1000DS SS ie: Base runs, Mufflers, etc

The new top end 2V Supersport model, the 1000DS dual spark engine is a fairly comprehensive update of the current 2V design, somewhat akin to the change from Desmoquattro to Testastretta. Basically, it is a mildly modified bottom end (basically the same as the 998/999 Strada bottom end) with new heads and cylinders as required. So, as well as having a capacity increase over the old 900 engine, it also has some fairly significant mods to air flow and, perhaps most importantly, cooling.

Compared to the old 900, it has more torque everywhere and, consequently, more power. The increase in torque through most for the rev range is proportional to, or better than the increase in capacity. The increase in peak power is also pretty much proportional, which surprises me. Peak power is much less dependant on capacity, based far more on how much air the inlet/heads/exhaust can flow. So being able to increase the peak power with fairly strong limitations on valve size, etc, is quite impressive. For an air cooled 1000cc 2V twin, the power is very impressive. The way it rides is also fairly impressive – I found myself relying on the brakes quite a lot more than I would expect (well, compared to the 851), due to the speed it generates very easily. The sort of thing you expect from a light bike with lots of torque I suppose.

For a full rundown on the changes made from 900 ie to 1000DS ie, check the "Comparison of 2V Models" report, but, in short, they are:

• New cylinders with revised fin design/arrangement
• 94mm bore with new pistons – up from 92mm
• New crank – 71.5mm stroke – up from 68mm
• New conrods
• Bigger valves – 45/45, up from 43/38
• Camshaft timing and lift revised
• Camshaft design revised – cam runs in machined bore in head without ball bearings like Testastretta, not interchangeable with any previous model
• Head design revised – twin spark plugs, exhaust port length reduced, header pipe cavity opened for better cooling
• Increased compression ratio
• Alloy clutch basket and plates
• Different exhaust headers to suit cylinder head re-design, diameter unchanged.

So, to the first graphs. This is the shop demo 1000DS SS ie. Green is all std. Blue is with some slip on mufflers. Red is with slip on mufflers and DP air filter kit. All runs are done with the std ECU, and no fuel changes. This shows 84 Hp std, and 89 Hp with the (not fully developed) mods. Very cool. Power first, then torque.

Now some runs for the steps taken with air/fuel mixture curves added. Again, green is std. Blue is slip on mufflers fitted with no other mods. Red is slip on mufflers and DP air filter kit with no other mods. As you can see, fitting the mufflers and even the air filter kit has pretty much no effect on the mixture – even less than on the 620. This mirrors comments Duane made after his US trip, when he said the 800SS ie responded very well to the remapping, but the 1000DS M ie didn’t feel a huge amount different. I’d probably like to see the mixture a bit richer overall for best power, but running it on the new breeds of denser, high octane/premium unleaded fuel should be ok at the high 13:1 air fuel ratio. I’m quite surprised at this, and really can’t explain why the biggest engine, with the highest demands on airflow, improves the least with open inlet and exhaust. Maybe something else is the restricting factor here – I’d like to see some tests with 45mm headers on one of these engines. That may bring even more power. The wacky lean spike at the start of the all std (green) air/fuel trace I can’t really explain. The bike certainly behaved itself and pulled strongly when the throttle was wound open at the start of the run, but the leanness is shown in all 3 "all std" runs. I didn’t notice anything in this range on the road at all.

So, unlike the 800, where I was looking for some extra fuel to find best power, the 1000DS seems quite happy as is. Maybe the dual spark plugs help here too – I’ve seen 4V go as high as 17:1 air/fuel at WOT and still make almost the same power as the correct fueling, so good combustion does help compensate for a lean mixture. With a plug on either side of the chamber, I’d expect combustion to be much more consistent and stable on this engine. Whether this also corresponds to improvements in fuel economy over the 900 we’ll have to wait and see, but I wouldn’t be surprised if it was better. The extra compression will help there too.

Next some graphs comparing the 1000DS to the superceded 900. In all graphs, red is 1000DS SS ie, green is 900SS ie.

First is power, then torque for "all std" trim. There is an approximately 20% improvement below 5,000 RPM, from a capacity increase of 9.7%. Impressive. Even with the change (raising) of gearing – std is 15/38, as compared to 15/40 on the 900 – the acceleration is noticeably better. With the 1.84 primary drive ratio all ’99 model on "big block" bikes (except 748) have, I like to use 15/42 or 15/43 (14/40 equivalent) with the wide ratio gearbox. This corresponds to 15/39 with the older 2:1 primary drive ratio.

The next two graphs show the differences with slip on mufflers and air filter kits. Here the 1000 loses some of its lower RPM advantage, but is still quite a bit stronger.

Next a torque comparison with a bike of similar capacity, but some more airflow – the 996cc ST4S. Generally, engines of the same capacity will produce a similar peak torque value at some point in their RPM ranges. However, the ST4S outdoes the 1000DS easily everywhere, making 12% more at its 7,000 RPM torque peak than the 1000DS does at its 5,700 RPM torque peak. Both bikes in this graph have air filter kits and slip on mufflers, the ST4S an Ultimap U59 ECU as well. The 1000DS is red, the ST4S green. The 1000DS’s calculated valve area, even with the 45mm inlets, is still 22% less than the ST4S, making the obvious difference. Helped by a little more compression as well, and bigger throttle bodies, bigger header pipes, you get the idea. The usual 2V- 4V thing.

That’s about the end of the 1000DS report. Good for a 1000cc air cooled 2V twin, but still somewhat behind the competing 1000cc water cooled 4V twins that it lines up against. I guess that’s been the Supersport thing since day one – less power, made up for in other areas. How that still applies depends how you look at it. Still better than a Guzzi or Buell at least (if that’s any consolation).

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