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How did I just fix my 91 FJ1200?

Started by fjankenstein, April 30, 2024, 11:49:31 PM

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Sorry for the long first post, I've been following this forum for years and used it for several repairs and mods.

I've owned this FJ for 7 years. When I bought it is was running poorly and seemed by pulling reading the plugs the 3rd plug was running wet and the bike was idling and running poorly at low rpm. I removed the carbs and cleaned them by removing jets and using carb cleaner, a carb jet wire cleaning tool etc. I reinstalled and synced the carbs and the bike ran great for 6 years until last summer and seemed to go back to running exactly like it did when I bought it. It was a big job pulling and cleaning the carbs again so I just stopped riding the bike. A few months before the bike started running poorly at a stoplight the bike was dumping fuel out of one of the carb hoses. I pulled them out and blew with my mouth into the one that was dumping fuel and it seemed to work again (stuck or dirty float jet??).

I noticed the battery was dead today so I charged it and went for a ride and it was running terrible still. For some reason I thought of the carb hoses so I fished them all out the side. I found the 4 smaller carb hoses and 2 larger hoses I don't recall what they are for. I shut off my air compressor and bled the tank PSI down to 70 and found a rubber blower nozzle and forced air into each of the 4 carb hose until I could hear bubbling in each carb. One or 2 seemed initially blocked?? maybe. I also gave the other 2 larger hoses a quick squirt of air. One of the larger hoses caused fuel to back out the 4 carb hoses so I repeated blowing into each of the carb hoses. I put everything back together and waited about 15 min to start it. It seemed very flooded at first so I retried with the throttle held wide open and it chugged to life. I took the bike out for a ride and was astonished to find it was running PERFECT again. Any ideas how this reckless act "fixed" the carbs? Unblocked them?

PS- Another issue with the bike was the tachometer had stopped working about 4 years ago. I found several threads on this forum and I located a nice one on eBay from Canada. It looked like a big job to remove the fairing etc. so I just never got around to it. This evening when I got back from testing my carb "repair" I notice the Tach was also working again? I realize how lucky I got with these "fixes" and I have had the bike out 3 times this evening to verify everything was still working and I wasn't dreaming. :wacko2:


2 months later and the carbs still clear and running great. Tach also still working. Now if I can just find that 6th gear that I can't stop looking for..



Try a can of SeaFoam (mixed to label specs) to get and keep the carbs clean.  That stuff is magic, but not instant magic.  It will take a couple of tank-fills to use up one can of carb cleaner, when mixed correctly.  Add the cleaner to the gas tank before you pump in the fuel.

If the tach quits again, check that the tach and instrument panel have solid, unquestionable grounds connected, at the panel and the frame.  Dull metal is corroded metal.  You want bright, shiny connections, and solidly secured at each terminal.

P.S. Life is too short, and health is too valuable, to ride on cheap parade-duty tires.


Never heard of Seafoam. Will look into it. I always fill up the tank with Mobil Premium. They advertise it contains Techron fuel system cleaner. I always try drive it at least once a week to keep the fuel moving. When I had the gum up issue I had not driven it for months.


You can find that 6th gear by simply switching to 18 tooth front sprocket and 38 tooth rear more hunting for 6th gear  :good2:

'89 FJ 1200 3CV - owned from new.
'89 FJ 1200 3CV - no engine, tank, bike for the future.
'88 FJ 1200 3CV - complete runner 2024 resto project
'88 FJ 1200 3CV - became a race bike, no longer with us.
'86 FJ 1200 1TX - sold to my boss to finance the '89 3CV I still own.


I tried that and felt it made 1st too tall for daily stoplight to stoplight driving. It was great on the highway, dropped the RPM a lot. I ran the just the 38 for a while too, now I think I am back to original if I recall. If ever travel a long distance on the highway I would consider putting them back. When I when back to original I bought a brand new old stock OEM 17 from randy and I swear it was quieter.