| Author | Message | ||
     Lemonchili_x1 |
Just wondering if anyone has ever bumped a short stroke engine out to 3-13/16" (1170cc) or 3-7/8" (1208cc) and what was the result? cheers, chili | ||
| Diablobrian |
IIRC there was a "short stroke attack" XB run over in Europe (Germany?) back in 04 or 05. I have also heard of several street riders running big bore 9's. Terry (Buelldyno_guy)<spelling?>  should be able to give you some solid figures as to what you get at the rear wheel. | ||
| Rsh |
Steve Slaughter has a 1170 race bike, and Jakecheez has a 1170 for the street. I believe you can get 100 rwhp fairly easy running a big bore and short stroke. | ||
| Jakecheez |
Yep- I got a big bore kit through Nallin Racing at NRHS.com. They have a couple different big bore kits and the one I got that's on the work order claims it is the "1200cc" big bore. That combined with a k&n, millenium heads, stage 3 porting, 585 redshift cams and a forc pipe= 107.7 rhp (all work done by NRHS as well as the dyno). It was done in Colorado, so I'm told that being in MN, I should be up to 110rhp. Not sure if there's truth to that, but I hope this helps. | ||
| Phelan |
That's because Longmont is something like 4,000+ feet above sea level. If Minnesota is close to see level, you will see more power because the air isn't as thin. | ||
| Lemonchili_x1 |
Sounds very cool  Jake - What's it like as a streetbike? Is it possible to compare to a mildly modified XB12? | ||
| Jakecheez |
Not sure as I've only ridden two bikes -my xb9r (xb12r now?) -my roomates s1w his is a 11 year old 1200 motor, but it runs like a dream. Our two bikes are very comparable riding. Mine "feels" bigger, but is as snappy as his riding on the street. The only differance I noticed riding is that I can't keep his front tire on the ground. On the highway 70mph+, I can pull away from him pretty easy. I have topped mine out at 136mph. I don't think he has gotten his over 100mph (he starts to redline at 90mph) I think that the 9r has a higher redline than the 12r, so I think it should have a higher top end? Not sure if I'm correct here, but that's just from riding two bikes- | ||
| Lemonchili_x1 |
Thanks Jake, that gives me a rough idea of what it's like, sounds *very* cool | ||
| Gentleman_jon |
The nine is geared lower than the twelve, so top end is probably about the same or a bit less, but acceleration is likely better. (Message edited by gentleman_jon on August 19, 2009) | ||
| Jakecheez |
Ok, weird......cuz I definetly top out WAY above his. Probobly has somthing to do with the fact that his bike is a 98 s1w (1200cc) not a 12r. Anyways- the exhaust that has been on my bike is robbing it of low end torque and who knows what else. The force pipe just got rewelded and is being put on this week....... But that probobly explains why his is as snappy as mine is right now. Again- I'm not educated on th subject to know for sure. It's just what I feel from riding the two bikes. | ||
| Lemonchili_x1 |
An S1 should pull a fair way beyond 100mph, given enough space. 120mph, 125 maybe? Maybe he's running different final gearing? For 136 what sort of rpm? Above 7000? 7500? | ||
| Bads1 |
Give Shazam a yell. He had his XB9S done by NHRS. He had a dyno on the forum years ago after they were done with it. 117 RWHP if memory serves. | ||
| Glitch |
LemonChili_X1_XB? | ||
| Slaughter |
My bike started as a 2003 XB9. I put the 2008 XB flywheels, CP pistons (kept compression at 10.5). Lightened and balanced the flywheels with the lighter pistons. 585 cams Other small stuff like Jims semi-solids (don't bother - keep full hydros) and roller rockers. XB12 throttle body bored to 53mm High pressure fuel pressure regulator (MUST DO) Valves to 1.9 inch (up from normal Stage 3) Bronze oil pump drive. When the spigot bore is done, you really see how LITTLE is left of the cases - I sure wouldn't want to attempt a bigger bore. In the pic you can see how little metal is left between jugs:  With the lighter whirling bits, it REALLY revs SWEET. I've only attempted to get mid-range and not so much HP but go for THROTTLE RESPONSE. With the cams and big valves and big throttle body, it doesn't like being below 5000 rpm. I bumped the rev limit up to 8000. I'm "told" that it's "safe" to bump it to 8300... but I don't have staff to do the work so I'm keeping the rev limit down at 8000 HAD to put oxy port on both pipes before I could really get a good tune on both cylinders. It runs flawlessly. No timing table adjustments necessary. If I had to do it for street, I think I'd stop at Stage 3 heads. Going out to 1.9 valves means decking about 0.090 - and that meant a lot of fiddling to get the throttle body re-positioned. | ||
| Slaughter |
I would NOT HESITATE to do this for a street bike. I'd just keep the valves a bit more on the lines of Stage 3 diameters and use an XB12 throttle body (WITHOUT boring an additional 2mm)... MAYBE have to get a high pressure fuel regulator but not sure. I can run 91 octane but will blend in 100 in the summer to avoid detonation (never had the problem but we commonly have 120 degree summers) Also will be installing the racing oil cooler - just because. (Message edited by slaughter on August 20, 2009) | ||
| Lemonchili_x1 |
"LemonChili_X1_XB?" How about LemonChili_X1_XB_CR_S1_RR1000??? I'm trying to arrange a long demo ride on an 1125CR among other things!) to see how much I like it, but the 1170 conversion sounds *really* appealing... and XB9S's are pretty cheap around here at the moment... Hmmm... Slaughter thanks heaps for posting the info and pics. (Note to self, must finish RGV project first... and finish house before that!) |
