cylinder head mods..

[neonjeffie]

bought a spare 94 head for my 600 kat.going to port it and put 91-92 gsxr cams in it. does anyone know how far you can mill the head? or if you even should?i went .020 on my car head to raise compression a bit and clean the sealing surface up, can i do the same for my bike?

[loudnlow7484]

I would guess that you could take .010" off without issue.... Just check how much valve-piston clearance you have before you have it done.

[mreedohio]

your cams are being mailed out tomorrow

[arsenic]

seriously porting a Katana head gets you noting. I have more engine mods then you could think of, you know what I didn't do? Port or mill the head

[loudnlow7484]

seriously porting a Katana head gets you noting. I have more engine mods then you could think of, you know what I didn't do? Port or mill the head

I'd guess you say that because the Katana 600 won't make much in the way of power by porting the heads (and you'd be right, it's just not necessary), and not because the katana 600 is just a model of port efficiency (because it's not)

I personally think that there could be some power found with a really good port job, but the cost vs results probably wouldn't be worth it.

[hardlydangerous]

Keep in mind when you mill the head you will have to re-machine the cam gears so they are adjustable so you can retatrd the cam timing.
.015" is doable.. easiest way is to research thinner gaskets to increase compression and no need to screw with cam timing
Remember though the lower the head is the longer the timing chain is also...so adjustment will be an issue if you mill it too much.

[arsenic]

a 600 period, you spend like what $750 bucks to gain what 3 HP?

[neonjeffie]

Keep in mind when you mill the head you will have to re-machine the cam gears so they are adjustable so you can retatrd the cam timing.
.015" is doable.. easiest way is to research thinner gaskets to increase compression and no need to screw with cam timing
Remember though the lower the head is the longer the timing chain is also...so adjustment will be an issue if you mill it too much.

exactly what i thought

a 600 period, you spend like what $750 bucks to gain what 3 HP?

the more air you can flow into your engine and back out of it and the smoother it happens the more power you make. i will spend less than $100 if i were to port and mill the head.i do my own work and im very good friends with my engine builder.has anyone rode a bike with head work done to it?versus a stock one?

[loudnlow7484]

the more air you can flow into your engine and back out of it and the smoother it happens the more power you make. i will spend less than $100 if i were to port and mill the head.i do my own work and im very good friends with my engine builder.has anyone rode a bike with head work done to it?versus a stock one?

I'm assuming you have a flowbench to work on then? If so, then have at it, and let us know what exactly you do to the port that ends up the best. Porting is sort of black magic to me..... I have no idea how you figure what is best in terms of cfm, velocity, port length, round ports/d-shaped ports, and how this all relates to the engine itself that you are porting it for. I know we do have a member on here somewhere that spends a lot of time on a flowbench......

[arsenic]

got news for you, porting a Katana head does NOTHING the main restriction point is the weld seams on the exhaust header which you can port yourself, but seriously, what do I know Yeah I have, it was a 1990 gixxer 750, same head, did **** I'm not trying to talk you out of anything, if you wanna do it, do it. I'm just telling you, when you end up with an engine that dyno's about the same as it did before, don't say I didn't tell you.

[FastJetta97]

yeah i would agree and say spend your money and time on other mods.....

but i deff agree in most circumstances there is a lot of power to be had in porting and polishing.....

[arsenic]

there is a lot to gain porting a Katana too, just not the head. The weld seams on the exhaust header.

[neonjeffie]

wow i didnt mean to open pandoras box here....

[arsenic]

you didn't

[hardlydangerous]

Opening up the ports too big can cost you HP too.
I highly doubt porting ther head will do you any good.

What I would recommend doing though in stead of just hogging out the ports is... just texture the intake runners, polish the combustion chamber and valve faces and exhaust port to a mirror shine. This will eliminate carbon build up.
Port match the exhaust port to the exhaust pipe and clean up the welds in the header. Thats about it.
Keep in mind this head was used in the factory race GSXR back in the day. Do you think Suzuki did any research on getting the most out of the porting when designing the head? Fact is smaller ports can increase intake velocity, and with more accurate tuning, cam profile/timing, and better carburation will make far more HP then porting.
Now if this was a 2 stroke... that's a COMPLETELY different story.

here are a couple pics of my engines that i have on this computer.
On many of my 4 strokes I actually build up the intake ports and change the runners using aluminum epoxy (devcon) to smoothen and reshape the runners for faster air flow with less restrictions. The mirror finish will eliminate carbon from building up even after years of use.