Throttle body sizing
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Tourer
Joined: Nov 2010
Posts: 400
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From: Buckeye State
Throttle body sizing
I have an 07 ultra classic. It is a 96" with a se air cleaner, stock tb, woods TW555 cams, stock heads and compression, Dragos dragula exhaust. I was wondering if I was to bore out my throttle body from 46 mm to 48 mm or even to 50 mm (if able) and do a port and polish of the intake runners if that would help me much. I know you can have too much intake and the low end will suffer but didn't know how much. I was looking at Fuel Moto's website and it looks like the newer bikes with the same cams and stock heads were making quite a bit more power than my bike.
thanks in advance
matt
thanks in advance
matt
Road Master
Joined: Dec 2007
Posts: 885
Likes: 14
From: SoCal
I have an 07 ultra classic. It is a 96" with a se air cleaner, stock tb, woods TW555 cams, stock heads and compression, Dragos dragula exhaust. I was wondering if I was to bore out my throttle body from 46 mm to 48 mm or even to 50 mm (if able) and do a port and polish of the intake runners if that would help me much. I know you can have too much intake and the low end will suffer but didn't know how much. I was looking at Fuel Moto's website and it looks like the newer bikes with the same cams and stock heads were making quite a bit more power than my bike.
thanks in advance
matt
thanks in advance
matt
HDF Community Team
Joined: Jun 2006
Posts: 12,774
Likes: 2,606
From: san antonio
I didn't think the 46mm TB can be bored to 50mm but did some digging and found that Johnsone Engineering Technology can bore the '06 and up 46mm TB to 51mm. Dyno testing shows power increases across the rpm range and not just at the upper end. Not huge gains but looks like 8HP/5TQ for $365 is fairly reasonable on a $$/HP-TQ basis.
Boring your cylinders to 103" and fitting a set of SE cast flat top pistons is also a good bang for the buck. About $400 if you DIY the job; that's about $40/TQ-HP; pretty cheap power.
Why not bore to 103" and bore the TB to 51mm?
Don't worry about dyno numbers you see around the internet; if you are happy with your bike; be happy and look for cost effective ways to get a bit more power. Check into changing the trans pulley; those six speeds were geared a bit tall. Dropping a tooth, or two, on the trans pulley will help as well.
Boring your cylinders to 103" and fitting a set of SE cast flat top pistons is also a good bang for the buck. About $400 if you DIY the job; that's about $40/TQ-HP; pretty cheap power.
Why not bore to 103" and bore the TB to 51mm?
Don't worry about dyno numbers you see around the internet; if you are happy with your bike; be happy and look for cost effective ways to get a bit more power. Check into changing the trans pulley; those six speeds were geared a bit tall. Dropping a tooth, or two, on the trans pulley will help as well.
I didn't think the 46mm TB can be bored to 50mm but did some digging and found that Johnsone Engineering Technology can bore the '06 and up 46mm TB to 51mm. Dyno testing shows power increases across the rpm range and not just at the upper end. Not huge gains but looks like 8HP/5TQ for $365 is fairly reasonable on a $$/HP-TQ basis.
Boring your cylinders to 103" and fitting a set of SE cast flat top pistons is also a good bang for the buck. About $400 if you DIY the job; that's about $40/TQ-HP; pretty cheap power.
Why not bore to 103" and bore the TB to 51mm?
Don't worry about dyno numbers you see around the internet; if you are happy with your bike; be happy and look for cost effective ways to get a bit more power. Check into changing the trans pulley; those six speeds were geared a bit tall. Dropping a tooth, or two, on the trans pulley will help as well.
Boring your cylinders to 103" and fitting a set of SE cast flat top pistons is also a good bang for the buck. About $400 if you DIY the job; that's about $40/TQ-HP; pretty cheap power.
Why not bore to 103" and bore the TB to 51mm?
Don't worry about dyno numbers you see around the internet; if you are happy with your bike; be happy and look for cost effective ways to get a bit more power. Check into changing the trans pulley; those six speeds were geared a bit tall. Dropping a tooth, or two, on the trans pulley will help as well.
Maybe a dumb question but here goes. I see that J.E.T. and Dan Vance Racing bore/smooth TB's and then use a super epoxy to help shaping for optimum air flow. Any chance of epoxy loosening up/possibly entering into the motor? Like I said, might be dumb but will learning something
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Tourer
Joined: Nov 2010
Posts: 400
Likes: 10
From: Buckeye State
DJL thanks for the reply... I was thinking that the 08 and up have the 50mm tb and there is no difference in my 07 from the newer 96". I am a machinist by trade so i was thinking of boring my own tb out to what ever would be the best for no $. Wife is in nursing school right now and $ is tight otherwise I would be dropping on a Fuel Moto 107 with level b head and a big bore tb but for now the power mods i can do myself are going to have to be good enough. The only real reason i want to do this anyhow is my riding bud has a 04 with a 95 s and s kit and was talking trash bout how his 95 will blow my 96" away and i want him to really eat his words. not really that important but you know how it is. o and btw the only reason he put the 95 kit on is cuz i beat his 88" pretty bad and he couldn't take it.
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HDF Community Team
Joined: Jun 2006
Posts: 12,774
Likes: 2,606
From: san antonio
DJL thanks for the reply... I was thinking that the 08 and up have the 50mm tb and there is no difference in my 07 from the newer 96". I am a machinist by trade so i was thinking of boring my own tb out to what ever would be the best for no $. Wife is in nursing school right now and $ is tight otherwise I would be dropping on a Fuel Moto 107 with level b head and a big bore tb but for now the power mods i can do myself are going to have to be good enough. The only real reason i want to do this anyhow is my riding bud has a 04 with a 95 s and s kit and was talking trash bout how his 95 will blow my 96" away and i want him to really eat his words. not really that important but you know how it is. o and btw the only reason he put the 95 kit on is cuz i beat his 88" pretty bad and he couldn't take it.
http://www.johnsonenginetechnology.c...ttle-body.html
I don't know what your buddy is running in his 95"er but your problem is low compression. With stock heads and head gasket, your static compression is barely above 9:1 and CCP is below 170psi. You can fix that two ways, drop in a set of S&S 583s with an early intake close or pull your heads for mild cleanup, SERDI valve job, larger intake valve, new guide seals, machined for compression releases, decked to set static CR between 10.5-10.8 for a set of TMans 590 cams. You will say bye-bye to your buddy when you hit 3d gear.
The '07 were geard a bit tall; another inexpensive upgrade would be to change you trans pulley from 32T to 30T. Work intensive and, JMHO, but not worth the effort for 31T, it would have to be 32T for me. Drops highway cruise rpms but you can still run 75-80 at 3000-3200, much like 5th in the five speeds which, for me, is about perfect. You will need a new belt to drop two teeth.
You could also R/R the heads for a .030"head gasket and advance the 555s 4* and bring the torque in a earlier.
I know you said money was tight, so just throwing things at the wall for you to think about.
I know you said money was tight, just throwing some stuff at the wall for you to consider.
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HDF Community Team
Joined: Jun 2006
Posts: 12,774
Likes: 2,606
From: san antonio
Hey Don,
Maybe a dumb question but here goes. I see that J.E.T. and Dan Vance Racing bore/smooth TB's and then use a super epoxy to help shaping for optimum air flow. Any chance of epoxy loosening up/possibly entering into the motor? Like I said, might be dumb but will learning something
Maybe a dumb question but here goes. I see that J.E.T. and Dan Vance Racing bore/smooth TB's and then use a super epoxy to help shaping for optimum air flow. Any chance of epoxy loosening up/possibly entering into the motor? Like I said, might be dumb but will learning something
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