[hardline71]

Hey guys- new member with a 1986 1200 GL (88k miles) here and need some help. A couple of days ago, filled the bike up with premium (93 octane) gas. Pulled out of the station and hadn't gone more than a mile down the road and bike started to "sound" like it was not firing on a cylinder. turned around and took the bike back to the house. I first checked the fuel filter and found it to be very dirty. I guess since I let the tank get almost empty it stirred up 25 + years of garbage in the tank. Changed the filter & lines, cranked bike up and headed down the road...same problem. took it back home and checked plugs. All plugs were a little dirty but didn't look fouled at all. replaced the plugs for my own peace of mind and still have the power loss issue. Thought that I may have gotten bad gas, so drained the tank & cleaned it. Filled tank back up headed down the street...same problem. I had to replace the pulse generator on the bike about three months ago and haven't had any issues with performance until the other day. Any ideas of what I could look at next? Any and all help would be greatley appreciated. Thank you.

 

[trike lady]

Hello and welcome to the forum.
1986 do you have CFI or carbs?
Check all electrical connections, battery, coils, stator and etc. Replace dog bone main fuse.

 

[detdrbuzzard]

hello hardline, welcome to GWOF. drain the crankcase breather over flow bottle

 

[2580]

hi hardline, sounds like some dirt an grit made it through your fuel filter an into the carbs. try a carb clean both low an hi speed jets an don't forget to blow out the fuel lines an cross over lines before reassembling the carbs. good luck.

 

[hardline71]

Hey guys, Thanks for the replies. I think I have found the problem. Was cleaning the carbs and discovered one of the rubber diaphrams is busted (vaccum leak). I would almost bet my right hand this is the cause of my power loss. I will update after getting them carbs cleaned & repaired. thanks again....hardline71

 

[knelson1969]

Well if the carbs do not repair your problem at least you have done some needed maintenance. Were you able to narrow down the problem to which cylinder wasn't firing properly? if so is the carb problem you found connected to that cylinder?

 

[budoka]

One other thing to check: there are small drain holes in the spark plug recess. They can get plugged and retain water and cause a mis-fire like you mention. Might not be but just incase. Welcome along.

 

[Cantankerous]

When that diaphragm leaks, it's not so much the vacuum leak, as it doesn't allow the needle to open the main jet. You'll definitely have a loss of power on the affected cylinder.

 

[badwing1200]

How did it work out hardline? Diaphram or just bad fuel from the previous fillup?

Not that it matters, neither one of us will ever come back!