Need help to diagnostic a weird engine noise when off throttle (video)

Hello everyone 1st time GRiSO owner here. (from montreal, Canada)

After a few years looking around I have finally found a GRiSO on sale near me. 2013/2014 model, decent price for its condition.
Previous owner had the airbox drilled, ECU not flashed, Mass muffler (not installed). It has the original muffler when I test rode it and it sounded "normal" I guess.

Yesterday morning I installed the Mass muffler and was doing the pre-winter storage prep and found it's making a weird pff-pfff noise when off throttle. (see the first part of the video)

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In the afternoon the pfff-pfff sound randomly disappeared:shock:  and now I'm not sure if the engine is ticking or not.... (it's my first V2, had duke390 and cbr929, nothing sound and feel like the GRiSO, my neighbor's V-rode sounds smoother than me. so I'm not really sure what a healthy GRiSO should sound like)

What could be the cause of such symptom?
Do I need to get the valve clearance check?  

thanks

Ticking is normal for an 8V, although rollers make more of "whiff whiff" sound.

Check and adjust the valves, followed by a throttle body balance (you will need a way to reset the TPS, so get GuzziDiag if you DIY).

Oh, and get an undrilled lid for the airbox. Use duct tape to cover them until you can replace it.

A while back, I was only riding a short distance, so didn't bother putting in my ear plugs. Oh my, I thought the motor was self destructing!! These are not Hondas. They make lots of happy clanky and rattly sounds. I love it.

Trying to isolate any issues from videos is very difficult. A couple of observations though.

The top end sounds pretty normal. The valves might need adjusting so that should be tackled. Very early in the vid I noticed what might of been a hint of big end knock which would suggest that it might be a good idea to swap out the sump spacer gasket. If you do a search you will find multiple references to why this is a good idea to do anyway.

The fact it was ‘Chuffing’ when you first swapped the pipe is probably as much to do with it changing the mixture and the ecu having to trim around it than anything else. That pipe is basically identical to one I had on my 1100. Back then it was marketed as a Lavizarri and, as long as the dB killers were in it worked well. When I bought my 8V I swapped the pipe on to it and it was awful! No idea why but I swapped it straight back off and sold it with the 1100! This was long, long before mapping options were available though so nowadays that could be addressed but I never liked the way it sounded and, as with any pipe on the 8V it will run far better with a dB killer/s installed than without. The fact that the previous owner chose to drill holes in the airbox lid would indicate that they may well of believed that ‘Freeing up the breathing’ and ‘Uncorking the exhaust’ would miraculously free up some secret, hidden horsepower that had been ‘Stolen’ by government regulation. This isn’t the case.

Check the airbox drains are intact, attached and plugged, if it has a ‘Reusable’ air filter? Junk it and go back to a paper one. Read up on how to tune a W5AM Guzzi and don’t touch the throttlebodies until you understand what you are doing!

Then you’ll need to do’s the greasing of the swingarm bearings and shock linkages and you should be pretty much set.

A decent tune-up and a good map will greatly increase the enjoyment of the machine but don’t expect huge power increases. Just a much greater flexibility and driveability. While you’re poking around look out for any aftermarket widgets connected to the engine sensors as well and be prepared to have to take them off. All of them are useless if not harmful and do nothing for performance.