Termignoni - pop & crackle?

[Brent S]

Hi all.

Just back from a 3 day ride through the mountains on my '14 Griso. The bike has a Termi pipe which I had fitted with the 1st service. It has the baffle left in, given I had read plenty of stories about how important it is to have the correct resistance in the pipes for the 4 v engine.

Now, I have a dilemma. The pipe sounds awesome under power and when cruising, but under a trailing throttle, it sounds like a WW2 Spitfire fighter. It pops crackles and basically makes quite a racket. It's particularly noticeable when engine braking on a downhill run into a corner. The bike has zero mods. Factory map. Valves were adjusted on 1st service. A bit of surging evident at around 3,500rpm. I use 98 octane fuel.

So, is the pop and crackle normal with a Termi, or is my bike poorly tuned? Is the factory map able to accommodate? Any help greatly appreciated.

Brent.

 

[GTM®]

Brent, first congrats on your '14 G8V, great bike. Hope you'll add your info to the Registry page here.
So your question is well answered here, try a search. It has nothing to do with resistance, and everything to do with über-lean fueling forced on the factory by Euro and US emission regs.
No factory mapping will help you. You'll need to spend some more money to fix it properly. You likely have been through the days of carbs when you wouldn't have imagined not re-jetting the carbs after putting an exhaust on, this is no different.
I have many options from affordable plug-ins up to a fully dynamic kit shown here; https://www.guzzitech.com/store/category/fueling/?filtering=1&filter_model=74
You've spent a great deal of money on the bike and muffler, just takes a bit more to give you an amazing bike with cooler running and great throttle response, and no closed throttle fireworks.

 

[Brent S]

Todd, thanks very much for your informative reply. I actually did a fair amount of research before choosing the termi, and this site was one of the most useful for info, so thank you. However, most of the info I found related to the need to retain the baffle, and in doing so, I was under the assumption that the Termi would run faultlessly on the Griso. This is where I feel a little disappointed to be honest. The pipe even has the Moto Guzzi logo on it, so It's reasonable to expect that it operates in an acceptable manner. Under power it's great. At cruise, great. It's just the decel that's bad to the point of being annoying.

Being a brand new bike, I know that whilst there may be some good products out there in terms of plug-ins etc, I also know that my warranty will be toast the second I start playing with the factory fueling system, so that's a problem. Also, you mention that it's probably the lean mixture causing this issue, so is this potentially harmful to the engine? The last thing I want to do is harm the engine for the sake of the exhaust note. Hell, I'll put the old muffler back on if I need to, and tell the dealer he can have his Termi back....... Am I risking damage?

I'm based in Australia (Melbourne) so if you know anyone here who you trust or who you could refer me to for advice, please feel free to PM me if preferred. Any assistance greatly appreciated.

PS. I'm consistently getting around 200kms (125 miles) out of a tank of fuel, prior to the light coming on. Not sure if that assists in terms of understanding the lean vs rich fueling.

Brent.

 

[Brent S]

Update on the above.......I may have found the culprit. I've noticed a leak in the exhaust, where the header pipes join a crossover pipe, down roughly in front of the gear shift. At idle I can actually feel a pulsing of air around the gasket. On both pipes. Is this possibly causing the crackling and popping on the overrun?

I had an extra close look because it was nowhere near as bad when I first had the Termi fitted. Seems to have got worse, and it would explain things if the pipes are progressively loosening in their gaskets at the crossover. Do you think this is the main cause??? Thanks.

 

[GuzziMoto]

While I understand where Todd is coming from, it should not run bad with that pipe and the fueling left stock.
An air leak could definitely causing the popping and it could also contribute to poor fueling as it could cause the O2 sensor to read wrong.
Once you correct the issues you may find it runs well enough as is. You may find that you still want more and there are a few ways to adjust the fueling to make it run better. I have Todds full kit on my older Griso 1100 and like what it does.
But I would first fix things so you are not trying to compensate with the fueling for physical problems with the bike.

 

[GTM®]

Yes, clearly an exhaust leak would cause an issue like you describe. Fix that and let us know how it goes.

 

[Brent S]

Ok, an update. Bike back from the dealer. Poorly threaded bolt that clamps the crossover onto the header pipes was apparently the issue. All tightened up now, and I can't seem to feel any air leaks now around the gasket. Riding home, no issues for the first 30 mins or so, but sure enough, the odd pop and crackle starts again. It's a warmish day today (about 30 degrees celsius) and It seems that the pipe only starts this behaviour when it's hot, for example, a long ride on a hot day. Start it up in the morning and it's fine.

So, in a nutshell, I'm at a bit of a loss as to the next step. Perhaps it is just the fueling combined with a warmer climate. Dunno.

For clarity, the problem noise isn't the normal burble you get on the overrun. That bits ok. It's a higher frequency pop which is quite a sharp noise. Think of hitting a tin can with a thin metal rod. Perhaps this is just the price I have to pay for the Termi pipe with the stock mapping.

Brent.

 

[GTM®]

Perhaps this is just the price I have to pay for the Termi pipe with the stock mapping.

Yes it sure is. Warmer weather causes leaner running per the factory mapping. Both my slip-ons and full systems with the fueling kit produces zero pop-on-decel and offer some of the most incredibly crisp throttle response one can imagine.
Edit: Long shot, but you might want to look at the stock Y-pipe connector around the support bracket for cracks as well.

 

[Brent S]

Thanks Todd. I'm not against the idea of throwing some money at the bike with ECU tuning etc, but whilst the bike is in its warranty period, this can make things a little awkward. I have to admit a degree of disappointment though that the Termi has these traits when it's listed as an 'approved' Guzzi option as such.

I'll do some more research because I'm not exactly knowledgeable on things like ECU reflash vs plug ins etc.

Regards,
Brent.

 

[GuzziMoto]

I have owned bikes that popped on decel stock. It may annoy you, but it is not in and of itself, something that will cause problems.
Personally, I actually like a little pop on decel. But I have owned some bikes with certain pipes that caused too much pop on decel.
If I were you, the first thing I would do is have the bike properly set up to make sure you are not trying to bandaid something that is a result of poor set up. Do not assume that because the bike came from the factory the way it is that it is properly set up. Nor should you assume that your dealer has done this or even knows how to do this. Read up on set up and talk to your dealer.
Once you are confident it is as good as it gets you can then decide if you need it to be better than stock. I went around on that with my dealer a few times, then I bought the kit from Todd. I have been happy ever since.

 

[Brent S]

GuzziMoto, thanks for your advice. However, at the risk of sounding like a total novice, what do you mean by "properly set up"? The bike is new. Its had its first service. The valves have been adjusted, and the throttle bodies balanced (supposedly). The exhaust leak around the crossover pipe has been fixed. In all honesty, I'm not sure what else I'm supposed to do in terms of the issue at hand.

Could the throttle position sensor be the issue???

Whilst I like bikes & cars etc, I'm not a mechanic. That's what I pay my dealer to do. Granted, if I wanted an ECU reflash, or a different rear spring or other after-market mods, I'd research further afield, because I wouldn't expect my dealer to be assisting me every step of the way with aftermarket stuff that has no factory certification. However, aside from sliding the termi slip-on onto the bike and doing up the clamps, I don't really know what else there is to "set up" as such for what is a factory-approved accessory.

Unfortunately there's not a wealth of other Grisos getting around with Termi pipes on in Australia at the moment, so its difficult for me to compare my bike to others to see if the problem is specific to mine, or more general. I'll keep researching in the meantime.

 

[GuzziMoto]

Proper set up refers to the basic set up of the motor. The throttle body balance (Guzzi's due to their odd layout, are trickier to do this right than most other motorbikes), TPS setting, valve clearance, all that fun stuff and more, needs to be done right in order for a modern FI Guzzi to run right. It often is not done quite right from the factory. If you don't want to get involved in all that, having your dealer do that for you is fine. But don't assume your dealer knows how to do all that right. I am not saying they don't, just that have been more than a few reports of dealers not knowing how to do those basic things. In some cases dealers have even messed things up and made them worse by doing things they should not have done, like adjusting the "sacred screw" (search here if you don't know what that is).
Again, not saying your dealer doesn't know, just saying don't assume they do.

As Todd mentioned earlier, Guzzi's are set up with fueling from the factory that is a compromise between emissions and running. Guzzi are not the only ones in this boat, pretty much all manufacturers are in the same boat. Other brands may have more resources to come up with better compromises, but when you have emissions standards to meet it tends to mean fueling is not what it needs to be for perfect running. There are a few options out there to adjust fueling. Much of it depends on you and your standards for how you expect a motorcycle to run. One person might think a bike fuels perfectly fine and someone else might ride the same bike and complain that it runs horribly. It also comes down to what you know and don't know, as they say "what you don't know can't hurt you". I am very happy with Todds kit on my Griso. It is an older 2 valve version, and I was pretty happy with the way it was stock. But I knew it could be better as my previous motorcycle fueled amazingly well. So I bought a pipe and fueling kit from Todd and all has been great since.

A simple and easy check would be to swap back to the stock pipe and confirm that it runs right in that configuration.
Termi's are a very common pipe for the Griso as it is what Guzzi sell as factory approved. There are more than a few around. Perhaps others with that set up can give you some feed back on how theirs runs.

 

[Stevie]

You're simply going to hear more trailing throttle popping with any after market pipe, with or without the DB killer. My 2013 Stelvio has the complete fueling package from GuzziTech. The PCV & Autotuner allows you to set air/fuel ratios for various throttle positions and rpms.

PC general guidelines say set the A/F ratios for 0% and 5% throttle positions at 0, this will do little to reduce trailing throttle popping. I've pretty much eliminated the popping by enabling fueling at the 0% and 5% throttle settings for all rpms from 1250 to 5000 with A/F ratios to 13.5. Leaning out those settings to 14.5 will result in more popping.

Keep in mind that this setup runs in closed loop all the time. It's constantly monitoring the exhaust gasses and adjusting the fueling to maintain optimal A/F ratios. I'm very pleased with the smooth throttle response the bike now has.

 

[Goodvibes]

Hey Brent. Todd offers a brilliant setup for your Griso when your warranty period concerns end. Me, I've been running an unbaffled Termi on my '09 Griso for better than 30K miles and it also sometimes pops on decel. I've learned to love it and know how to quiet it down if I want to by feathering the throttle (rarely do this though). Enjoy your ride (pops and all).

 

[GTM®]

Todd offers a brilliant setup for your Griso when your warranty period concerns end.

Thanks for that... but know that long term concern should begin immediately if you plan on keeping the bike past the warranty period. The fueling on all of the 8V motors is cringeworthy to all even slightly knowledgable with Air/Fuel ratios, much less amazing that the factory will honor any warranty with how they deliver it. Popping is a lean fuel condition as noted above, but I do *NOT* recommend letting AutoTune correct those areas. They should be done statically.

 

[Brent S]

Thanks for all the replies on this so far. Some great info for me to consider. Safe riding everyone.

 

[moose]

I love all noisy fireworks possible on overrun / throttle-backing off. The more popping and backfires the better. Might not be too good for it though?

 

[Trout]

I love all noisy fireworks possible on overrun / throttle-backing off. The more popping and backfires the better. Might not be too good for it though?

Not good at all!!!
Get her tuned correctly & enjoy music not noise.

 

[V700Steve]

+1 Trout, Todd has plenty of options available --https://gtmotocycles.com/collections/fueling