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Makotosun

Air and idle 73 dt3

  • principal282
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Air and idle 73 dt3 was created by principal282

Bike starts. Idles, albeit sketchy until warm. Not much power. Seems like when I hit the throttle not much happens,  then a sputter of fuel must hit.  Any ideas about the procedure for setting air and idle would be great.
Carbs just been cleaned up.  Fresh nice gas.  New fully charged yuasa batt. Not much fuss starting when warm. It's a  cranky when cold. 
04 Sep 2021 15:36 #1

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Replied by RT325 on topic Air and idle 73 dt3

No tricks to setting it, just 1.5 turns out so sounds like something else is the problem if you're sure every jet & airway is clean. Video would be great please. Not much power opens a can of worms if you mean it will barely drag itself along or an i misreading things. Battery won't affect starting or running. Lack of power has me thinking exhaust, or ignition points almost closed down, but getting way ahead of things as we know it. Choke jet is important for starting cold on a Closed Throttle. Jet is fixed in the bowl cavity. Shine a light down there, it's only wire brush strand size or thereabouts. Cranky when cold--yep look at that jet, & it only operates on a closed throttle. If it isn't blocked or restricted then when its running & warmed up, just put the choke on & see if it richens up things or increases revs through adding air & no fuel. Still on a closed throttle that is, but idling.
Better add, the choke jet draws from the bowl so its feed hole from the bowl can get crap in it. You can see how it feeds under the jet, so stuff can get lodged under the jet.
& i forgot the Oring on the jet setter but think you're describing a lean not rich issue so not relevant but'is' important all the same as goes drowning rich if that's stuffed or even missing. No7 in this link.
www.partzilla.com/catalog/yamaha/motorcycle/1973/dt3/carburetor
Last edit: 04 Sep 2021 16:05 by RT325.
04 Sep 2021 15:57 #2

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Replied by principal282 on topic Air and idle 73 dt3

New o ring and jet setter.
exhaust a possibility...

I thought (perhaps wrongly) that a dead battery would result in poor spark or misfiring. 

I'll try take a video again in a bit.
04 Sep 2021 16:19 #3

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Replied by RT325 on topic Air and idle 73 dt3

I have seen it written the battery is somehow involved but i'm yet to be convinced. If i use all my fleet as reference, none have the battery but run perfect. Take the DT1MX, they run the DT1 mag with lighting coils going nowhere & no battery--& no problem. But i believe the source coil is earthed withing the lighting coil, so if the lighting coil is rattling around on its post & shorting out it could compromise the source earth. Might've shot myself in the foot here as i 'think' with both mine i've removed loose lighting charging coils & earthed the source on its own. Always new things to learn & i'm still learning. But i vote for definitely not a battery problem in your case.
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Last edit: 04 Sep 2021 16:50 by RT325.
04 Sep 2021 16:49 #4

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Replied by principal282 on topic Air and idle 73 dt3

Pilot jet. Anything to set there? I just screwed it in so it's snug 
04 Sep 2021 17:44 #5

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Replied by RT325 on topic Air and idle 73 dt3

Yes jet itself is just snug & has a taper on the top end. They're nearly always overtightened & hard to crack free.
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04 Sep 2021 18:25 #6

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Replied by RT360Fan on topic Air and idle 73 dt3

Pilot jet snug. Yep, you're good
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04 Sep 2021 18:27 #7

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Replied by principal282 on topic Air and idle 73 dt3

Carb off again. No obvious gunk in choke passage. Slight bend on the mechanism.  Straightened and replaced. 

Tail pipe thing in two parts, why is that??
see photos
      
05 Sep 2021 08:53 #8

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05 Sep 2021 09:24 #9

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Replied by principal282 on topic Air and idle 73 dt3



05 Sep 2021 09:24 #10

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