'12 Griso throttle response like a hi/low switch

[starford]

'12 Griso is my garage queen. I bought it new and keep it safe in the garage most of the time but now it has 700 miles and I had the first service done.

TL;DR: why does the Griso have a crazy throttle response at 4k and what can I do to fix it?

Since the beginning, the Griso has had a weird throttle response, with the first few thousand RPMs being like a ordinary bike, pulls fine but nothing special. As soon as I hit 4k RPMs, the whole engine lights up and it's like a different engine, full of pep and pull. 4k RPMs is like hitting a hi/low switch in the engine.

I asked the mechanic who did the service what that is and if there are any ECU updates from Guzzi for this. He said he checks and zero maps were available from the factory but this behavior was probably due more to a vacuum leak or low fuel pump pressure or some other issue, which he'd be happy to look for if I'd pay the shop time.

Granted, this bike is a 5 yr old, low use garage bike that I keep dry most of the time but not all of the time. Maybe there's been an issue since delivery (bought this bike new out of the crate, no sitting). I think I've read here somewhere that the early fuel maps for these big block twins were terrible and fixes have been published since then.

Or, can I just throw a Power Commander and it and call it good?

 

[Trout]

Contact Todd thru this forum & he can make it right.
I have a 2013 Grizz with his fuel mods & well...it's a thrill to ride.
Smooth from idle to red line.

Power Commander with Auto Tune & Todd's maps = more fun.
Just putting a Pwr Cmndr on won't fix the issue.

Just noticed yours is a 2012 so you may want to run the VIN number to see if it is the old flat tappet motor.
If it is you'll want to fix that first.

 

[starford]

I thought that's what people would say, do the GuzziTech fueling mods and be good. What I'm questioning is: is it systemic. Are all bikes from the era like this?

Also, I ran my VIN at the Piaggio site and came up with a connecting rod recall but nothing to do with tappets. Is there a source for the tappet recall other than the factory's web site to look up eligability?

 

[john zibell]

I thought that's what people would say, do the GuzziTech fueling mods and be good. What I'm questioning is: is it systemic. Are all bikes fro the era like this?

Also, I ran my VIN at the Piaggio site and came up with a connecting rod recall but nothing to do with tappets. Is there a source for the tappet recall other than the factory's web site to look up eligibility?

Guzzi didn't issue a recall on the flat tappets. If your dealer inspects the tappets and find wear, Guzzi will provide the kit for the conversion, but you may be on the hook for the labor charge. Probably a good idea to get the recall done as well. It might cover some of the labor to perform the conversion.

 

[Trout]

Yes it is systemic to almost all new bikes because of EPA & Euro emission regulations.

The most common complaint on the Griso's was the low speed, in town drive ability.
The "snatchy" throttle that made it less than fun to ride in parking lots or neighbor hoods.
It's from a very lean fuel mixture to pass regulations but it can be corrected.

RE: The flat tappets.
The problem you will run into with warranty is the fact the you have such low mileage.
With only 700 miles the tappets are not likely to show signs of wear & that seems to be the criteria that Guzzi goes by.

You know I just re-read your post & what I'm talking about is not the problem you are describing.
Sorry if I was confusing the issue, I'm getting older & sometimes the brain doesn't work so well.

It seems like you are describing hitting the power band.
4000 would be a little soon for it. Most of my newer Guzzi's seem to come in around 5000 then go like crazy to red line/speed limiter.
Hopefully some one else will comment on this.

 

[starford]

Yeah, drivability and powerband are the right terms. Anything under 3k RPM is pretty awful and I want to downshift to get away from it. Above 4k, right at that point, engine runs like a different beast, almost a shock at how much better it is, to the point of being a little scary.

Reason I'm asking is the mechanic at the Guzzi dealer (RPM in Dallas) seemed adamant that there was a mechanical issue leading to this behavior (maybe fuel pressure, air leak, cracked fuel line, dunno) and I'm pretty sure it's the nature of the beast. BTW, the dealer charged 4 hours of labor on that 1st service, which I felt was pretty high for oil, filter and finding TDC a few times to set the valves. But, whatever. I suspect they see all of three Guzzis a month in that shop.

On the tappets, yeah, that's what I read as well. Gotta get a few more miles on then see what's what in there and make my case to the shop for an upgrade. Also have the connecting rod recall (not noted by the dealer when I was there this week, an oversight?) so an excuse to go back again.

 

[GTM®]

Reason I'm asking is the mechanic at the Guzzi dealer (RPM in Dallas) seemed adamant that there was a mechanical issue leading to this behavior (maybe fuel pressure, air leak, cracked fuel line, dunno) and I'm pretty sure it's the nature of the beast.

You are correct, and they are wasting their time and showing their lack of knowledge. Well documented here on the running issue, try a search. I have the fix for it that Guzzi can't do, click HERE -- Proven over 16+ years now.

 

[kiwi dave]

Also, I ran my VIN at the Piaggio site and came up with a connecting rod recall but nothing to do with tappets. Is there a source for the tappet recall other than the factory's web site to look up eligability?

It's not associated with the VIN but instead the engine number of A813524 Build Date 12 April 2012. All engines after this number are supposed to have rollers already installed.

 

[Clayton Sietsema]

Starford, do you ever get to Oklahoma? If you do feel free to ride my Griso and see if it's any different that yours.
I don't have Todd's full fuel mods but I do have one of his Tunes in it, along with his open air box mod and some sweet exhaust that is came with.

 

[starford]

Ordered and installed the full fueling kit from Todd here on GT. Big shout out to Todd for being really timely in his replies to questions and getting me the supplies. Thanks!

Some thoughts on installation from having just done this work:

-It's not very difficult to do mechanically as long as you have standard mechanics tools
- The electrical isn't a lot of fun, digging out connectors and posi-tapping wires. There's not a lot of guidance on exactly which wires go where.
- The cables were too short by about a foot to place the PC-V and AT200 behind the air box.

- The series of events to do this wasn't real clear as instructions are in two places. This is the order I followed:
--- Use scan tool (touchscreen) on bike before touching anything else. The socket you want in under the seat tucked in by the frame and air box. DL the factory map and mail it in.
--- Disassemble the valve cover body panels, battery & box and the little block wiring cover at the tail where the seat locks in
--- Don't remove the air box cover unless you have to- save some future pain
--- Route the injector cables left and right, connect them to the existing and route the now-loose injector cable back away from the cylinder. You'll have some extra wire to deal with now so don't let it rest on a cylinder or get into a throttle linkage.
--- The AT200 has to be powered from somewhere (the PC-V needs only separate ground). I tapped both pwr and ground from the tail wires (two wire connector with yellow (positive) and blue (ground)). There's no better grounding point under the seat than the battery itself.
--- The AT200 will power on with a green light when ignition is turned on. The PC-V will NOT, just do some blinking then nothing until engine is running.
--- The new O2 sensor's connector is huge compared to original and has to fit under the plastic starter shield, Route cable accordingly.

- After this is all done but before re-assembly, write the new map to the bike with the scan tool (touchscreen). The PC-V already has a map in it so nothing to do there. A smallish Windows 7 (or newer) laptop is really handy during this process; you have two different apps to use that are Windows only.
-Power up the bike and let it warm up. With laptop attached to PC-V, reset the throttle sensor and stab the throttle to set the values.

Impressions from the upgrade:

- It exorcised the main sin I wanted it to: the crazy 4K power band behavior. It's just simply gone and all RPMs work like you'd expect them too, with linear power and torque.
- 3K RPM is now usable and not so bogged that you have to rev over it
- Warm-up is faster; idle is smoother and less labored
- A little less heat? Certainly less under load than before.
- Pipes a little louder? Maybe just a bit.

There's no magic super bike hiding inside this one; it's the Griso I know, just so much better behaved. Thanks for a solid upgrade!