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#11
Maintenance / Re: Octane Booster
Last post by Pat Conlon - Yesterday at 10:48:33 AM
Hey John, Dynojet has their own proprietary jet sizes so disregard my Mikuni jet sizes.

I thought you had stock jetting. I think your Dynojet jetting should be fine.

Storing your bike with 87 octane ethanol free gas is fine. Short rides are fine.

On a hot summer day @ 5,500' the air density in Lakewood is low, meaning air flow for our engine cooling cooling is less, so in my opinion, I would avoid riding in summer stop and go traffic with 87 octane gas. Perhaps I'm being overly cautious.
Other folks can chime in....

If you want to do a plug reading, be sure to disconnect and cap off, the vacuum advance, pop in fresh plugs then ride to get the plugs to the proper color.

With the vacuum advance connected, you will find your plugs are white.... not an accurate color reading.

More info on the vacuum advance: https://fjowners.com/index.php?topic=11690.0

Cheers Pat

#12
Maintenance / Re: 85 FJ 1100 front fork main...
Last post by Jpn - March 22, 2026, 05:22:17 PM
LOL it was quite the sobering dream!
#13
Maintenance / Re: Octane Booster
Last post by Jpn - March 22, 2026, 05:20:06 PM
Hi Pat,

After I bought the bike last spring I overhauled the carbs and installed a dynojet stage 3 Kit with 120 main jets and 144 pilot jets then tuned the carbs accordingly. Bike runs good as far as I can tell but don't have anything to compare it to. I havent checked plug color yet...

Would you suggest reverting to your recommendations?

Regarding octane I was running 91 on hot days and never had any pinging and wasnt sure if E free 87 was ok.
#14
I'll stay tuned if anyone has a cure but my bike rides fine 
#15
It seems like the RPM's are stable even while the needle is ticking, going by the sound. Good to know that it's not just my bike that has a RPM needle that likes to dance.
#16
The rapid ticking up and down on the rpm:

Option 1: Is it just the RPM gauge needle that is bouncing around but the engine RPMs are consistent?

Or

Option 2: Are the engine RPM's going up and down and the RPM gauge is just accurately reflecting that?

My RPM gauge need does the same, seems to get drunk between 3k-6k rpm and bound around but the engine RPM's are fine so I chalk it up to the bike being 40 years old
#17
Update, finally had a good day for more testing and putting more miles on the bike.

60F outside temp, low wind's. Brand new Metzeler Lazertek Tires. Stock 1100 pistons. Stock exhaust. Replaced exhaust header gaskets to correct exhaust leak. Replaced intake boots recently. Resynced Carb's on digital man-O-meter. Pilot Fuel Jet's are 42.5's. I'm not sure if the mains are 110's or 115's right now.

Idle adjust screws are currently at 2.25 turns out.

Bike doesn't hesitate at 4k rpm, but still has the rapid ticking up and down by a thousand rpm, every second, whenever the RPM is between 3.7 to 4.5k rpm. Above or below those RPM's and the needle on the cluster is behaving.

Bike is also wanting to rocketship as soon as it touches 4k rpm, taking only a moment to hit 6-7k, when in first gear. I've been told that is normal. For the bike to "Wake up" and want to go.

I'll keep fiddling with it to get it more dialed in.
#18
West Coast Rally / Re: 2026 Willits California - ...
Last post by Pat Conlon - March 22, 2026, 01:53:50 PM
Derek, it will be great to see you, Donna and Captn Ron!

Time has flown by....

Pat
#19
Maintenance / Re: FJ1100 won't run in neutra...
Last post by Pat Conlon - March 21, 2026, 12:17:32 PM
The most common issue with the side stand switch is the switch itself....a simple continuity test on the switch leg will identify any side stand switch problem.
#20
Bikes for Sale / Re: 1985 Yamaha fj 1100 for sa...
Last post by Pat Conlon - March 21, 2026, 12:09:07 PM
Maverick lives in Augusta Georgia.

You've done some nice work on this bike Mav...I hope she goes to a good home.

Cheers

Pat