Sorting my GRiSO Exhaust.

Carlotto Posts : 36 Join date : 2022-01-22

Recently bought an 07 GRiSO. I had a 2v Sport 1200, but the GRiSO itch never went away. Found this beauty and I love it. For me, the riding position and style are better than the 1200, although the 1200 engine felt smoother. Anyway…

On the GRiSO, the exhaust smells gasey at times, and I wonder if the engine could be a bit more smooth and crisp. I’m mostly certain it’s never been remapped, which is something I plan to do. (Mark helped me out with my V7 and Sport 1200)

The bike has a wide open GPR can, and I wonder if I should add a DB killer. It sounds great but is a bit loud for my tastes…but boy when I roll it up it does make me smile. I know there’s a map to work with an open can, but I’ve read that maybe more restriction has a better outcome in the long run for smoothness?

I could add a generic DB killer that I have, but worry that that’s just pure guess work. Do I remove the little cap on the end, add more holes around the outlet, etc. Maybe I should start with a new slip on that is more appropriate? I plan to balance the TB’s, but wanted to start with the exhaust before I remapped it.

Thoughts? Thanks in advance!

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GRiSO Capo Posts : 10704 Join date : 2013-05-29 Age : 67

Start by giving it a full tune. Valves, throttlebody balance, after the balance reset the TPS and clear the trims. No point in screwing about with anything unless the tune is correct first.

Grignapoco Posts : 118 Join date : 2022-09-19 Age : 57

GPR cans are known to have 2 db-killers: one at the end of the connecting pipe and one at the end of the silencer itself. They obviously are such a cheap design they can´t get them legal without that "double-trick". With both silencers out they become obnoxiously loud, so I´d guess that you go with the inner one.
I heard my Agostini once without baffle: nice and throaty, but definitely too loud. The baffle went back in immediately, as I prefer to ride fast but stay under the sound-barrier instead of notifying every cop around that I´m approaching and make neighbours throw their piss-pots at me ...

GRiSO Capo Posts : 10704 Join date : 2013-05-29 Age : 67

el capitan wrote:: but stay under the sound-barrier instead of notifying every cop around that I´m approaching and make neighbours throw their piss-pots at me ...

This x 1,000! cheers

Carlotto Posts : 36 Join date : 2022-01-22

Pete Roper wrote:: Start by giving it a full tune. Valves, throttlebody balance, after the balance reset the TPS and clear the trims. No point in screwing about with anything unless the tune is correct first.

Agreed. I hope to dig in today on the valves, and then the TB balance.

Carlotto Posts : 36 Join date : 2022-01-22

el capitan wrote:: GPR cans are known to have 2 db-killers: one at the end of the connecting pipe and one at the end of the silencer itself. They obviously are such a cheap design they can´t get them legal without that "double-trick". With both silencers out they become obnoxiously loud, so I´d guess that you go with the inner one.
I heard my Agostini once without baffle: nice and throaty, but definitely too loud. The baffle went back in immediately, as I prefer to ride fast but stay under the sound-barrier instead of notifying every cop around that I´m approaching and make neighbours throw their piss-pots at me ...

Appreciate the info as I know little about the GPR stuff. I pulled the can today, and it's clear all through, so no DB killers. I wonder if I was to experiment, if I would start with the tail end of the can with some generic DB killer. (as pictured above).

There's a QD slip on for sale in the classifieds and I wonder if that would be a better starting point? (although my CAN money gets killed in the conversion Sad

) And I agree about being too loud. It's sounds cool, but hard to live with.

Does my bike have a cat? Somewhere in the 2-1 or the loop with the sensor?

Thanks!

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Grignapoco Posts : 118 Join date : 2022-09-19 Age : 57

The QD in the classifieds is in Germany - once you get it across the pond you could´ve bought a new one locally ... And yes, your GPR-"silencer" sure has no db-eater or cat inside.

Squinternotto Posts : 2 Join date : 2023-06-08

el capitan wrote:: The QD in the classifieds is in Germany - once you get it across the pond you could´ve bought a new one locally ... And yes, your GPR-"silencer" sure has no db-eater or cat inside.

Are Quat-D exhausts still in production? Never seen one on a GRiSO, only on V11s and (imho) those look weird without the double silencers.

Grignapoco Posts : 118 Join date : 2022-09-19 Age : 57

Yep, [You must be registered and logged in to see this link.] even your model is still available for 644,98 Euro new: [You must be registered and logged in to see this link.]

And this db-eater for oval exhaust cans, albeit for Mistral mufflers: [You must be registered and logged in to see this link.]

But try your made-in-China db-eater first, it could possibly sufficently tone down the volume while still sounding good. Our 2-valve-engines seem to be far less critical when it comes to tune/exhaust/airbox-combos. The 1200 guys are worse off in this respect.
If anything changes at all I´d suspect gains in driveability and low-down torque with the db-eater installed.

Carlotto Posts : 36 Join date : 2022-01-22

Pete Roper wrote:: Start by giving it a full tune. Valves, throttlebody balance, after the balance reset the TPS and clear the trims. No point in screwing about with anything unless the tune is correct first.

I set the valves, changed all 4 plugs, and did the TB balance. The TBs were out 4 cmHg as measured on my Carbtune @ 3500 rpm, which seems significant. I could tell from the yellow paint that the bike had never had a TB sync. (it has 30k kms)

I reset the auto learning, and the TPS came in at 4.6. I had to go find an older version of GuzziDiag to work on my MBA, and I couldn't find "TPS reset", but maybe it's always been called auto learning? (I forget what I did on my Sport 1200)

The bike runs a smidgen smoother in the midrange, but still has the tiniest of a surging at cruise just above 3k.

And I still wish it was a tad smoother. I wonder if a new map would run smoother, even on an open exhaust? My only experience was my Sport 1200 which was a bit smoother, but I've read that that's a common sentiment between the 2v 1100 and the 2v 1200.

Thanks.

GRiSO Capo Posts : 10198 Join date : 2013-09-30

No, there is definitely a TPS reset actor. The autolearning reset only clears the fuel trims.

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In GRiSO we trust!
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Carlotto Posts : 36 Join date : 2022-01-22

beetle wrote:: No, there is definitely a TPS reset actor. The autolearning reset only clears the fuel trims.

Can't believe I didn't see it. Went back and reset the TPS.

Thank you!

GRiSO Capo Posts : 10198 Join date : 2013-09-30

Oh, and I don't put Marshmallows in my maps. Very Happy

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In GRiSO we trust!
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Carlotto Posts : 36 Join date : 2022-01-22

beetle wrote:: Oh, and I don't put Marshmallows in my maps.

Ah yes, sorry, didn't mean to suggest your maps had marshmellows... Embarassed

I moreso wondered if maybe a wide open GPR exhaust was not the best path to great results...other than annoying the neighbourhood—and my own ears. Smile

I've used your maps in my V7 and Sport 1200 with great success!

GRiSO Capo Posts : 10198 Join date : 2013-09-30

Well, you probably know my thoughts on wide open pipes.

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In GRiSO we trust!
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GRiSO Capo Posts : 10704 Join date : 2013-05-29 Age : 67

And if you want me to go off like a frog in a sock you can ask me about noisy exhausts as well! cheers

Carlotto Posts : 33 Join date : 2020-07-26

Nice bike!!

Sfregiato Posts : 410 Join date : 2021-08-19

[quote=Are Quat-D exhausts still in production? Never seen one on a GRiSO, only on V11s and (imho) those look weird without the double silencers. [/quote]

Hi Nocheiner,
I have a QD and I'm happy with it. They come with a DBKiller, a small Cat on the can inlet, and an homologation certificate for Europe
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Don Abbondio Posts : 52 Join date : 2017-05-22 Age : 54

Matias wrote:: [quote=Are Quat-D exhausts still in production? Never seen one on a GRiSO, only on V11s and (imho) those look weird without the double silencers.

Hi Nocheiner,
I have a QD and I'm happy with it. They come with a DBKiller, a small Cat on the can inlet, and an homologation certificate for Europe
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That looks nice, but is it quiet? I love the look of smaller cans, i think the stock one looks way to bulky. But I have kept it out of fear that what i like appearance wise will be way to loud or will mess up the map. The latter i am not as worried about as i am sure bettle probably has a map he would happily sell me that will get things back to normal.

Sfregiato Posts : 410 Join date : 2021-08-19

Hi,
With the db-killer on it is quiet and has a nice sound. QD sells this can with an homologation certificate.
It runs perfectly with the map beetle has created for the stock exhaust.
I have already tried it without the db-killer. It's a bit louder, but not to agressive

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