Don't try and take ST 1300 PAIR reed valves apart...

CYYJ

CYYJ

Michael
Joined
Jun 10, 2013
Messages
2,150
Age
70
Location
Toronto & Zürich
Bike
None any more.
Hi All:

This story can be classified as "A lesson from the School of Hard Knocks". :)

A few weeks ago, I took the cylinder head covers off my ST 1300 to do valve clearance measurements. While I had the covers off, I took the cap that covers the PAIR (Pulse Secondary Air Injection) reed valves to inspect the reed valves and ensure that they were not stuck or blocked. I found both the PAIR reed valves and the perforated port plates under the PAIR reed valves to be very dirty, just covered in carbonized gunk.

Closer inspection of the PAIR reed valves revealed that portions of the valve around the perimeter of the reed valve opening had been coated with some kind of anti-stick compound by Honda - maybe teflon, maybe molybdenum, I don't know, but very similar to the coating on the inside of the throttle bodies. That meant that I couldn't use really harsh chemicals like gasket remover to clean them.

My attempts to clean the PAIR reed valves with generic solvent and a toothbrush helped a bit, but there was still a lot of gunk stuck to the valves. I noticed that a single small cross-head screw held the PAIR reed valve assembly together, so, I thought the obvious next step would be to remove the screw, take the reed valves apart, and clean the pieces individually. The screw put up a lot of resistance when I turned it, but eventually broke free. I thought the resistance came from the gunk coating the screw. Wrong. The resistance was there because the threads on that screw are deliberately deformed in the manufacturing process, likely to comply with emission control 'anti-tamper' legislative requirements. The resistance I felt was the deformed end screw coming up against the plate, and the sudden drop in resistance was the result of the screw breaking in half, leaving the last millimeter jammed in the plate.

Net result: I had to buy four new PAIR reed valves at a cost of about $70 US plus shipping. I hope the EPA and the atmosphere appreciate my efforts. The photos below tell the story.

Michael

PAIR reed valve cover.jpg

The dirty PAIR reed valves & port plates
PAIR valves - dirty.jpg

A dis-assembled reed valve (don't try to take them apart!)
PAIR valve disassembled.jpg

Note the intentionally deformed end of the screw on a new PAIR reed valve
PAIR valve close up.jpg

New PAIR reed valves and (cleaned-up) port plates in place
PAIR valve in place.jpg
 
CYYJ said:
Net result: I had to buy four new PAIR reed valves /QUOTE]
Are you saying that we should not bother inspecting these? I assume your PAIR valves were working fine despite the crud on them?
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SMSW said:
Are you saying that we should not bother inspecting these? I assume your PAIR valves were working fine despite the crud on them?
Click to expand...
No, I'm not suggesting that we not inspect them - I think it makes sense to inspect them periodically and ensure that the reeds are free to move.

What I intended to convey was "don't try to take them apart" by removing the small cross-head screw, this for reasons cited above. If I had to do it all over again, I would have cleaned them up as best I could using a mild solvent that would not damage the teflon or molybdenum coating, confirm that the reeds were free to move, and put them back in again. I would also clean the perforated port plates by soaking them in gasket remover (solvent alone didn't remove the crud from them).

I don't know if they were working or not before I began this misadventure. My guess is that they were working OK, because the reeds were free to move despite the great amount of crud on them. When I saw all that crud, my first thought was "better clean that off, otherwise, the reed might not be free to move much longer".

Michael
 
They are PAIR. The crankcase rebreather system is a different component, it is a hose that originates from the left cylinder head cover and terminates at the right forward bottom part of the air cleaner housing. It is a pretty simple system, as far as I can tell, there are no moving parts in it.

Michael
 
PAIR permits fresh air into the exhaust to facilitate the catalysors with extra oxygen.
This also allows the engine to run a little ‘richer’ because the oxygen sensors are ‘further down the lane’ towards catalysers/mufflers.
 
I just dissassembled mine, a few days ago. I cut the screws so I could take them out and put new ones, which I hammered softly until having the end completely fixed up. I didn't know about the coating, so I'm guessing mine will get stuck in no time again.
 
W0QNX said:
Grind the flattened thread part off, screw it out? Might even have to drill up through the bottom. But I won't even look at mine...It doesn't bother the way my bike rides with dirty pair valves one bit.
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I second this. Usually a flat file will take the deformed end off.
 
I know some would consider this controversy, but jeez you have gone that far, yank the pump out,
add covers over the pair area and be done with it!
Looks like... simular...different bike.

Pulling the reeds off...

Clean the "frames" and reinstall the gaskets.

Clean the "seat" area on the bike and reinstall the spotlessly cleaned frame and gaskets.

Pair Cover installation..

Bolted down and done.

Pump pulled out....

Plugged airbox port...


Pair valve maintanance done for the life of the bike!

There's never been any negative drawback on any bike I have done this too...
 
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mello dude said:
Pair valve maintanance done for the life of the bike!
Click to expand...
Please don't rush out and start yanking the pair valve system,, everyone. There is no significant performance advantage to be gained. One of my st13's has it,,, and one does not. I removed the one's pair system just to make afr mapping easier. And, I have no plans to remove the other one. It's interesting that many methods were used over the years to deactivate pair's on various models. One invisible method was to plug the lines with marbles. On BlueSTar,, I considered, and looked for blocking plates, which were now rare for our aging bikes. In the end,,, just used the caps and zip-ties supplied by Bazzaz. That part took less than a minute each. cheers, CAt'
 
Catmandu2 said:
There is no significant performance advantage to be gained.
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Absolutely true... Other than cleaning up some of the interior of the engine area on the bike... and alternatively required if the bike is going to use a Fuel mapping Dynojet or Rapidbike unit or simular...Its more of a "while your are in there" job or if you need maintenance on it, just yank it out of there.

Just seems like every bike I get into, eventually off they go.. Usually if the plumbing gets in the way of a job....

For the halibut... I made plates that fit VFR and Blackbird (currently out of stock), guys have liked it.
 
My parents had a '68 Cadillac Sedan de Ville with a 472 cu in engine that had a belt-driven A.I.R. (Air Injector Reactor) pump that blew fresh air into the exhaust manifolds right at the exhaust ports.
 
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Catmandu2 said:
Please don't rush out and start yanking the pair valve system,, everyone. There is no significant performance advantage to be gained. One of my st13's has it,,, and one does not. I removed the one's pair system just to make afr mapping easier. And, I have no plans to remove the other one. It's interesting that many methods were used over the years to deactivate pair's on various models. One invisible method was to plug the lines with marbles. On BlueSTar,, I considered, and looked for blocking plates, which were now rare for our aging bikes. In the end,,, just used the caps and zip-ties supplied by Bazzaz. That part took less than a minute each. cheers, CAt'
Click to expand...

"There is no significant performance advantage to be gained." But isn't it for catalyzer protection that they burst air inside the exhaust? I don't want those things to get stuck with carbon.
 
Larry Fine said:
My parents had a '68 Cadillac Sedan de Ville with a 472 cu in engine that had a belt-driven A.I.R. (Air Injector Reactor) pump that blew fresh air into the exhaust manifolds right at the exhaust ports.
Click to expand...
Just another expensive means of cheating emissions requirements of the time.
 
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