Author Topic: Valves, can the stem be bent?  (Read 1350 times)

Offline Eldrick

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Valves, can the stem be bent?
« on: June 14, 2024, 02:31:37 PM »
 Just cleaning the valves and seats on the bike, removing them one at a time. I noticed one of them needed tapped with a hammer to get it out. (#1 cylinder). After the springs were removed the valve is tight in the socket so I removed #2 valve and that runs free in #1. The #1 is tight in #2 so I am guessing I need at least one new valve.
Am I correct with my reasoning?
 When the bike was running last week there was nothing wrong with the firing on #1 however, I don’t want to ‘force’ the valve back in if it is a sign that the valve may not function when the bike is running. I did run some 400grit sandpaper over the stem to clean that up, it did not make any difference to the tightnes of the fit.
1975 Honda CB400f - Red

Offline Nurse Julie

  • 1977 CB550/4 Mongrel Brat. 1974 UK 500/4 K1. Honda CD250u.
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Re: Valves, can the stem be bent?
« Reply #1 on: June 14, 2024, 02:46:49 PM »
Yes, the valve could be bent, or the valve guide may have a crack in it.
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Offline McCabe-Thiele (Ted)

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Re: Valves, can the stem be bent?
« Reply #2 on: June 14, 2024, 02:57:01 PM »
I think I have a good  used valve spare - yours foc for the cost of postage.
I need to double check first that it's not the inlet I have.
I'm out at the moment so will be a couple of hours.

Update  I have one ex: & one in: valve both serviceable - they look original factory cut angle. PM me which one you need plus your address. cheers Ted
« Last Edit: June 14, 2024, 03:54:30 PM by McCabe-Thiele (Ted) »
Honda CB400NA Superdream (current money puddle)
Honda CB500 K1 (second money pit)
https://www.sohc.co.uk/index.php/topic,28541.0.html
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html
This is a neat 500 restoration in the USA.
http://forums.sohc4.net/index.php/topic,151576.msg1731556.html#msg1731556

Offline Bryanj

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Re: Valves, can the stem be bent?
« Reply #3 on: June 14, 2024, 03:29:57 PM »
Yes it could be bent or the stem is mushroomed

Offline Eldrick

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Re: Valves, can the stem be bent?
« Reply #4 on: June 14, 2024, 03:52:33 PM »
I think I have a good  used valve spare - yours foc for the cost of postage.
I need to double check first that it's not the inlet I have.
I'm out at the moment so will be a couple of hours.

It is the Inlet valve (larger of the two heads) that is sticking so if you have one I would be grateful, if not I will source one.
1975 Honda CB400f - Red

Offline McCabe-Thiele (Ted)

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Re: Valves, can the stem be bent?
« Reply #5 on: June 14, 2024, 03:55:19 PM »
See my updated post & ,PM me.👍
Honda CB400NA Superdream (current money puddle)
Honda CB500 K1 (second money pit)
https://www.sohc.co.uk/index.php/topic,28541.0.html
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html
This is a neat 500 restoration in the USA.
http://forums.sohc4.net/index.php/topic,151576.msg1731556.html#msg1731556

Offline Eldrick

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Re: Valves, can the stem be bent?
« Reply #6 on: June 14, 2024, 05:47:48 PM »
See my updated post & ,PM me.👍

Thank you
1975 Honda CB400f - Red

Offline McCabe-Thiele (Ted)

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Re: Valves, can the stem be bent?
« Reply #7 on: June 15, 2024, 12:43:09 PM »
Item posted out today should arrive by Wednesday.
Honda CB400NA Superdream (current money puddle)
Honda CB500 K1 (second money pit)
https://www.sohc.co.uk/index.php/topic,28541.0.html
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html
This is a neat 500 restoration in the USA.
http://forums.sohc4.net/index.php/topic,151576.msg1731556.html#msg1731556

 

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