SlightlyOffAxis

Thank you, all good points and thank you for the link , now I know were to go to get parts I feared would be impossible to find. After having bench synced the carbs again and double and triple checking all the jets, settings and connections, I can get the engine to turn over freely and on every third or fourth revolution I can hear the engine attempt to continue on its own, but it doesn't. I get a hazy smoke around the carbs and an occasional backfire. Then I get disgusted and walk away. Progress is slow indeed considering as it is set up right now it was running except or the flat spot at 1/4 throttle a few days ago.

The 1984 FJ600

Any help is welcome. I am trying to lube all the areas that mostly time and miles strip away and have done the wheel and steering bearings but I cannot figure out how to add grease to the rear pivot shaft. The owner’s manual, granted not a great resource, says apply it until it begins to show. It fails to show you were to apply it and were it will show. The last place I have to check is this area and the various rear suspension linkage connections and I am sure they are in need. Any advice is welcome. Thank you in advance. I wanted to add one more thing. If you remove the caps one either side of the bike at, what I believe is the swing-arm connection you find a large bolt and a smaller hole. The hole only seems to be 10mm or so deep. Is this a lubrication point? The one side has a hole at the bottom as well and I believe that is just a moisture drain. Thanks

I have a 1984 FJ600 that ran perfectly until I did something, I’m not sure what. I pulled and cleaned the carbs (Mikuni BS 32 type 2) that are jetted Stage 3 with pod filters and a Kerker 4-1-2 system. Fuel mixture screw is 3 turns out, and jet needles are on the 3rd position as it has been for several years. I installed the larger main jet when I put the cone filters on and it ran well except for a slight flat spot just after ¼ throttle that cleared up before ½. The bike pulled hard all the way to redline in any gear. I adjusted the needles and fuel mixture screws and thing did not improve. I attempted to vacuum synch the carbs and in the process of all of this I ran into some issues that changed the throttle stop setting as well. I bench synced the carbs and cleaned them, I am meticulous, everything is cleaned and adjusted back to where it was but it will not start. It turns over fine. I have a suspicion it is how I have the throttle stop set that is making the difference. When I bench synced them yesterday I have them closed completely at the start position. Question 1. Is the throttle stop position correct? Question 2. Assuming the carbs are perfectly clean and there are no worn or dirty part what else should I look for. Question 3. I was able to get a copy of the Mikuni BS32 handbook that describes, among other things, how to vacuum sync their carbs and it is different than what Yamaha has in its service manual. Mikuni says you need to sync the #1 and #4 carbs to be even and slightly higher than the #2 and #3 carbs which would be level with each other. Yamaha says, as does everything else I have seen on the web, to sync them until they are all level based on the #3 carb setting as it is fixed. Why the difference? They way the carb appear to work to me is that I HAVE to adjust #2 to #3 first as #2 is only adjustable with the adjustment screw that adjusts the set, then adjust #4 to #3 and #1 to #2.