Brutale 750 Eprom Development and Casoli Midpipe - Written 11/05
The Brutale is a very cool little bike certainly fun to ride with a real manic intake note as the revs rise and the ability to make me forget (on many occasions) that I should move the gear lever tip. By the time I’d get off I’d forgotten all about that. You can see why the people who ride them like them so much.
One issue we’ve had with them, however, is that they use a lot of fuel. The first time I rode one, a bike we borrowed for a few hours from Feeney’s (the Australian importer) when Hunnybunny and I were on our honeymoon (note to self do not put new bride on back of Brutale for 4 hours and expect her to be happy). It ran quite nicely and did everything it should, but I was told not expect too much in the way of fuel range.
So I decided I should have a play with one. At one point we had quite a few in boxes so we demo’d a couple of them, but as usual when they’d clocked up enough km for me to play they’d get sold. So in the end I had to use a customer’s bike. This bike had a Casoli midpipe fitted to the exhaust. This eliminates the central box which has pipe work inside it to lengthen the system (I assume that’s the reason anyway) - it’s not a catalytic convertor.
First I refitted the std exhaust box, carried out our TPS reset procedure as someone else had played with it (it had a Techlusion box fitted when I got to it) and got stuck in. I figured the fuel economy thing may have had something to do with the spark map, but I was also quite surprised by how rich it was overall. Playing with both of them gave me what I wanted. Realistically I didn’t expect it to make any more power, and on the dyno it doesn’t, as the WOT mixture was pretty good as was. What I was after was overall smoothness and fuel economy. Some people seem to think they can’t have fuel economy and good power at the same time, but that’s not true. It’s all about the mixture being right across the load/RPM range, and with digital control as this fuel injection is it’s easy to achieve.
Once I had what I wanted with the original setup I refitted the owner’s Casoli midpipe and tuned it for that. Generally, once you have a base map you’re happy with any mods from there are much easier to tune to. The owner had told me that Casoli midpipe had made quite a bit of difference to how the bike felt, but the dyno didn’t reflect that. The graph is a spreadsheet generated graph as I had to combine a few runs for each combo to get the ‘fuel for max power’ curves it’s much less time consuming to just do a series of +/- fuel runs and work it out later from there. Green is all std with fuel and spark advance set for max power, red is Casoli midpipe fitted, again with fuel and spark advance set for max power.
I was surprised with the Brutales power output, as I thought it had been retuned for midrange (the usual naked bike curse). They do run different cams, but maybe they’re just better ones. The next graph compares this Brutale with a couple of std F4. Brutale is green, F4 red and blue. Retuned for midrange yes (even with the shorter exhaust length), but with the same top end. Although the F4 does feel stronger as you get up toward the rev limiter, which is something you often get with bigger cams even if the dyno doesn’t really show it.
From the feedback we’ve received so far it appears our eprom has made the bike a little smoother overall, more responsive in the lower RPM range with quite a bit better fuel economy and much the same power output. Which is just as I expected and was as much as I could hope for, given the std eproms mapping. Owners have reported an increase in range of around 60 km per tank of fuel, going from 190ish originally to 250ish with the eprom fitted. Which pleases me greatly as (for some reason) I always get paranoid when I remap a bike, especially when it takes some time to get feedback. The eprom numbers are MVB01 for all std Brutale and MVB02 for Casoli midpipe.
The report “Weber Marelli Throttle Position Sensor Setting Notes and Procedures with photos for MV” is a detailed TPS setting procedure with lots of general information and some specific to the Brutale. Fitting our eprom requires this basic setup to be carried out correctly to get the most from it.