Author Topic: 400/4 won't idle when hot.  (Read 4440 times)

Offline Nurse Julie

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400/4 won't idle when hot.
« on: August 31, 2014, 03:27:33 PM »
Hi All  :)

Just been for a great ride on the Honda 400/4. Starts really easily, rides great, runs great except when the engine is hot she won't tick over. Revs just go down and down and down and then cuts out.Ticks over fine when cold. Any simple solutions most welcome. Anything more than simple will have to wait till off the road in winter !!  :-*

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Offline Trigger

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Re: 400/4 won't idle when hot.
« Reply #1 on: August 31, 2014, 04:08:40 PM »
give it a couple of paracetamol and tell it to come back in a week if there is no change ;).
« Last Edit: August 31, 2014, 04:11:32 PM by trigger6969 »

Offline Nurse Julie

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Re: 400/4 won't idle when hot.
« Reply #2 on: August 31, 2014, 04:57:01 PM »
Ha, bloody Ha. I was thinking of giving it an enema actually,I find that sorts most problems out, want one !!!
LINK TO MY EBAY PAGE. As many of you know already, I give 10% discount and do post at cost to forum members if you PM me direct.
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Offline Harold 400/4

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Re: 400/4 won't idle when hot.
« Reply #3 on: August 31, 2014, 05:34:43 PM »
Nurse Julie. Do you lose power when it's hot as well as it not ticking over??

Offline Bitsa (Ralph Wright - RIP)

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Re: 400/4 won't idle when hot.
« Reply #4 on: August 31, 2014, 07:09:41 PM »
Calm Down you gits tell her how to fix it thats if you know.
From what I can recall its the other way round cold tickover crap hot good.Sorry I just can not remember when I had a 400/4
Cheers
Bitsa

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Offline Harold 400/4

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Re: 400/4 won't idle when hot.
« Reply #5 on: August 31, 2014, 09:03:23 PM »
My 400/4 started stalling when it was hot, but I also lost power. Turned out to be a slight kink in the fuel line from the tank to the carbs which was restricting fuel flow.  All seemed ok when it was cold. Not sure this is what's up with yours but may be worth a check. Someone on here will have the answer. Good luck!

Offline Nurse Julie

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Re: 400/4 won't idle when hot.
« Reply #6 on: August 31, 2014, 10:16:37 PM »
Thanks to those of you that gave me some advice. It doesn't seem to loose power when hot, fly's along quite happily. Harold 400/4, I will look at the hose to make sure not kinked. And yes Bitsa, I am totally legit, no wind up. I'm a Nursing Matron who still see's the funny side of life. I have been a Nurse on and off for 34 years and have been riding bikes for 35 years. If people on this Forum want to have a laugh at my expense, that's fine by me. Just answer the question I ask as well and we will get on just fine. Must go now, on a night shift.
LINK TO MY EBAY PAGE. As many of you know already, I give 10% discount and do post at cost to forum members if you PM me direct.
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Offline Dan

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Re: 400/4 won't idle when hot.
« Reply #7 on: August 31, 2014, 11:22:02 PM »
Is the choke fully off? The nut holding the choke lever in place on my bike came loose once allowing the choke to come on and give similar symptoms. Obvious when I spotted it.

May need a carb clean otherwise.
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Offline Lobo

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Re: 400/4 won't idle when hot.
« Reply #8 on: September 01, 2014, 12:58:04 AM »
Hi Julie, never got to say welcome .... so, WELCOME!

Forgive me given your biking experience; I know this sounds daft, but the 400F at full choke will have a high tick-over due the choke mechanisms lifting the idle stop @ full choke. In other words... set the idle (1200) when the engine is warm.... and then expect high'ish revs at cold /from start up.

I assume the carbs are clean / balanced etc.

With the choke OFF, set the distance 'B' @ 0 to 0.3 mm / 0.012"
Start the engine, warm it up, and then via the throttle stop screw (top pic) set the idle to 1200 rpm.

You also might want to check the choke valves are fully opening... as a starter for 10 I'd simply check the linkage & grub screw (lower pic & bottom right'ish) are at indeed full travel stop when the choke lever is OPEN (ie choke OFF). Taking the Airbox off etc to visually check is a real pain....

If no use, then perhaps a carb clean & full set-up, though hopefully not necessary as you do say she's otherwise  running nicely.

Cheers,
Simon

(my better half a nurse, but alas shows nil interest in the bikes - so we refer them as 'the red one, the yellow one & the green one'. Any tips?)
« Last Edit: September 01, 2014, 02:46:26 AM by Lobo »

Offline Nurse Julie

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Re: 400/4 won't idle when hot.
« Reply #9 on: September 01, 2014, 09:15:20 AM »
Thanks Lobo and Dan. All sounds straight forward. Will have a tinker when I get time and let you know what happens.
LINK TO MY EBAY PAGE. As many of you know already, I give 10% discount and do post at cost to forum members if you PM me direct.
https://www.ebay.co.uk/sch/julies9731/m.html?item=165142672569&rt=nc&_trksid=p2047675.m3561.l2562

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline Nurse Julie

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Re: 400/4 won't idle when hot.
« Reply #10 on: September 03, 2014, 05:49:32 PM »
Hi All
Had a tinker today and bike idling just perfect now, it seems to be reving more freely too. Also re adjusted the mixture and she now feels very much like a flying machine.
Thanks for those that gave advice
Julie
LINK TO MY EBAY PAGE. As many of you know already, I give 10% discount and do post at cost to forum members if you PM me direct.
https://www.ebay.co.uk/sch/julies9731/m.html?item=165142672569&rt=nc&_trksid=p2047675.m3561.l2562

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline Bitsa (Ralph Wright - RIP)

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Re: 400/4 won't idle when hot.
« Reply #11 on: September 03, 2014, 06:49:48 PM »
Good for you I did like the 400s but to small for my big arse
Cheers
Bitsa
Long Live Best Bitter.Status Quo and Sohc Bikes and common sense which you can not teach

 

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