since youre into getting a new head anyways, might as well get some head work done while youre there. Just take the head into an engine rebuilder and get them to plane it. That will give you a true flat surface as well as SLIGHTLY bump up your compression. You could also ask them about valve guide modifications. On some heads, gas lays in a portion of the valve guide and gets burnt up. Sometimes countouring the valve guides fixes this problem.

If youre looking for custom pistons, dont bother checking out Wiesco as they require a minimum order of 20 before custom making any pistons.

And its not likely you'll be able to bore out to 700, theres only about 1/4 inch if that of space between the cylinder walls and the water journals in the engine. If I were you, I would just get them re-sleved and go from there. If you get too much of a bore you're going to get into needing a hotter spark plug as well as a conventional Hurricane jetkit will not be sufficient as youll need much more fuel to get top performance.


My advice rebuild it to stock, so you know you got a good base to start with, then start modifying.

 

The 89 is same as my 87 here. i bought the Blue 87 CBR600F1 really cheap from a guy that bought an F2 motor for 200$ and seen it wouldn't fit.
but now that i look at it. although the motor mounts are slightly different with a little engineering work it can fit. but the motors are made different internally so crankshaft and cams and transmission are not the same. but i believe pistons and rods are interchangeable.
i only gave a 200cc custom chopper for the F1 Bike with title, it's original motor and the F2 motor. i maybe had 100$ and 5 hours time invested in the mini bike. score 🤟😁

 

??? Really? I'd like that to be true. It could mean a cheap bolt in overbore job for the F1.
The F1 bore is 63mm, the F2 bore is 65mm.

 

They are not interchangable. Pin height is too low in the F2 and raises the piston dome too high in the F1. The top ring comes out and is flush with the deck surface on measurements. I never checked on the rod length, but as they have almost the same stroke I would expect the F2 is slightly longer due to pin height differences.
Wiseco will do custom orders of 1 set, but you do pay extra for it. I did it back in 04 with my13:1 set. My friends have done it recently for single cylinder huge overbore XR builds(XR600 bored to a 749). They already have the overall piston forging blank dies for the F1, it just needs to be machined to your overbore and application.
Easier to just fabricate the F2 engine in with custom motor mounts.

 

Drakito, hanks for that useful info!

 

There are very few if any parts that are interchangeable between F1 and F2 engines. Generational changes throughout the CBR life cycle were designed to reduce weight, and increase horsepower. The engines became dimensionally smaller as time progressed. This meant that cylinders were closer together, making carburetor and header spacing different. Bore and stroke moved around in order to increase RPM to gain horsepower. That’s why pistons, rods, crank and cams are not interchangeable. Within the 4 years that the F1 was produced changes in carburetors and cam timing were made to gain hp although these changes are somewhat interchangeable. It just shows how fast the target was moving to have the fastest best performing bike in class.

 

Very different from the Suzuki GSXR SACS series. The bikes I'm more familiar with.

 

Not familiar with the Suzuki’s but my guess is if they stayed the same it was due to development and manufacturing cost in the horsepower wars. Honda tried hard to stay ahead of the competition in the 600 class during the late 80’s and thru the mid 2000’s. It was a weird time. We were used to engine designs that stayed the same for years.

 

Yeah, Suzuki was never competitive in the 600 classs, because all size engines 600 thru 1100 used the same case. Same with the bike frame.
1st thing I noticed after stripping the panels off my CBR600, was the frame resembled the Suzuki Katana, but was scaled down to suit their 600 engine.
The CBR engine is also a decade more advanced that the Suzuki GSXR.

 

Yes and each generation F1, F2, F3 and F4 were more advanced with only about 4 years between each one. By 2001 the CBR was producing 110 HP. That’s quite an engineering achievement. Consider if a Honda Civic had the same HP to CC ratio...it would put out 330 HP.