What hap­pens when you re­place ‘ that’ ex­haust?

We fit a slip-on Yoshi to find out 1

Motorcycle News (UK) - - Garage - michael.neeves@mo­tor­cy­cle­news.com

Suzuki’s new GSX-R1000R might have a new chas­sis, a swathe of elec­tronic rider aids and clever VVT mo­tor, but when it was fi­nally un­veiled, all the talk was about its hu­mungous si­lencer. It had to go and in its place I’ve fit­ted a Yoshimura Ti­ta­nium R-11sq slip-on race can (£734 www.per­for­man­ceparts-ltd. com). But to see how much dif­fer­ence it would make to per­for­mance, I first took my Suzuki to Geoff and Mark at Hill­top Mo­tor­cy­cles (www. hill­top­mo­tor­cy­cles.co.uk) to see what power it makes in stan­dard trim on their Dyna Pro ram-air dyno.

How much power does it make out of the box? 181bhp, with an im­pres­sively smooth spread of power and torque. The fuel mix­ture is ban­gon al­though on the road it’s snatchy off a closed throt­tle at low revs.

And with the can? With the 1.2kg lighter Yoshi can power in­creases to 188bhp, but the engine runs lean, los­ing a chunk of midrange. It sounds fruitier, but not too loud (96db@5500rpm on Brands Hatch’s noise me­ter with­out the baf­fle).

What about the fu­elling? The fi­nal piece of the jig­saw is to al­ter the fu­elling. Hill­top write their own maps, which they load into the stan­dard ECU. Tak­ing read­ings from Suzuki’s air­flow sen­sor the map­ping is self-learn­ing and can con­stantly change the fu­elling de­pend­ing on con­di­tions.

With the map­ping com­plete power re­mains at 188bhp, but the stock power curve and fu­elling re­turns, giv­ing you the best of both worlds: elas­tic power low down and a sear­ing top end. The throt­tle pick up has im­proved, but it still comes in too harshly es­pe­cially in low speed cor­ners in track.

What all this proves is that firstly the stan­dard can may look ugly, but it works bril­liantly. It doesn’t con­tain any Euro4 gub­bins, just clev­erly routed, si­lenc­ing tubes, so it’s not heavy, ei­ther.

Se­condly, if you’re go­ing to fit a slipon can, you may un­leash more power, but you’re likely to mess up the engine’s ev­ery­day road man­ners.

The guys at Hill­top are wizards when it comes to fine-tun­ing your bike’s fu­elling

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