Pulsed Air Removal CAUTION

I removed the pulsed air injection system last November using this thread clicky as a guide. I chose to use the Dorman bypass caps to plug the ports on top of the engine.

Tonight when I lifted my tank to route wires for my new Starcom Digital I noticed that TWO of the plugs were split along their length and were allowing unmetered air into the exaust. The other two were showing signs of heat damage and starting to crack. If you used the dorman caps you may want to lift the tank and check!

OGRE said:

I removed the pulsed air injection system last November using this thread clicky as a guide. I chose to use the Dorman bypass caps to plug the ports on top of the engine. Tonight when I lifted my tank to route wires for my new Starcom Digital I noticed that TWO of the plugs were split along their length and were allowing unmetered air into the exaust. The other two were showing signs of heat damage and starting to crack. If you used the dorman caps you may want to lift the tank and check!

Click to expand...

Orge,

Good catch. Periodical checks are very important.

Your "clicky" is referencing MY guide to removing the air induction system.

Just for clarification......

I did not use and/or did not recommend the use of the "Dorman bypass plugs" that you used.

This was a recommendation and posted response from another member attempting to improve my guide...

My setup (illustrated in my guide that you referenced) has worked flawlessly for the last 18,000 miles.

WW

Sorry WW shoulda made that a little clearer... one of the suggestions by another member, on page three, was the dorman caps... It happened to be the way I chose to plug up the open holes.

OGRE said:

Sorry WW shoulda made that a little clearer... one of the suggestions by another member, on page three, was the dorman caps... It happened to be the way I chose to plug up the open holes.

Click to expand...

Orge,

No worries. I just wanted to let the members know that this was not an issue with my guide.

BTW, I don't think the leaking (as a result of those caps cracked) would hurt much.

Did you notice some popping on decel?

WW

I did in hindsight notice a little popping last week but I thought it was due to the cold weather.

OGRE said:

I did in hindsight notice a little popping last week but I thought it was due to the cold weather.

Click to expand...

Glad you caught it.

Go with the 1/2 inch irrigation plugs into the 1/2 inch hoses. They are self tapping plugs and take a lot

of elbow grease to get them seated all the way into the hose. I did all mine first before attaching and

clamping the hose pieces to the bike. They are barbed to prevent them from backing out.

Take care,

WW

I just checked mine after only about 150 miles and 2 of them had split! I had these on my last FJR for an entire summer with no problems. I wonder if it was the more extreme temperature changes in the winter from 28 degrees to operating temperature and back that caused the failure.

That's a shame, because the bypass cap approach was so simple and clean looking.

UselessPickles said:

I just checked mine after only about 150 miles and 2 of them had split! I had these on my last FJR for an entire summer with no problems. I wonder if it was the more extreme temperature changes in the winter from 28 degrees to operating temperature and back that caused the failure.
That's a shame, because the bypass cap approach was so simple and clean looking.

Click to expand...

It did look good but apparently its not a viable option.... I'm having trouble finding the plugs Wicked Webby used to go in heater hose... so I'm gonna try to make plugs out of heater hose and high temp copper silicone.... I hope it will work out.

OGRE said:

UselessPickles said:

I just checked mine after only about 150 miles and 2 of them had split! I had these on my last FJR for an entire summer with no problems. I wonder if it was the more extreme temperature changes in the winter from 28 degrees to operating temperature and back that caused the failure.
That's a shame, because the bypass cap approach was so simple and clean looking.

Click to expand...

It did look good but apparently its not a viable option.... I'm having trouble finding the plugs Wicked Webby used to go in heater hose... so I'm gonna try to make plugs out of heater hose and high temp copper silicone.... I hope it will work out.

Click to expand...

Another option (for the way I did it) would/could be 1/2 inch pex brass end caps.

If you used them you might want to clamp them.

WW

Interesting that my lawn chair vinyl caps (feet) are over 2 years old, have over 25k on them, and look as new. Whoda thunk?

I used the same method I have used over many years and bikes without a single failure. High temp GE or Dow Corning silicone to make plugs and then let it cure for 12 hours before riding. Use just enough to seal the openings about 1/4 inch deep, no more. Never seen one fail and they are easily removable.

Would taking the PAIR system off of a bike with stock exhaust & ECM have a negative affect ?

Will the O2 sensor see less oxygen and lean up an already lean running engine ?

I don't know, but it seems possible. Anyone have any thoughts ?

I would like to take it off my bike, but it's all stock, and I don't want to make it run any leaner than it already is.

A.C.

road runner said:

Would taking the PAIR system off of a bike with stock exhaust & ECM have a negative affect ?
Will the O2 sensor see less oxygen and lean up an already lean running engine ?

I don't know, but it seems possible. Anyone have any thoughts ?

I would like to take it off my bike, but it's all stock, and I don't want to make it run any leaner than it already is.

A.C.

Click to expand...

1. If you do nothing else but remove the pair system (block injection of air into exhaust) yes the O2 sensor will see a slightly richer mixture.

2. Will it cause the motorcycle to run dangerously lean if nothing else is done--no but the bike will no longer be emissions compliant.

3. There is no point in doing this modification except to (A) reduce clutter above engine for ease of servicing ( B) Get accurate exhaust

O2 readings (uncontaminated by pair air injection) for dyno tuning. I use a innovate datalogger to tune F/A ratios and the O2

exhaust sensor readings would be thrown off by the pair system injecting raw air into the exhaust system ahead of the O2 sensor.

I see no reason to do this mod unless you intend to tune the fuel injection on the bike with the barbarian mod, a power commander

or another aftermarket fuel injection tuning device.

I'm running out of time before I leave for daytona so I decided to fix it "for now" by using more of the dorman caps.... I'll find the right plugs after daytona and get it fixed for good.

The main reason I removed mine was to reduce decceleration popping with my Holeshot full system.

Nice find! I have not gone and remove my pair system from the fjr but I did from my RC-51. I used Red RTV. This is what we use inside...the cowlings on the jets at work. If can stand up to that heat it will do fine on the bike. Enjoy.

This is what I'm trying now:



Some 1/2" "heater hose" from the auto parts store, some rubber stoppers from the hardware store and some silicone adhesive to keep them together (although, they did fit together pretty tightly without the adhesive). The original clamps from stock hoses are re-used to hold the custom cap in place.

The end of the rubber stopper plugs the hole nicely:



I'll get a picture of them installed after the adhesive dries.

I didn't use high-temp adhesive, but I think it'll be fine because the area that is being glued is quite insulated from direct contact with hot parts by the rubber stopper and hose. The adhesive is only at the wide end of the stopper. I'll keep an eye on it and report back after I get some good miles with this setup.

UselessPickles said:

I didn't use high-temp adhesive, but I think it'll be fine because the area that is being glued is quite insulated from direct contact with hot parts by the rubber stopper and hose.

Click to expand...

Looks like the clear adhesive I used (Permatex 66B) can handle up to 400 degrees Fahrenheit: https://www.neelyindustries.com/p-1481-perm...bead-725oz.aspx

I think that'll be good enough

jstewart said:

I used the same method I have used over many years and bikes without a single failure. High temp GE or Dow Corning silicone to make plugs and then let it cure for 12 hours before riding. Use just enough to seal the openings about 1/4 inch deep, no more. Never seen one fail and they are easily removable.

Click to expand...

Same method I use and it works well. Squeeze some over the opening and simply wait long enough for it to set up before starting. Don't need no stinking hoses or plugs at all.

UselessPickles said:

I'll get a picture of them installed after the adhesive dries.

Click to expand...

Here's by custom block-off caps installed. I left the Dorman bypass cap on the air box because it's quite a bit thicker and further away from engine heat (edit: as compared to the smaller Dorman bypass caps that were used on the 4 air inlets; those are the caps that were causing problems).