ok was riding the bike and all the sudden the rear cyl. drops out under 1/4 throttle. change plugs check timming checked spark changed out gas change oil rebuilt carb, i even cussed it out. read and reread clymer trouble shooting. with all i did it didnt change the problem even a little anyone with any suggestions i would greatly appretaite it at the point of saying f it and putting it in storage until i cn find a shop thats willing to work on a 1985 fxrs 1340. the dam thing only has 22000 original on it and has been freshed in 2000 with about 6000 sense. help

 

Check compression, if OK, check for intake leak.

 

Try switching plug wires and see if missing is on front cyl. If so, replace plug wires. They do go bad.

 

And if it happens to have been upgraded to single fire ignition, it could be the coil.

 

If you still have compression in the rear it's electrical , wires or one hole of the coil died on you if the comp is low or not there check the pushrods see if one tightened up or backed off on you holding a valve open or closed .

Swap the wires between holes on the coil and new wires like suggested before bike that old needs wires trust me . Pull the plugs and hold them against the heads and see if both are sparking when you turn her over

 

ok ckecked comp 165 both cyl. checked spark good out of both holes switched wires runs a bit smoother but back cyl. still not firring like it should checked pushrods i know if comp is good didnt need to but did anyway seems to be fine ckecked plugs swithed plugs went and got another set to rule them out no change thinking maybe bad cam but i'm stumped so any other ideas? i just moved to north carolina lincolnton area to be exact so dont know any indies or where any shops are. if anyone is in the area i would pay to get this looked at just have no idea where to take it.

 

Ignition module or the pick up is funky them .

 

bad lifter? Low oil press ? How does the compression build slow at first then build or fast .Maybe the lifter is not getting proper oil press at low rpm . See how compression builds in each cyl .Im not saying that its not an ignition issue im just saying .

 

All options are on the table when chasing gremlins , kudos for kicking in .

 

I'm thinking Brainless is on the right track with a lifter problem. If it was electrical it would show in both cylinders.