Author Topic: no fast idle on cold start-up  (Read 1477 times)

eamartin

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no fast idle on cold start-up
« on: November 18, 2017, 10:37:42 AM »
2011 Super 8 2T, if the bike is started daily it starts right up and idles.  Sometimes it fast idles properly until it warms up (bystarter functioning properly).  Sometimes it never fast idles (bystarter circuit not open?).  When it does fast idle when cold as it should, it starts, it idles at regular rpm's for a few seconds before transitioning to fast idle.  My understanding is that malfunctioning bystarters fail in the open position (fast idle).  If my problem is the bystarter, it seems to be failing in the closed position.  Any ideas on this?

CROSSBOLT

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Re: no fast idle on cold start-up
« Reply #1 on: November 18, 2017, 04:10:09 PM »
One idea is to remove the bystarter from the carb, leave it plugged in and turn on the key. Watch the plunger on the bystarter to see if it moves. Better to hook it to 12 volts (spare battery, car battery) so you won't discharge your bike's battery.

Karl
Karl

Three motorcycles 1960-1977 (restored a 1955 BSA)
Agility 50
Yager 200i
Downtown 300i
Navy tech, Ships Engineer, pilot and aircraft mechanic

eamartin

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Re: no fast idle on cold start-up
« Reply #2 on: November 18, 2017, 06:34:09 PM »
When I cleaned the carb, I bench tested the bystarter with another 12v battery I had handy.  The bystarter heated up as it should and the needle moved maybe 1/8" or so.

CROSSBOLT

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Re: no fast idle on cold start-up
« Reply #3 on: November 19, 2017, 02:00:30 AM »
Well, starting to sound like it is not consistent which may be an electrical intermittent. There is a resistor in that circuit, I think, that may have a couple of push-on terminals.

Karl
Karl

Three motorcycles 1960-1977 (restored a 1955 BSA)
Agility 50
Yager 200i
Downtown 300i
Navy tech, Ships Engineer, pilot and aircraft mechanic

eamartin

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Re: no fast idle on cold start-up
« Reply #4 on: November 19, 2017, 02:55:52 AM »
You are correct.  And I tested that resistor some months back.  It was within range at that time.  I'll do a variety of tests tomorrow and report back.

CROSSBOLT

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Re: no fast idle on cold start-up
« Reply #5 on: November 19, 2017, 01:44:39 PM »
My point is some electrical intermittents are bad contact either terminal to terminal or wire to teminal. Very hard to find, easy to fix.

Karl
Karl

Three motorcycles 1960-1977 (restored a 1955 BSA)
Agility 50
Yager 200i
Downtown 300i
Navy tech, Ships Engineer, pilot and aircraft mechanic

eamartin

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Re: no fast idle on cold start-up
« Reply #6 on: November 19, 2017, 02:48:01 PM »
Thanks for reiterating your point.  I saw "resistor" in your comment and thought, "Oh, I checked that already.".  But I  did not pay close attention to the actual point of your comment.  To be continued.....

eamartin

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Re: no fast idle on cold start-up
« Reply #7 on: April 23, 2020, 02:59:51 PM »
Karl,  Stay tuned.  I may have new information on this. 

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