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Old 04-14-2018, 05:04 PM   #1
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Default Help with 1973 CT 1

So I have had this 1973 CT 1 that I got 3 years ago and I finally got around to working on it.
Problem is it's hard to start when cold.
Kick ...runs for a second...repeat does same for 6 or 7 times.
Finally I guess its warm enough where I don't have to use the choke and can give it some throttle.
Once warm it runs great.
Carb is clean
floats are where they are suppose to be
pilot jet and circuit is clear and clean.
I don[t know the history of this bike
pilot jet is #35
Main is 180.
any ideas?


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Old 04-14-2018, 09:06 PM   #2
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I know your serial number starts with "CT1"... from 69 to 73 they all did. Check out the VIN listings though and if you really have a 1973 it's a "CT3" model.

There's a brass tube in the carb body that extends into a "well" in the float bowl. In the bottom of the well is a tiny jet that lets fuel from the main float bowl into the well which is then sucked up into the carb when the starter (choke) plunger is open. That jet is what they call the "starter jet" and is usually not removable or replaceable but can easily get partially or fully blocked and pulling the starter knob won't add enough fuel. Make super-sure that jet is not blocked or partially blocked. Clean it 20 times if you have to... just to be sure.
1970 CT1B
1979 DT175F
1991 RT180B
1963 Yamaha YG1-T "Trailmaster"
1965 Yamaha MG1-T "Omaha Trailmaster"
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Old 04-15-2018, 11:01 AM   #3
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I had the same(ish) problem with mine, exactly how you described. I ended up totally stripping down the carb and soaking it in pine-sol over night, complete with all jets etc.. then went at it with some hot water and an old toothbrush, then carb cleaner.. There must have been some hard to see orifices that were cleared out because it is a MUCH more reliable starter now.

To Evil!
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Old 04-15-2018, 02:55 PM   #4
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.... as mentioned many times in this forum.. when you think the carb is clean - clean it again, but what I've learned here has been extremely valuable... take a set of the long welding tip cleaners and go through all of the orifices but just be careful not to enlarge them - just clean. Then what I 've done is used spray carb cleaner and blast through those orifices one more time then used compressed air and blow through them again - where you can, in both directions. This solved a long standing issue I had and was really surprised at the gunk that came out even though I thought the carb was squeaky clean Randy
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Old 04-15-2018, 11:37 PM   #5
Rick C.
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If you use Pine sol, rinse with boiling water.
RINSE IT don't boil it in a pan.
It does leave a residue that can haunt you. Blow out all little openings with compressed air. and make sure you take out #4 ( main nozzle and do that ) EASY DOES IT !!! use a chopstick to pop it out of the top. Great tool to have on hand.


Listen to these guys. then ride soon.
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