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Old 08-07-2008, 10:22 AM   #1
Shinglejohn
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Default Bike runs poorly without the choke.

So my 79 cm400t is up and running, ive been riding it about a week now. It runs fine with the choke on, but it is not so smooth with the choke off. It doesnt run horribly, but it sputteres a little bit, and doesnt have the power it should. i can find no air leaks. any ideas?
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Old 08-07-2008, 10:27 AM   #2
seruzawa
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It's been parked a long time? Have you dismantled and cleaned out the carburetors?
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Old 08-07-2008, 10:45 AM   #3
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Yes. The carbs have been completely dismantled and cleaned.
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Old 08-07-2008, 10:52 AM   #4
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New air cleaner? Fuel filter? No rodents nesting in the tank? Carbs adjusted to spec? Petschlong cleaned of old gas gunk?
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Old 08-07-2008, 01:16 PM   #5
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SJ,

As hinted at above, the bike isn't getting enough fuel. The only way it runs is if you strangle (choke) it, thus getting the proper air/fuel mix.

If you believe the carb(s) are clean, you'll need to work back through the system all the way to the tank to find the restriction.

Good luck!
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Old 08-07-2008, 02:46 PM   #6
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everything between the tank and the carb is brand new. anyone know any good tutorials on carb tuning?
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Old 08-07-2008, 03:48 PM   #7
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Since the CM400T motor was used as the model for the new Triumph Bonneville powerplant, maybe you can get some good info from a Triumph website on how to fix it.
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Old 08-08-2008, 06:31 AM   #8
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Go through the carbs again. Something has to be clogged which is why its pulling it from the choke circuit.Sometimes it take a few times. Those carbs arent that complicated.

The only adjustment besides a/f mixture is synching them. This only insures that each bank is pulling the same amount of fuel, at idle only.
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Old 08-08-2008, 08:51 AM   #9
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What you can do real easy (this worked on my Honda 55 Super Sport with rust in the tank) is get the bike going real fast, downshift to 1st gear, while closing the choke plates, and hold the throttle wide open, while dumping the clutch. It'll suck those carbs inside out, and anything stuck in the jets will be passed through like crap out of a goose.
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Old 08-08-2008, 09:22 AM   #10
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Thats hularious! Ms!

Although I wouldnt go too fast, that rear will surly lock up.
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