‘79 xs650 won’t start ..backfires out of left cylinder on kick

[Batterylizard]

Hey y’all. Just bought this 79 xs650 from a friend for a couple hundred dollars. Forgive my ignorance this is the first motorcycle I’ve truly worked on.

After getting a new battery I kick started it and got it to run while giving it gas, although it seemed to be only left cylinder. Now it won’t run at all and only backfires every few kicks.

i got new spark plugs and it’s getting sparks. Has good compression too. I set the valves and set the points. while setting the timing at F, I’ve noticed that moving the timing plate back and forth doesn’t open and close the points, only when I manually advance the motor do the points open and close. I have also noticed then when I try to kick it over there’s sparks coming out of the points. Would a bad Condenser cause it not to even start?

I’m trying to figure out what to do next to get this thing running. I’ll take the carbs out to clean them soon but wanted to at least get it started first if it’s an ignition problem.

buy new points, new condenser ,.. ?

Would any other information be useful to help me diagnose what’s next? The guy who owned it before said it ran ok for a while then went out he replaced the advance unit and it wouldn’t start after that.

Thanks to anyone who could help

 

[nj1639]

Welcome aboard!
Bought it for a couple hundred......if you got a title with it then you stole it!
Post some overall pics as we all would like to see what you have, include a shot of the points side and the opposite advance weight side for the points guys - of which I'm not.

 

[JJames]

I'd head straight for the carbs on a new to you bike. Even though it ran its quite possible that it sucked in some gunk from the fuel system, lodged in pilot circuit. Of course you need healthy spark. Best of luck. Have fun.

 

[gggGary]

A bad condenser will make a weak spark at the plugs and sparks across the points. Any chance you swapped a couple points wires while working on it? That'll have the motor just misfiring in one side.

 

[Batterylizard]

I'd head straight for the carbs on a new to you bike. Even though it ran its quite possible that it sucked in some gunk from the fuel system, lodged in pilot circuit. Of course you need healthy spark. Best of luck. Have fun.

Cleaned the carbs out, new condenser installed. Trying to start again no luck, still just misfiring out of left cylinder every few kicks. Going to replace the fuses according to the manual, one seems a bit burnt.

Could a small air leak somewhere cause this not to start and just misfire? Could this still be a timing issue? I’m wondering if it could be an electrical thing. Not sure.

Thanks anyone for the help.

NJ asked for a photo here’s one of the point.

 

[Batterylizard]

Got to figure this out

 

[gggGary]

Swap the points wires side to side, easy at the plug up by the coils, try again.

 

[Batterylizard]

Got it started , running pretty good! I guess the rotor was installed so the original TDC mark was not accurate, found that someone had markered in the true lines of TDC and fire at about 2 o’clock position and now the timing is locked in , fired right up after a few kicks. Rode it around and it sounds great with a few misfires or backfires but I figure I may have a small air leak somewhere near the exhaust boot connection. Thanks all for the help I’m very excited to get riding

 

[5twins]

It shouldn't be possible to do that because there's a woodruff key that locates it in only one spot (the correct one). Unless maybe it's an aftermarket replacement rotor and the key slot is in the wrong spot in relation to the timing mark.