Messed up my carbs? - Triumph Forum: Triumph Rat Motorcycle Forums
Hinckley Classic Triples 885cc Classic Styled T3's: Legend, Thunderbird, Thunderbird Sport & Adventurer.

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post #1 of 37 (permalink) Old 04-07-2019, 05:50 PM Thread Starter
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Messed up my carbs?

So I opened up the airbox on my '00 Thunderbird. Dismantled and rejetted my carbs. Put in 42 pilots and 140 main jets, set my slow screws to 2-1/2 turns out, put in new float needles and left the height at about 19mm. Now the bike won't start. Turns over but sounds like no gas. FRACK!
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post #2 of 37 (permalink) Old 04-09-2019, 11:40 AM
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s km

Time to backtrack. "Where did I go wrong?" First time I did one of these [16-17 yrs. back], I got it a block down the street [downhill of course] and it quit. Had a neighbor help me get it back in my shop and found I kinked the fuel line putting the tank back on. Just have to go back over it carefully. ...J.D.
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post #3 of 37 (permalink) Old 04-09-2019, 12:54 PM
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Open one of the bowl drains and see if fuel comes out.

Pull one of the spark plugs out. Wet or dry? Does it spark?

John
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post #4 of 37 (permalink) Old 04-10-2019, 07:13 AM Thread Starter
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Yeah, pretty bummed to not have it run after all that work. (For me it was all a new experience) There is fuel in bowls. It sounds as though it's sparking. I'd be surprised if it isn't.
I did change the plugs but the rest of the ignition ran before I did the carbs and air filter mod. I will pull one plug to make sure it's sparking. I guess Backtracking is my plan. Take the cabs off again and make sure everything is clear. Thanks.
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post #5 of 37 (permalink) Old 04-10-2019, 03:28 PM
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Do you smell gas as you're cranking with no sputtering/sparking?
42 mains may be a little rich for startup at 2.5 turns, even with air intake mods. You may want to back down to 2 turns.
Mine are happy at 1 7/8 turns.
Also, since the carbs were off, hopefully you didn't disturb the balance screws...that will also add problems at cold starts.

One problem with these motors is that they can be very picky at startup.
Make sure your battery is nicely juiced up, and then go after confirming your spark if nothing fires.

Good Luck!

Dan
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post #6 of 37 (permalink) Old 04-11-2019, 05:49 AM Thread Starter
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Quote:
Originally Posted by Jamanimal View Post
Do you smell gas as you're cranking with no sputtering/sparking?
42 mains may be a little rich for startup at 2.5 turns, even with air intake mods. You may want to back down to 2 turns.
Mine are happy at 1 7/8 turns.
Also, since the carbs were off, hopefully you didn't disturb the balance screws...that will also add problems at cold starts.

One problem with these motors is that they can be very picky at startup.
Make sure your battery is nicely juiced up, and then go after confirming your spark if nothing fires.

Good Luck!

Dan
I did try charging the battery with my car. Didn't think it would help but figured it was worth a try.
The bike definitely cranked better but still no start. There is gas in the float bowls but I do not smell any near the engine or exhaust. Ballance Screws? Not sure. I looked at bench syncing the carbs but the the butterfly valves all seemed pretty tight in line with each other. I'll go over it all again this weekend.
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post #7 of 37 (permalink) Old 04-11-2019, 04:47 PM
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Don't really think your pilot jet or mixture adjustment would be the problem. If it is a little rich it would probably start easier. I am wondering what your bench settings are on your throttle butterflys. Should be a spec. for that somewhere [I don't have it at hand]. You would measure the distance between the butterfly and the throttle bore and set all three the same. Then after you get it running you can balance the carbs. ...J.D.

Last edited by Wire-Wheels; 04-12-2019 at 09:51 AM.
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post #8 of 37 (permalink) Old 04-15-2019, 08:49 AM
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Maybe be sure the float needles are correct. If there is fuel in the bowls , not sure why it wouldn't run, even if it ran poorly still should start .
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post #9 of 37 (permalink) Old 04-15-2019, 08:47 PM
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Real dumb thought but I did it when I rebuild something on my bike. Did you hook the spark plug wires up to the right cylinder? I spent 4 days fighting my own stupidity.
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post #10 of 37 (permalink) Old 04-15-2019, 09:15 PM
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Did you block the air vent of the tank??


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