| Author | Message | ||
     Dooley |
i'm replacing my blown 03 9 motor with an 06 xb 12. I had to swap the heads because the 12 had broken motor mount holes in them. Heres the question..I liked my xb9 but I wanted more torque (hence swaping to a 12) should I also swap the primary chain? what are the pros and cons? whose done this? will it kill my top speeds? is it worth it? | ||
| Nillaice |
keep the 9 primary drive. it'll costs you ~20 mph off the top, but the 9 primary in a 12 has gotten much praise on badweb. | ||
| Petebueller |
I though my 12 was geared too low so I had a custom crank pulley made that has 4 extra teeth. IMO a 9 pulley on a Uly could make sense, but I wouldn't personally run it on an R,S or Ss. We need to remember that the 12 doesn't rev out as far as the 9, so your top speed would actually be reduced by keeping the 9 pulley on the 12. It would feel very close to running around in 4th gear. 60mph at 3300. | ||
| Hogs |
Petebueller, LoL YEah but it sure is Fun with the 9 pulley and chain, Gets there Super fast and a whole lot more Grunt Torque taking off LoL...Fun FActory Goes WAY UP... Who cares about Top end I wd. say since the wife Rides a 12 Scg and I a 12 R , Her rpms are like about 500 rpms lower than mine on the highway... Mines seems to go to around 220/225 klms an hour and at that it is Screaming...But I never hold it there for miles on end.For me 220 Clicks is fast enough for this old fella, for the Odd times  that I wd. take it to the higher top end with the stock 12 pulley maybe around 240/245 Klm or so Nice Torque for coming out of the corners down Low, anywho Had mine done for the past two years No Worries... | ||
| Ourdee |
Two main reasons I've seen for the 9-drive on the 12 have been; a. The XB12X needs a lower first gear for crawling in the dirt & b. Someone thought they wanted closer ratio shifting. I understand a. but disagree with b. as the 12 has plenty of torque. | ||
| Diablobrian |
The 9 primary would only really make sense on a street 12 if you were stunting or possibly drag racing, but in either case a (much more adjustable) chain final drive would do the job better IMHO. The 9 and 12 heads are identical. If the 9 pistons are good I would seriously consider putting them into the 12 since you are going to have the top end apart anyway to give yourself higher compression. With a pipe, filter, and race ECM you should be close to 100hp (conservatively) and it will run fine on high octane (91-93 octane) pump gas. ECMspy and direct link tuning have made this kind of mod provide bigger returns while at the same time making them less prone to pinging. Good stuff! FWIW my street 'bolt runs 11.43:1 CR and while I usually run 93 octane I have run it on 91 in the summer with the full fairing. It is still alive and well with the biggest motor issue being a cross-threaded front plug that got "spit-out" last summer and that was the fault of an inept mechanic, not the motor or it's mods. Just my $.02 since you were undertaking mods with the intent of improving performance. | ||
| Hogs |
Diablobrain, 11.43:1 is that what you ended up with just using 9 pistons or?? Btw Now ya got me thinking,Yeah guess this old fella had been known to Stunt thee odd time..Wd think a good strong 100 rwhp wd be there then along with my other mods etc. as you say...CAn only Imagine what that wd. do as well as using the 9 pulley  Not sure Buddy can use ECMspy know I can`t at this time,Never played with it yet... | ||
| Petebueller |
Hi Hogs The speedos can be out a bit at speed. Stock you have 100kph at 3,000 rpm. On a pre-08 XB12 the rev limit hits at 6800 rpm. 1000/3000 * 6800 = 226 kph (140 mph). '08 and '09 can get to almost 235 kph on a higher rev limit. With the 9 pulley you get 226 x 34/38 = 202 kph, which is still fast enough. With a 42 tooth pulley I can pull 200 in 4th which makes 5th like half way to a 6th. I get better fuel consumption on the highway. It was what I was looking for when I had the pulley made. | ||
| Hogs |
YEah speedos are differently not true, especially at them speeds...Them figures sound right,never to concern to look at the speedo when flying... That must be interesting as you have had done, So what wd. that take your top end to with regards to them figures? | ||
| Diablobrian |
My bike was a special one-off built by Terry G. and the guys at Hal's (credit where due) but it is essentially the same thing, the domed 9 style pistons with a 12 crank. In my bikes case there is some head work involved and a custom cut X1 crank because the XB12 had not yet been shown to anyone outside of the factory at the time. Hal's built my bike to show off what their race shop could do, and it was kept durable enough to taken out on demo rides by people buying race motors and they certainly didn't risk it going BOOM! on one of those rides no matter how hard these guys pushed it. With stock cams and the original xb9 inner air box my bike posted up these numbers on the dyno...repeatably: http://www.badweatherbikers.com/cgibin/discus/show .cgi?tpc=3842&post=519178#POST519178 It pretty well details the build (build sheets posted) so there shouldn't be a lot of mystery outside of the custom map in the ECM, the exact details of the head work/flow numbers and the little tricks that Terry and the guys at Hal's have honed through years of building these motors. With pro builders you are paying for the knowledge they have accumulated as you are the actual labor on your motor, so as always, your results may vary especially using stock heads, but you should be able to get in the neighborhood of 100rwhp. The real story is the 86ftlbs of torque and the smoothness of those curves. I LOVE this bike! If you have any questions about anything I can help with as always don't be afraid to ask. If I don't know, or someone else knows better I'm not afraid to say "ask this guy, he knows more than I do!" | ||
| Diablobrian |
FWIW I lucked out and found a firebolt that had most of what I wanted to do already done to it by a reputable shop and even though I paid more than blue book for it at the time I still paid far less than what it would have cost to do it myself. Plus very little down time to make mods  | ||
| Hogs |
I remember reading that back in 2005 now, Yes thats a sweet package , It always seems to be better to keep it in and around the 1200/12500 cc`s range seems ECM and others tune these packages well, not the same for the 1450 kits etc... Wd. think perhaps they dug some meat out of the combustion chambers to lower the Compression etc... Nice Ride there for sure ..YEah I loves Da Torque myself, Be nice to have 100 Plus RwTorque Eh...Guess thats where them 1450 kits Shine,... | ||
| Petebueller |
Hogs, it was a bit of fun. My last post makes it sound like it was the fuel consumption I was chasing, but it was delaying the first up-change and always lifting my boot looking for a 6th that really go me going on it. The increased range is really a bonus. I get 330km on 14 litres. 330 km (205 miles) is a respectable distance, especially for a Firebolt. The bike was about two weeks old when I started running around looking for ways to get taller gearing. Couldn't do the secondary belt drive; couldn't run a Baker 6 speed in a later model XB; so the primary was the option. Keeps the speed sensor correct as well, whereas a belt to chain conversion mucks up the speed reading and is expensive. The first cog I had made was a 41 tooth (instead of the stock 38). Had an extended primary chain with 2 extra links. We put that in a friend's track bike and it pulled 240 kph at the rev limit. It was a '07 Firebolt with a Micron and tuning (stock otherwise) pulling 100+ RWHP SAE. I made 42 and 43 tooth versions. The 41 tooth took up a lot of primary chain adjustment. 43 went on but the chain was too tight to be safe. 42 with the extended chain had adjustment just like the stock setup. That's what I put on mine. The rev limit is now theoretically at 250 kph. When I had a Micron fitted it may have been capable of that going downhill. Here are a couple of attempts and a stock pulley.   | ||
| Hogs |
Thanks Bueller, I seem to remember you talking about this now some time ago, Thanks for the recap... | ||
| Petebueller |
Mmm Hogs. I'm going to have to find another favourite topic. Anyway 2c back on topic. I'd leave the XB12 pulley in the XB12 engine |
