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running rough

Started by Tapartacus, July 18, 2012, 02:13:46 AM

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movenon

Andrew
            I just took my 1990 FJ out "yard saleing" and ran it 1000 to 1500 RPM in second all morning with no problems. Nice and smooth. Last winter I rebuilt the carbs and adjusted as per factory spec's. All I can say is that the FJ will run at low rpm just fine if things are in tune unless your bike in pretty modified (Cam's etc). I would spend some time adjusting the carbs first. Easy to do and you can make a sync. tool for 15.00 bucks that's as accurate as it gets. On the idle air adjustment I found it easier to adjust by lowing the main idle screw down as low as I can get and still keep it running. Mine idles at 500 RPM nicely, adjust, then put it back up to 1050 + -. I sync my carbs at 1050 RPM. Some raise the RPM up for syncing. Agian, I find it helpful to do it like Yamaha's Service manual instructs when all else fails :).
                                                                                                                                                                                                       George
Life isn't about having the best, but about making the best of what you have...

1990 FJ 1200

Tapartacus

Hi George thanks for the reply. I know exactly what you mean I have an 89 and it purrs like a kitten at all rpms. Will talk to Randy at RPM soon.
Andrew
92  FJ1200
89  FJ1200

Alf

Even with the 42,5 pilot jets (std fitments in EU models), the bike surges at 1500 rpm

The solution: DJ 155 air corrector jets, ignition advancer and mixture screws turned 3 turns out

Without the advancer is near impossible to avoid the surge because it is produced by the ignition going abruptly from 5º to 35º in 500 rpm only. Only with the advancer the bike gains a lot in that area

Regards

Alf