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Buell Motorcycle Forum » Buell RACING & More » Racing - Circuit/Road Racing » Archive through October 13, 2009 » ANYONE ELSE WONDERING WHY THE 1125RR IS SO FAST? » Archive through September 19, 2009 « Previous Next »

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Avc8130
Posted on Friday, September 11, 2009 - 12:46 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

I guess one of the main questions is whether DMG is really looking for factory teams or if they want privateers at all of the races. I believe they had 40+ entrants at NJMP...MotoGP has 17.
ac
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Court
Posted on Friday, September 11, 2009 - 01:59 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Next year will be exciting.
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No_rice
Posted on Friday, September 11, 2009 - 02:17 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

thats what i hear...
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Xb9er
Posted on Friday, September 11, 2009 - 04:45 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

how long until we see a diecast replica of eslicks bike in the toy isles?
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Jimidan
Posted on Friday, September 11, 2009 - 08:23 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

The 600's are race bikes with lights on them, as they are designed to run in classes that limit modifications, so the manufacturers add race-ready mods to their stock bikes. That is why they update the bikes every two years or less. All you have to do is read the Cycle World or Motorcyclists mags to read about what race parts of two years ago are now stock. All engine, frame and suspension components are subject to be lightened as much as possible at each iteration, and the weights of these stock bikes (sans lights) are well within race spec these days. The RPMs are astronomical on these street bikes.

Can these 600 bikes still be modded when the rules allow...sure they can, but the manufacturers have made great strides for these bikes to be competitive right off of the showroom floor.

Because I cannot afford to race my air-cooled old Buells, I have a Honda 600 F4 racebike. It is nearly stock except for the billet race bits, Erion exhaust system, race glass and 15 thou milled off of the heads. It is light, scary fast and cheap...and it is an older model. The new ones a amazing. The 1125R is my next purchase for a track bike however.
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Vagelis46
Posted on Tuesday, September 15, 2009 - 09:49 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Is there an intake air restictor for the 1125RR? I think not. What is the intake throttle size of the 1125RR ?? Same as the 1125R ?

There is a 50mm air intake restrictors for the Ducati 1198R racing in WSBK, which is competitive against 1000cc IL4. So if a 1200cc & 50mm restricted 1198R is competitive against IL4s, why people think that a 1125cc & unrestricted Buell stands no chance ??

I am interested to know what the superbike riders think about the performance of the ZTL2.
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Elvis
Posted on Tuesday, September 15, 2009 - 10:14 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

It will be interesting to see what the arrival of Buell and KTM twins to the Superbike scene will do to the rules structure.

Until now, any rules written for "twins" have basically been written for "Ducati".

I hear people saying: "You can't compete unless you've got an inline 4.", but how competive any configuration is can be tightly controlled by the rules committee.

In theory, everything being equal, a 1200 cc twin should be fairly competitive with with a 1000 cc inline 4. If there are a few more twins on the scene, the rules may become more fair and based on the nature of a V-Twins . . . not just Ducati's particular circumstance.

(Message edited by elvis on September 15, 2009)
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Slaughter
Posted on Tuesday, September 15, 2009 - 05:25 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

1200 twin isn't really competitive with an I4 litrebike - hence the intake restrictions for WSBK 1000cc - advantage Ducati.
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Vagelis46
Posted on Wednesday, September 16, 2009 - 05:44 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

The Ducatis are restricted, not the IL4s
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Slaughter
Posted on Wednesday, September 16, 2009 - 09:57 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Really?

Now I gotta go look it up.

Why restrict a bike which in stock form is 15-20% down on power at 1200 compared to the others at 1000?

I gotta look it up though.
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Blake
Posted on Wednesday, September 16, 2009 - 12:35 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

I thought the 1198R was 170 BHP.
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Backcountryme
Posted on Wednesday, September 16, 2009 - 12:48 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

According to Ducatti.com the 1198R is 180hp. With the track only kit it is up to 186hp.
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Vagelis46
Posted on Wednesday, September 16, 2009 - 12:53 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Ducati's 1198 stock street bike is dynoed at the same level as the stock street IL4s.

This is impressive.

The 1198R is restricted to 50mm intake for the WSBK, but is still competitive against the IL4s.

So I would think that a highly tuned Buell 1125RR with no intake restrictions, would be competitive against IL4s.
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Backcountryme
Posted on Wednesday, September 16, 2009 - 01:01 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

I don't know. It would have to be highly tuned. The stock 1125r is only about 145hp. So you are talking a 35hp tune job. That seems like quite a bit to me.
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Anonymous
Posted on Friday, September 18, 2009 - 05:00 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Apparently quite a few posting here didn't watch or pay attention to the Superbike race at New Jersey. If you want to ask how the Superbike racers liked the ZTL, I can assure you there were quite a few on Suzukis that didn't like the ZTL being on the Buell as they were outbraked by the 1125RR.

If anyone ever wanted to see confirmation of Buell's chassis design, you should have been there. Although noticably down on power, the 1125RR was clearly the best handling bike on the track, with brakes equivalent or better than anyone out there. Caliber of the riders they were competing against? Mladin, Hodgson, Bostrom, Hayes, etc.

Performance in American Superbike? Don't think these guys are riding your grandma's stock bikes. Pegram's 1098R is actually one of Nori Haga's last year's 1198 motored WSBK motorcycles straight from Bologna.

As far as WSBK rules are concerned, the restrictor rule is a flexible one. It starts out at 50mm, but allows movements of 2mm at a time until the bikes are competitive. So we don't know what they are actually running.

Also, the whole package of cam, valve size, port shape and airbox/ram air is what makes air flow. 50mm throttle bodies can flow a lot of air under the right conditions.
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Backcountryme
Posted on Saturday, September 19, 2009 - 12:45 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Anonymous, you are right about the throttle bodies. In one of our midget heads our old head guy actually restricted the port and made it flow better. It isn't always the size of the port. Velocity, shape, finish, and flow are all really important. I have seen so many times where guys have hogged out their ports and it kills the power.
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Blake
Posted on Saturday, September 19, 2009 - 07:51 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

I think we all saw Cory and Taylor assassinate the bumpy twisty stuff on the Buell Superbikes. I think the guys above are talking about the power deficit that will become more of a problem at the higher speed venues.

We're hoping that Rotax and Buell have something significant up their sleeves for next year in that regard.

: )
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Vagelis46
Posted on Saturday, September 19, 2009 - 08:24 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

It is still 50mm in WSBK.

The rules say that fistrly there is a +-5kg weight penalty to play with. If that is not enough, then there is a +-2mm from the throttle bodies.

Good to have factory people posting.
Good to know that ZTL2 is performing OK.
So what is the throttle bodies of the 1125RR ? Or is this a secret ??

If Ducati can do it, so can Buell-Rotax, to make enough power from a V-2.
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Anonymous
Posted on Saturday, September 19, 2009 - 01:39 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Throttle bodies on the 1125RR are stock 1125R parts, absolutely no changes.
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Jimidan
Posted on Saturday, September 19, 2009 - 01:47 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

In theory, everything being equal, a 1200 cc twin should be fairly competitive with with a 1000 cc inline 4. If there are a few more twins on the scene, the rules may become more fair and based on the nature of a V-Twins . . . not just Ducati's particular circumstance.

Maybe Honda will come back with a 1200cc iteration of the RC-51 ;0)!


We're hoping that Rotax and Buell have something significant up their sleeves for next year in that regard.

Like punching it out to 1200cc? Ducati has a 75cc advantage out of the gate and the desmo drive which is worth something because of no valve spring tension to overcome. That has to be worth something because DMG restricted Ducatis to 850cc in the Daytona Sportbike Class.}
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Vagelis46
Posted on Saturday, September 19, 2009 - 02:28 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

61mm for the 1125RR, compared to 63.9mm for the 1198R. That is very close. The 1100cc Duc1098 had 54mm throttle bodies, maybe the 1125R was designed to upgrade to 1200cc.

I do not think that at 12000rpm redline, desmo offers any advantage compared to Rodax's advanced valvetrain.

Since we have a factory man here, any "hot" news for Buell and moto2 ??
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Jake318
Posted on Saturday, September 19, 2009 - 02:43 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Maybe im just showing my age but I cant see how 1200cc is enough displacement for buell to run agaist 1000cc fours. I know Ducati is getting away with it but the desmo valve have an advatage of not floating. Now even the Ducs are out of development and down on power in WSB . Dont get me wrong the 1125 i has a great motor ( have the bike myself) but the inherant advantage more power pulses is a BIG advantage .
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Backcountryme
Posted on Saturday, September 19, 2009 - 02:46 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Desmo valves allow for no valve springs. This allows that valve train to be lighter and it eleminates valve float. Valve float kills the top end on an engine, and the only way around it is to run high spring pressure. High sping pressure then puts more drag in the engine because it takes more power to open the valve. The Desmo setup has huge advantage.
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Anonymous
Posted on Saturday, September 19, 2009 - 04:29 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

The huge advantage wasn't evident at New Jersey...
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Backcountryme
Posted on Saturday, September 19, 2009 - 06:43 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

No, but wait until they race at a track where the bikes can really streach their legs. NJ was a tight track where none of the big bikes were able to get out their low gears. I love the Buell, but I am not to sure how it will do at the tracks with long straights. It will get there, but next year will be a year of growing pains and progress I think. I do think it needs to be a 1200 though.
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Gentleman_jon
Posted on Saturday, September 19, 2009 - 06:54 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

The desmodromic valve system was a great advantage when it was first used in its modern form in Mercedes' iconic W 196 Gran Prix cars, and by the great Ing. Taglioni of Ducati in the nineteen fifties.

However, time goes by, and great ideas of the past are often left behind.

While Ducati has managed to develop its desmo system to a very high level, no other high performance engine manufacturer uses the method, because modern valve springs and pneumatic systems allow much higher rpms and higher specific output than is achieved by Ducati's desmo system.
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Backcountryme
Posted on Saturday, September 19, 2009 - 07:18 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

I don't know. The desmo is used in MotoGP and it still seems to run pretty good. Pneumatic valves are prob the future though. Springs require so much seat pressure to keep the valve from bouncing back open that the seats get beat out of them in no time. It is very hard to control valve rebound with just springs alone. I know that in our old pushrod midget engine the valves would float at about 7800 rpm. It really didn't matter how high a spring pressure you used. Now granted, that was a pushrod motor. Overhead cams help that out a ton. But I think that springs will be on the way out.
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Blake
Posted on Saturday, September 19, 2009 - 07:56 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

The 600cc IL4 engines rev to 17,000+ rpm using conventional valve springs.

I very much doubt that at 12,000 RPM the valvetrain on the 1125 is a limiting factor.

Desmo is a good system, still is, but it isn't massless. There'e plenty of mass being flung around there too and it requires HP to do so.

Much of the energy expended in compressing the valves springs is returned on the valve closing stroke. For instance, remove the cam chain and put an intake cam at full lift, now slowly try to rotate it by hand until the valve gently closes. You cannot. At some point, the spring pressure creates too much torque and snaps the valve closed no matter how hard you try to prevent it. The spring is returning the energy used to compress it, back to the engine, less of course parasitic losses (mainly friction).

As engine speeds increase that spring energy recovery effect diminishes due to dynamic/indertial effects. At the onset of valve float, the spring is chasing the cam trying to keep up and so never has a chance to return the energy to the engine.

In a Desmo system, there is no valve float, but as engine speed increased, the power required to move the lifting and closing fingers becomes just as significant as that required to compress a valve spring.

(Message edited by blake on September 19, 2009)
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Backcountryme
Posted on Saturday, September 19, 2009 - 10:36 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

I know the Demso is not massless. That would be the perfect valve train. But I doubt that the rebound of the valve spring returns any energy to the engine. As the cam spins I would think that it would be just a tick faster then the return on the spring. I do know what you are saying about trying to manually turn an engine over, but remember that the spring will act faster then you can turn the engine. I mean an engine turning at 17,000 rpm means that the cam is turning 28,000 rpm. That is quite a bit faster then you can turn an engine. I would love to see what kind of friction and mass loss comparisons there are between a Desmo and spring setup.
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Dentguy
Posted on Saturday, September 19, 2009 - 11:28 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

but as engine speed increased, the power required to move the lifting and closing fingers becomes just as significant as that required to compress a valve spring.

I don't think so. Like you Blake, I like facts. Is that just your thoughts (if so, that's fine) or do you have something to back it up? If you do I would love to read it.

Not trying to argue Desmo with you or anyone, but I am interested if someones got some proof of that.
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