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100" twin cam

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Old Apr 5, 2015 | 11:56 PM
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Default 100" twin cam

Any one build a 100" twin cam motor 4" bore 4" stroke.
I know in the world of all these big inch motors it may sound small but a perfectly square motor seems like the perfect route to go.
Any info on a motor like this
 
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Old Apr 6, 2015 | 08:51 AM
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Not a common configuration; better cost/benefit ratio, i.e., more for the money by going with a larger bore. Same cost to case bore for larger cylinder spigots, same cost for bigger bore cylinders and pistons so for the same money might as well go to 107" (4.125" bore x 4" stroke). That configuration is referred to as an "all bore" 107" motor and being "over square", is a real work horse. Spending the same $$ to end up with nearly 10% less displacement and performance doesn't make sense.
 
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Old Apr 6, 2015 | 03:18 PM
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Any idea what the bore and stroke would be for a 113"?? Im just trying to figure out my plan of attack if I have to get a new fly wheel assembly for my bike
 
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Old Apr 6, 2015 | 04:44 PM
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Originally Posted by fxd666
Any idea what the bore and stroke would be for a 113"?? Im just trying to figure out my plan of attack if I have to get a new fly wheel assembly for my bike
113" = 4.060" bore x 4.375" stroke but if you have to case bore and replace the 4" crank with a 4.375" crank, might as well increase bore to 4.125" and go to 117"; same scenario, same cost but more displacement which means more TQ/HP. Believe me, if you stop at 113", you will be kicking yourself in the butt bigtime.
 
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Old Apr 7, 2015 | 06:21 AM
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Originally Posted by djl
113" = 4.060" bore x 4.375" stroke but if you have to case bore and replace the 4" crank with a 4.375" crank, might as well increase bore to 4.125" and go to 117"; same scenario, same cost but more displacement which means more TQ/HP. Believe me, if you stop at 113", you will be kicking yourself in the butt bigtime.
+1
 
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Old Apr 7, 2015 | 06:27 AM
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Originally Posted by fxd666
Any one build a 100" twin cam motor 4" bore 4" stroke.
I know in the world of all these big inch motors it may sound small but a perfectly square motor seems like the perfect route to go.
Any info on a motor like this
Prior to Axtell manufacturing their 4.125" cylinders, they had intially ran off some 4"ers, back in 1999/2000.
They actually gave us a set to use on a clients engine to R&D, and in turn we gave them to the client.
Bike is still in service over in Syracuse, NY, with 116/116, carbed, Wood cams, staggered dual Supertrapps.
Scott
 
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Old Apr 8, 2015 | 02:23 PM
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10 years ago or so Wiseco actually had a kit that included a re-sleeve cylinder and piston kit, A good 98 will get you very close to square boring stock cylinders and there are many great piston choices available.
 
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Old Apr 9, 2015 | 04:45 AM
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A "square" engine that really produces very well is an 88" XL.
3 13/16" X 3 13/16".
We've built many of these here, with one of the top-producers coming in at/near 120 hp.
Bear in mind that this is a result of the cylinder heads ability to allow power to continue out past 6500 rpms, with the dedicated engine combo.
Scott
 
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Old Apr 9, 2015 | 12:19 PM
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Default scott @hillside

Originally Posted by Hillsidecycle.com
A "square" engine that really produces very well is an 88" XL.
3 13/16" X 3 13/16".
We've built many of these here, with one of the top-producers coming in at/near 120 hp.
Bear in mind that this is a result of the cylinder heads ability to allow power to continue out past 6500 rpms, with the dedicated engine combo.
Scott
If I was to do the 100" what head work and cams would you recomend? I want more tq than anything. I would also want my case machined for a timkin bearing. I currently run a super trapp 2:1 exhaust with a mikuni 42 carb with a zippers air cleaner
 
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Old Apr 9, 2015 | 12:37 PM
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Axtell no longer manufactures those 4" holes.
98" is the way these days and we bore your OE cylinder here, using our proprietary Wiseco piston/Cometic gasket kits.
In order to ramp the torque in asap, a Wood TW-6H would be a great cam.
At .590" lift, it would also require a set of valve springs.
A DTT ignition would bring it all togather.
Scott
 
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