Hard start, stumble off idle and then idle dies

HelmetTester

XS650 Member
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Gday gents,

Picked up my first xs650 about a month back and have slowly been chipping away at it to get her running properly.

She’s a 1982 special, rigid frame with a 43° rake, batteryless with HHB Capacitor, XSCharge PMA and what appears to be a mikes xs ignition and mechanical advance.

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The day I bought it the previous owner pulled it out and had it started in 3 kicks from cold, idled alright, a little rough but nothing too bad. The bike would stumble just off idle and if you carried on it’d die. Thought it was carb issue so I pulled them and found the diaphragms had holes in them. Replaced everything worth replacing while I was in there and cleaned everything up and used TIG rod to sync carbs as best as I could without vacuum, previous owner has replaced the manifolds and there is no vacuum valve on them anymore.

Put everything back together, adjusted cam chain tensioner, checked valves for clearances but couldn’t get started on timing as there aren’t any marks on the PMA rotor (there are some on the case so they’ve made some attempt), thought it must be timed alright since the previous owner had said it was running sweet before leaving the petcock on and letting it sit for 3 months.

Got it idling twice in about 15 kicks and still had the same issue. Would idle rough blowing smoke out of the right cylinder only, if I tried to give it gas it would stumble off idle and die.

My only idea to try find what’s wrong is to pull plugs and find TDC so I can check timing. If that doesn’t fix it I’m at a loss, never dealt with batteryless bikes before so if there’s something obvious I’m missing and should check I’d appreciate the knowledge all you XS gods can provide me.

*compression pictures are from cold engine

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