What are your dyno run results?

[jimbemotumbo]

Could some one please explain to me how Buell gets close to 100hp out of the Sportstar engine??

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Easy ... extremely modified heads, cams, valves, compression. Buell also does a nice job using coated surfaces for things that rub together and for using very light and balanced rotating or moving parts. Hard to consider a buell motor stock, but it's a very nice design, esp for something you can buy with a warranty.

 

I had 92 RWHP out of my 84 Sporty 1100. Just cams, carb, intake/exhaust, valve train, and some tuning. Could do a roll on wheelie shifting into third. Could also melt valves, break pushrods, and cannabalize piston rings.

 

My buddies 00 Lightning breaks hard and often. This should tell you something.

Listen to Al R., and remember the saying "Power corrupts. Absolute power corrupts absolutely." I have corrupted several bikes trying to squeeze out the ponies. Now I am happy with modest improvements and changes made more for driveability than top end HP.

 

The money I save on engine mods allows me to afford stylish MG ties and polo shirts.

[Skeeve]

Could some one please explain to me how Buell gets close to 100hp out of the Sportstar engine?? Please.

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Easy: practice!

 

The Evo Sposta mill is going on what, 20 years old now? [Last iron-head Sportster was '85, iirc, concurrent w/ the XR1000 engine: *that's* the deal if you want serious HP from a classic Harley; the XR1k motor was the basis for Buell's original BOT racebike, only oversquare motor Harley has made since the '20s...] With that kind of development time & more importantly, sales #s, the capabilities of that motor are known factors.

 

Let's see Buell's engine development process: 1st, take a head developed by Jerry Branch for the 883 under H-D contract and slap it on the 1200. Compression is up, flow is up. Add big valves; flow is now way up. There, you're done!

 

Seriously, for MG to produce a comparable engine as delivered stock, they'd need to purchase some Mick Rich heads and then base their head casting molds on those. Switching to roller cams, lifters & rockers would put the finishing touches on the improved flow by reducing internal frictional losses. But it still won't put out as much power as the Buell, since Erik started with a better *combustion chamber* [bathtub] shape for more efficient combustion to start with. Plus the Buell has a 100cc advantage...

[Guest Steve_W]

The March '05 edition of Psycho, er, Cycle World had a long article about Buell's AMA Formula Extreme race bikes, including a good bit about the engine. The stock engine is, of course, undersquare, 88.9mm x 96.8mm bore/stroke, 1203cc. Their race engine uses Nikasil-lined cylinders and a destroked crank, 96.8mm x 91.4mm, 1348cc. It's supposedly safe to 8500 rpm using the XB9 stock hydraulic lifters. They've also used the still-shorter stroke from the XB9 engine (79.4mm, 1170cc) a few times and, while it made less power, it revved higher (duh!) and had a smoother, wider powerband. They apparently may focus on the XB9 stroke with bigger bores to get more power.

 

Having seen (and heard ) these beasts run last year, I must admit to cheering for them. They weren't exactly being run over on the straightaways; my non-calibrated eyes had them outrun only by the factory Honda hot rods revving to 16k rpm.

 

The article had this to say about reliability:

...it's hard to test real-world reliability to the "six sigma" level (six standard deviations, or 3.4 failures per million products) with even the accelerated and rigorous test schedule Buell currently uses, which throws in wheelies and full-throttle acceleration runs galore.  "You run into that 0.01-percent rider - usually European - who just hammers the bike," he (Erik Buell) explains.  "The only duty cycle that exceeds what he does is racing."

Erik likes to race.

 

ObGuzzi: It's a pity Moto Guzzi will never get the chance to try the MGS-01 in Formula Extreme; would have been fun to watch, especially if they took it seriously.

[Skeeve]

ObGuzzi:  It's a pity Moto Guzzi will never get the chance to try the MGS-01 in Formula Extreme; would have been fun to watch, especially if they took it seriously.

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Word!