Wondering what the largest bore factory caes can handle thinking about stepping up the cubes.already maxed out th 95 ci crap and Im bored need more,Would go to blower but cash short right now.
&nbsp\\; I know ill have to split the caeses but then have to do so anyway.so might as well see how big I can make it.also if know of anyone selling big 140 plus tcs that might be next option.

 

Funny, Im bored with my 95 too!
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I called Doug at HQ today: a 4 3/8 crank dose a 103. If U go to 3.900 bore (rounded off) you can have a 98 with a 4 inch stroke or a 107 with the 4 3/8.
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then you need to case bore for 113 and up. I have a Dyna and a good 107 should do the trick for me.
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I think a HQ 113 or larger would be very scarry! maybe with other brand cams it would not be as fun, and Id have to go larger.[&:]

 

You can go 4.25" with case boring of course, however, I wouldn't push it any further than 4.125".&nbsp\\; That'll get you 124" with a 4.625" stroke which can make all the power you need. &nbsp\\; A 4.25" bore would make for a 131" with that stroke.

 

"Would go to blower but cash short right now."

Just read that part.&nbsp\\; I think I'd learn to be content with the maxed out 95" in that case.&nbsp\\; You can sink alot of money into these bigger builds.&nbsp\\;

What kind of power are you making with that "maxed out" 95"?

 

thanks guys I thought the 124 was do albe.
&nbsp\\; Colonel&nbsp\\;&nbsp\\; there no such thing as all the power I will need.
&nbsp\\; My old toy was alcohol dragster 2000 lbs with 3000 hp.
&nbsp\\; to be equal thats close to 1200 lbs tq and 1400 hp.
&nbsp\\; Ok myabe that would be little bit much on two wheels

 

LOL!&nbsp\\; I know what you mean about never enough power.&nbsp\\; I have an 800 HP (NA) C5R engine waiting to go in one of my Camaros one day when I get back into drag racing.&nbsp\\; After she runs NA 8s I'll have to fight the temptation of tossing the bottle back in it!&nbsp\\; And my last bike was an '07 GSXR 1000...so yeah, I agree, power is addictive!

124" is no problem and is what I'd recommend for something you plan to actually put some miles on.&nbsp\\; Give Steve at GMR a call.&nbsp\\; He can give you all the in's and out's of different combos.&nbsp\\; BTW, this moderately built 124" of mine made 137 RWHP.&nbsp\\; Build it hotter and they can do more.

 

Easy build is the 4.625&nbsp\\; (4-5/8") stroke and 4.060 bore for 120"&nbsp\\; The 4.060 cyls are HD "bigger bore" cyls.&nbsp\\; Doug at HQ bores the cyls to 4.065 to true them up and has CP pistons to fit.&nbsp\\; I am running the HQ 120, as is Phil and I got to ride with him and Kevin who has a 113.&nbsp\\; These are killer torque motors with the HQ 575 Cams making 150+ tq.&nbsp\\; We were climbing mountains without shifting, and on the flat they would run all day long at 85 and still return 40+ mpg.

 

We have been boring engine cases for well&nbsp\\;over 20 years, and we would go to 4.125 bore(4.312 spigot bore diameter for Axtell cylinders. The 4.250 stuff, we feel, is too close to the stud holes.

 

Colonel try going from 500 ci blown alcoho dragster.After 300o hp in 2000 lb car it hard to push the fun button.

 

I'd agree with what has been said already...
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4.125 is about as big as you'd "safely" wanna go with the stock cases. Among other things, there is very little meat left between the spigot bore &amp\\; cylinder stud bore.
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Done right, 4.675 x 4.065 (121") or 4.675 x 4.125 (124") will make for a mucho fun street ride. Additionally... "done right", they are as (or more) reliable as stock AND get BETTER fuel economy.
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On a recent ~3k mile ride (Dalton mentioned), I averaged ~46mpg, with a high of 50.0!