| Author | Message | ||
     Japbikeboy |
Ok, to those of you who have done it, or to some of the sponsors who do this sort of work, I am wondering about this conversion. I have read many different threads on Badweb but cannot find the info I need. Can this conversion be done without any head work? More to the point: will the dome of the 9 pistons hit the valves? Thanks guys and gals. | ||
| Blake |
Yes, it can be done without headwork. No, the pistons will not hit the valves. | ||
| Japbikeboy |
Well, that makes me feel better. Now, can someone tell me what SHOULD be done to accomodate for the pistons? I am thinking that headwork should be done regardless, but should cams be involved in that decision? Thanks for the reply Blake | ||
| Jimidan |
Cams should definitely be considered in that equation, as with the SEII .536" lift cams, the intake valve will hit the Thunderstorm piston, which isn't as domed as the XB9 I do not believe. It is the sum of the parts that make the engine perform, so look at it all as a unit. Wes Orloff, a HD engineer who club raced, built several engines using the XB9 pistons with XB12 heads, which creates 12 to 1 CR, I think. I can attest to how well they ran as I was running my 88" at the same time and he was keeping up with me down the straight away. One of my buds bought one of Wes's bikes and the engine is heavily modified, but he used only HD/Buell parts to do it. He told me that he could get those parts free, so that is why he didn't use any others. He ran on 93 octane pump gas, with no pinging! He was just plain faster than me on the rest of the track too, but that was my limitations not my bike's. jimidan | ||
| Beerman |
Hey Guys, I went to a superbike road race in Topeka last weekend. Awesome! I was surprised and happy to see so many Buells. Most of the riders I talked with mentioned using xb9 pistons in the xb12. What kind of HP/Torque do you get? Is it worth the expense. All the racers thought so. Thoughts?} | ||
| Puddlepirate |
Anybody have any good information on this? I also have been searching around for a couple of hours, and haven't been able to find anything either. Have any of you guys actually done this, or is the scarce bit of information that is running around here secondhand or thirdhand? I picked up a set of 2005 XL1200 heads (same as the XB heads) with 300 miles, last night off of Ebay for $315. I'm planning on doing the 883/1200 conversion here shortly, and I'd love to get the best bang for the buck. Would 12:1 compression ratio be too hot for street use anyway? | ||
| Blake |
People have done it. A carburetor would sure make it a much easier tuning exercise compared to the EFI of the XB. I think the CR actually works out to around 11.5:1 for the XB9 piston in the XB12. | ||
| Rick_a |
It is 12:1 as stated by Jimidan. The dome displaces 12.3cc. (Message edited by rick_a on August 11, 2007) | ||
| Diablobrian |
For the street be sure you use 93 octane gas and you should be fine. | ||
| Gearhead |
What do you need to tune an XB12 with 9 pistons? Will the race (regular over the counter model) compensate for the additional compression? What about ballpark costs on this swap. | ||
| Björne666 |
Also extremely interested in this! 100RWHP with just new pistons?? Hehe great! So piston to head/valve clearance is no issue. So it is only Gearheads question that remains, will the OEM (race or not) ECM cope with the higher comp? |
