BikeBoy.org -BMW K1200R

K1200R Base runs and Staintune muffler - Written Sept ‘05

The new K series bikes have generated quite a bit of interest as they are a total new design aimed far more seriously at performance. Overall they seem pretty good things, with good power and a chassis that works very well on the road. Some of the design features – like the long wheelbase – put off many people used to serious sport bikes. However, there is good method behind the apparent madness. That long wheelbase allows it to launch hard and stop with truly amazing stability and poise – with both wheels still on the ground.

Compared to the K1200S the K1200R has only one air inlet snorkel to the airbox instead of two which is supposed to cost it 5 or so hp I believe. I haven’t got to dyno our K1200S demo yet so can’t compare the two. Also, given they’re knock sensored, I’d expect fuel quality to have a definite impact on dyno results. Run a lower than ideal octane fuel and they’ll start reducing the ignition timing to stop detonation. Once that happens the dyno power would drop. I would like to run them back to back with our highest octane premium unleaded and std unleaded fuels, but that’s a bit hard to co-ordinate.

Our first demo K1200R was sold just before I got the chance to get my hands on a Staintune muffler for it, but I managed to coerce the new owner into meeting me at the dyno one Friday soon after he picked it up to give the muffler a test. Instead of removing it once the runs were done I asked him to take it for the weekend and let me know what he thought. As often happens, we had a sale on Monday. Given the price of the muffler it’s no surprise he took it – it looks good, works well and isn’t that loud, even with the baffle out. Certainly not the 4 cylinder wail I was expecting.

The graphs below show the result. Green is std, red is muffler fitted and blue is muffler fitted with removable baffle. The removable baffle really did kill the top end – the acceleration was noticeably reduced as it approached the rev limiter. Maybe it needs two outlets with baffle to work well – it is trying to flow a lot of air at 11,000 RPM. Power first, then torque and air/fuel.

Lastly I’ll compare it to a K1200RS fitted with the Staintune full system (std system is all one piece on the RS). Although the graph shows the RS has an advantage until high in the RPM range the R feels much stronger, due no doubt to the lighter engine components and lighter bike in general. Maybe gearing also plays a part here, but the R is certainly more enthusiastic than the RS, which always had a “wait for it” feel when you held it open. Green is K1200R, red is K1200RS. The RS is rev limited to just over 9,000 RPM, the R hits the limiter just on 11,000 RPM.

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