head volume
Thread Starter
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Tourer
Joined: Jan 2008
Posts: 359
Likes: 21
From: Midland Tx.
the magic number is 9.6:1 corrected if you put 10:1 wiseco in it and a .045 head gasket you will be at 9.6:1 corrected the bike will be a beast.
right now your motor has to big of a cam its probably a little soft on the bottom end. go with a ev27 or wood w6
or more compression.
right now your motor has to big of a cam its probably a little soft on the bottom end. go with a ev27 or wood w6
or more compression.
Looking at the 10:1 piston but with a .060 gasket the corrected is 9.41:1
I changed the gasket to drop from the 9.6:1 you mentioned because around here it's hard to find 91 octane let alone 92.
Think this will run? provided of course that I can somehow fit the intake without it leaking horribly.
Club Member
Joined: Aug 2008
Posts: 22,857
Likes: 17,908
From: Lafayette, Louisiana
John is a knowledgeable guy although I watched him get into a few spats with a couple of guys on this forum.
He sometimes comes off rougher than I think he intends. and probably doesn't mean anything by it, although Spanners and John got into it last year.
I am surprised Spanners hasn't chimed in. He's another sharp guy and very practical. Also quite funny.
Back on topic, I think the current volume of your heads is pretty close to screamin eagle Evo head volume, therefore Pistons that work with the screamin heads may work with yours and yield the right compression. With today's low quality ethanol gasoline, I probably wouldn't push the limits of compression on a daily driver type of bike.
Pick up an EV27 cam, eBay the EV51, and send an email to wiseco for piston recommendations.
Hey, you can't blame a guy for trying to make peace.
Thread Starter
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Tourer
Joined: Jan 2008
Posts: 359
Likes: 21
From: Midland Tx.
Yeah, I know that cam came with it but it is why it was suggested to go with a different cam instead of trying to get numerous other components to work with that cam.
John is a knowledgeable guy although I watched him get into a few spats with a couple of guys on this forum.
He sometimes comes off rougher than I think he intends. and probably doesn't mean anything by it, although Spanners and John got into it last year.
I am surprised Spanners hasn't chimed in. He's another sharp guy and very practical. Also quite funny.
Back on topic, I think the current volume of your heads is pretty close to screamin eagle Evo head volume, therefore Pistons that work with the screamin heads may work with yours and yield the right compression. With today's low quality ethanol gasoline, I probably wouldn't push the limits of compression on a daily driver type of bike.
Pick up an EV27 cam, eBay the EV51, and send an email to wiseco for piston recommendations.
Hey, you can't blame a guy for trying to make peace.
John is a knowledgeable guy although I watched him get into a few spats with a couple of guys on this forum.
He sometimes comes off rougher than I think he intends. and probably doesn't mean anything by it, although Spanners and John got into it last year.
I am surprised Spanners hasn't chimed in. He's another sharp guy and very practical. Also quite funny.
Back on topic, I think the current volume of your heads is pretty close to screamin eagle Evo head volume, therefore Pistons that work with the screamin heads may work with yours and yield the right compression. With today's low quality ethanol gasoline, I probably wouldn't push the limits of compression on a daily driver type of bike.
Pick up an EV27 cam, eBay the EV51, and send an email to wiseco for piston recommendations.
Hey, you can't blame a guy for trying to make peace.
Road Master
Joined: Feb 2014
Posts: 913
Likes: 5
From: indiana
Is the Big boyz compression calculator a decent estimator?
Looking at the 10:1 piston but with a .060 gasket the corrected is 9.41:1
I changed the gasket to drop from the 9.6:1 you mentioned because around here it's hard to find 91 octane let alone 92.
Think this will run? provided of course that I can somehow fit the intake without it leaking horribly.
Looking at the 10:1 piston but with a .060 gasket the corrected is 9.41:1
I changed the gasket to drop from the 9.6:1 you mentioned because around here it's hard to find 91 octane let alone 92.
Think this will run? provided of course that I can somehow fit the intake without it leaking horribly.
ok what I came up with was 10.41 static and 9.40 corrected so big boyz calculator is pretty good.
what specs I used
bore 3.518 .020 over your going to rebore for new pistons
top of piston 3.595
top of ring to top of piston .180
head gasket .060
head gasket bore 3.6
cam ABDC 44
deck height .003 in the hole
in my opinion your safe but I would still get a good programmable ignition like the dyna 2000i/ultima and don't use the VOES switch
when its all done and broke in check your cold cranking compression you should be right at 196psi.
Thread Starter
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Tourer
Joined: Jan 2008
Posts: 359
Likes: 21
From: Midland Tx.
ok what I came up with was 10.41 static and 9.40 corrected so big boyz calculator is pretty good.
what specs I used
bore 3.518 .020 over your going to rebore for new pistons
top of piston 3.595
top of ring to top of piston .180
head gasket .060
head gasket bore 3.6
cam ABDC 44
deck height .003 in the hole
in my opinion your safe but I would still get a good programmable ignition like the dyna 2000i/ultima and don't use the VOES switch
when its all done and broke in check your cold cranking compression you should be right at 196psi.
what specs I used
bore 3.518 .020 over your going to rebore for new pistons
top of piston 3.595
top of ring to top of piston .180
head gasket .060
head gasket bore 3.6
cam ABDC 44
deck height .003 in the hole
in my opinion your safe but I would still get a good programmable ignition like the dyna 2000i/ultima and don't use the VOES switch
when its all done and broke in check your cold cranking compression you should be right at 196psi.
Seasoned HDF Member
Joined: Nov 2006
Posts: 12,878
Likes: 5,449
From: la la land jerzey
in my opinion your safe but I would still get a good programmable ignition like the dyna 2000i/ultima and don't use the VOES switch
when its all done and broke in check your cold cranking compression you should be right at 196psi.
you are incorrect about the VOES i still think you do not get what it is that it actually does -- but that is your opinion as you said
some of the box engines do not use it the VOES because of cam timing and they are selling numbers not riding peformance off an engine dyno in a closed room
rob85WG --- on this site sells a cable so you can adjust your own timing curvs to fix what the normal curvs dont - is you do have 190 plus static you will need his cable good guy and helpfull
when its all done and broke in check your cold cranking compression you should be right at 196psi.
you are incorrect about the VOES i still think you do not get what it is that it actually does -- but that is your opinion as you said
some of the box engines do not use it the VOES because of cam timing and they are selling numbers not riding peformance off an engine dyno in a closed room
rob85WG --- on this site sells a cable so you can adjust your own timing curvs to fix what the normal curvs dont - is you do have 190 plus static you will need his cable good guy and helpfull
Thread Starter
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Tourer
Joined: Jan 2008
Posts: 359
Likes: 21
From: Midland Tx.
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Road Master
Joined: Feb 2014
Posts: 913
Likes: 5
From: indiana
this is a debate that never ends. on high compression engines you don't want to use it. you don't want to take a chance melting a hole in your pistons if the switch sticks. if it sticks on a stock motor it will just ping a little under load. the only benefit from running one it gives you a better bottom end throttle response and a little better fuel mileage which is good for a stock motor.
with your cam you don't have to worry about bottom end response since your cam doesn't even wake up till 2500rpm and if fuel mileage is a problem may you should rethink building a hot rod motor.
with my 80" evo without a voes I smoke 110 twinkies and im getting around 48mpg that's good enough for me.
Seasoned HDF Member
Joined: Nov 2006
Posts: 12,878
Likes: 5,449
From: la la land jerzey
we see it different and i am correct on this -- the switch default is off NO vacuum at all < and the default is the retard mode IE off < the adjustable spring is pushing the switch to the off position, its off and with the key on its in the retard mode and that is off - i hope we agree because that is how it works
with the motor running at speed 65 MPH on a Hwy / parkway what ever - the vacuum signal at a slight opening of the throttle - the intake has a high vacuum signal ( its sucking vacuum and the engine timing is in the advance mode as the spring is overcome and its lifted it off the retard mode < the default is retard and the spring makes sure it goes to the default when no vacuum or a low vacuum is present - sporty has a different like 3.5 inches vacuum number than an ultra at 5.5 inches
even if a vacuum hose falls off it no longer can advance it then defaults to off and thats the retard mode - base timing 35 degrees only obtained when the vacuum is high at part throttle crusing - or at high engine speed /// 10 degrees is what the VOES removes from the system when does that happen ?? - when you open the throttle wide to take off or climing up a hill
now having said all of the that -- at high engine speed the volumn of air being used by the engine, and the speed that said air, that is passing the venturi in the carb creates a vacuum on the back side of the venturi, and the switch spring is over come by that vacuum and the timing is at full advance at that point and will stay untill the engine slows down and the throttle is again opened sending the VOES to default - retard --- all of this is to keep the motor from pinging
show me what i am missing in this
with the motor running at speed 65 MPH on a Hwy / parkway what ever - the vacuum signal at a slight opening of the throttle - the intake has a high vacuum signal ( its sucking vacuum and the engine timing is in the advance mode as the spring is overcome and its lifted it off the retard mode < the default is retard and the spring makes sure it goes to the default when no vacuum or a low vacuum is present - sporty has a different like 3.5 inches vacuum number than an ultra at 5.5 inches
even if a vacuum hose falls off it no longer can advance it then defaults to off and thats the retard mode - base timing 35 degrees only obtained when the vacuum is high at part throttle crusing - or at high engine speed /// 10 degrees is what the VOES removes from the system when does that happen ?? - when you open the throttle wide to take off or climing up a hill
now having said all of the that -- at high engine speed the volumn of air being used by the engine, and the speed that said air, that is passing the venturi in the carb creates a vacuum on the back side of the venturi, and the switch spring is over come by that vacuum and the timing is at full advance at that point and will stay untill the engine slows down and the throttle is again opened sending the VOES to default - retard --- all of this is to keep the motor from pinging
show me what i am missing in this
Last edited by johnjzjz; Feb 19, 2015 at 06:04 PM.