| Author | Message | ||
     Riderx09 |
does anyone know how big you can bore stock xb9 cylinders? | ||
| Gentleman_jon |
You might want to inquire at several of our sponsor who are performance specialists such as Cycle Rama, Tilley's and Revolution Performance. You could find them in the sponsors section of this web site: http://www.badweatherbikers.com/buell/messages/17143/17143.html?1140642826 | ||
| Slaughter |
3 13/16 is the max bore on the stock XB9 cases. There's just not hardly ANY metal left between the cylinders after boring to 3 13/16 That is what I've done to mine and it makes a sweet motor - QUICK revving and a higher redline (for racing, we can set it to 8200) If you're getting the beast bored, ask the machine shop about lightening/balancing the crank while you're at it. Not too expensive and you get a teensey better throttle response - but at the possible expense of more of a beating on the bottom end (insert rude humor smiley here) I've kept my compression ratio to 10.5 to 1 so I don't fry the engine and can run pump gas if I have to. With stock redline, the motor at that bore would probably last for-freaking ever. | ||
| Xb9 |
You can go to 3 7/8", Talk to Brian at Revolution Performance. Gives you 1208cc with the 9 stroke.. | ||
| Alex |
3 7/8 is the biggest bore size as it uses the same case spigot bore as the 3 13/16. But that was probably not the question. Iīd say You can safely bore the stock XB9 cylinder to +.030" oversize as this is what Harley did with the Sportster cylinders for the last decades. But be prepared that You wonīt get XB oversize pistons from Buell (at least I canīt find any in the books). Funny that they offer oversize piston rings though. Best regards Alex | ||
| Riderx09 |
so then could you bore out the stock cylinders to obtain 1050cc.i have access to a boring bar so i figured i could save money by not buying the new cylinders from revolution if it would all work out- thanks- | ||
| Slaughter |
oops - he asked about cylinder boring. My bad | ||
| Blake |
Riderx09, The stock cylinders may be "over-bored" but only by - some smart person please help me here - like 0.050"? You'll need some new all aluminum alloy nicasil lined cylinders in order to achieve 1050cc. BadWeB sponsor Revolution Performance provides the exact kit you would need.  | ||
| Riderx09 |
guess ill jus save my pennies then thanks- | ||
| Blake |
Me too. | ||
| Diablobrian |
Boring cylinders is a separate science in itself requiring specialized equipment. To take on this project you need to know what's involved. here goes. You would want to buy the pistons and rings first. They determine all the sizes that follow. You could press out the old cylinder liner, (20 ton press min) then bore out the outer sleeve to match (interference fit remember) a properly sized replacement inner sleeve matched to pistons Then press that new sleeve in, then rough bore it to .005 or so under final size, then purchase a flex-hone of the proper size and finish the cylinder out to final size. then you'd need to bore the cases to match the spigots (ends of the liners). machine clearances in spigots as needed to avoid contact with other spigot and crank. After that you get into assembly and valve clearance, compression, deck height, etc. Remembering all this while this is vastly over-simplifying the process. please don't flame because I left out a step. I just want to demonstrate how relatively cheap these kits are and how much "homework" is done by the shops. I have a mill, and press in my garage, and have several years experience as a manual prototype machinist. I would not attempt to bore motor cylinders in my shop. In fact Hal's has built a couple of motors for us because at the price it's a bargain. Hal's, Revolution, Cycle-rama, and NRHS will do a fine job as well. check-em out! Let them earn your business, they are good at what they do and there is a reason these specialty shops exist! (Message edited by diablobrian on February 23, 2006) | ||
| Riderx09 |
the only reason i brought it up cause i work at a shop an we have a machinist that does all of our work, we do sporty 883 converstions and twin cams all the time..so if it was possible to bore stock cylinders it would be cheaper for me personally | ||
| Diablobrian |
cool, that's a little different than "having a boring bar". In that case I'd still order the kit and have your machinist bore the cases to match. assembly should be a no-brainer if you do 883 conversions. | ||
| Blake |
Careful. One of the most important things is to have and properly utilize special tooling that will preload the cylinder while being bored so that it is clamped just like when it is installed with cylinder studs fully torqued. Even with some additional added to account for thermal strains as well. Without that simulated clamping load during the boring process, your close-tolerance bored cylinders turn all goofy shaped when they get installed, torqued up to operating temperature. I think they call the tooling a "torque plate." It simulates the cylinder's condition as it is installed and clamped between the cylinder head and engine cases. | ||
| Diablobrian |
exactly my point Blake. "Boring cylinders is a separate science in itself requiring specialized equipment." however, just about any good machine shop can bore the cases for you since that does not require special tools, just a careful set-up. | ||
| Riderx09 |
not to be rude but it seems often on this board topics go astray so much you get away from the question at hand... i mean my question was really never directly answered..we have a full service machine shop i know theres many things involved with boring out cylinders an i wouldnt atempt to do it myself an i hope nobody else would either it is very in depth an requires the upmost perscion...i was jus unclear on how much sleeve was actually there.....thanks- | ||
| Diablobrian |
Okay, I thought that had already been addressed. You can safely go to .030 over. .050 looks pretty questionable. I'd go with a nicasil cylinder kit at that point. Revolution has a selection of quality pistons on their web site. http://www.revperf.com/xl.aspx?action=pistonKits The point Blake and I were trying to make is tat this is not a mod that can be done at home on the drill press.  There are people other than yourself that will read this thread and not have a machine shop at their disposal. We are trying to help them avoid a world of hurt that could have been avoided because we assumed a certain level of knowledge. Blake made this same point to me on an earlier thread about engine mods.  | ||
| Alex |
Riderx09, the smallest diameter of the cylinder liner (where it protrudes into the crank case) is around 3.67". The 1025 Revolution Performance Kit has a 3 9/16 bore (but itīs made of different material). So if You dare to go this big it would leave around a .05" wall thickness of the liner. You may want to ask some of Your shop guys if they think that it will break under load. I wouldnīt do it although I have done many weird things to engines (I prefer Brianīs Cylinder Kits). Best regards Alex | ||
| Buelldyno_guy |
I am also a big fan of the REV PERF Bolt on and Big Bore Kits and now that the question been answered, there is still something not pointed out, which is max size you can bore the cases to. ... The RP Big Bore Kits have a 4.00 inch spigot and require a 4.010 case bore and that is as big as they can go. ... Terry |
