Author Topic: #*$&#$ Valves - CB650 Nighthawk (Read 2940 times)

jeepster · « **on:** September 03, 2009, 09:21:44 PM »

Confused... Clymer is saying that a cylinder at TDC should have "free play" in it's rocker arms. How much free play? Also, if the rocker arms have "free play" wouldn't they become tight once you adjust the valve??? So the next revolution of the crank back to cylinder 1, TDC, they should be at .002 and .003...i.e. tight. With no free play. WTF??

Also, is there any way to tell by looking at the position of the cam which cylinder is at TDC?

jeepster · « **Reply #1 on:** September 03, 2009, 10:37:30 PM »

Anybody? I'm trying to look online and now am even more confused...The clymer says to turn the engine to T 1.4 so the #1 cylinder is at TDC, then ROTATE THE CRANK 360 #$%*ING DEGREES so that the #4 cylinder is at TDC??!?!! Isn't #4 at TDC when #1 is at TDC??!!

Is this a typo??!!

Frankenkit · « **Reply #2 on:** September 03, 2009, 11:18:13 PM »

It's kinda confusing.
Here's how the Honda shop manual describes it:
"Rotate the crankshaft clockwise and align the "1.4T" mark with the index mark. Make sure the #1 piston is at TDC of the compression stroke.
(both of the rocker arms on 1 should have free play, as in on the low egg-curve of the cam lumps, instead of the pointier rises. You should be able to wiggle both freely.)

At that point, you measure the valve clearance for the valves by putting the feeler gauge between the camshaft and the rocker arm 'slippers'.

Honda's manual says 0.05mm(0.002 in) on the intake and 0.08mm (0.003in) on the exhaust.
Hondaman suggests 0.05mm (0.002 in) on the intake, and 0.005in on the exhaust for valve longevity.

With Cyl. 1 at TDC compression, you check IN and EX on 1, then the EX on 2, and the IN on 3.

Adjust so there's just a little drag on your feeler gauge, then double check with the next size up- make sure it won't go in. Go-nogo gauging.

Torque that lock nut down to 9-12 ft-lb, according to the honda manual, (this is where that little tool comes in REAL handy, otherwise that adjustment screw moves pretty easily.) Recheck just to make sure, because you just know the darn adjustment screw moved.

Rotate the crankshaft one full turn clockwise (the way the wheels go, for a mental picture). (here's your 360*)
Align the 1.4T mark with the index mark again. This time 4 should have the same play that 1 had on both the little rocker arms.

Check and adjust IN and EX on 4, then EX on 3 and IN on 2.

This is about verbatim out of the honda manual with my additions here and there. I can't pretend to be any kind of expert, I watched Paulages do mine, and related it to you the way I did so if I need to check my valves, I can come back and read it all in one place.

We've all gotta be newbies sometime, let's be newbies together, right?

Buber · « **Reply #3 on:** September 03, 2009, 11:52:35 PM »

I have a different approach to valve setting. So first - when the valve must have its biggest "free play"? Logically (and technically) if I want to set for example, exhaust valve on the 1st cylinder, then I will set the crankshaft, so that the inlet valve is at its working position, that is, pushed by crankshaft. And then I will set the ex valve. Actually I go a little further. I will use here mm, but it doesn't matter. So, when e.g. exhaust should have 0.08 mm, I will squeeze in (by lifting the valve a bit) the 0.09 feeler, and the I will rotate slowly the crankshaft to find it there's the moment when the gap widens - feeler becomes loose. Usually I find this spot very easily (it's just before the opposite valve gets lifted) and I would set the valve at this spot. And proceed that way with all of them. That way I don't even need to think about tdc, which valves to set now, etc. I just do them one by one. And it works flawlessly.

Hush · « **Reply #4 on:** September 04, 2009, 12:05:42 AM »

Yo Jeepster.
Because the valves work on a cam and the lobes are offset once you have set #1 cylinder valves then you need to rotate 360% so the cam now allows the #4 valves to fully open, if they were all open or closed at the same time they would have to be both firing at once (if you could get the spark to arrive in time

)

I also have a wee trick (don't we all) I remove plug #1 and slip a longish screwdriver into the cylinder, as I rotate the engine the screwdriver will go up and down, when I see that the screwdriver cannot raise any higher that has to be TDC, just an old habit from my teenage years.

Nice description Kit

even I understood that!

Frankenkit · « **Reply #5 on:** September 04, 2009, 12:33:41 AM »

Quote from: Hush on September 04, 2009, 12:05:42 AM

I also have a wee trick (don't we all) I remove plug #1 and slip a longish screwdriver into the cylinder, as I rotate the engine the screwdriver will go up and down, when I see that the screwdriver cannot raise any higher that has to be TDC, just an old habit from my teenage years.

Nice description Kit even I understood that!

I suggest you go with a long straw from McD's or somewhere instead of the screwdriver. Don't want to risk jamming the screwdriver in w/ the piston and marring the sides of the cylinder

I've heard horror stories, that's all...

jeepster · « **Reply #6 on:** September 04, 2009, 01:09:54 AM »

Quote from: Kit on September 03, 2009, 11:18:13 PM

It's kinda confusing.
Here's how the Honda shop manual describes it:
"Rotate the crankshaft clockwise and align the "1.4T" mark with the index mark. Make sure the #1 piston is at TDC of the compression stroke.
(both of the rocker arms on 1 should have free play, as in on the low egg-curve of the cam lumps, instead of the pointier rises. You should be able to wiggle both freely.)

At that point, you measure the valve clearance for the valves by putting the feeler gauge between the camshaft and the rocker arm 'slippers'.

Honda's manual says 0.05mm(0.002 in) on the intake and 0.08mm (0.003in) on the exhaust.
Hondaman suggests 0.05mm (0.002 in) on the intake, and 0.005in on the exhaust for valve longevity.

With Cyl. 1 at TDC compression, you check IN and EX on 1, then the EX on 2, and the IN on 3.

Adjust so there's just a little drag on your feeler gauge, then double check with the next size up- make sure it won't go in. Go-nogo gauging.

Torque that lock nut down to 9-12 ft-lb, according to the honda manual, (this is where that little tool comes in REAL handy, otherwise that adjustment screw moves pretty easily.) Recheck just to make sure, because you just know the darn adjustment screw moved.

Rotate the crankshaft one full turn clockwise (the way the wheels go, for a mental picture). (here's your 360*)
Align the 1.4T mark with the index mark again. This time 4 should have the same play that 1 had on both the little rocker arms.

Check and adjust IN and EX on 4, then EX on 3 and IN on 2.

This is about verbatim out of the honda manual with my additions here and there. I can't pretend to be any kind of expert, I watched Paulages do mine, and related it to you the way I did so if I need to check my valves, I can come back and read it all in one place. We've all gotta be newbies sometime, let's be newbies together, right?

Well, I guess my main problem is that ALL the rockers started out loose as I loosened them when I took the cylinder head cover off.

I tried sticking a chopstick in the plug hole and I marked off the depth it went in with a sharpie...cylinder 4 is EXACTLY THE SAME DEPTH AS CYLINDER 1???!!! Cylinders 2 and 3 are way deeper, but there is NO DIFFERENCE between 1 and 4.

Hush · « **Reply #7 on:** September 04, 2009, 04:42:59 AM »

OK I'll stop laughing now sorry, the tears are getting in the way of my typing.

The picture you yourself posted is an exact replica of what an in-line 4 looks like in profile.
#1 piston will be TDC and spark will be fired/gas has been compressed, "BANG" #1 fires.
#4 piston is also at the top of it's travel but is not firing, it will have the exhaust valve closed and the inlet valve just starting to open drawing gas in preparing for it's next "firing" stroke which is 360% away.
The other two pistons will be half way up or down, one will be expelling fumes having just fired, the other will be sucking in gas for it's next firing stroke. (depending on which valves have been opened by the cam)
Sorry it's the best way i can explain it, just understand that if #1 is firing then it will have both valves closed (so tappets will be slightly lose) and on the other end of the crankshaft #4 will have one valve closed and one partly open, so even though the pistons are both at top of stroke only #1 is at TDC.
Hope that helps.

jeepster · « **Reply #8 on:** September 04, 2009, 02:00:31 PM »

Quote from: Hush on September 04, 2009, 04:42:59 AM

OK I'll stop laughing now sorry, the tears are getting in the way of my typing.
The picture you yourself posted is an exact replica of what an in-line 4 looks like in profile.
#1 piston will be TDC and spark will be fired/gas has been compressed, "BANG" #1 fires.
#4 piston is also at the top of it's travel but is not firing, it will have the exhaust valve closed and the inlet valve just starting to open drawing gas in preparing for it's next "firing" stroke which is 360% away.
The other two pistons will be half way up or down, one will be expelling fumes having just fired, the other will be sucking in gas for it's next firing stroke. (depending on which valves have been opened by the cam)
Sorry it's the best way i can explain it, just understand that if #1 is firing then it will have both valves closed (so tappets will be slightly lose) and on the other end of the crankshaft #4 will have one valve closed and one partly open, so even though the pistons are both at top of stroke only #1 is at TDC.
Hope that helps.

Ok... so how do I tell which cylinder is at TDC when all the rocker arms are loosened? I know this sounds idiotic, but there is no way to tell at the crank as it's the same exact setting for both.

mlinder · « **Reply #9 on:** September 04, 2009, 02:07:21 PM »

OK, slow down and calm down.

When the crank is at 1-4 TDC, both 1 and 4 are at TDC.
What you are looking for is camshaft position in relation to crank.
First time around at 1-4 TDC, one piston has both valves closed, while the other only has one closed. When you spin the crank 360 degrees from that position back to TDC, the other one has both closed while the second has one closed.
You are looking for the one that has both closed to make the valve clearance adjustment.

manjisann · « **Reply #10 on:** September 04, 2009, 02:21:57 PM »

I'm afraid I can't shed any light on the process. I think our frustrated brother is saying that all the tappets are currently loose from when he removed the head, so even when he rotates the crank he can't tell which is in the firing position and which one isn't. Is this correct Jeepster?

Brandon

jeepster · « **Reply #11 on:** September 04, 2009, 02:45:28 PM »

Quote from: mlinder on September 04, 2009, 02:07:21 PM

OK, slow down and calm down.

When the crank is at 1-4 TDC, both 1 and 4 are at TDC.
What you are looking for is camshaft position in relation to crank.
First time around at 1-4 TDC, one piston has both valves closed, while the other only has one closed. When you spin the crank 360 degrees from that position back to TDC, the other one has both closed while the second has one closed.
You are looking for the one that has both closed to make the valve clearance adjustment.

I think I got it now. Right now the "point" of the lobes on cylinder 1 are facing downward, opposing one another. This means both valves are closed right? i.e. when they turn so the point is facing upwards, this pushes on the foot of the rocker arm and forces the valve open...

Spanner 1 · « **Reply #12 on:** September 04, 2009, 03:08:33 PM »

YEEEAAAH..! ya got it..!! It's not just TDC for the piston it also has to be on its compression stroke....you can shove your finger into the plug hole ( stop laughing ! ) and feel the compression as the piston comes up in the cylinder, proves your not 360 deg. off and both valves can be set for that cyl.

jeepster · « **Reply #13 on:** September 04, 2009, 04:52:26 PM »

All right. It's all going swimmingly now.

except for the actual adjustment with is a pain in the #$%*ing ass to get right.

Did all the valves for cylinder 1 TDC at .002 and .003. Thinking that I might start over and do .003 and .004...seems like it would be a bit easier to get perfect as the .002 feeler is as thin as tin foil. So, longer cam life, but a slight decrease in HP. OK

Frankenkit · « **Reply #14 on:** September 04, 2009, 06:16:22 PM »

You want to keep intake as close to the manual as possible, but that .004 won't hurt ya. Neither would .005. Good luck. I really, really hate doing valves.

jeepster · « **Reply #15 on:** September 04, 2009, 06:41:49 PM »

Quote from: Kit on September 04, 2009, 06:16:22 PM

You want to keep intake as close to the manual as possible, but that .004 won't hurt ya. Neither would .005. Good luck. I really, really hate doing valves.

Well I have the intakes at 3 now...actually considering getting in running and then taking it to a shop to have them set the valves perfectly...

Just out of curiosity, did you use a fancy pants motion-pro feeler gauge tool or just a regular set? I wonder how much easier it is with the motion pro...

I couldn't believe how difficult it was... :-\so much for the Nighthawk's "screen style valve adjusters" whatever the hell they are.

mlinder · « **Reply #16 on:** September 04, 2009, 07:01:28 PM »

After you do it a few times, it becomes much easier. Do not take it to a shop. Soon you'll be doing 10 times faster, and twice as good.

Buber · « **Reply #17 on:** September 06, 2009, 11:25:32 PM »

If you would try "the other approach" - that is set the opposite vale to the one that is actuated, then you don;t need to even look at the crank. Then TDC is irrelevant.
I found it simply more "foolproof".

Hush · « **Reply #18 on:** September 07, 2009, 04:51:47 AM »

My dear boy I think he's got it!

Excellent progress, you'll never forget that again now.

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Author Topic: #*$&#$ Valves - CB650 Nighthawk (Read 2940 times)