| Author | Message | ||
     Moxnix |
Are they a direct swap to an XL883? If not, what the drill? Is the advantage better porting, and breathing, or something else? Thnx. | ||
| Moxnix |
Oops, just to clarify, that would be a circa 1995 XL883. | ||
| Aaomy |
well yes and no,, the 883 uses standard stroke and a smaller bore to achieve its original sportster displacement. same as when first introduced in 1957. the xb9 actually use 1200 cylinders to achieve this.. 883 bore is 3" while a 1200 or a xb9 is 3.5".. the xb9 has reduced displacement because it uses a shorter stroke,, xb9= 3.125"? sporty 883 and 1200= 3.8125" to make this all work out the xb9 has longer rods, and a largely domed piston. another difference i think is either cam base circle or head thickness,, at any rate it changes pushrod length by like .025" which changes it like .040" on the valve side,, ok hears the short on the issue.. will they fit yes,, but to do it right and get really nice bang 4 your buck go this way.. 1200 cylinders or have you stock ones bored out ,, new flat top pistons " stock 1200 sportster " your xb9 or xb12 heads and a set of adjustable pushrods.. youll now have a 1200 sporty that has a lot more go than a standard 1995 1200 due to better porting, dual squish bands, and higher compression,, stock 1200 pistons will give you 9.7:1 while xb12 pistons will give you 10:1 ... hopefully this help you out.. and if i got anything wrong one of the other quys will quickly chime in and help too,, great thing about badweb... any more questions feel free to ask.. | ||
| Ingemar |
I don't think you can fit the breather hoses on the XB heads on a sporty. They are on top instead of on the sides on a sporty. | ||
| Racerx1 |
XB9 heads will not fit an 883 due to valve interference issues....you have to go to a 3 1/2 inch bore (1200 bore). Also the front motor mount bolt spacing is narrower, and the side draft breathers are unmachined. To retain side draft breathers, you have to drill and tap the XB 9 heads (you have to drill and tap holes for the carb mount plate anyway), or you can go to XB valve covers/breathers. 2004 and up XL1200 heads have the same ports/valve sizes/combustion chamber as XB heads and are already machined for side draft breathers. Another piston option when you go to a 1200 bore is the XB9 piston which results in about a 12.5:1 bore. You can run this combo on pump gas with e-cams, but you will see some serious knock if you retain your stock cams. good luck! | ||
| Rick_a |
e-cams? | ||
| Rick_a |
H-D's Screaming Eagle division has a forged and plated 10.5:1 piston for the XL1200R/XB heads. | ||
| Racerx1 |
e cams = production 0.550" lift XB cam. Quite a bit more overlap than the 883 'D' cam so cylinder pressures in the bottom half of the rpm range are lower/less prone to knock. | ||
| Moxnix |
Cancel that idea, and thanks for the information. Plumb forgot about sidedraft/downdraft differences. Should pay more attention to post-tuber Buells; actually I thought if God made anything better than tubers, he kept it for himself. (But that CityX looks kinda hip). The 883 plan was to build a little motor (that breathes) up from bits and pieces to swap into an S2 and still use an Aerocharger, now that turbines are being made to original specs in Kansas City, to run in under 1000cc classes. Thanks again for the insight. | ||
| Firemanjim |
"to run in under 1000cc classes." Really,and where were you gonna do that??Somebody finally got started making the variable vane unit again.About time. Was one of the fellows Bob Packer of the Turbo Doc? One of the options I was considering with my bike was slapping another smaller set of cylinders on and running the 1000cc classes at Bonneville,but the need for speed will probably outweigh the need for just records. So what heads are we all running that we have been getting from Aaron--I thought it was XB's?And mine have the proper holes on the side for carb mounting. | ||
| Aaomy |
mine are my own mods, mainly stock xb with the side draft carb mounts, will post pict in a while ,, the projects are getting crazy,, tried going a little different on the breathers too.. well see how it all turns out,, pics for the s2 guys with all the new fun and madness will be up soon i hope.. oh yeah my name is aaron so i guess mine are from aaron too.. in that strange sort of sense.. | ||
| Moxnix |
Fireman Jim- IMO, the shortcoming of Bonneville is decreased traction on salt. Now that the Autobahn has a speed limit, that's out too. What this country needs is good traction on a lonnnnnngggggggg paved course in a location w/o sidewinds. Or a way to have speed trials on pavement the way the cannon ball run people do it on the sly. I just wanted to build a little motor for the lower rung of a 3 engines/one bike theme. There is a chap in Hamburg mit a brand new 200-inch Sportster engine for sale using S&S cases & heads, & cast iron cylinders, but it probably won't fit the S2 w/o extensive modifications, if at all. If you need to be the cubic king on the salt, I'll pass on his email address. I see Basti bought some XR1000 cases on eBay. Does this mean he bought the RR1000 ex-drag bike? | ||
| Firemanjim |
Yeah,fitment on that motor would require a welder and a surgeon.I know a 100" will just fit,that's big enough if ya forcefeed it.Got me a bigger Aerocharger this year.We'll see how that works. | ||
| Thunderheart69 |
racerx1, I was skipp'in through the post and noticed the xb head swap issue. what is the highest compression You can run an XB at and survive on 92 octane? Also how much of a gain does Your airsystem add throughout the RPM range. What kind of throttlebody and ecm system are You using on that race XB? | ||
| Wyckedflesh |
Wish they would open up the Silverstate Classic to Motorcycles...even if they had to make a requirement that MC riders had to have a racing liscence from one of the sanctioning national bodies (CCS/AMA etc) Could you see running 90 miles of Nevada roadways trying to hit a target average of 132mph? That just makes me go all giddy with the thought... | ||
| Racerx1 |
Thunderheart, I'm a little leary about making any sort of recommendation about how high a compression ratio you can run on pump gas, just because its very system sensitive. My XB12 race bike is running the stock e-cams with XB9 pistons and the race ECM and is coming in at 12.5:1, and i run pump gas in it without knock issues...of course it operating primarily between 4000 and 7000rpm. Might be a different story on a street bike at lower speeds/higher loads sitting baking in traffic. I'm not sure i would want to go much over 10.5:1 in a 1200 bore for a street bike. I'm running essentially the same combination as a side draft carb powertrain in my Drag race X1 with the stock X1 'B' cam and have ridden it on the street many times in the summer on pump gas without knock issues. I use a program-able crane ignition with max advance of 30 degrees at 7000rpm. I haven't done any back to back dyno runs with the ram air system on the XB, however I was radared 2mph faster than last year at Daytona, and that was with a 20mph head wind that wasn't there a year ago. The throttle body is a mildly cleaned up 49mm XB12 part. I'm running the Buell race ECM as delivered, although my learned AFV value is 149.4%! It runs very well in this configuration and has a very friendly powerband |
