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1989 FZR400 Engine swap from 1995 FZR600

Posted: Sun Jul 14, 2019 4:07 pm
by kcallowai
Hi All!

I decided to pick up an 1989 FZR400 as a project bike...I just love the small bikes...and..well Im short too.

I just picked up a complete 1989 FZR 400 to work on, but it came with a parted out 1990 FZR400 and the 1990 frame is still registered here in CA so Im considering an FZR600 engine swap to resurrect this little guy as well. I can pick up a VGC 1995 FZR600 with no title very reasonably.

Sooo, my questions are how easily will the 600 motor mate up with the 400 frame...and what is the best course of action with the rest of the 600?...use most of the 600 on the 400 frame or ??

Thank you in advance

Re: 1989 FZR400 Engine swap from 1995 FZR600

Posted: Sun Jul 14, 2019 8:17 pm
by Evilchicken0
Ok so usa bikes are slightly different to models and years we have here. California also got the SAC which is close to the 3en2 it has an EXUP. Have a look at the frame I'm guessing has frame rails and the engine has mounts at the front of the gearbox ???
The 600 / 400 engines have common cases the 600 is just a longer stroke. Good news it will bolt straight into the 400 frame.
You'll need the 600 down pipes, the cdi and clocks are good due to the 600s lower red line and mph speedo. The carbs would useful although the 400 are same they would need retuning.
The radiator fan fouls the top of the down pipes, some put the fan on the front with the impeller turned to push air. Some respace the rad, some use computer fans.
The 600 being taller puts the carbs and therefore the airbox higher - space the tank cover up by about 20mm.
You might need a different link pipe for the exhaust can.
Dyno tune it after
That's it ... easy conversion

Re: 1989 FZR400 Engine swap from 1995 FZR600

Posted: Mon Jul 15, 2019 3:52 pm
by kcallowai
Thank you!

both bikes are 3FH.

Let the madness begin...

Re: 1989 FZR400 Engine swap from 1995 FZR600

Posted: Mon Jul 22, 2019 6:30 pm
by Evilchicken0
Cool :grin:

Re: 1989 FZR400 Engine swap from 1995 FZR600

Posted: Wed Oct 14, 2020 9:19 am
by RoadDogma
Pretty much what Evil said. I'm also in California (OC) and have swapped a YZF600 motor into an '89 FZR400 SAC. The '89 Cali bike is a 1WG with an EXUP pipe. The '90 FZR400 SAC was upgraded with 4 cylinder front brake calipers and Deltabox swing arm, so it's like a 3EN2 with 1WG bodywork and steel sub-frame. Keep in mind the front brake rotor off-set differs between the '89 and the '90 bikes, so the forks and the brakes will only swap over as a package.

Anyway, I would run the 600 ECU. The 400 ECU rev limiter would let the 600 motor spin past 14K before cutting in. Some aftermarket 400 exhaust systems have been known to fit, so you could get lucky. I think I've seen an example with a 400 Hindle pipe. I tried FZR600 Kerker 4-2-1 pipes, but they fouled at the front of the lower fairing. I have an FZR600 Yoshimura duplex pipe and it fits very well. I have also been successful with a YZF600 Hindle. I fabricated radiator mounts from aluminum stock sourced at Home Depot and have no clearance issues with a YZF600 radiator/fan, but ZX6R radiator would be a better choice. The 400 carbs we have here are not the same as the FZR600. Run the 600 carbs and airbox/snorkel with a Factory or Dynojet jet kit. Hybrids are cool. Good luck and enjoy