Honda-SOHC

SOHC.co.uk Forums => CB350/400 => Topic started by: McCabe-Thiele (Ted) on April 03, 2022, 04:57:39 PM

Title: Checking the valve timing on a 400.
Post by: McCabe-Thiele (Ted) 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?
Title: Re: Checking the valve timing on a 400.
Post by: Bryanj 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
Title: Re: Checking the valve timing on a 400.
Post by: McCabe-Thiele (Ted) on April 03, 2022, 05:57:58 PM: Perfectly thanks Bryan.
Title: Re: Checking the valve timing on a 400.
Post by: McCabe-Thiele (Ted) 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.
Title: Re: Checking the valve timing on a 400.
Post by: Bryanj 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
Title: Re: Checking the valve timing on a 400.
Post by: McCabe-Thiele (Ted) 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".
Title: Re: Checking the valve timing on a 400.
Post by: McCabe-Thiele (Ted) on April 06, 2022, 07:43:19 AM: All work stopped - last night we both tested positive for Covid. My temp is 102F.
Title: Re: Checking the valve timing on a 400.
Post by: K2-K6 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.
Title: Re: Checking the valve timing on a 400.
Post by: Nurse Julie on April 06, 2022, 08:53:15 AM: I hope you both feel better soon Ted.
Title: Re: Checking the valve timing on a 400.
Post by: Rozabikes Tim on April 06, 2022, 09:03:33 AM: Take care both of you.
Title: Re: Checking the valve timing on a 400.
Post by: smoothoperator 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.
Title: Re: Checking the valve timing on a 400.
Post by: Laverdaroo on April 06, 2022, 10:35:53 AM: Go steady, and Mrs Ted

Get well soon mate.
Title: Re: Checking the valve timing on a 400.
Post by: oldchuffer on April 06, 2022, 11:38:21 AM: Take it easy Ted, hope you both feel better soon.
Steve P
Title: Re: Checking the valve timing on a 400.
Post by: Johnny4428 on April 06, 2022, 12:04:33 PM: Yes indeed! Rest, feet up, hope your symptoms are not too bad. Get well soon.
Title: Re: Checking the valve timing on a 400.
Post by: taysidedragon on April 06, 2022, 12:09:06 PM: Get well soon Ted, and the boss! 🤒🙂
Title: Re: Checking the valve timing on a 400.
Post by: McCabe-Thiele (Ted) on April 06, 2022, 03:31:27 PM: Thanks for your best wishes - atm it's a cough, slight fever, general fatigue, swollen throat glands, very sore eyes - plus the roundtuits count is below zero
So far proper Man Flu. lol
Title: Re: Checking the valve timing on a 400.
Post by: McCabe-Thiele (Ted) on April 10, 2022, 09:05:28 PM: Not sure if it's genuine shoots of recovery or that we opened a bottle of red this evening but I was driven into the garage for just 15 minutes this evening.
With spark plugs all out with some soft bungs wrapped in cloth over the plug holes checked the valve timing (again) as directed by Bryan.

Started with number 1 cylinder at Tdc mark - gently rocked the T bar a few degrees either side of T - no movement in the Inlet or Exhuast valve rockers. CHECK

Rotated the engine a full 360 deg turn so mark on Tdc again (exhuast stroke) -gently rocked the T bar either side - both Inlet & Exhuast valves moved immediately up & down at the same time either side. CHECK

Looks as though I had just forgotten how I did it all those months ago so all anxious over nothing. On re- reading my CB400 & CB550 Haynes Manual I do recall it flitted between the two models but the photo markings in the book clearly show the T mark.................................relief.

Anxiously awaiting affirmation from Bryan ...........
Title: Re: Checking the valve timing on a 400.
Post by: Bryanj on April 11, 2022, 07:07:12 AM: Sounds good to me and the valves cant be hitting as it turns over easily!
Title: Re: Checking the valve timing on a 400.
Post by: McCabe-Thiele (Ted) on April 11, 2022, 10:10:47 AM: Quote from: Bryanj on April 11, 2022, 07:07:12 AM
Sounds good to me and the valves cant be hitting as it turns over easily!

Thanks for your guidance Bryanj. Cheers Ted
Title: Re: Checking the valve timing on a 400.
Post by: McCabe-Thiele (Ted) on May 04, 2022, 04:12:52 PM: Yesterday I spent some time reading my Project Board Rebuild Blog from the start there was a photograph I had taken from when I fitted the timing chain - including the timing mark at 1/4 TDC all that angst for nothing! lol

P19 there was this photo here so I did fit it at TDC mark - I took a photo but did not type text in my documented log.

(https://live.staticflickr.com/65535/51509828202_f057dcacca_k.jpg) (https://flic.kr/p/2mtKkmf)TDC crank marks (https://flic.kr/p/2mtKkmf) by Macabe Thiele (https://www.flickr.com/photos/187487200@N03/), on Flickr