'86 FJ1200 Backfiring

[benesja]

I recently got an '86 FJ1200 from my dad. It had been sitting for some time (about 4 yrs). It ran fine when he put it away. I dusted it off last fall and couldn't get it to run past idle. Will idle when "choked" and idle rough when not. Roll the throttle wide open and it just bogs and backfires into the carbs up to around 3-4000 rpm and then gets a bit livier with a bit of backfire but clearly not all there. I have cleaned up the carbs and it seems as though the diaphrams are still holding vacuum. What could be wrong?  

[andyb]

Sounds like the carbs need cleaned again until successful.  Possibly a vacuum leak going on also, what with the rubber drying out and getting cracked.

[Harvy]

I recently got an '86 FJ1200 from my dad. It had been sitting for some time (about 4 yrs). It ran fine when he put it away. I dusted it off last fall and couldn't get it to run past idle. Will idle when "choked" and idle rough when not. Roll the throttle wide open and it just bogs and backfires into the carbs up to around 3-4000 rpm and then gets a bit livier with a bit of backfire but clearly not all there. I have cleaned up the carbs and it seems as though the diaphrams are still holding vacuum. What could be wrong?  

G'day Ben......... firstly, post into the intro section.....let us know where you are etc.

Your problem sounds typical of FJ's that have sat for a while. You say you cleaned up the carbs.....but not what you actually did.
You will more than likely find that the jets are plugged up with varnish from evaporated fuel. A good tear down and clean in something like a sonic cleaning bath, re-assembly with new o-rings, maybe replacement of floats and/or float needles.

Have a search through the forum, in the maintenance section. You will find many posts on this subject.

Cheers
Harvy

[jack02]

When I got my FJ it had been stood for an incredible seven years. It ran but was shockingly rough at low revs then took off like a ridiculously tuned two stroke further up the band. I tried sorting the carbs myself but gave up and bought a secondhand set. Those,and the swapping of 15(!!) shims restored normal service.......