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I recently purchased a 1981 Ironhead and am going through a few maintenance issues since it has sat for several years. I had always thought that the ironheads had a manual choke on the right side behind the air cleaner although I can't find one. Could the choke actually be automatic or am I missing something? Can't wait to get it on the road. Thanks.
The choke **** is on the left side, near the ignition switch. The stiff wire from the choke **** connects to the high idle cam on the front of the carb, behind the front of the air cleaner housing.
Last edited by yellowstone kelly; May 20, 2012 at 10:10 PM.
Reason: corrected terminology
The choke **** is on the left side, near the ignition switch. The stiff wire from the choke **** connects to the high idle cam on the front of the carb, behind the front of the air cleaner housing.
Thanks Yellowstone - I'll check that out and let you know.
There is no **** on the left side although after I pulled the air cleaner and housing, I found a three-position lever on the right side of the carb that controls the butterfly. At the base of the lever is a cable nut although nothing is attached to it. I'm assuming that this is the manual choke but that brings up my next question. The carb looks original and is a Zenith. If there is no cable attached, how is the butterfly operated under differing fuel demands. The bike is running rough and backfiring and I'm now thinking that the butterfly may not be changing position when needed. What's the next step ??
That shoud have a Keihin carb on it, just an FYI. Zenith goes back a ways, Bendix came after those even. Pull the air cleaner off to see what going on.
That shoud have a Keihin carb on it, just an FYI. Zenith goes back a ways, Bendix came after those even. Pull the air cleaner off to see what going on.
I was expecting to see a Keihin on it but after pulling the air cleaner, it clearly has "Zeneith USA" stamped on the front (right) side.
there are two 'butterflies'; the front one is the choke. In your case it will be operated by any means you find works for you. Most have a stiff cable wire that runs between the juggs and is operated from the left side of the bike (sitting on the bike). but you can just reach behind the air cleaner and operate it if you don't have the cable.
the other is at the back of the throat of the carb and is operated by the throttle cable.
If your choke is open when you are riding then the tuning issue is something else.
there are two 'butterflies'; the front one is the choke. In your case it will be operated by any means you find works for you. Most have a stiff cable wire that runs between the juggs and is operated from the left side of the bike (sitting on the bike). but you can just reach behind the air cleaner and operate it if you don't have the cable.
the other is at the back of the throat of the carb and is operated by the throttle cable.
If your choke is open when you are riding then the tuning issue is something else.
That makes sense considering what Yellowstone Kelly said before too. If I understand it correctly, full choke would be with the butterfly closed (up and down orientation) and warmed up and running would be open (left and right orientation). Since this outer butterfly is only operated manually, then I'm assuming is does not respond to any action of the throttle after start-up.
It looks like to might be time to pull the carb and clean it up. Are the Zeniths any more complicated than others? There doesn't appear to be much information available on the web. Does anyone have a good reference or link?
... It looks like to might be time to pull the carb and clean it up. Are the Zeniths any more complicated than others? There doesn't appear to be much information available on the web. Does anyone have a good reference or link?
I believe that the Zenith and Bendix are the same; something about one company buying out the other. The 1970 to 1978 Service Manual 99484-78 has full information on the Bendix.
If I understand it correctly, full choke would be with the butterfly closed (up and down orientation) and warmed up and running would be open (left and right orientation). Since this outer butterfly is only operated manually, then I'm assuming is does not respond to any action of the throttle after start-up.
Yep, that's exactly the way mine works. The choke can move the throttle valve when pulled out, but the throttle has no effect on the choke plate.
The manual says there are 4 choke positions: **** pulled all the way out, the choke plate is vertical (full choke) and sets the throttle valve to highest idle for cold starting. Next position in and the choke plate is half open but keeps the high idle. Next position in the choke plate opens fully, but you still have the high idle position of the throttle plate. Choke **** all the way in sets the throttle plate to low idle.
In practice, I pull the choke **** all the way out to start, when the engine is cold, then push it in all the way after a few seconds and away I go.
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