| Author | Message | ||
     Ridrnkink18 |
i was wondering if its possible to put xb12 heads and pistons and everything on an xb9 | ||
| Froggy |
XB 12 and 9 use the same heads, so yes. As for pistons and everything else, I do not know. | ||
| Xl1200r |
Heads are the same. Pistons (AFAIK) are the same). Define "everything"... Are you trying to make a 12 out of a 9? | ||
| Rocketsprink |
9 pistons will give you higher compression. That's one of the hot tickets for the race bikes. | ||
| Rocketsprink |
You need a 12 crank to make it a 12. | ||
| Spatten1 |
Aren't the headers bigger on the 12s? Are the ports actually the same size as the 9s? | ||
| Lazyj |
headers have larger diameter pipe YES | ||
| Old_man |
To make a 12 out of a nine, you need the 12 crank, conecting rods and pistons - the heads and cylinder bore are the same. You would need the flat 12 pistons as the 9 pistons are domed and would result in a very high compression ratio with the 12 crank. The headers on the 12 are also larger than on the 9 Just changing the crank and connecting rods would give you the 12 displacement and with high enough octane fuel might work and give you a very powerful engine. I'm sure reliability would suffer | ||
| Evil_twin |
Just tossing this out there, but if I'm not mistaken, the cases would have to be machined to accept the 12 crank. I don't think it's as easy as just changing the major internals. Just my $.02. Rich  | ||
| Steve_mackay |
No, you don't have to machine the cases. They are identical. It really is as easy as splitting the cases and replacing the crankshaft. | ||
| Bcool83 |
Wow, that's ridiculous. The only thing different is the stroke? Bore is the same huh... If the heads are the same, I assume the valves are the same too? | ||
| Halsracing |
Bcool83 Yes Head pipe Dia. Stroke and throttle body. XB9 45mm Xb12 49 Stroke XB9 3.125 XB12 3.812 | ||
| Budc |
Evil_twin-no the cases do not have to be machined to accept the 12 crank. The cylinders and heads are the same. The 9 uses a shorter stroke and high compression pistons to get the same 10:1 ratio as the 12. It does have an rpm advantage and spins up quicker coming out of the corners. So, Ridrnkink18 if you want to stroke your 9 I would suggest using the '08 crank. It's got better connecting rods and a larger crank pin. You will have to change to the new style rotor and sprocket but this is also a better design because it replaces the crank nut with a bolt that is less likely to spin off. I would also suggest that you keep you 9 pistons. This will yield a compression ration of about 11.25:1 and about 95 hp at the rear wheel. This is a Hop-up kit that Hal's H-D/Buell has done for years. You will of course need a fuel management system and I have a great suggestion for you. While you are in there you may also want to consider our new High Performance Heads. With our head design you will gain about 26 cfm of air flow through the intake. This should yield another 6-8 rear wheel horsepower. The greatest thing about all of this is you will have a reliable, powerful engine for the street or the track and best of all it still runs on pump gas! Give me a call at 262-814-8685 and we can talk about it some more. Thanks, BudC | ||
| Old_man |
You would need to definitely change to the connecting rods of the 12 since the rods of the 9 are longer than the 12 and would not work with the 12 crank | ||
| Ridrnkink18 |
wow you guys are fast at responding...thanks for the info...budc i will def give you a call sometime...can i ask where you are located? im also planning on putting the xb12 primary drive gear in just to give it that extra top end...and with the motor work i plan on doing it should turn out to be a really fast bike so im hoping.thanks again for the info | ||
| Vwflat4driver |
In looking at the exhaust shootout on another web sight I'm wondering if theres gains in top end power on the 9 model using the 12's exhaust header?It seems the 9 gains more horsepower per item changed then the 12.(i.e 8hp for the 9 as apposed to the 4-5hp for the 12 for the same item changed)JAP bike's have way more horsepower in there engines cause they can rev em so high but they have little in torque department. as for the the 9 to 12 conversion i think id personally stay away from that as I prefer the higher revving engine of the 9!(i'm under 150 pounds)but id probably think about it only for the low end torque available from the longer stroke in the 12 model.I'm disipointed in the fact buell retained the rpm limit on the 9 model this year but raised it on the 12. you'd think they could raise the 9's the same amount maybe netting more horsepower.Any thoughts on this? | ||
| Glitch |
Any thoughts on this? With the higher revs they gave to the 12, the cost was some heavier components, can't remember off the top of my head (I'm sure someone will fill us in), so the price paid for higher revs, was a slower build up of revs, and I *think* a little less in the peak HP department. I do know some of the performance shops aren't as quick to promise HP gains on the newer 12s. Yes the 9s show a lot of improvement in performance with exhaust and intake mods, over the same mods on the 12s. As long as you tune the bike that is, there's only a limited amount leaving everything up to the race ECM to tune, even less if you're leaving everything up to the stock ECM. ECMspy and dyno time will give marked performance gains on a slightly modded 9. Buelldynoguy (Terry) got 100 peak HP out of a 9 with an open airbox and Micron exhaust, using Direct Link software, and a lot of dyno time. If I'm not mistaken, he helped on the Exhaust Shoot Out, the one on the American Sportbike's web site. | ||
| 1324 |
Can the stock valvetrain go any higher (safely) than the 9's redline? Might be why they retained the current redline... |
