Okay false alarm on the compression Ran her to operating temp from a funnel...

Okay, false alarm on the compression. Ran her to operating temp from a funnel and retested. These are the results.

  • Oops... Cylinder numbers are inverted. It's 4,3,2,1. And, that 130 should be 140

  • Still check your valve clearances. easy to do. tune up. FJ valves take a beating. Besides you need a base line to trouble shoot. That aside your problem is in the carbs as I see it. :).

  • Do a leak-down test if you can.

  • George, just did the valves 1000 miles ago. Doubt they've changed much, but we'll see. But I agree, that's not what's causing the problems.

  • I've never had trouble with my valves, three adjustments in 140k. Maybe I'm just lucky. :)

  • I am not saying they are bad, just in a high heat and wear area. Typ of any air cooled engine. And truthfully these older bikes seem get less "love" than they should. When the FJ's were new they keep up with the service at the point when they become cheap or inexpensive to buy the owners do not keep up with the services. Some don't even know what to service. It is nice to see people now restoring or keeping them up in better shape. At 140 K it is clear you keep yours in good shape. :)

  • Sam remember compression tests should be wide open throttle to be valid

  • Yep. Ran a test on one cylinder before I realized that. The reading was way too weird to be believable!

  • the strange thing is (as you stated) it came out of the blue, suddenly .It only leads me to think about an electrical issue,fuel related issues never come right off they begin slowly and get worse as time passes by

  • Fernando, only time I had a fuel thing come out of the blue was with my '72 R5. Rode to a gas station, topped of the tank, and the bike wouldn't start. Turns out that the main jet in my left carb had come unscrewed and was sitting in the bottom of the bowl, so the left cylinder was getting insane amounts of gas.