660 Engine build for FZR400 - Need Help

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660 Engine build for FZR400 - Need Help

Postby neroneuman » Thu Jul 09, 2020 9:01 pm


After running the FZR400/600 for almost 5 years and enjoying the build :grinnod: , I'm planning to build a 660 motor for it.

I'm going to follow ReelRazor's method using FZS rods for 660cc.

I'm using the below components

1) FZR600 (3HE) bottom end, head, carbs, powerpak, cams and coolant tubes.
2) YZF600 (4TV) Cylinders, pistons, rings, pins, clips, base gasket and head gasket.
3) FZS600 (5DM) rods

bore x stroke

FZR600 - 59 * 54.8

YZF600 - 62 * 49.6

FZS600 connecting rod (5DM-11650-00) has same length as fzr600 rod and has the small end size which fits the YZF piston pin.

These rods on the FZR600 crank (54.8mm) along with the 62mm cylinder/piston from YZF600 gives 660 cc.

I have bought FZS600 rods from a 21k mile engine and YZF600 cylinder/pistons/rings/clips from a 4500 mile 2006 engine.

I don't have much idea building 4 stroke engines and it will be done by a mechanic.

I have few questions on this build :headscratch:

1) For this engine build, is it necessary to change the piston rings, pins and clips and hone the cylinder?
since the cylinder and pistons are from a low mile engine, will it be ok to fix it as such?

2) Do I need to replace the big end bearings on the connecting rod?

3) Can the connecting rods be installed on the FZR600 bottom end without splitting the crank case and can it be done with engine on the frame?

4) Any other bearing or gaskets need to be changed or any specific things to note while tearing down and putting back the engine?

5) Does the YZF600 cylinder base gasket go on FZR600 bottom end without any trimming?
I believe the YZF600 head gasket will need some trimming to fit on the FZR600 head.

I think the valves need to be adjusted once the engine is put back together.

Right now I'm running 115 Mikuni size mains and stock pilot/starter jet sizes on my FZR600 carbs.
I'm planning to upjet it to 120 mains and see how it runs after the 660 build.

FZR Experts, please chime in

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