Big Bore Kits

[RickyBobby]

I have a 2004 Buell XB12s. Looking at maybe doing a big bore kit to my bike. What are your thoughts and suggestions for witch kit to buy.

[Tony216]

How big? Keep in mind, that you might have to bore your cases as well if you go too big.

[RickyBobby]

Was thing the evolution 90 bolt on. No machining needed to the casing.

[buelladdicted]

There is no way to go over 1250 without boreing ,the cases.Also when you go too much over,you have to consider things like stronger rods,flywheel reballancing,etc.So unless you go the 1250 bolt on route ,you open a whole expensive,time consumeing , can of worms.When my top end is ready,I will probably go with a 1250 kit and headwork.I dont even want to consider cams or valve springs as I learned w/ my sportster project the expense never ends,and the practicle use and dependability gets less and less.

[brightbuell]

Good to know.

[wolfo68]

yea, that 90 ci kit you have to pretty much send someone your whole engine. I'm assuming you're talking the rev perf stuff?

puts it at 1474.6 ish cc

[GAXB9R]

^^ 1474.6 ish cc would be pretty bad ass. If got the money I say to for it. But I'm that devil on your shoulder talking:D

[venompwr2]

Has anyone here done the 1250cc or bigger kits? Or the stage 1 or 2 headwork. I'm very curious about how the bike performs with these upgrades, given the cost. I see some claiming 125rwhp with 1250cc, headwork and tuning.

[Tony216]

My 88ci has machined cases. I'd love to see how the 90ci cases come out...

I would suggest while you have it apart that you put valves spring in it too. Stock springs are like $4.50 a piece. I think all of the top-end parts were less than $150, plus a a couple hundred and cut the valves and new guides.

I don't have current dyno numbers on mine.

[buelladdicted]

If you mean the stage 3 set up that NRHS tuned,you have to consider the stage 3 head work envolves crazy large valves,yery extensive port and combustion chamber work,200lb seat pressure valve springs,which arent a good match for your lifters,,,,GET MY DRIFT?High lift cams,It makes more sense to stage 2 the heads,go 1250,and rear wheel dyno around 110hp and around 90 ft lbs of torque.Which on a buell would be a great step up.