| Author | Message | ||
     G4string |
Has the XB12 always been 103HP out of the box? At least that is what Buell is claiming the RWHP to be on the 08' XB12's. Also, how long have they been using the Thunderstorm engines? Is from 07' to present? Whats the difference between the Thunderstorm and what was used before it? | ||
| Trojan |
I think you'll find that the BHP is measured at the crank and not at the rear wheel. Average RWHP for all the XB12s I have measured (stock) has been in the mid to high 80's. The Thunderstorm engine goes back to 1998 with the S1 White Lightning, although the actual motor traces its heritage right back to the basic Sportster lump. The term 'Thunderstorm' originally referred to the modified cylinder heads and not to the whole engine. If we were being very pedantic the current motors are not Thunderstorms at all because the head design changed with the introduction of the XB in 2002. The 08 engine is substantially different enough from previous incarnations to be called something new in my opinion. | ||
| Luxor |
'03 was the 100% redesigned Thunderstorm. It is truly Buell in and out. The engine was redesigned, re-tooled, and re-cast from the ground up, it looks HD and sounds HD, but it's all Buell. If I'm not mistaken the Buell mill rotates 180 from an HD plant. Previous variants used HD Sporty mills beefed up by common hi-po practices. Again, I might be mistaken though. And 103 has been claimed, not sure if Buell stated it at the rear wheel though. I was under the impression that it was taken at the crank(the proper way in my opinion). EDIT, 1 min too late. (Message edited by luxor on September 21, 2007) | ||
| New12r |
If I'm not mistaken the Buell mill rotates 180 from an HD plant. Only the cams. | ||
| Xl1200r |
How can the cams be rotated by 180 and not the crank? And if they're both rotated, is it really rotated at all? | ||
| Spike |
The XB12 has been rated at 103hp (at the crank) since it's inception as a 2004 model back in 2003. Stock XB12s tend to put 85-90hp to the rear wheel. As Matt(Trojan) noted, the Thunderstorm name originally referred to the Thunderstorm heads that showed up on tube-framed Buells back in '98. Back then the engines were true HD Sportster engines that had higher compression, better heads, hotter cams, and lighter flywheels. The engine received a thorough redesign in 2002, although it retained the same layout and architecture of the previous engine. It was released first in the short-stroke 984cc configuration in the 2003 model XB9R. This updated engine was called the Thunderstorm and is essentially the same engine that powers current XBs. The long-stroke 1203cc configuration arrived in the 2004 model XB12s, and a detuned version of the updated motor was used in the 2004 Sportsters. The 2008 model XB engines have quite a few changes over the previous Thunderstorm engines including larger crank pins for high-RPM durability, a new ignition pick-up, a new cam chest with an improved oil pump, a larger oil cooler, and a new fuel injection system. |
