58mm TB, When to upgrade?
#11
I think the 57's will be fine for you, but do you think you're really going to gain much? Is it going on your current build?
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lionsm13 (01-21-2018)
#12
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#13
A 58mm throttle body is an improvement on anything over a stock 103 engine. Now is it worth the coin to do it, becomes a question only you can answer. When we build these bike engines its not cheap and the extra for a throttlebody might not be in everyone budget. I can assure you there will be an improvement but each case is different based on your build. All I can tell you is I see about 2 ft lbs and 3 HP on the dyno on a stock 103 with exhaust. I can also measure the restriction in the intake system. While that's not a lot it does show it improves a stock 103, so what is it going to do for your build and is it worth it to you?
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Raccerx67 (11-10-2018)
#14
My C ported heads from FuelMoto have 1.76" intake ports. More than likely am leaning towards the HPI-55FBW-76. Probably won't see much gain under 3k rpms but all gains above that! Thanks for that Dyno graph!
Engine build is similar to the older FM Hellraiser 107 build with a few changes, just never upgraded the throttle body.
Engine build is similar to the older FM Hellraiser 107 build with a few changes, just never upgraded the throttle body.
#15
Our 2.02" valve heads with a 1.800" port opening, favor a 55mm-58 mm t/body.
Scott
Scott
__________________
HILLSIDE MOTORCYCLE & MACHINE, INC.
HARLEY-DAVIDSON SPEED & SERVICE CENTER
5225 SOUTH MAIN ST., MUNNSVILLE, N.Y. 13409
Sales/Support 315-495-6650
www.hillsidecycle.com
Walk-in Retail Showroom
Complete H-D Machine Shop
Case & cylinder boring
Complete Cylinder Head Shop
High-Performance Engine Kits
Crank Rebuilding
Direct Link & PowerVision Tuning
Goodson HD Tooling Manufacturer
Maxton Mile World Record
4500 sq ft. facility
OVER 35 YEARS OF H-D ENGINE BUILDING.
See us on Facebook.
HILLSIDE MOTORCYCLE & MACHINE, INC.
HARLEY-DAVIDSON SPEED & SERVICE CENTER
5225 SOUTH MAIN ST., MUNNSVILLE, N.Y. 13409
Sales/Support 315-495-6650
www.hillsidecycle.com
Walk-in Retail Showroom
Complete H-D Machine Shop
Case & cylinder boring
Complete Cylinder Head Shop
High-Performance Engine Kits
Crank Rebuilding
Direct Link & PowerVision Tuning
Goodson HD Tooling Manufacturer
Maxton Mile World Record
4500 sq ft. facility
OVER 35 YEARS OF H-D ENGINE BUILDING.
See us on Facebook.
#17
I am in the process of clearancing the rocker covers for S&S roller rockers, and installed a SE 58mm throttle body. I feel better with the new TBW motor than HPI using my old one due to pin fretting.
Engine ran pretty good as it was, first time i maxed out the speedometer rather quickly and go power is present when needed. I wish the cams had a little more torque on the bottom end, but am not going to replace them any time soon.
Engine ran pretty good as it was, first time i maxed out the speedometer rather quickly and go power is present when needed. I wish the cams had a little more torque on the bottom end, but am not going to replace them any time soon.
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