Crankcase breather hose

[Fairlaner]

After putting the holeshot system on my FJR I noticed that during decelaration the i was getting a poping noise from the exhaust. On tuesday i took it to OC motorsports for some dyno time, the tech there block off this hose while he did the dyno runs and it did not pop at all. he told me to just remove the hose and cap off both ends. So what do you guys think is it ok to do this or what?

Here is the hose in question

 

[radman]

I removed the AIR system completely, except for the reed valve plates on the valve cover (don't know of any block offs available, must make my own). The system is indeed the source of the pops, decel pulls fresh air into the exhaust and combined with the heat lights off any remaining mixture in the stream. Several here have eliminated the system, with no bad results reported. Cap it at the pipes exiting the cover (4 of them), cleans up the area nicely. Don't forget to cap the source at the air cleaner housing.

 

[Fairlaner]

I removed the AIR system completely, except for the reed valve plates on the valve cover (don't know of any block offs available, must make my own). The system is indeed the source of the pops, decel pulls fresh air into the exhaust and combined with the heat lights off any remaining mixture in the stream. Several here have eliminated the system, with no bad results reported. Cap it at the pipes exiting the cover (4 of them), cleans up the area nicely. Don't forget to cap the source at the air cleaner housing.

Ok thanks Rad. right now i have just removed that 1 hose, i capped the aircleaner housing and one side of the T bar. no probs doing that right?

Richard

 

[ionbeam]

I believe Rad is saying that he removed not only the hose between the air box and the solenoid that you did, the one specified by Dyno Guy, but he also removed the solenoid and all other plumbing right up to the four ports on the reed valve assemblies.

If Rad did remove the solenoid I'm wondering if the ECU misses it and set a code ???? All I see is diAG code 48, which is just an actuation test where you listen for the solenoid operation.

Of course, you living in CA and all, the Green Police will hunt you down like a dog and TERMINATE your noxious ass for violating the clean air act by disabling the AI system.

Other than the Green Police there are no problems with disabling the AI system. The fact that you were hearing POP-POP-POP does indicate that the fresh air was lighting off a rich exhaust.

 

[v65]

Well now this is interesting. On the gen II bikes there is an air control valve in this system that is in the way for the cc cable. See here. Like others I have mine installed around this valve, but taking this system out would be easier.

 

[Fairlaner]

I believe Rad is saying that he removed not only the hose between the air box and the solenoid that you did, the one specified by Dyno Guy, but he also removed the solenoid and all other plumbing right up to the four ports on the reed valve assemblies.
If Rad did remove the solenoid I'm wondering if the ECU misses it and set a code ???? All I see is diAG code 48, which is just an actuation test where you listen for the solenoid operation.

Of course, you living in CA and all, the Green Police will hunt you down like a dog and TERMINATE your noxious ass for violating the clean air act by disabling the AI system.

Other than the Green Police there are no problems with disabling the AI system. The fact that you were hearing POP-POP-POP does indicate that the fresh air was lighting off a rich exhaust.

Not sure i know what this reed valve is, but i have removed that hose and there is no more pop so thats good.

R

 

[madmike2]

Keep the parts and the pictures of the removal so you can put it back together for the inspections that CARB is planning for motorcycles. :blink:

 

[Fairlaner]

Keep the parts and the pictures of the removal so you can put it back together for the inspections that CARB is planning for motorcycles. :blink:

yep that and the exhaust system. <_<

R

 

[radman]

Not sure i know what this reed valve is, but i have removed that hose and there is no more pop so thats good.

I placed caps on the port circled in red. The device circled in blue is the reed valve assembly that resides beneath each of the 4 ports (3 cap assemblies). The reed prevents exhaust from backing into the AIR system. The removal of the solenoid may have set a code (haven't checked the ECU), but did not trip a check engine light, so I doubt it. Sure got a lot of junk outta the way though.

 

[Fairlaner]

Not sure i know what this reed valve is, but i have removed that hose and there is no more pop so thats good.

I placed caps on the port circled in red. The device circled in blue is the reed valve assembly that resides beneath each of the 4 ports (3 cap assemblies). The reed prevents exhaust from backing into the AIR system. The removal of the solenoid may have set a code (haven't checked the ECU), but did not trip a check engine light, so I doubt it. Sure got a lot of junk outta the way though.

Wow thats a lot of junk.

I just removed hose number 25, that will do for now next time i take the tank off i will remove the rest.

Richard

 

[GAPS]

The popping on decel, any harm in it?

 

[Fairlaner]

The popping on decel, any harm in it?

I dont think so just frigging loud.

R

 

[TexasFJR]

doesn't the Power Commander fix this ??

 

[radman]

doesn't the Power Commander fix this ??

No, if anything, it worsens it. Understand, the popping is unburned fuel being lit off by the residual heat in the exhaust, aided by the fresh air introduced to the exhaust stream by the AIR system. A vacumn is created on deceleration at the exhaust ports which draws the fresh air in past the reed valves, creating the condition you hear as popping. A leak at the exhaust pipe seals at the head can also cause this. The PC can actually make it worse by richening up the mixture introduced into the cylinders, and thusly, the amount of unburned fuel exiting the cylinders. While it doesn't hurt anything, it is annoying.

 

[zorkler]

wow now i no whats what **** it i have to left hands . i just thought it was running lean .

 

[jestal]

That hose in question is indeed the AIR system supply hose and NOT the crankcase breather hose. You do NOT want to plug or block the crank case breather hose. Besides, the crankcase breather or PCV hose would not cause popping in the exhaust as described. The AIR system does that.

Not sure i know what this reed valve is, but i have removed that hose and there is no more pop so thats good.

I placed caps on the port circled in red. The device circled in blue is the reed valve assembly that resides beneath each of the 4 ports (3 cap assemblies). The reed prevents exhaust from backing into the AIR system. The removal of the solenoid may have set a code (haven't checked the ECU), but did not trip a check engine light, so I doubt it. Sure got a lot of junk outta the way though.

RAD...I assume you capped the ports on parts 4 and 5 in addition to the ports circled in red on 3 ...correct...???

I took my complete AIR system off also some time ago and it has not set any sort of code or engine light.

If you remove the reed valve there is a small, drilled passage below it to the exhaust ports. Very easy to simply run a tap into the hole and screw in a small set screw to totally plug the system and elminate the need for the reed valves or any of that hardware. I kept the covers (parts 3, 4 and 5) in place to clean up the look of the top of the cam cover but there is nothing under them. I plugged the air ports in 3, 4 and 5 with a plug of black RTV. Just filled up the ID of the port and smoothed off the end with a swipe of a plastic spatula. Once set up the RTV is neat and clean and adds no bulk to the OD of the fitting.

The AIR system on the FJR is a type of "pulse air" design that uses the negative pulses in the exhaust system to pull air in without an auxiliary AIR pump. That is the real reason that the reed valves are in the system. They keep exhaust flow from backing up into the system and then the reeds open momentarily everytime there is a negative pressure pulse in the exhaust to allow air to flow thru. They are just a one way check valve.

Yes....there are actually very strong negative pressure pulses in the exhaust in addition to the very strong positive pressure pulses you might expect.

AIR stands for Air Injection Reaction. It provides extra free oxygen to help oxidize HC and CO in the exhaust stream. With a catalytic converter system it helps the cat warm up sooner on cold starts as the AIR system is enabled to provide air for the rich mixture to convert in the cat to get it up to temp sooner. After that, the AIR system only turns on sporadically as the ECM demands to help with HC and CO efficiency. It isn't operating most of the time anyway as it would cause erroneous readings on the O2 sensor. An AIR system will definitely lead to some popping in the exhaust as it will promote combustion of unburned HC in the exhaust system and that is what you will hear. Ditch it for less complexity, less heat and less popping. If you have a PCIII that is richening up the system and running it open loop anyway the AIR system is not really that effective and can make the popping worse.