Jetting for Fj1200 with Wiseco 81mm big bore motor

[Inps]

Hi Does anyone have any suggestions on jetting for a wiseco 81mm 1314cc motor
  Thanks

[Millietant]

It all depends what you've done with your intake and exhaust systems as well. With a full list of what mods you've done, someone may be able to help with a starting point.

Or possibley, contact RPM (Robert/Randy) directly.

[Inps]

IT has a stk exhaust, stk carbs, k&n air filter and wiseco 1314 pistons

also has anyone replaced the rear calaper with someting different with the stk bracket

[Pat Conlon]

You're adding about 10% to your displacement so it makes sense to plan on adding roughly 10% more fuel.
The bigger issue is compression.  Unless you have headwork to add volume to your squish area and/or shaved piston domes, the concern is the bump in compression from the added displacement. 12:1 to 13:1 compression (or higher) is common with these high domed Wiseco pistons. At those compression levels, you need more fuel, and/or higher octane fuel, to counteract pre detonation.

My advice, get professional help. Find a tuning shop with an eddy current dyno or at least an inertia dyno for your fuel/air checks.

On my 1380, 83mm Ross pistons (shaved) w/head work: 10.5:1 compression, 5°ignition advance, stock exhaust w/Cobra F-1R slip ons, UniPod's and running 91 pump gas,  I'm at #127.5 mains, #45 pilots, 160 air bleeds with the special Hank Scott needles raised all the way up.

Hope this helps...

Cheers

Pat

[Millietant]

Pat speaks as someone who has gone through the same process. Aviation Fred and Giantkiller (Dan) might also chip in with their experiences with big bore engines.

As for the rear brake caliper, quite a few have used Suzuki rear calipers, but from GSXR/GSXF models when changing their rear wheels to 17" GSXR wheels. I don't know of anyone who has used a different caliper on the stock FJ bracket - but the big question is "why".

The rear caliper on the FJ is serviceable (with readily available, cheap parts) and well up to the job.

If you need another, then there are quite a few Yamaha's that use the same caliper unit, including the FZ 750 and FZR's. The YZF 600 R caliper also fits the FJ bracket.