Smog Canister Question

Got an ST in the garage with a melted smog canister line. The line is the large one that comes straight out of the bottom of the can, and is called "canister air suction hose".
It should exit the bottom of the canister, route along the frame, behind the engine, and come to rest in the metal band near the speed sensor switch. It somehow got loose and the exhaust pipe got it and melted a hole through it.
My question is, since this sucks the air into the canister, and is open to the air, does it need to be routed to the back of the engine? I am considering cutting it off cleanly about 5 inches and zip tying it to the crash bar bracket.
Anyone think this will cause any issues with air flow, being behind the lower cowling and shielded from the elements, rather than hanging down sucking up rain water?
Does the length of it matter (did I really just type that)
Thanks for any input in this matter.
Igofar

Knowing very little about the function of the smog canister.

How much vacuum does this line see?
The reason I ask is because if it's low vacuum perhaps the extra length and long routing is there to prevent water intake.

I refer to my first sentence again


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This sounds like a California problem. . . Lol

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Larry,

What year is the ST? Are you referring to the Fuel Vapor Canister that collects vapors from the tank and or carbs (ST1100) as the "Smog" Canister or some other emission device? Last time I encountered smog it was the brown stuff in the air around LA.

Chuck

Its the Kalifornia Evap Canister. The canister air suction hose on the bottom that draws air into the canister.

Might the length of the hose (I believe i wrote that) have more to do with admitting cool air and not engine heated air? While hot air is welcomed in some professions, might it have a deleterious effect on the vapor soaked charcoal in the canister?

The hose length is not critical to operation however you might want to replace it with the correct length hose. Here is why.
If you have ever experienced heavy fuel odor from your bike on a very hot day it is probably coming from that bottom hose.
This diagram is from a Honda Civic. Same principal but the Purge control valve is Vacuum operated on this one and Electric Solenoid on the 1300. You are right about the bottom hose being an air inlet when the engine is running however when the engine is off the purge valve is closed and the lower hose becomes a vent or outlet to prevent pressure buildup inside that canister when the fuel tank is sending vapors to the top hose. Hopefully the carbon absorbs the fuel molecules before they reach the atmosphere. The length of the lower hose is primarily to send the smell or any combustible vapors away from the engine and rider.

[IMGL]https://www.st-owners.com/forums/attachment.php?attachmentid=187045&stc=1&d=1506276425[/IMGL]

Problem solved...found some of the correct dia. vacuum hose and replaced the entire length back to the stock configuration.
Feel free to delete this thread now if you want.
Thanks to all those who replied.
Igofar

Good call. You also want the full length exiting where it is because if the material in the canister becomes saturated, you probably don't want anything additional draining off where the heat would be excessive.

--Mark

I would follow the service manual for routing and length of hose. The diagrams for the hoses are towards the front of the manual. Getting water in the evap canister will clog it and a new one costs at least $150.

Reginald said:

I would follow the service manual for routing and length of hose. The diagrams for the hoses are towards the front of the manual. Getting water in the evap canister will clog it and a new one costs at least $150.

Click to expand...

Or go to ebay and pick one up for under $25. There are parts on these bikes that don't sell very good, therefore the cheap prices. The canister are one such item....beware though, there are those that think they have gold in them, so they over price them.

For a whole list of them....