Author Topic: Checking the valve timing on a 400.  (Read 2056 times)

Online McCabe-Thiele (Ted)

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Checking the valve timing on a 400.
« on: April 03, 2022, 04:57:39 PM »
Whilst working on my timing this afternoon I briefly got confused with where TDC is I started to use the 1-4 double mark on the right instead of the "T" on the far left.

That got me thinking if I could have made a similar mistake when I fitted the camshaft in place - I probably did not but I am concerned enough to need to double check.

Is it possible to check the valve timing without having to remove the top cover?
Honda CB500 K1 (new pit dug out ready)
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html

Offline Bryanj

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Re: Checking the valve timing on a 400.
« Reply #1 on: April 03, 2022, 05:30:20 PM »
Yes Ted, remove the tappet caps from the cylinder by the timing marks and rock the engine backwards and forwards over the T mark whilst observing the rocker arms, on one tdc they will not move(compression stroke) on the other (one turn of crank=1/2 turn of cam) the rockers will each move up and down an equal amount ( exhaust stroke tdc)


Hope that makrs sense

Online McCabe-Thiele (Ted)

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Re: Checking the valve timing on a 400.
« Reply #2 on: April 03, 2022, 05:57:58 PM »
Perfectly thanks Bryan.
Honda CB500 K1 (new pit dug out ready)
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html

Online McCabe-Thiele (Ted)

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Re: Checking the valve timing on a 400.
« Reply #3 on: April 05, 2022, 02:07:46 PM »
Well despite feeling crap I decided to check if my valve timing is as it should be.
Firsty with number 1 cylinder on Tdc I moved the engine forwards and backwards over the T mark neither moved. I then rotated the engine a half turn (2-3 T mark) I only observed movement on number 1 exhuast - number one inlet did not move.

Looks like I've messed up Bryan so I will need to get it sorted groan........it was going so well.
« Last Edit: April 05, 2022, 02:15:06 PM by McCabe-Thiele (Ted) »
Honda CB500 K1 (new pit dug out ready)
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html

Offline Bryanj

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Re: Checking the valve timing on a 400.
« Reply #4 on: April 05, 2022, 03:19:44 PM »
NO you dont check on 2/3 you both checks on 1/4 one at tdc comp one at tdc exhaust
You should move the CRANK one full turn which moves the CAM 1/2 turn

Online McCabe-Thiele (Ted)

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Re: Checking the valve timing on a 400.
« Reply #5 on: April 05, 2022, 04:49:11 PM »
Okay (again) the first thing I checked was with No:1 at Tdc on compression - both valves were shut with the right tapett clearance - rocking either side of "T" no movement at No1 rocker.

Tomorrow I rotate the engine one complete turn to look if both No:1 arms move at the same time one up one down when repeating the rocking at "T".
Honda CB500 K1 (new pit dug out ready)
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html

Online McCabe-Thiele (Ted)

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Re: Checking the valve timing on a 400.
« Reply #6 on: April 06, 2022, 07:43:19 AM »
All work stopped - last night we both tested positive for Covid. My temp is 102F.
Honda CB500 K1 (new pit dug out ready)
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html

Offline K2-K6

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Re: Checking the valve timing on a 400.
« Reply #7 on: April 06, 2022, 08:09:42 AM »
Oh no ! Hopefully you'll get these symptoms and nothing more serious as it seems to be running through this iteration of it.

Best wishes for you and Mrs Ted.

Offline Nurse Julie

  • 1977 CB550/4 Mongrel Brat. 1974 UK 500/4 K1. Honda CD250u.
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Re: Checking the valve timing on a 400.
« Reply #8 on: April 06, 2022, 08:53:15 AM »
I hope you both feel better soon Ted.
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 Rozabikes Tim

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Re: Checking the valve timing on a 400.
« Reply #9 on: April 06, 2022, 09:03:33 AM »
Take care both of you.
One day I'll have the time to restore it, not just talk and dream....

Offline smoothoperator

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Re: Checking the valve timing on a 400.
« Reply #10 on: April 06, 2022, 09:45:44 AM »
Put your feet up Ted and take it easy, the bike will wait for you. Get well soon.
Steve
2017 Triumph Bonneville T100
1977 Honda 400 Four Restored April 2022

Offline Laverdaroo

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Re: Checking the valve timing on a 400.
« Reply #11 on: April 06, 2022, 10:35:53 AM »
Go steady, and Mrs Ted

Get well soon mate.
Mornings are the invention of the devil!

1977 CB550F (current money pit!!)
2002 VFR800 VTEC (The Beloved)
1977 CB400F (the last money pit!)
1998 Ducati 748\853 conversion(sold :()
1980 ish CB750KZ in a billion bits (need to get rid, anybody want one?))

oldchuffer

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Re: Checking the valve timing on a 400.
« Reply #12 on: April 06, 2022, 11:38:21 AM »
Take it easy Ted, hope you both feel better soon.
Steve P

Online Johnny4428

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Re: Checking the valve timing on a 400.
« Reply #13 on: April 06, 2022, 12:04:33 PM »
Yes indeed! Rest, feet up, hope your symptoms are not too bad. Get well soon.
1952 Cymoto on Triumph bicycle.
1961 Matchless G3
1974 Honda CB550K1. Running resto,
1978 Honda CB550K3.
1999 ST1100 Pan European 50th Anniversary.
1975,1980,1984,1986 Honda C90’s
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Offline taysidedragon

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Re: Checking the valve timing on a 400.
« Reply #14 on: April 06, 2022, 12:09:06 PM »
Get well soon Ted, and the boss! 🤒🙂
Gareth

1977 CB400F
1965 T100SS

 

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