V7 850, Evap Canisterectomy thread...

[Utrider]

Hello All, I know I saw a thread on here about the removal of the EVAP canister, but for the life of me I can't seem to find it or the search function... Did I miss something?

Regards,

Roy

[YellowDuck]

Remove left side cover.  Disconnect the hoses from the top and bottom of the purge valve, but leave the purge valve plugged into the electrical connection.  Plug the hose that came off the top of then purge valve with a bolt (M5?) and clamp. 

Remove the plastic starter cover to expose the vent line and green and white plastic valve.  Disconnect this line up at the nipple connector above the purge valve.

Under the bike, snip the big thick zip tie that secures the cylindrical EVAP cannister in its cradle.  Remove the cannister and associated hoses  and vent line valve out the right side of the bike. 

The hose on the cannister that used to go to the bottom of the purge valve is the right length to extend the vent line.  Attach it with a clamp to the nipple in the vent line above the purge valve, then route the line to a convenient place under the bike.

 

[YellowDuck]

On my bike this mod made a HUGE difference in the fueling at low throttle angles.  Completely transformed the drivability of the bike.  Best zero-dollar mod you can do, and also better than many $1000 mods.

[Bulldog9]

Does the V750 have those reed valves on the exhaust port?  I'd want to remove that system too.

I've removed the EVAP system on all my CARC bikes, but left it in place with the V7/750's as I don't have problems with it.

[Moparnut72]

Thanks Duck, after reading your post I went out and attacked my new '26. What a difference, where it would buck at lower rpm in lower gears is now gone. It runs so much better, actually so good I don't have to keep it over 3 grand in first going through the neighborhood. I can now ride it in the low 2's in 2nd without it bucking. This makes a great bike even better. Thanks again for your tutorial.
kk

[MikeP996]

I find this interesting.  I've read posts about this but my '21 V7 850 Special does not exhibit any issues with low RPM running as described.  It is quite comfortable at bumbling along at low RPM in low gears.  I bought the bike with 6800 miles on it so maybe that has something to do with it (??).  The previous owner had installed Mistral mufflers though I can't imagine that would have any effect on low speed operation.

Wonder why there would be such differences between "identical" engines.  I have also read a lot of the "keep it above 3000 RPM," and "It's happy between 3000 and 5000 RPM."  But it runs great at all RPM ranges from just above idle to bouncing off the rev limiter (oops).  I have receipts for service/parts and there is no indication of any mods to the engine (ECU, etc).  The only mods to the bike by the previous 3 (!!) owners was the Mistrals and front fork cartridge replacement.  I have to admit I wonder why three previous owners didn't keep the bike -  I think it's great!!

[YellowDuck]

I find this interesting.  I've read posts about this but my '21 V7 850 Special does not exhibit any issues with low RPM running as described.  It is quite comfortable at bumbling along at low RPM in low gears.

I am not sure if the 2021 has the same EVAP system.  There is actually a diagram of the system under the seat, so you can easily check.  See if it shows an electronic purge valve connected to the ECU.  When the valve is open it draws air through the cannister from atmosphere and into the intake manifold.  So that's a built in vacuum leak, by design. 

[Vagrant]

Mopar nut has gotten my attention. I haven't messed with the emissions since my 98 and 01 EV's. I have had no complaints on my 2020, 22, 23, or 25 V85 bikes. Or my 17 V7III. But now I wonder if there really is something to the E vap delete.

[Kev m]

I'm on the record for usually saying these systems are scapegoats for other problems and to leave them alone.

But there's a super easy way to test if they are a problem on any given vehicle.

Simply seal the purge line leading to the throttle body using a hose pinching tool and take a test run. If the symptom is gone with the tool installed and back with it removed you have irrefutable proof of the culprit.


Now, I also heard mention of the SAS (Secondary Air System) being an issue. But the SAS is simply a reed valve used to inject fresh air (O2) at the exhaust port where the stream enters the exhaust itself. This is to help afterburn in the pipe and cat to clean leftover HCs through more complete burning. It shouldn't disrupt combustion in the chamber in any way unless MAYBE MAYBE MAYBE reducing scavenge ever so slightly but even then I'm skeptical it's an issue.

[Moparnut72]

Where do I start. I had 1400 Audace with the SAS system. Modifying it as per GTM had no effect as far as I could tell. Low speed engine smoothness was non-existent. That motorcycle was terrible, Beetle hadn't developed a reliable map for it during the time I owned it. I also had at the time up until I just got my V7850. Fueling on it was absolutely perfect. I left it totally alone and rode it just like it came from the factory. My 850 wasn't bad but had enough of an issue that if something would definitely help I would be all in. I thought I would give this mod a try and if it didn't work or make a difference I would it put it back to stock. As I said above it has made a big difference for the better. If I were to do it again I would make the mods without taking anything out but what is done is done. Just disconnect the necessary hoses and plug the others. Just looking at where hoses came from and where they went didn't make a lot of sense to me, some seemed to be self defeating. Probably just what had to be done to meet the latest Euro emissions requirements. These bikes are some of the last air cooled engines to meet these standards without going to water cooling. I may be a Luddite but I am happy to have the simplicity of a V7.
kk

[Utrider]

Thank you all for your input.  I have pipes and an UP tuner to install as well and wanted to knock it all out at the same time.

Roy

[T607]

Does anybody here actually know under which conditions the ECU will open the connected valve to purge the canister? I have a 2023 V7 850 and no fueling problems at low RPM at all.  So I left the evap system alone.

[Dr. Enzo Toma]

Thank you all for your input.  I have pipes and an UP tuner to install as well and wanted to knock it all out at the same time.

Roy

You may want to check with UpMap, but my understanding is that once you flash the ECU with one of their tunes, it will be locked into open-loop fueling, and the purge valve may never open.

Does anybody here actually know under which conditions the ECU will open the connected valve to purge the canister? I have a 2023 V7 850 and no fueling problems at low RPM at all.  So I left the evap system alone.

Speculating here, but I suspect the purge valve remains closed anytime open-loop fueling is happening (reading directly from the fuel map without adjustments), and it would only open during closed-loop operation (when fuel trim is applied to the map based on o2 sensor feeedback) which is *usually* when an engine is up to temp and off idle but not under heavy load (WOT). Since it's feeding fuel vapor on the intake manifold side of the throttle body, it would make sense that o2 sensor feedback should be incorporated to trim fueling when the purge valve is open. Prior to using an electronically controlled valve, some vehicles (such as my 1980s Jeep) used a thermal vacuum switch and purged the charcoal canister to the intake manifold side of the throttle body once the engine was up to temp. I've not had fueling issues tied back to the EVAP system on any of my EFI bikes that have it, not even my V7 850, so I've also not had a reason to remove it. Opposed to the carb'd bikes without it, I appreciate the EVAP bikes not stinking up the garage with fuel vapor. I suspect many canister removals may be lead by the notion of "emission controls = bad" rather than a performance issue, or for simplicity as mentioned, or aesthetics though it's not very visible hanging below the V7 850. Whatever the case, your bike to do with as you please :)


Here's a diagram from the workshop manual for the V7 850 for those curious about the flow of things.




If you have an early V7 850 running a factory tune, do make sure a dealer has done a software update on it as there was apparently a not-great tune on early bikes. My 2022 was updated on delivery, after an update was out to address those issues, so I never encountered them.

[MikeP996]

Emission controls:  I remove/defeat some emission controls on a motorcycle BUT I agree with banning cigarette smoking in public spaces.  Makes me a hypocrite I think... ;) 

Hmmm... Vehicles used to have NO emissions controls and smoking USED to be allowed on airplanes (as was carrying a gun...or anything else you wanted to carry)...  Life is confusing, complicated and constantly changing.