Ohh, Yes, he did...660 the easy(?) way

[cntryboy85]

how did this work out because i am seriously thinking about doing this while i have mine tore apart and it is cheaper than doing what i was thinking about

[cntryboy85]

also do i need to use the yzf or fzr gasket for the cylinders. i know i need yzf head gasket but what about between the cylinders and the casing?

[reelrazor]

Stock 4tv base gasket.

The 3he cylinder block has sleeves that protrude into the cases-which get o-rings, plus the standard base gasket. The yzf base sits right up tight to the bores and the case opening.

The yzf head gasket will need to be opened up on a couple of coolant passages-very minor work with a pointy die grinder bit

[cntryboy85]

for the cylinder block are you talking the cy.inders that came off or are you talking about the casing for with the crank. i got 2003 yzf head, pistons, and cylinders coming in soon. with the yzf cylinders i do not need the o-rings? or are the o-rings to fill the gap that is left behind where the yzf does not go into the block?

[DonTZ125]

YZF block, head and pistons - why does the YZF head gasket need to be modified? Or do you mean the base gasket?

[cntryboy85]

also as far as the cam chain goes do i need to get one for the yzf or keep using the fzr one.

[reelrazor]

YZF block, head and pistons - why does the YZF head gasket need to be modified? Or do you mean the base gasket?

mine=

yzf cylinder block, pistons, FZR head

[cntryboy85]

why did you use the fzr head on the yzf block. is there any differences performance wise or just a preference?

[DonTZ125]

The compression ratios of the FZR and YZF engines are the same, so the combustion chambers should have the same volume (= same +10% compression increase), but the FZR bore is 3mm smaller in diameter, making the chamber taller and narrower. Unless I'm talking out my backside, the extra 1.5mm radial distance of the YZF block should equate to a rather higher squish ratio. Unless the head gasket is some ungodly thickness, this should reduce the chance for detonation at the periphery, and also increase the turbulence in the main volume of the chamber itself. This should in turn improve combustion efficiency, allowing for both more spark advance and more fuel burned = more power.

[KaspenOne]

ive been thinking of doing a 660 upgrade, man this looks sweet. cant wait for a write up hopefullly before i tear my engine down for rebuild youll have one up? in the meantime would you be so kind to make a list of parts needed?

[reelrazor]

The compression ratios of the FZR and YZF engines are the same, so the combustion chambers should have the same volume (= same +10% compression increase), but the FZR bore is 3mm smaller in diameter, making the chamber taller and narrower. Unless I'm talking out my backside, the extra 1.5mm radial distance of the YZF block should equate to a rather higher squish ratio. Unless the head gasket is some ungodly thickness, this should reduce the chance for detonation at the periphery, and also increase the turbulence in the main volume of the chamber itself. This should in turn improve combustion efficiency, allowing for both more spark advance and more fuel burned = more power.

From what I could see, Yamaha just increased that squish land on the 4tv pistons as you are alluding to, Don. The actual raised portion of the pistons (4tv and 3he) is identical. I'm an old two stroker, too...and know the value of squish.

It is my thinking that it is exactly that, coupled with the overall compactness of the chamber in general which allows me to use mid-grade fuel at 5° before base advance, and the increased compression.

That being said, and considering that chamber volume is the same between the two heads (4tv and 3he), and that aftermarket cams are sold as being usable for 3he and 4tv motors, I don't think yamaha re-engineered anything in the head except maybe the coolant passage casting...

It is my understanding that the 4tv bikes' intake manifolds will not fit the FZR carbs, but I am betting the 3he manifolds are a bolt-on proposition.

None of this thinking came into play in my choice of 3he or 4tv heads..the fact was, I had two 3he heads-one a ported 3he head with aftermarket valves, springs, and cams.

the first build used my stock 3he head..(because I was unsure of valve to piston clearance using the hot cams)....which fairly promptly spit a valve collet.

After talking to the spring people ( http://www.rdvalvespring.com/ ) and catching a very cool trick from them for checking clearance, the next install got the ported/sprung/cammed head.

[reelrazor]

ive been thinking of doing a 660 upgrade, man this looks sweet. cant wait for a write up hopefullly before i tear my engine down for rebuild youll have one up? in the meantime would you be so kind to make a list of parts needed?

This was the write up.

[DonTZ125]

Were you pinging on Regular? What is this nifty valve - piston clearance checking trick?

[cntryboy85]

ok somy buddy is asking me what all he needs to do to make this work and i have no clue how to explain this to him. could some one tell me what exactly has to be done when i am using an 03 yzf jug, head, and piston with fzr con rods. and what is the squish ratio and is there any upgrades that can be done to the transmission to help it hold the extra power that is going to be put to the ground?

[rsaddo]

Hi m8 not 100% sure on what a 4tv is I'm presuming its a late yzf thunder cat barrel your using
Hence the difference in head gasket coolant differences.
On my 660 I've used a 94 fzr600 4jh barrel and pistons you have me paranoid now
I'm about to get her fired up this week and I'm nearly at the point of opening her back up but
I'm sure I match the new to old gasket and found no differences could this just be down to you using the later motor parts ?.
What jetting did you settle on in the end my carbs are like new and I'm thinking of using standard mikuni jets
Rather than going for a jet kit
Regards
Neil