| Author | Message | ||
     Rbuck53 |
Just need to verify what primary gearing is in the 08 xt I purchased cause rpm's seem a bit high at cruise speeds. So, stock: 60mph= _______rpm? Thanks! | ||
| Argentcorvid |
with the stock primary, mine does about 3100, IIRC (maybe that's 65mph). XB9 primary should put it closer to 3500 (calculated 3441, with 11% increase). (Message edited by argentcorvid on November 08, 2013) | ||
| Etennuly |
Stock Uly gearing works out pretty close to 3,000 RPMs = 60 MPH. Relatively 4,000 RPMs = 80 MPH. Not exact, but close, and don't forget that Buell's speedometers are a little off on the conservative side. When mine reads 70 MPH my GPS says 66~67. | ||
| Froggy |
http://www.froggypwns.com/Buell%20Gearing.xlsx  | ||
| Teeps |
RPM per MPH changes depending on tire (make/model/size) and wear too... | ||
| Rbuck53 |
Thanks all for the info. 3000rpm just seemed a bit high for 60mph with a Sportster based engine. I expected more like 26-2700 @ 60. Not being used to the revs, I find myself always looking for that non-existant 6th gear. I guess in time I will get used to it. Thanks all, Buck | ||
| Argentcorvid |
For what it's worth, the gearing on my 98 sportster works out about the same, with the same "where is 6th gear" reaction. | ||
| Rbuck53 |
I Googled "Sportster 6th gear", and only came up with an offering for the early designed Sportster gearbox and for some reason not ours. Not that I would or could do such a project, but as general information, is anybody aware of a 6 speed gear box swap into a late model Buell? | ||
| Froggy |
The short answer is that it can't be done. Even if someone made a 6 speed that fits, you would have to split the engine cases to install it. The older tube frame bikes had the same engine cases and transmission as a Sportster, so the Baker 6 speed could easily be installed. If you really want a 6 speed, get an 1125R | ||
| Sagehawk |
I asked the baker folks at galveston rally two years ago what they offered for xb buells and he said nothing. I'm still needing that 6th gear for commuting. Actually, I hardly ever hit 4000 rpm anyway. I adapt well. I appreciate the spreadsheet tho as that provides a lot of combinations of scenarios to play with. | ||
| Kag |
60mph Speedo - 3000rpm 70mph Speedo - 3450rpm 70mph speedo - 66mph GPS I do my best to keep the rpm above 2800 rpms as the bike just responds so much better for me above that. | ||
| Argentcorvid |
I'm not so sure it can't be done, just that it isn't practical to do, because you have to split the cases. I guess I've never seen with my own eyes how the transmission from a post 2003 sportster or an XB is different from the earlier ones to say one way or the other. The transmission swap on the pre-2003 sportsters is super easy, as there are 4 bolts to take off on the left side along with the front belt pulley, and the whole thing slides out the left side as a cassette. The price of the transmission being more than what the bike is worth is why I don't do it. | ||
| Ratbuell |
These engines breathe MUCH differently than a Sporty motor does. Higher compression, different head porting, different cam profiles - all combine to make a much higher-revving engine. The basic architecture/geography of "where stuff is", is about the only similarity left to the old XL motor. That said, I'm getting used to my new XB9 primary swap. It lowers the gearing (raises the RPM at a given speed) and does actually make the bike feel 'torquier'. The flipside of that is, cruising RPM has gone up about 250-500rpm. While I'm still getting used to the increased RPM...the engine doesn't seem to mind at all. There actually are trapdoor XB cases out there...I've had one in my hands. I believe they were initially on the XBRR bikes, but I do remember seeing street cases that were either cast with a trapdoor, or were machined to accept one. It is a shame they got away from the trapdoor, but my understanding is they had to do it for case strength. (Message edited by ratbuell on November 10, 2013) | ||
| Rbuck53 |
I recall when I was searching out a Ulysses for purchase, I was surprised at the number of low mileage Buell/Sportster engine failures I was seeing. 07's seemed to be especially vulnerable to crank failure. After researching more about this I decided to seek an 08 or later due to the redesigned lower end. I can only think that Buell/Sportster engines are more prone to failure because they are built to perform at a higher level than the HD/Sportster counterpart, whereby it operates under more stress, part of which is higher rpm's. I know one of the big draw backs of this engine, in this application, is that it is air cooled. Some of the other foreign & metric v-twins on the market crank out much higher hp and rpm's at 60 mph, and also live much longer than the Buell engine mainly due to liquid cooling. I've got what I've got...and knowing the shortcomings of this engine and where it resides, I know what to expect out of it for performance and life. | ||
| Ratbuell |
Actually the 07 crank failures were pretty much a "bad batch" of parts from the foundry. Yes, the 08-up bikes got larger crankpins as well as updated DDFI-III hardware and software, but that was more evolutionary than a band-aid. And revs are more a factor of pushrod architecture versus overhead cams, than air versus liquid cooling. The only "drawback" to an XB being aircooled is the fact that Erik and team designed the XB to be liquid-cooled, with the fuel-in-frame design shrouding the engine, only to be nixed by HD at the 11th hour. Too late to redesign the entire platform, they adapted the aircooled 1203 to the new platform for its late '02 release. Then, came the XBRR as a way to test the platform in high-HP applications...er...sorry...as a way to go racing...and the 1125 family came along in '08. | ||
| Rbuck53 |
Yes..the push rod design is a huge limiting factor for building a high rpm engine. That is why I am so surprised to hear these engines running at 3-4000 rpm at highway cruise speeds. It seems to me that one would be better served with the Buell/Sportster engine exerting its muscle in the low to mid rpm range as opposed to up in the higher rpm range. For the Uly, hi-tq output at 2600 rpm @60 mph sounds more usable than where the gearing/tq/hp formula is now. A side benefit to a lower rpm engine at cruise would be reduced engine heat. I know there will be all points of view on this but this would be my preference. Beside, the Uly being of such light weight, I would think it could easily handle a lower rpm cruise. Just my 2 $. | ||
| Ratbuell |
One factor to consider - HP versus TQ. Cruising on the highway requires HP, not TQ. My S2 has taller gearing (it also has a near-comparable setup - thunderstorm heads, X1 cams, race ignition and appropriate jets for the setup which produce a very similar HP/TQ output and curve). I find myself downshifting to pass because, while 2000 rpm is just fine in lower gears and on the twisties (TQ), it's just too low to overcome airframe drag at higher speeds (HP). | ||
| Hdxbones |
But of course HP is only a mathmatical calculation derived from measured TQ...... | ||
| Tootal |
Although push rod engines are not the best answer for a high rpm engine the fact is they will do it. Look at NASCAR for instance. They are turning some high rpm's yet I know, it's not F1 territory! On our engines it's more the length of stroke that's keeping the revs down. The XB engine is closing it's intake valves much later than a sportster. That's how we can run such high compression ratio's. That's also the reason our engine go "on the cam" at a much higher rpm than a sportster does. That long stroke is giving us low end torque along with high end HP due to the radical cams. If you were to lower the compression and put in a cam that closed it's intakes at say 36 degrees then we would have a lot more low end torque but we would lose that high end rush to the rev limiter. | ||
| Buewulf |
I think it is the stroke in this particular engine that is limiting factor with respect to revs (it was the bottom end in the pre-08's) rather than the valve train or the air-cooling. I believe those valves and pushrods would would run just as reliably at 8500 rpm as they do at 7000 (with solid lifters at least). I've also always thought that the Uly would probably work better with a different cam profile that gave a broader torque spread and less peak hp than one that focused all the power to the upper end of the tach. I understand that Buell probably wanted to hit that 100bhp rating very badly from a marketing standpoint; but the resulting powerband is so narrow, and the engine seems pretty anemic below 4K rpm for such a large, long-stroke engine. A milder cam would also allow the spark to be dialed back a bit. You might give up 8hp or so at redline, but you'd have a stronger, wider and more usable midrange between 2.5K and 6K rpms as well as a cooler running engine. The way it is set up now seems like the XB12 is just trying to be something that it isn't. I'd agree with Rbuck that it just seems weird to have to downshift a 5-speed tranny on a long-stroke twin to pass someone at 60mph. Personally, I think the ideal engine for this platform would have been a bored out XB9 engine in the 1200cc range. A larger bore with the shorter stroke would have made a much more playful engine IMO. Don't know how much room is in those cylinders to take out, though. | ||
| Froggy |
You mean like the 1350cc short stroke (with optional turbo that brought it to 150hp) that never made it into production because of Harley? | ||
| Tootal |
Buewulf, I agree with what you said since having a Ducati 904cc with it's 2-3/4" stroke and pancake pistons I can attest to a really fun engine with instant revs however being over square the engine could only produce 39 mpg no matter how I rode it. I do like the XB engine but you're right in pointing out that marketing produced it's 2 stroke like character. In essence it's two engines. Short shift it and play with the torque or rev it like a dirt bike in the twisties! | ||
| Sagehawk |
I bet with all these test mules out there, we could put together almost any combo for any need. Some fool with gearing and have really good luck. I know there aren't many bikes with as many choices for performance parts out there. Stock stroke is 3 13/16" if I'm correct. S&s offers a 4 5/16" stroked crank for those inclined. One place offers 3 13/16" cylinders which is absolute the largest bore you can run due to cylinder spigot n case diameter. I just know I've spent time with my flhr and it runs better but the best hop up for it was to scoot it over in garage and put the 12x beside it. I've got sorta fast, loud, n obnoxious and then I've got my quiet, fast, permagrin ridden tweezerglide! Alls well! | ||
| Buewulf |
"You mean like the 1350cc short stroke" Yes, sir, that would have been the (.)(.)'s. Even without the Turbo. Was that a XB-based mill, or a clean-sheet design? I am always stunned by how poorly H-D understood Buell's target market. "39 mpg no matter how I rode it." The air-cooled Ducatis certainly never won any awards for being fuel efficient. I know a lower revving engine will, all thing equal, produce better fuel economy than a higher revving engine. That said, every bike I have owned besides the Uly has been over-square, and the two that were of similar displacement as the Uly got roughly the same mpg (low forties); so there is much more to it that bore and stroke. Frankly, so long as a bike can hold enough gas so that I can go at least 150 miles before sweating a fill-up, I really don't care what kind of mileage it gets. I regretted my Uly purchase initially because I was having trouble adjusting to the engine character, but I eventually learned to appreciate it for what it was and accept what it wasn't. However, I still get a buzz whenever I hop on a quick-revving bike that can hammer out a potent midrange and still provide a nice rush a 8K+ rpms. A big-bore XB9 would be a step closer to that sensation. | ||
| Hdxbones |
It seems to me that the TQ 'curve' on the XB12 is already very flat and consistent. While a little more TQ is always nice, hovering around 80 ftlbs from 3K to redline is fairly impressive. And it's steady and flat. There aren't many engines that can rival that. Some make TQ early, others make it higher in the rpm band, but few make it consistently from bottom to top. If anything, I think the Uly is in need of some taller gearing to take advantage of the TQ, when it really comes on around 3-4K. I generally ride mine in that range, and have no complaints about roll-on power. If you're trying to twist the wick in 5th gear at 55mph, of course it's not going to get up and move, you're nowhere near the engine's peak operating rpm range. I think the XB9 primary is in my future to make it a little more trail friendly. Her's a graph of a stock bike dyno run, TQ and HP to the rear wheel-  | ||
| Froggy |
If I recall correctly, the original plan was for the XB9 to be the base model, then there being a 1350cc version above that, and then a turbo version above that. We ended up with the XB9 then later due to Harley getting in the way, Buell couldn't use different cylinders to get a bigger bore so we ended up with the longer stroke to make the XB12. These were after Harley ruined the V-Rod motor, which was originally being developed for use in both the XB and Harley models. | ||
| Reepicheep |
We have hashed this to death here, and it is simply wrong. But I can't resist making the case again. Every time I do it I make it a little shorter (and hopefully clearer). A 10 pound bag of flour hung on the end of a 10 foot long 2x4 nailed to a tree is a 100 foot pound "torque motor". It is, at all moments and forever, producing 100 foot pounds of torque. But it will never do any work, because it isn't a sustained torque at a given velocity. Likewise, I can hook a dremel tool to a gear reducer, and easily get 100 foot pounds of torque out of it... to move a truck at about 1 inch an hour. Again, torque without velocity isn't that much use. Torque with velocity however is a measure of how much work you can do. For a given amount of torque, the more velocity you can produce while maintaining that torque, the more work you can do over a given period of time. So a 100 foot pound motor at 1 RPM isn't doing crap to move a motorcycle. A 100 foot pound motor at 10,000 RPM is going to launch you into low earth orbit. HP is a measure of torque at a velocity. It is every bit as "real" as pure torque, and FAR more useful and relevant in terms of what it means to accelerate a motorcycle. | ||
| Ratbuell |
Torque gets you moving. It overcomes inertia. HP keeps you moving. It overcomes other forces - wind, gravity (hills), rolling resistance, airframe drag, etc. | ||
| Court |
The Space Needle weighs 125tons . . . . about a quarter MILLION pounds. It rotates. It's powered by a 1.5 horsepower motor . . upgraded from 1.1 hp. | ||
| Blake |
Torque is the angular (rotational) equivalent to force, how hard something is pushed. Power is the measure of how hard AND how fast something is pushed. Torque means absolutely nothing without power. You can apply a million FT*LBS of torque to a drive shaft, but if it can't rotate, you have nothing but a wound up torsional spring. The power of an engine or motor is the only parameter directly indicative of its performance. Hdxbones Posted on Monday, November 11, 2013 - 03:06 am: But of course HP is only a mathmatical calculation derived from measured TQ...... Inaccurate. You don't need to know torque to determine HP. Power = Force x Distance / Time Interval, which is to say Energy per Time Interval. |
