Dyno Figures -- SB6R

[dnovo]

One subject of interest to most riders -- or at least to this rider -- is actual horsepower versus builder claims. And, to coin a phrase, builders' claims are not the same as what shows up on a dyno, and power figures at the crank are not as important as where the real result show up, at the rear wheel, where the power meets the road and the real work gets done.

My SB6R, recently acquired and dead stock, was delivered to my local dealer for general clean up and tune up. The bike hadn't been used much before my purchase from the second owner, and while in good shape, the carbs were gunked up beyond belief (the pilot jets almost filled up) and I decided to ask one of the mechanics to tear them apart, rebuild and replace as needed, and then set the bike and the jetting up on a dyno.

The dealer (Corse Superbikes in Saukville, WI, just North of Milwaukee) was formed, in part, from the former Bimota dealer in Wisconsin. They are a Suzuki dealer as well and the mechanic who worked on the SB6R, TJ, is an ex-Bimota wrench. The result of the work on a dyno and by a tech who knows both Bimota and Suzuki? The bike started out after the intial work at 124 HP at the rear wheel. After a lot of tuning and rejetting, the stock Suzuki 1100 engine (Bimota only changed the airbox, and exhaust and played with the carbs a bit) ended up at with a reading of 136 HP at the rear wheel.

That is about what I have seen at the rear wheel of some current bikes, especially the Ducati 1098S. Not bad for a decade old design and an engine a bit older than that.

When I get some miles on my DB5 and my SB8R, they will go up to Corse for the same procedures, although no carb rebuild on these fi motors. Since Corse and TJ work on both powerplants (Ducati 1000DS and Suzuki TL1000) I hope to report back with some real world figures in the near future.

Dave

[ZAWA]

Sounds like you got a screamer, It always amazing how bikes age when they just sit. Look forward to you getting the SB8R on the Dyno.

[dnovo]

Finally got a photo of the actual Dyno run. The curve is not as abrupt as I expected, and now that I have ridden the bike, the dyno run mirrors the feel, smooth, ever-increasing power, not 'pits' and all in all, one very powerful motor and bike.

Also please note, I was given a conservative reading, the actual print out was 136.82. Happy, happy, joy, joy. Dave

[dnovo]

Re-reading Alan Cathcart's test of the SB6R, his comments regarding the improvements Bimota built in to the newer version after their initial effort with the SB6 mirror my own observations posted yesterday based on both my seat-of-the-pants impressions and the dyno sheet:

"The biggest improvement we have made on the SB6R is in the airflow to the carbs , Marconi explained . First we increased the size of the fully sealed airbox , and optimised the inlet flow through new intakes above the new bigger radiator in the revised bodywork . But most the most important change as to pressurise the float chambers of the carburettors to the same level as the airbox . Why ? because this delivers a better flow of fuel , which Is already primed for mixture with the incoming air , and allows us to run 10 % bigger main jets , as well as obtaining - well yes , the same throttle response as a fuel injected bike .With no other mechanical changes , apart from a new exhaust system with a shorter collector and revised silencers , we have significantly improved midrange performance , and have a 5 % more maximum horsepower at peak revs - up from 138 bhp at the back wheel on the old SB6 , to 145 bhp on the new bike . We also have a substantial increase in top speed , in homologation tests the bike was trapped at 292 kph (181.04 mph) , but that was only on a 2 km (1.24 miles) airport runway , with insufficient room to accelerate an stop to best effect .I am convinced we can beat the Honda CBR1100xx's 303 kph top speed in magazine tests with this bike on a banked track like Fiat's Nardo test venue in southern Italy , and will be trying to prove that the SB6R is the fastest production street bike in the world there sometime next spring when the weather warms up .Absolute top speed is pretty irrelevant in real world riding , though , unless you live in Germany and even then only on Sunday mornings on the right stretch of autobahn . But much more important is the vastly improved pick up from low revs at pert throttle openings that the SB6R's new induction system delivers , as well as the midrange response while hard on the gas at higher speeds .Through the various chassis changes only reduce dry weight by 2.2. pounds from before to 418 pounds , the R model really does accelerate more crisply and eagerly than before - and considering the old SB6 had every right to wear the crown of undisputed speed king of the streets , before the CBR1100xx came along , that is rally saying something .
But , whereas before you had to get the Suzuki motor wound up above 7000 rpm to really get going when combined with the bimota exhaust and induction system , now it really starts to motor more than two grand lower - and it is more crisp and responsive in doing so . The SB6's rather soggy midrange has now been filled in , which makes the R bike more rewarding to ride because you do not have to use the five speed gearbox so much . It also makes the changes to the running gear quite welcome ."

The changes he describes as what they were looking for seem to have been realized, as least as far as my impressions of my newly acquired and newly-tuned SB6R and my memories of my former SB6. However, Marconi and my dealer's dyno disagree as to rear wheel horsepower figures, of course he may have been referring to those smaller Italian horses, well known not only in the motorcycle field but in the automotive realm as well Dave

[TonyTuzz]

I used to race a GSXR750 with that 1100 motor in it. It had 41mm flatslides, open velocity stacks, degreed cams, and a full exhaust. The most we ever saw out of it was 135 at the rear wheel.

[dnovo]

I suspect Bimota changed cams was well as carbs on the SB6R. In addition, when I pulled the bodywork to look at the exhaust routing, etc and then reviewed a bunch of Euro tests and comments on this model, there appears to be some serious work done on at least some of the SB6R engines by Bimota. The bottom line is that Bimota went all out to produce an extremely strong engine. So, God knows what else they did to it, and I'm not about to tear it down and try to find out.

Is the dealer's dyno off? Hard to say, but the dyno figures seem to match up with performance as the SB6R is a heavier bike than the 1098 (which has about the same stock rear wheel horsepower as I understand it speaking to some of the dealer's techs) but had little trouble staying with a well ridden 1098 this weekend. Since the weight is closer to that of my 999S, and it appears to be a tad faster, I'd say the 136.82 on the dyno is a real world number, and one I am very happy with, especially as it is delivered quite smoothly.

My current Bimota dealer (Bob at Bimota Spirit) told me that the factory test rider, Gianluca, said the SB6R was consistently the best performing Bimota -- period. Since he rode virtually everything they built, I'd consider him to be 'the horse.' Dave

[dnovo]

Attached is a dyno run someone else posted at the Superbike portion of this forum, showing the 1098 vs an MV 1000. Note that the 1098 (blue line on the chart below) has a tad LESS power (and I presume that this is rear wheel as well) than my SB6R. Since it gives up a bit less than 100cc, and is a decade or so older in design, I think that we can safely say that Bimota did a LOT of fiddling with the supposedly 'stock' Suzuki 1100 --- bless their hearts The Bimota power curve also looks a bit more smooth and progressive than either the Ducati or the MV, something I found riding my own MV F41000R and a friend's 1098S. Bimota clearly took the time to iron out the flat spots noted in the earlier SB6 and contemporary GSX1100Rs, aided in part by TJ when he retuned and rejetted this bike. No wonder this bike is so damn much fun to ride. A keeper for sure. Dave

[TonyTuzz]

I vaguely remember looking into the SB6R tweaks to see if any could be used on my racebike. Interestingly, the Bimota spec was very close to stock euro-spec Suzuki. In the US we got a strangled version (of the GSXR1100) with 36mm carbs that were smaller than the 750 at the time, which were 38mm. The euro gixxer got 40mm cv's, which is what your Bimota should have, as well as a euro ignition box that eliminates timing retard in lower gears that we got in the US.

It's a great motor, with gobs of smooth power. It just needed to be unshackled and stuck in a great chassis like your Bimota. Cheers!

[dnovo]

Originally Posted by TonyTuzz

It's a great motor, with gobs of smooth power. It just needed to be unshackled and stuck in a great chassis like your Bimota. Cheers!

Thanks . The motor sure found the right chassis in the SB6r. Dave