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Discussion in 'Moto Bellissima: All Other Dualsports' started by young skywalker, Jan 8, 2006.
Exactly why I changed the stock can for a Mistral Carbon Oval.
OK, I just looked at the carbon Mistrals on AF1, pretty sexy!
I've always been partial to that color!
Absolutely nothing 'wrong' with the stock exhaust, except I could not hear the engine with helmet and ear plugs in, it's quite heavy and puts that weight high on the bike, puts a lot of weight/vibration stress on the collector gasket, and even with all the heat shielding -- gets quite hot due to the cat's placement...
I just wanted to see if taking the weight high off the bike, and a less muffy muffler would let me better hear what the engine was doing, run cooler, and offer any felt weight improvement as far as CG...
This was my reaction in an email to GBTW that I reposted here on the forums, that I may have inspired him and others (I take no responsibility, this is just me gushing):
Mission Scarico Completo!
Nothing could have prepared me for how my Stelvio sounds now! Seriously, I've never been impressed by 'loud', I'm still not, and I've owned far louder bikes then either that I own now... All I wanted to do was shed a few pounds high on the bike, dump the heat of the small nuclear reactor, and to be able to hear what my engine was doing in terms of torque, load, vacuum/exhaust volume, and RPM. Not only does the GPR exhaust deliver, it does so in Spades!
Now I 'get' what Moto Guzzi fan boys are talking about regarding Moto Guzzi 'character' -- the exhaust note combined with the other sounds the bike makes is literally what GPR advertises 'the perfect soundtrack to your perfect ride'; I've never heard anything like it except in movies and I thought that was was heavily edited to sound histrionic.
The exhaust song, I can't call it a 'note' because it's never the same, constantly varies depending on how you're pushing the bike, inertia pushing the engine, load, engine speed, how much or how fast you're giving it gas etc. -- and it makes some of the most beautiful engine sounds from a sorrowful sort of plaintive sound, to lusty smooth sound, a giggly sot of bubbly happy putter sound if your just donking along city streets in a high gear at low RPM, to menacing growl, and of course a balls-to-the walls snarl that's very pleasing and while not deafening or offensive, is, well... very easy to hear... And there are all kinds of emotive and colorful deceleration sounds (with nice little unexcessive stack pops unlike the XTZ that sounds like a 40mm cannon if you let inertia drive the engine too much), with the GPR Ghisa the Stelvio emits just about every vowel sound in the English alphabet.
Best (and easiest to install) exhaust I've ever had! Heat reduction because of no fucking cat of course is enormous, and while the weight savings is considerable, Moto Guzzi's Cat/Muff while sligtly less of a boat anchor then just Yamaha's separate Muff (no shit Guzzi's Muffler with Cat and all the heat shields weighs less then just the XTZ's muffler alone!). But the weight savings with the GPR Ghiza is still substantial and you can feel it immediately.
I took out the dB killer from get go, and again, the bike is NOT loud, in fact I've had complements at intersections and cars chase me to the next stop to say 'nice/cool sounding bike -- what is that?' and that was just my first little twenty minute test ride circuit to see how it behaved. Needless to say I think this is really worth owning, the weight savings, heat reduction and that it's the least expensive muff for the Stelvio made it an easy buy -- the simple installation great, and incredible voice it gives the bike was simply shocking!
No need to change the exhaust for performance reasons. Some change cans for weight savings, and to reduce heat radiation. And to enjoy some more Guzzi noise, of course.
Ok, SOLD. I just might have to wait till after my Inuvik trip, and for my wife to go off of "High alert".
Pete (if I remember correctly) says the stock can works well and is optimized for the bike and changing out to an aftermarket can will result in a few lost hp, 3-4hp, something like that. For me it's worth the savings in weight and heat and I love the sound of the Mistral. The bike still has plenty of hp for my needs as I'm not doing 1/4 mile speed tests..... well, not officially.
It's important to leave the db killer in if the bike hasn't been remapped. I didn't find any noticeable difference in performance when I put my Mistral with the db killer in.
I did however, notice the weight savings instantly.
Well in case you are curious:
I knocked it out (no longer care much how it looks but need it to work). What you see was what rattled lose inside, only one screw remained attached and that was about to fall out too! I reckon some red locktite would take care of it for another 10,000 miles?
I'm loving the sound of mine since I ripped the 'Cat out (standard Silencer).
With that and the 'Swiss-Cheesed' Airbox Cover (ditched the Rubber 'Snorkel' too), it sounds just about perfect.
Nice 'Growl' without being too obtrusive, still capable of burbling through quiet Villages without upsetting anyone.
Still pulls as strong as ever right through, maybe even a little better in the mid-range, just from the feel of it.
All this exhaust talk reminds me I need to email Elisa at GPR about mine. I sent it back over a week ago and need to make sure they got it. I had no issue communicating with the GPR people and they arranged the DHL pickup for the return and paid for it to be shipped back to them. Quick recap to save anyone who missed it, I couldn't fit the muffler onto the included mid-pipe as there wasn't enough clearance to make it work. I had paint on the inside of the muffler that seemed to be causing the issue.
Hey Drac you have your's off, is there paint inside where it fits onto the pipe?
 just got an automated reply from GPR, they are closed until the 26th so no word until at least then.
I need to update to John's map, which I have. He's designed it to work with the db killer in. Others that know say the bike needs some back pressure to run correctly. I won't run without a db killer.
No paint inside of mine. Well, no thick layer of paint that I can notice.
And when you do change the exhaust you should also get ping @Xlratr for his map or you may well loose some performance.
Cool beans! I thought it might just be a t-nut rattling around in there... Since it's all stainless all you have to do is bolt it back together, sand it a little and very lightly dust it with VHT paint and it will look better than new. Since it's stainless you could also buff the thing to a mirror or mat finish...
Maybe I actually do have allen nuts on there that have been over painted; considering OtterChaos's story I'll have a closer look tonight...
you meant bbq paint? I love that better.. thanks for point out to the VHT paint. The pipe can be completely repacked, as once the end is open can see the packing stuffed to the sides. Mine did still have some after 10,000 miles of high speed farting, so maybe it's not so horrible quality wise as I thought. Getting the end cap nicely in place was another task because it must go on perfectly straight else it wont!
Par for the course... Consider burned and expanded gas volume, heat, vibration and pressure at higher RPM that a 1200cc power plant can belch out and you can understand why exhaust gaskets and muff caps have to be pretty sung.
Nice thing about stainless muffs is they clean up so nice no matter what happens to them; you can roll and sand dents and scratches out, polish or paint them and they look brand new with very little work -- and they'll last longer then the bike they're bolted on.
Mmm. Okay. Mine runs fantastic. In fact it is way happier with the Db out.