slow return to idle
slow return to idle"63 CB 77. I've been searching the forum for this ailment and have come up with the obvious "air leak" but not too much else. A blip of the throttle to 2000 and it will return to idle no problem. A blip to 4000 and I'll be lucky if it returns at all and if it does it's VERY slow untill 2000 then it will drop right down. Plugs look good, I was looking for a white one indicating an air leak but went ahead and removed the carbs, checked the insulators for any warpage and replaced "O" rings with new. Fiddling with the mixture screws affects this problem very little. Cleaned and gapped the points and checked the timing which was a tiny bit off on the right so corrected that but no effect. Removed and checked air filters and boots and everything seems to be in order. The throttle cable is not hanging up and a visual check shows the slides snapping back down in unison. I should mention otherwise the motor runs great and this problem only seems to occur after the bike warms up a bit ( only a few minutes). Any suggestions on where to look next? Thanks
return to idleMy CB750 four would do this occasionally and in my case it was always related to linkage. I ended up adding an additional return spring to the throttle bar at the carbs....hope this helps.
68' 305 Dream, 75' Honda 750-four, 74' Honda CL 125, 72' Honda CA 70, 80' Honda Passport, 74' Aerimachi Harley Sprint 125, 64' Yamaha 90.
It's probably the ignition timing advancer spring that is a bit sloppy.
It probably needs replacement. Thats what I think it is if you are really sure that there are no air leaks, and you carb slides are oke. 'Of course I've already taken a very modest position on the monetary system, I do take the position that we should just end the Fed.' - Ron Paul
To confirm the advancer spring issue, remove the points cover, start engine, let it warm up so the idle problem occurs, then with the idle high, press on the end of the advancer cam to see if the idle returns to normal. The drag you'll put on the points cam should fully retard the advancer. Regards, Chase
Tried the pressure on the end of the shaft while it was running but didn't slow it down at all. This has got me totally perplexed so off comes the tank and the carb slides. Maybe I've missed something obvious. The fact that it only happens after the motor warms up must be a clue....thanks for the advice.
Re: slow return to idleDid you check the carb flanges for warpage? Sprayed carb cleaner or wd40 around the flange/insulators to see if it affects how it runs? Checked to make sure the float level is not too low? Checked jetting for #135 mains and #42 slow jet? Confirmed it has #24231 jet needle? If all of the above is okay and correct try raising the needle one notch at time. Dick Johnson
'61 CB92 '63 domestic CL72 Type 2 '63 CL72 '65 CL77 '66 CB77 '67 CB450D '71 SL350 '71 XS1B I would also do a static check of the play in the points cam with the bike off.
I did it and posted a video at one point, which LM confirmed was too much play. If you can wiggle it and post a video, we should be able to confirm or eliminate the cam springs, although it sounds like the running check described below did not indicate a spring problem.
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