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Ca. Gas Tank Issues-Need Help

5453 Views 12 Replies 8 Participants Last post by  qwerty
Hello guys,

I seem to have an issue with my gas tank, and I am only going to assume that it is my tank.

It is a California bike and has the odd vent type deal in the tank,(excuse my ignorance to what it is), some type of overflow or vapor catch system? Anyways, when I purchased the bike used, the tank was not overly rusty inside, but I did what I could to clean it out.

Installed a new Petcock, inline filter, new lines and fully cleaned the carb.

The bike runs great.....Until I get down to about a half a tank of gas, then it acts starved for fuel. This has only happened twice, and maybe it is coincidence, but when I top off the tank it runs fine until half a tank again.

Is there a dirt/rust issue that I did not handle with that vent/vapor/overflow deal in the tank? Or has this happened to anyone else? Filter is clean, Petcock screens are clean, I am just baffled.

Of course my next option is the Clarke TW tank, and then I have rust no more, my only concern is, will my bike be street legal with that tank?

Thanks in advance.

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This is most likely a petcock or float issue, but some things to check:

Is the canister hooked up or did you cap the vent line? If you capped it your tank won't vent.

Check to make sure you didn't pinch the vent hose against the frame tube when installing the tank. I've done it myself.

Remove the tipover valve (plastic hex-head chingas under the tank that the vent hose to the canister attaches to) and run a wire through the tube to see if it's obstructed. I've never seen an obstructed tipover valve but make sure it rattles.
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Some moron who was unclear on the concept has De-Californicated your bike. Check to make sure he hasn't capped the undertank fitting and that he HAS capped the extra fitting on the carb.

The Cali system is bulletproof and has many advantages over the 49-state bikes with regard to water crossings, bike drops and garage fumes. Still the rumors persist that it affects performance. It doesn't, unless some jerkweed removes it improperly. All it is is a tank vent. Simple as a rock.

I have plenty of canisters if you want to put it right. If not, cap the carb fitting and make sure the vent is clear and it will work just like a 49-state bike, puke gas on your head if you drop it on yourself, suck water into the tank if you only make it half way across the stream before you drop it, your garage will stink like fuel all the time and the ADVrider crowd will prolly give you a special commendation(?). Yay! Stick it to da man!

Alternately make sure the vent tube isn't obstructed in any way and run a line from the undertank fitting direct to the carb. This bypasses the canister but leaves you with most of the advantages, including the tipover.

Those of you with Clarke tanks can run the Cali system minus the tipover feature by running the vent line from the fuel cap fitting to the canister instead of the stock undertank fitting-to-canister.

The only downside is that the charcoal may become temporarily saturated in a bike drop causing some momentary higher revs from the fumes when you restart it. It'll dry out within a few hundred yards.
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See what I mean? Even your mechanic doesn't get it. There is no vacuum associated with the system in any way. It's a tank vent. Period. Finito. End of story.

If your tank vent in a 49-state bike gets clogged your tank will cavitate and not pass fuel. If your tank vent on a Cali bike gets clogged your tank will cavitate and not pass fuel.

The charcoal never goes bad and even if it turned to powder it wouldn't affect anything. It's in the lowest part of the system and in addition the charcoal is stored in the lower part of the canister. Gravity will keep it in the canister and out of the line. Some canisters which are mounted horizontally with their fittings on the ends or the sides can in fact disintegrate and cause problems, but this is not true of ours.

If you're not sold on its advantages you can completely bypass it and it will make no difference in how the bike runs. I'm just trying to dispel some of the myths surrounding it. I keep it and in fact I would add it to a non-Cali bike if I owned one because I consider it a plus. But don't tell the dinks in Sacramento that they've accidentally given us a plus, because it was most certainly an accident.
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I like the Cali system, but retrofitting it could prove a bit costly. How often do you really drop your bike, and how likely are you to swamp it midstream?

I mostly put the info out there so folks can make a more informed decision before they "de-Californicate" a bike needlessly.
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