bluemax89
Junior Member
compression ratio is different due to the pistons. They are the same size just different dome shapes.
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R6 big bore kit...can it work on an FZ6?
- Thread starter Wolfman
- Start date
compression ratio is different due to the pistons. They are the same size just different dome shapes.
MRGM
Junior Member
well i have done a bit more research this morning, and i now know that Wiseco do a high comp piston kit for the 2001-2005 R6, same size as the JE kit, 637cc, 2mmm over bore, but with a higher compression ratio of 13.5, as opposed to the JE kit, which is 12.5.
compression on the R6 motor stock is 12.4., and the FZ6 motor is 12.2
the guy who will be doing the work, is looking at it himself now....and by the end of the day i should know where i sit....this guy knows his stuff...is one of Australia's leading drag bike engine builders....
as for then going one step further, and fitting the R6 cams, this could also be on the cards....the increased engine displacement, may make up for the loss of low end torque associated with fitting the R6 cams...we are looking to try and get rear wheel power up to about 110-115hp, by doing all of this...
one othere thing i do know now as well, is that the piston kit should cost about $750 australian...still dont know how much it's going to cost to get the cylinders re-lined, after the re-bore... am thinking about $800.
and before anyone else tells me to get another bike...that's not the point of all this, the point is to get an FZ6 to really get up and boogie! not an R6, an FZ6.
:thumbup:
compression on the R6 motor stock is 12.4., and the FZ6 motor is 12.2
the guy who will be doing the work, is looking at it himself now....and by the end of the day i should know where i sit....this guy knows his stuff...is one of Australia's leading drag bike engine builders....
as for then going one step further, and fitting the R6 cams, this could also be on the cards....the increased engine displacement, may make up for the loss of low end torque associated with fitting the R6 cams...we are looking to try and get rear wheel power up to about 110-115hp, by doing all of this...
one othere thing i do know now as well, is that the piston kit should cost about $750 australian...still dont know how much it's going to cost to get the cylinders re-lined, after the re-bore... am thinking about $800.
and before anyone else tells me to get another bike...that's not the point of all this, the point is to get an FZ6 to really get up and boogie! not an R6, an FZ6.
:thumbup:
proxxx34
Junior Member
Capo79
Viking spirit
Wolfman: I'm pretty sure I read in my FZ6 Haynes manual that it isn't recommended to bore up the cylinders. It suggests that if the cylinders from whatever failure are so scratched up that honing won't cut it, then the whole block should be replaced...
As far as I understand, this tuning of yours implies boring up the cylinders, right? Sure you want to do that?
As far as I understand, this tuning of yours implies boring up the cylinders, right? Sure you want to do that?
Capo79
Viking spirit
stink989
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Wolfman: I'm pretty sure I read in my FZ6 Haynes manual that it isn't recommended to bore up the cylinders. It suggests that if the cylinders from whatever failure are so scratched up that honing won't cut it, then the whole block should be replaced...
As far as I understand, this tuning of yours implies boring up the cylinders, right? Sure you want to do that?
he is talking about getting them bored out and replated so it is the same coating on the bore as when original.
Replating it is a very common thing to do to nikasil (spelling) and crome bores when worn out its the cheaper way then replace the whole block or barrel most of the time. I think the fz runs nikasil bores:thumbup:
Wyotech kid
Junior Member
Most if not all modern bikes have nikasil plating. Makes the cylinder walls hold up better and last longer. Usually its not meant to be bored out but it can be. Replating can tend to be more exspensive than buying a new block but not always.
As for the compression ratios on the FZ6 and R6 the combustion chamber has alot to do with it. Idk what the cc numbers are on heads of the 2 but I'm pretty sure they are different. I found that a 05 r6 has a combustion chamber volume of 10.6cc. this link look helpful for some numbers.
05 Yamaha YZF-R6
As long as the cams dont mess up the timing the ECU has for a stock setup things will more than likely go off without a hitch. But i do express concern for the stock injectors. Having more cylinder volume to fill in the alotted time seems to be a bit of a tall order for stock injectors. Injectors should be run at 50% of their duty cycle. Pushing them harder and you should get bigger injectors to keep that 50% duty cycle. And perhaps increasing the fuel pressure since cylinder volume increased and you need alot more fuel to fill that much space in a short time.
As for the compression ratios on the FZ6 and R6 the combustion chamber has alot to do with it. Idk what the cc numbers are on heads of the 2 but I'm pretty sure they are different. I found that a 05 r6 has a combustion chamber volume of 10.6cc. this link look helpful for some numbers.
05 Yamaha YZF-R6
As long as the cams dont mess up the timing the ECU has for a stock setup things will more than likely go off without a hitch. But i do express concern for the stock injectors. Having more cylinder volume to fill in the alotted time seems to be a bit of a tall order for stock injectors. Injectors should be run at 50% of their duty cycle. Pushing them harder and you should get bigger injectors to keep that 50% duty cycle. And perhaps increasing the fuel pressure since cylinder volume increased and you need alot more fuel to fill that much space in a short time.
McLovin
plain evil
Someone needs to open a tutoring thread. You guys need to teach the rest of us what you are talking about 
Well, an update on this whole shebang...work looks like starting at the end of next week.
We are just finalising details re getting the head re-bore done, with a nikasil re-lining done at the same place...A.P.E. (American Performance Engineeering)...yes, i have to send the block to the US!!!
We are moving closer and closer to using stock R6 cams...but may still use something from somewhere like Web Cams, but we are eering towards going with a product we know works...OEM, and will probably stress the motor less in the long run.
And it looks as if we will be using the Wiseco pistons, over the JE pistons...
:thumbup:
We are just finalising details re getting the head re-bore done, with a nikasil re-lining done at the same place...A.P.E. (American Performance Engineeering)...yes, i have to send the block to the US!!!
We are moving closer and closer to using stock R6 cams...but may still use something from somewhere like Web Cams, but we are eering towards going with a product we know works...OEM, and will probably stress the motor less in the long run.
And it looks as if we will be using the Wiseco pistons, over the JE pistons...
:thumbup:
RJ2112
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You are most likely talking about a valve grinding job.... the goal of which is to improve the seal, and air flow through the valve seat/valve interface.
The improvement in seal is often referred to as 'valve lapping'. I used to watch my dad do that by hand, with a gizmo that looked like a toy arrow suction cup. Put some polishing compound on the edge of the valve, slide it into the guide so it rests on the valve seat and spin it with the shaft of the suction thingy. Smooths out any burrs or imperfections between the valve, and it's seat.
'3 angle' valve jobs were popular in hot rodding 30 years ago. The idea is to make the edge of the valve seat more curved, so the airflow over it is smoother.... less turbulence, less drag = better airflow = more charge in the cylinder = more power.
The valve job didn't make much sense until someone had 'flowed' the head..... buffing out all the rough casting marks and then doing port work to reduce turbulence in the airflow going to the valves, and out the exhaust port. Fill in the 'dead spots', grind away the sharp angles...... Jerry Branch was a master of this.
RJ2112
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Someone needs to open a tutoring thread. You guys need to teach the rest of us what you are talking about
Back when engine blocks were Iron, and the rings were Iron.... the rings wore away the cylinder walls at a fairly slow rate. But over time, the rings would wear, and expand.... the open end of the 'C' would spread as the cylinder bore opened up. Round cylinders ofter took on an oval profile with high mileage. This is why cars in the 50's and 40's tended to smoke a lot.
All of that was acceptable and considered typical. Emissions controls, better mfg processes, etc., changed all that.
The advent of aluminum engine blocks introduced accelerated cylinder wall wear. Iron scrubs away aluminum much more quickly. Iron sleeves were added, by pressing the cylinder liners into the aluminum blocks. Durability was very nearly the same as iron/iron. You could even replace the liners, with thinner units, to increase the bore, there by increasing engine displacement.... Same as you could bore an Iron block.
The solution is not ideal..... the difference in expansion rates between Iron and Aluminum can cause issues with sealing. And it's a complex fiddly process which is labor intensive. Not ideal for motorcycle applications. Those two different media also conduct heat at different rates.... heat transfer is not as good with the media change.
BMW(I believe) went to plating the bores of their aluminum cylinders first, with a nickel - silica compound (hence Nikacil) first...... the iron rings now ride on a plated surface that is somewhere above 1000 grit sandpaper, that is bonded directly to the aluminum. Very tough and durable. The spaces between the silica bits hold the oil film the rings have to have to make the thing work.
Around this time, the race was on to make the most compact engine you could..... the spacing between cylinders kept getting tighter and tighter, until there really isn't a whole lot of metal between the cylinder bores, any more. 'Siamesed' bores have become popular...... when you go to plating the aluminum, you don't need to have enough material to support the liner being pressed in..... and you don't need to leave enough metal to allow for an over bore or two, as the plating is tough enough to last the 'life' of the engine. Water cooling is efficient enough, that you can have very little surface area, and still dump enough of the heat into the coolant.
Soooooo, back to our man Wolfie...... is 2mm on each bore too much? Is that diameter, or radius? (I think Diameter...) How much metal do you remove between cylinder pairs? Can the block support (potentially) 4 mm thinner walls, between bores? We already know there is not enough meat there to bore it all the way out to 750cc...... our intrepid engineers at Yamaha would have already done that, if they could....... But how many more mm would it take, spread across 4 cylinders to do it?
The Ol' top end re-build, Valve grind, port & flow job! Works real well on older motors, but generally, the gains to be made by doing this in modern engines are less, due to the fact, that the manufacturers have become much better these days, at getting closer to optimum high performance figures out of the motor to start with.
I reckon i might be right in saying that Yamaha have increased compression in the R6 motor, by simply fitting a thinner head gasket, so theoritically, and to over simplify... i could put on a R6 cylinder head, with thinner head gasket, a set of R6 cams, ands away i go with better hp numbers...but then there are the differences in injector systems, etc, etc...
:thumbup:
Discofrank
Junior Member
hey wolfman instead of sendign the block to to the US
thoughte about sourcing a block over there and then sending the block back to AUS
to save u a ****load on shipping
thoughte about sourcing a block over there and then sending the block back to AUS
to save u a ****load on shipping
We are investigating this option right now...But it seems that even costing in shipping, the price difference wont be that much different, whichever way we go...
As for time difference, there is only a week or two difference, and seeing as the weather is going to be awful for the next 3 months...i am in no big hurry...it can take all winter to finish the job...plus i am doing other stuff whilst the engine is out, so i will have more time to work on those mods, while block is off being re-bored.
:thumbup:
RJ2112
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Wolfman, has anyone looked at the windage? That's another good winter's talk, LOL. There's just as much air moving under the piston, as above it.... If you can get it to whoosh back and forth without turbulence, you'd 'gain' HP that would otherwise be lost squirting that air back and forth....
Another area that bears consideration..... how about stroking the motor? That's pretty much what Honda did to get the 919... it's the long stroke version of that gen 600cc motor.
Shinn
Junior Member
You are a mad man!! I am so watching this thread carefully. Plus I am learning a whole lot of new things. Best of luck mate!
There would be a lot more variables, in terms of outcome, if you stroked the engine...yeah more capacity, more torque, but potentially, the engine characteristics would be completely different...
Going the Big Bore route, is less costly, and probably an easier way to gain some torque & hp reliably, as long as we dont go too wild on the Cams...
As for "Windage", i aint even heard of that!
RJ2112
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There would be a lot more variables, in terms of outcome, if you stroked the engine...yeah more capacity, more torque, but potentially, the engine characteristics would be completely different...
Going the Big Bore route, is less costly, and probably an easier way to gain some torque & hp reliably, as long as we dont go too wild on the Cams...
As for "Windage", i aint even heard of that!
Every time the pistons move 600cc of air through the cylinders.... the lower end of the motor has to move just as much air. This is one of the reasons adjoining cylinders typically run at opposite ends of their stroke. The power stroke of one cylinder is pushing 150cc of air 'down' beneath it's piston..... that air has to have somewhere to go, or it gets compressed, and 'fights' that power stroke.
If the adjacent piston is going the opposite way; that air being displaced can potentially aid in that cylinder's compression stroke, by 'pushing' the piston 'up'. There has to be adequate opening between the two bores for this to be beneficial, or the wind can't blow up the skirt of that piston.....
Boxer twins have problems with this... they act like an accordian. If you want more power out of a 'boxer', change the throws so they are both going the same direction...... but it will shake like there's no tomorrow.
Ducati's L twins with 90° crank timing just throw that charge back and forth under the skirts. As the 'path' is only a 90° bend, it's more efficient than the 180° bend required of an inline 4.
tuningfork
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Every time the pistons move 600cc of air through the cylinders.... the lower end of the motor has to move just as much air. This is one of the reasons adjoining cylinders typically run at opposite ends of their stroke. The power stroke of one cylinder is pushing 150cc of air 'down' beneath it's piston..... that air has to have somewhere to go, or it gets compressed, and 'fights' that power stroke.
If the adjacent piston is going the opposite way; that air being displaced can potentially aid in that cylinder's compression stroke, by 'pushing' the piston 'up'. There has to be adequate opening between the two bores for this to be beneficial, or the wind can't blow up the skirt of that piston.....
Boxer twins have problems with this... they act like an accordian. If you want more power out of a 'boxer', change the throws so they are both going the same direction...... but it will shake like there's no tomorrow.
Ducati's L twins with 90° crank timing just throw that charge back and forth under the skirts. As the 'path' is only a 90° bend, it's more efficient than the 180° bend required of an inline 4.
doesn't the PCV/crank breather pretty much eliminate this pressure though?
