Author Topic: Initial valve adjustment after rebuild  (Read 1185 times)

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Offline Scott S

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Initial valve adjustment after rebuild
« on: April 15, 2012, 09:30:59 AM »
 I just did a top end rebuild on my CB550 (overbore, ported head, CB650 cam) and it's time to adjust the valves.

 I have a manual and I know how to adjust the valves, at least when the engine has been previously running.
 However, I backed all the adjusters out and used the rubber band trick when re-installing the head. How do I know if the cam lobes are on #1 for proper valve adjustment?

 I have the timing mark on 1/4 and I can look into the spark plug hole and see the #1 piston at TDC, but so is #4. Normally, I'd check to see if the tappets are loose on that cyl. and then adjust it (and the others that line up with that mark), but they're ALL loose because of the rebuild.

 How do I get started?
'71 CB 500 w/ CB650 engine
'78 CB550K
'75 Yamaha XS650
'87 Yamaha Radian
 and too many projects...



Offline DavePhipps

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Re: Initial valve adjustment after rebuild
« Reply #1 on: April 15, 2012, 09:46:57 AM »
Funny, I'm having exactly the same problem  :o
I'm hoping someone can help us out. I want to ride the cb500 again.
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78 GL1000
72 CB500K



Offline Grey

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Re: Initial valve adjustment after rebuild
« Reply #2 on: April 15, 2012, 10:21:19 AM »
As long as your #1 piston is at the top it doesn't know if it's on the compression or exhaust stroke UNTIL you put the cam in. Then when you put the cam in it should have the lobes pointing away from the rockers so the base circle is where the rocker lays on the cam. At this point the cam/sprocket should have have some type of alignment marks. The FSM should indicate what those mark align to. Then move the cam to that position and put the chain on so the marks are still aligned to what ever the book says. Then set valve clearance to #1 and proceed from there.

If you have a degree wheel, dial indicator and know how to use it, you then can check alignment according to the cam specs. ex should be X degrees (on degree wheel) at X (like 40mm) amount of lift AT the cam and not the rocker/valve retainer unless the rockers are 1:1 ratio. I don't know any rockers that are 1:1. That's why you can't check at the rocker/valve retainer.

Just looked up what the alignment marks are here's what the book says:

Position spark advance mark to the 1-4 line to the timing mark on the case. Position the cam shaft so the center notch on the right end of the camshaft is aligned to the cylinder head flange surface. Then mount the camshaft sprocket.
 
This is for the stock 550 cam. I'm assuming the 650 cam is the same. I don't have a 650 manual so I don't know for sure if the 650 is the same.
 
« Last Edit: April 15, 2012, 10:41:01 AM by Grey »



Offline DavePhipps

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Re: Initial valve adjustment after rebuild
« Reply #3 on: April 15, 2012, 10:40:11 AM »
So, basically take the cam cover off, rotate till cam mark is aligned. Replace cam cover and set #1?
Bikes:
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74 CB550k
78 GL1000
72 CB500K



Offline Grey

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Re: Initial valve adjustment after rebuild
« Reply #4 on: April 15, 2012, 10:43:35 AM »
Yep.



Offline Bailgang

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Re: Initial valve adjustment after rebuild
« Reply #5 on: April 15, 2012, 10:44:13 AM »
During a full a complete 4 stroke cycle (720 deg crank rotation) the piston will come to top dead center twice, once at the end of the exh stroke/start of the int stroke and again at the end of the comp stroke/ start of the power stroke and it's at  TDC where it has stopped its comp stroke and beginning it's power stroke is when you want to adj the valves for that cyl. So if your timing marks are showing 1 and 4 are at TDC and say for example the #1 cyl rockers are loose but #4 are tight then it's the #1 cyl that is at TDC at the end of it's comp stroke/start of it's power stroke and those are the rockers you adjust first.

Once you're done with the #1 cyl then rotate the crank 360 degrees onto the 1-4 TDC timing mark again and the #4 rockers should be loose now and you can adjust that. The same goes for the 2-3 cyls, once you have the timing mark showing 2-3 are at TDC then check to see which of the cyls rockers are loose and do that one and so on. Get the idea?

What's going on is that say when #1 cyl is firing on it's power stroke then that means #4 is on it's intake stoke, the same goes for 2-3.
Bail is my last name guys so just call me Scott


73 cb750 k3
75 cb550 k1
77 cb750F
98 cbr600 f3



Offline Bailgang

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Re: Initial valve adjustment after rebuild
« Reply #6 on: April 15, 2012, 10:56:35 AM »
Normally, I'd check to see if the tappets are loose on that cyl. and then adjust it (and the others that line up with that mark), but they're ALL loose because of the rebuild.

 How do I get started?

Whoops my bad, I didn't spot that at first Scott. Sorry for telling you something you already knew.
Bail is my last name guys so just call me Scott


73 cb750 k3
75 cb550 k1
77 cb750F
98 cbr600 f3



Offline Scott S

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Re: Initial valve adjustment after rebuild
« Reply #7 on: April 15, 2012, 11:53:42 AM »
 There are no marks on the 550 cam sprocket. Here's how I did it...which is taken directly from my genuine Honda manual:

 " Adjustment of valve timing.
  Remove the point cover, rotate the crankshaft in the clockwise direction and align the "T" (1.4) mark of the spark advancer to the timing mark. Next, position the camshaft so that the center of the cutout notch on the right end of the camshaft is aligned to the cylinder head flange surface."

 There is a diagram and that's how we did it.
 Then, it just says to mount the sprocket to the cam shaft...we just put it on and bolted it together. I don't have a degree wheel.
'71 CB 500 w/ CB650 engine
'78 CB550K
'75 Yamaha XS650
'87 Yamaha Radian
 and too many projects...



Offline DavePhipps

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Re: Initial valve adjustment after rebuild
« Reply #8 on: April 15, 2012, 03:32:45 PM »
unfortunately this didn't work out well for me.
Can I get a step by step with the cam cover in place?
Bikes:
90 FZR600 RA
74 CB550k
78 GL1000
72 CB500K



Offline DavePhipps

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Re: Initial valve adjustment after rebuild
« Reply #9 on: April 15, 2012, 03:39:30 PM »
Just found a method that bwaller suggested in another thread
http://forums.sohc4.net/index.php?topic=50774.0
I'll give it a shot after homework and thunderstorms are done
Bikes:
90 FZR600 RA
74 CB550k
78 GL1000
72 CB500K



Offline Scott S

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Re: Initial valve adjustment after rebuild
« Reply #10 on: April 15, 2012, 07:05:55 PM »
 The method he mentions in that other thread, where you can adjust four valves, rotate it 360 degrees and then adjust the other four, is the method listed in my Honda manul. Easy....if everything has already been adjusted before.

 We figured it out. Basically, tightened up slightly on ALL adjusters...just to get us closer than a mile away. Then, set it on the 1.4 mark, tried to determine if the #1 cyl. was on compression stroke and adjusted the 4 valves listed. Turned the engine over once and figured out that #1 was NOT on compression stroke, but #4 was.
 Readjusted for #1 again, rotated engine, adjusted four remaining valves.
 Adjusted cam chain again (we had done it after the re-assembly), rotated the engine a couple of times and rechecked all clearances. That got it.
'71 CB 500 w/ CB650 engine
'78 CB550K
'75 Yamaha XS650
'87 Yamaha Radian
 and too many projects...



Offline DavePhipps

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Re: Initial valve adjustment after rebuild
« Reply #11 on: April 15, 2012, 07:37:16 PM »
You did better than me. NOthing was working right so I took the cam cover off and found that I set the notch to 2-3 instead of 1-4.
Now that that's fixed I'm finally able to adjust mine.
Bikes:
90 FZR600 RA
74 CB550k
78 GL1000
72 CB500K

 

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