What is this?

Arkterra

Arkterra

Joined
Dec 27, 2021
Messages
32
Location
Nebraska
Bike
1999 Honda ST100
Hello, I'm new to the forum and to having an ST1100.

Recently I removed my carbs to replace the coolant hoses and elbows beneath. On my carbs they had the normal tubing around them but it also had a two black valves. One was mounted just behind the thermostat housing and had a vacuum tube running to it. What do these black valves do and can they be removed? Below is a picture I borrowed from another carb rebuild on this forum and it's what my carbs do not look like. Mine only have one tube running to the front just above the PAIR breather outlet and one of the black valves to the right of the PAIR outlet. Thoughts?
 

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Air Vent Control Valve. The one at the left front side is the Purge Control Valve. Pages 1-31, 1-34, and 5-17 in the Honda Service Manual.

John
 
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That's an old picture of my 49 State non-emission carb bank out of my '96. I don't recall posting that here on this forum.

It sounds like you have an ABS, or a California emissions bike. As my good friend John Oost has mentioned, those are vent and purge valves. You also have a charcoal canister down at the center stand, along with a mile of vacuum hoses and fittings...

Due to legal regulations, YES you can successfully remove the entire EVAP and PAIR systems, for "closed course-off road" purposes only. ;)

You can then jet and tune for what your looking to get out of the bike, but can only go so far due to the lazier emission camshafts. I've totally gutted several emission bike's. I did one this past fall and I have another one sitting in my shop, all ready to undergo the same treatment. I have all the photo's and procedures, but have yet to write the article. You'll see it in the AOW sometime soon.
 
I'd really like that article! I fully understand how to remove the PAIR system but don't quick grasp everything that has to be done with the EVAP system. For example, what do I do with the gas tank vent hose that goes to the canister by the rear swing arm? Just questions I haven't found answers to.

I found an archived article on another website that I think at one time had pictures that better explained the process. But now it doesn't. Hope to see that soon. I'll link the article below.

Smog System Removal ( ST1100 )

Smog System Removal ( ST1100 )
www.st-riders.net
 
Leave the Tank vent hose in place or extend it all the way under the Bike. I just left mine in place.
If you extend and then overfill it will dump the excess on the ground.
 
Arkterra said:
I'd really like that article! I fully understand how to remove the PAIR system but don't quick grasp everything that has to be done with the EVAP system. For example, what do I do with the gas tank vent hose that goes to the canister by the rear swing arm? Just questions I haven't found answers to.

I found an archived article on another website that I think at one time had pictures that better explained the process. But now it doesn't. Hope to see that soon. I'll link the article below.

Smog System Removal ( ST1100 )

Smog System Removal ( ST1100 )
www.st-riders.net
Click to expand...

That's a VERY old "My-Mc.com" post. Unfortunately, My-Mc fizzled out several years ago, so all of the pix probably got lost. However, the printed version STill remains at ST-Riders.
As with some of the other articles I've written, this next one will go to the same place @ ST-Riders.net "Archives Of Wisdom" AOW...
 
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