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Discussion Starter #1
Ok I finally got a new carb and installed it. It has a 116 main jet in it now. And the needle is shimmed at the second notch. The bike will not idle. Barely even starts. And when it does, it will only run with the choke on full. And only for a short time. The mixture screw is out 2.5 turns. Any ideas?
 

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A new carb built specifically for your bike should come with the right jets, shims and pilot adjustment shouldn't it? (although it may be lean for emissions) This is a new carb? Or did you mess with it before installing it?
 

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Discussion Starter #3
A new carb built specifically for your bike should come with the right jets, shims and pilot adjustment shouldn't it? (although it may be lean for emissions) This is a new carb? Or did you mess with it before installing it?
Used.
 

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Discussion Starter #4
I have an airbox mod though. And it's still idling just like it was when the carb body was cracked. I don't know what to do at this point. There are no air leaks left. It's idling scary high with the choke on. The exhaust is also popping.
 

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Discussion Starter #5
All I did was clean it. So could be the wrong setup for my bike. Should I go back to the 114? I should keep the shim for my airbox mod right?
 

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Not sure what your air box mod is - but it's still running way rich if the exhaust is popping

Go back to 114 and start from there .....

(What is the air box mod) ?
 

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OH GOODY! Here we go again. Never, never, ever mess with jets and shims in a carb that is not already running right! So you bought a used carb and cleaned it and then went and did some fiddling in it before you ever knew if it was a working carb. Not cool IMO. You just don't honestly know if there is some orifice in it clogged or even if there is some reason why the seller sold it. It only takes a tiny little issue to make a carb not work right so my suggestion is to take it off, disassemble it completely and soak the body in carb cleaner, maybe for a few days or a week. Then you inspect all the little passages and if possible push a thin wire through them all. Start with all good stock jets, O rings, needle valve and the diaphragm and make sure you put it all in correctly. Once you get the bike running right you can then try to make it run better with different jets and shims. You just don't know now if it is something you did or if the carb has some internal issue tossing you off.

GaryL
 

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Discussion Starter #8
OH GOODY! Here we go again. Never, never, ever mess with jets and shims in a carb that is not already running right! So you bought a used carb and cleaned it and then went and did some fiddling in it before you ever knew if it was a working carb. Not cool IMO. You just don't honestly know if there is some orifice in it clogged or even if there is some reason why the seller sold it. It only takes a tiny little issue to make a carb not work right so my suggestion is to take it off, disassemble it completely and soak the body in carb cleaner, maybe for a few days or a week. Then you inspect all the little passages and if possible push a thin wire through them all. Start with all good stock jets, O rings, needle valve and the diaphragm and make sure you put it all in correctly. Once you get the bike running right you can then try to make it run better with different jets and shims. You just don't know now if it is something you did or if the carb has some internal issue tossing you off.

GaryL
True. That's just how it came. I'll soak it in my ultra sonic and clean it real good.
 

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True. That's just how it came. I'll soak it in my ultra sonic and clean it real good.
That was not a slam on you! Many of us have been through this problem a number of times and it always seems to turn out the same. Auto stores sell a carb cleaner in a one gallon paint can that does work great on these carbs, think it is Bikirk's or something close to that name and the carb fits right in the can. You can use it hundreds of times until it is filthy. The point I am trying to drive home is know that the carb is OK before you try tweaking the jets and other stuff. The ultrasonic might work too but you can lose a lot of hair chasing carb issues to find the tiny problem with them.
Just for fun, I bought a used carb for $100 and then bought all the parts to completely rebuild it with OEM Yamaha innards, all of them. That cost me another $105. The used carb still did not run right so I bought a brand new old style carb from Boats.net for $263 and put it on and drove away very happy.

GaryL
 

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....Auto stores sell a carb cleaner in a one gallon paint can that does work great on these carbs, think it is Bikirk's or something close to that name and the carb fits right in the can...
GaryL
Hi Gary!



Good for dissolving body parts too.

If I remember some of your old posts, it's possible to put that old carb back together with parts in the wrong place.

jb
 

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Hi Gary!



jb
YUP! Brain cramp I guess but that is some good stuff for these old carbs. I was off a day or two somewhere else here also so I guess I am just getting too old for this crap!

Thanks JB.

GaryL
 

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I had my carb of probably 6 times before I got the bike running half decent then I realized it was the CDI causing all my problems..Well the bikes problems mine are a work in progress.
 

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Discussion Starter #14
Your probably running lean. Running lean will cause popping.
Air/fuel is not right or you have a vacuum leak.

The stock TW carb sucks balls. Do the BW200 carb mod.
Must be the mixture. All leaks have been checked.. A lot.
 

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I agree that you are probably running lean;
1. have to choke to get it to run at all
2. pops

Try this;
Take off the air cleaner.
Try to start the bike.
put your hand over the carb intake where the air cleaner was.
If the bike will continue to run with your hand completely blocking the intake air flow, you have a bad carb or a bad boot between the carb and the motor that is sucking air someplace it's not supposed to.


Also verify your tank and petcock are able to flow sufficient gas by taking the fuel line off the carb and testing the petcock. Gas should flow free. Then connect to your carb with the bowl off and also verify the fuel will flow free through the drain screw.

The point is; with air and fuel the bike will run. It's just a matter of the ratio. Yours sounds like there is too much air for the amount of fuel. By confirming the very basics of where the air and where the fuel come into the carb, you eliminate other, outside sources of problems with the mix ratio.
 

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Must be the mixture. All leaks have been checked.. A lot.
Did you check the intake boot very well, sometimes the crack is under a clamp. If you get it to start spray starter fluid at the boot and see if it changes the rpm's. If it does then it sucking air in through there. The crack in mine was difficult to see.
 

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If ya don't have starter fluid spay like Ebbanflood but have WD-40 try that. I sprayed WD on a suspected carb boot leak and the engine stalled after spraying. Confirmed results a couple more times. Now I just have to find the exact point of origin. Lazy ain't looked yet!
 

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Discussion Starter #18
I agree that you are probably running lean;
1. have to choke to get it to run at all
2. pops

Try this;
Take off the air cleaner.
Try to start the bike.
put your hand over the carb intake where the air cleaner was.
If the bike will continue to run with your hand completely blocking the intake air flow, you have a bad carb or a bad boot between the carb and the motor that is sucking air someplace it's not supposed to.


Also verify your tank and petcock are able to flow sufficient gas by taking the fuel line off the carb and testing the petcock. Gas should flow free. Then connect to your carb with the bowl off and also verify the fuel will flow free through the drain screw.

The point is; with air and fuel the bike will run. It's just a matter of the ratio. Yours sounds like there is too much air for the amount of fuel. By confirming the very basics of where the air and where the fuel come into the carb, you eliminate other, outside sources of problems with the mix ratio.
Thanks! Great write up. I'll give it a go around Sunday before work and see where I'm at then.
 

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Discussion Starter #19
Did you check the intake boot very well, sometimes the crack is under a clamp. If you get it to start spray starter fluid at the boot and see if it changes the rpm's. If it does then it sucking air in through there. The crack in mine was difficult to see.
It's brand new. New oring as well
 

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Discussion Starter #20
Ok I decided just to pull it out and go through everything... After it wouldn't even start! Very very very clean. All of the Jets and passages are clear and clean now. So, is this the correct float height? Normal operation?
 
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