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Carbs and Fuel System
From the gas tank to the carbs
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  Topic Review (Newest First)
03-30-2017 08:10 AM
OleDirtyDoc Gotta get the motor over to my place, that is pretty much what I'm waiting on

Sent from my LGL34C using Tapatalk
03-30-2017 07:05 AM
Brooklyn_Vulcan
Quote:
Originally Posted by OleDirtyDoc View Post
the tw200 is a Yamaha dirt bike.the petcock bolts right on our bikes,but you need to plug the vacuum line

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thanks doc

hows that bike coming along?
03-29-2017 09:21 PM
OleDirtyDoc the tw200 is a Yamaha dirt bike.the petcock bolts right on our bikes,but you need to plug the vacuum line

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03-29-2017 06:59 PM
Brooklyn_Vulcan
Quote:
Originally Posted by Goofyfoot2001 View Post
Do the tw200 petcock mod. Had ZERO problems with that.
not fully sure what that is but i will look into it...thank you
03-29-2017 06:58 PM
Brooklyn_Vulcan
Quote:
Originally Posted by michiganteddybear View Post
ok, the pic of the carbs off the bike are correct as far as I can tell on the hoses. the nipple on left (front) carb will go to center of the petcock. the 2 that are 't'ed together are the bowl vents. they are correct, and the loose end of that hose goes to 'dead' air (under tank if your ear shaved, in right air filter box if not). right carb (rear) there is a vacuum line that is either capped off (if ear shaved), or goes to some emissions crap under seat if still stock.

on the 1st pic, I am going out on a limb and saying that they connected both vacuum ports (where petcock gets vacuum from on left carb) together. you only need the left carb connected to the petcock's vacuum nipple.

the underseat emissions crap is a vacuum operated valve that allows fresh air to be drawn into the reed valves (on side of head, large hose) to clean up emissions on decel conditions. also commonly causes lots of popping in exhaust.

very very interesting thanks...
03-29-2017 10:53 AM
Goofyfoot2001 Do the tw200 petcock mod. Had ZERO problems with that.
03-29-2017 08:37 AM
michiganteddybear ok, the pic of the carbs off the bike are correct as far as I can tell on the hoses. the nipple on left (front) carb will go to center of the petcock. the 2 that are 't'ed together are the bowl vents. they are correct, and the loose end of that hose goes to 'dead' air (under tank if your ear shaved, in right air filter box if not). right carb (rear) there is a vacuum line that is either capped off (if ear shaved), or goes to some emissions crap under seat if still stock.

on the 1st pic, I am going out on a limb and saying that they connected both vacuum ports (where petcock gets vacuum from on left carb) together. you only need the left carb connected to the petcock's vacuum nipple.

the underseat emissions crap is a vacuum operated valve that allows fresh air to be drawn into the reed valves (on side of head, large hose) to clean up emissions on decel conditions. also commonly causes lots of popping in exhaust.
03-28-2017 08:17 PM
Brooklyn_Vulcan
Quote:
Originally Posted by michiganteddybear View Post
a 't' fitting on the inlet side of the bowls is not a disaster, but it means that the petcock has been replaced with a single outlet, or one outlet does not work.

there is supposed to be a 't' on the bowl vents (connecting them together), with the other end of the 't' going to a spot with dead air (right side air filter box if still using them, or under tank someplace if the airfilters/airbox have been removed).

there is a vacuum line from the left (front) carb to the petcock (stock petcock), and the same location on the right carb (rear) goes to emissions control crap (if its still installed), or plugged if thats stuff has been removed.

sounds almost like you had originally connected the fuel lines from petcock to the bowl vents. that will dump fuel all over the place.
Quote:
Originally Posted by gidaeon View Post
Not really true. Myself and others run a replacement petcock with one output and T to each carb without issue (and have upped the pilot and jet sizes on top of that). If carbs drank gas at full gravity output from a fuel hose you'd be filling that tank in minutes.

OP- you could post pictures if you feel uncertain about any vac line plugged and your line routing.
Thanks to my friend Jo - she posted the pics ...the first two are of the current running bike....the last is a carb i recently bought with the hoses on...you can see the rear carb side vacum line has nothing hooked to it...other than where a cap should go in my belief..I strongly think the carb purchased is correct...Im just at a loss cause I havent put in a bike yet...and yet the other set up runs..

wrong pic sorry of the purchased..thats the front carb side...my error
03-28-2017 07:15 PM
gidaeon
Quote:
Originally Posted by jgs000 View Post
assuming its original petcock, one line to each carb, cheap petcocks with one output, I don't think they work, not enough gas to each carb using a "t"
Not really true. Myself and others run a replacement petcock with one output and T to each carb without issue (and have upped the pilot and jet sizes on top of that). If carbs drank gas at full gravity output from a fuel hose you'd be filling that tank in minutes.

OP- you could post pictures if you feel uncertain about any vac line plugged and your line routing.
03-28-2017 07:01 PM
Brooklyn_Vulcan so if understanding correctly - there are two vacum lines hooked together as one off the new T and thats what is restraining me?..because ?.almost like to positives working against ea other?....or too much draw of air in the line?
correct?
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