no spark on left side after running about 10 miles

[debikerman]

I have a question . because i'm getting tired of guessing with this bike.i've had this 1982 maxim 400 for 5 yrs . rode it hard for the first 3 yrs it sat for a year. now i'm trying to get it to run right . but for the last 4 months it takes fits. it runs great for the first 4 to 8 miles then back fires shuts off & has no spark on the left side. then let it set for a half hour & it fires back up. i've changed the coil on the left side . changed the stater just for the heck of it . changed cdi box. & put new plugs in it twice. it also spits & sputters some times when i give it gas when i start it. any suggestions would be awesome .

 

[Ruined1]

I had the same problem... With the same cylinder... My clutch rod seal was going bad and it was losing at a minimum oil pressure (not sure if it would effect the compression of that cylinder or not. I checked my spark by pulling the plug and grounding it to the side of the engine. Factory Gap seemed a little weak... So I sanded the hell out of it and adjusted the gap SLIGHTLY bigger (i mean slightly like 1mm) and shes purrs like a kitten now. Here's what yours could potentially sound like (if you have custom fishtail exhausts lol)
http://smg.photobucket.com/albums/v236/Ruined1/xs400/?action=view&current=Video0086.mp4

Are your plugs going bad btw? Are they staying a healthy tan color? Are they black (rich fuel)? Anything like that? White and corroded? I know mine get's black because the left cylinder is getting slightly too much fuel (im getting my carbs done monday)

Does it leak any oil at all?

Does it act the same with an open choke (cold start) as with a closed choke (warmed up)?

Is there ANY way you can video the sound like I did? Remember, try not to rev above 4k in neutral... Just good practice.