or where the points go, it's the PMA alternator!

Yup lesson learned i assumed the previous owner kept it stock

 

[toglhot]

Well it's far from stock: no electric starter, no battery, PMA conversion and probably electronic ignition.

 

[WideAWAKE]

Well before you look into it and try to figure out what's wrong you probably need to know the picture you posted is not the points or where the points go, it's the PMA alternator!

He did post it. You just didn’t see it.

Pump the brakes.

 

[gggGary]

Most of those PMA crank fired ignitions do not have a moon key in them that locks it's position in relation to the crank. So it's possible for the coils to rotate on the taper and go out of time. Remove, carefully and completely clean both surfaces of the taper, reinstall/retime, you should be good.
This might help.
https://www.xs650.com/threads/installing-a-vape-all-in-one-charging-and-ignition-system.56346/

 

[WideAWAKE]

Most of those PMA crank fired ignitions do not have a moon key in them that locks it's position in relation to the crank. So it's possible for the coils to rotate on the taper and go out of time. Remove, carefully and completely clean both surfaces of the taper, reinstall/retime, you should be good.
This might help.
https://www.xs650.com/threads/installing-a-vape-all-in-one-charging-and-ignition-system.56346/

Never put one in, but I was always taught to lap tapers so they don’t do this.

Might be a good idea to make sure the tapers are making full contact.


Anyone got thoughts? A bad idea for some reason??

 

[gggGary]

Haven't worked with a Hughes PMI ignition but some tapers I've seen were "lacking" in machining quality and or had varnish epoxy in them. It's been a while since that thread I posted but only did a test fire of that system. It was fine AND tricky to set as the magnets wanted to rotate it a bit as it was installed. If clean and well machined, tapers hold their position............
Start with a timing light, you have the timing reference mark sticker on the cover

 

[Ben10]

Sounds good thanks guys. Also sometimes when my bike starts up the rpms just fly up like crazy it sounds like its at full throttle but the throttle cables are adjusted fine and the throttle isnt being touched. It just revs all the way right after kickstarting any ideas? Air leak?

 

[toglhot]

'Moon key'? Never heard it called that before, but shouldn't that be 'half moon key'. Personally, I call them them 'Woodruff keys'!
I better add this to help you out - LOL...

That aside, there's probably no half moon key in there, half the time the rotor pushes them out as it's installed.

I bash the keys a little to make them a tight fit.

 

[gggGary]

'Moon key'? Never heard it called that before, but shouldn't that be 'half moon key'. Personally, I call them them 'Woodruff keys'!
I better add this to help you out - LOL...

That aside, there's probably no half moon key in there, half the time the rotor pushes them out as it's installed.

I bash the keys a little to make them a tight fit.

You of course are correct, a half moon or woodruff key would be the proper name. LOL
Don't know what I was thinking....