defining "top dead center on compression stroke"

hop along · February 22, 2014, 07:13:11 PM

If I understand correctly, "top dead center on compression stroke" would mean the intake cam lobe is about to make contact with the valve spring, yes?
Thanks for confirming the simplest of questions

Hop Along

hootmon · February 22, 2014, 08:51:05 PM

Actually it would be when both valves are closed..
The next to open would be the exhaust valve...
It is the top of the compression stroke...

hop along · February 23, 2014, 11:46:06 AM

Thanks Hoot. I'd been having doubts. The manual states Intake clearance at .006", Exhaust clearance at .010".

The reason for my doubt being, checking valve clearances most all are .001" shy of ideal spec (but still in spec)

Intake clearance on cylinder 1: ZERO Nada. Can't even see light through it.

The only other out of spec measurement is a .007" on the #4 exhaust.

I know, I'm using imperial measurements on a metric machine... but those are the measurements most closely aligning with my feeler gauges.

Hop Along

hootmon · February 23, 2014, 03:31:06 PM

I believe there is a TDC (CYL #1 of course) mark under the round cover on the clutch cover plate...
Hopefully the service manual talks about it...

Smoked U · February 23, 2014, 09:05:12 PM

I don't know if I want to step into this conversation or not (and I am not attempting to insult anyone's intelligence here either).

First:

Hop Along do you have a factory manual for this 3rd gen?

hop along · February 23, 2014, 10:02:05 PM

Yes, following along the factory manual, which talks about first cylinder top dead center on compression stroke, but doesn't describe it (at least that I found); though after hearing from Hoot I'm confident I've got it all straight. Hoot's additional comments about the timing cover, etc are correct as well, T1 marks the spot, so to speak. So I am proceeding. Just got off work (inside on a gorgeous Sunday... argh) and will continue Monday PM. But I do need to get my hands onto a few shims; I may order in from Bike Bandit along with a few other things.
Thanks Smoked U,
Hop Along

Smoked U · February 24, 2014, 08:41:04 PM

Good luck with the shims, Bro. You have to tear the whole camshaft mechanism apart to install them. In the good ol' V65 days, the adjusters are on top of the rocker arms and you can use a wrench and a screwdriver to adjust the lash.

hootmon · February 24, 2014, 09:15:15 PM

I also think you have to buy a whole shim pack, but I could be wrong...

magnagregcan · February 24, 2014, 11:19:52 PM

You can re-use some of the shims, depending on the thickness they are. Not to be too concerned on the intake valve - those never burn out. But the exhaust: the bigger the gap, the less distance the valve will open. If it doesn't open up all the way (in tolerance) excess heat will build up, causing the valve to over heat and burn. I think that's how it works. A valve job in Halifax NS is about $600.00, + or - (CDN$).

hop along · February 25, 2014, 06:28:40 PM

Quote from: Smoked U on February 24, 2014, 08:41:04 PM
In the good ol' V65 days, the adjusters are on top of the rocker arms and you can use a wrench and a screwdriver to adjust the lash.

Rub it in, rub it in, go ahead

I am aware though not exactly eager!
FWIW I've also confirmed the HOnda shop will sell me individual shims, have yet to call the local independent bike shop in Norman to see if he has/will sell individual shims (a lot less travel that way, and get to support the local independent shop)

Hop Along

hop along · February 25, 2014, 06:37:32 PM

This is what the left side of the front/left cylinder looks like, and the position of the cams, while checking the valve clearances.
EG if I were to rotate the crank 360 degrees back to T1 mark, the exhaust cam is fully depressing the exhaust valve.
(thus my logical conclusion I'm checking this correctly)
Hop Along

Smoked U · February 26, 2014, 01:32:20 AM

Let me tell you what you already know.

The #1 cylinder is on the left side of the rear cylinder head if you are seated on the bike. The #3 cylinder is on the right side of the rear cylinder head. The #2 cylinder is on the left side of the front cylinder head and the #4 cylinder is on the right side of the front cylinder head.

The T1 mark on the starter clutch indicates top dead center (compression stroke) on the #1 cylinder and the #4 cylinder. When the T1 is lined up with the index mark on the right crankcase cover either the #1 cylinder is at TDC or #4 is. The way to tell is the camshaft eccentrics (lobes) will have the exhaust valves completely depressed on one cylinder or the other. This cylinder is on the exhaust stroke and not at TDC. The other cylinder will not have any of the valve lifters depressed indicating that all the valves are completely closed on that cylinder and it is at TDC. This is when you check the valve clearance on the intakes and exhausts for only that cylinder. Next you rotate the starter clutch 360 degrees to align the T1 mark again. Now the exhaust valves will be fully depressed on the cylinder that you just checked and the other cylinder will be at TDC with both sets of valves closed so that you can check the valve clearance on that cylinder.

When the T2 mark is aligned with the mark on the crankcase cover either the #2 or the #3 cylinder is at TDC. Again, see which one has the lifters depressed on the cylinder (exhaust stroke) and check the clearance on the other cylinder which is at TDC. Rotate the starter clutch 360 degrees to realign the T2 mark and now the other cylinder will be at TDC and you can check the clearance on that cylinder.

The key is to always recognize that none of the high points of any of the cam lobes are pressing down on the lifters when a cylinder is at Top Dead Center of the compression stroke. This is the only time you can properly check the valve clearance/lash of the intakes and exhausts of that cylinder..

As you know, if the valve lash is excessive the valve train makes a pecking noise. Really bad stuff happens when the valve lash is too tight because the valves either don't seat when they are supposed to or do not touch the seats. Now the seal is lost in the cylinder and compression suffers. Valves must contact their seats to transfer heat from the valve to the seat and from the seat on to the cylinder head. This is especially true of the exhaust valve which gets hit with the high temps of the exhaust gases passing over it on the way out of the cylinder (hello burned valve). Intake valves do not typically get burned because the incoming charge of gasoline vapor and air are cool and keep the temps on the intake valves lower than the exhaust. Of course if they have too tight of a lash, they don't seal properly and your compression suffers.[color]

hop along · March 01, 2014, 01:35:21 PM

Quote from: Smoked U on February 26, 2014, 01:32:20 AM
Let me tell you what you already know.

The #1 cylinder is on the left side of the rear cylinder head if you are seated on the bike. The #3 cylinder is on the right side of the rear cylinder head. The #2 cylinder is on the left side of the front cylinder head and the #4 cylinder is on the right side of the front cylinder head.
.[color]

Smoked U,
Thanks for this post. I owe you a beer. Or three. I'd misread the manual 'front' and 'right' info on the cylinder layout diagrams. All my original valve checking were incorrect.

Finally got to working on the bike just this morning. It was the shortest valve check ever. Everything was within spec except one intake valve that was within .oo2" instead of.oo1" within spec.

Now I'm waiting til Tuesday for the cam chain guard to arrive before buttoning things up.

While valve checking I took a cursory glance at the intake and exhaust marks on the cam sprockets-nearly freaked out while looking from the left side of the bike, just how far off the marks were. My buddy who was helping (not our Buddy) didn't understand why I was so astonished. After re-checking the manual, and looking from his side (the right side) I realized all was well-dead on, front and rear cylinders. So a question I'd had to myself is confirmed by evidence: replacing cam chain tensioners, even after riding while one is broken, seems to have no ill effect on the cam chain sprocket timing.

So, hopefully the end of next week I'll be good to go. We are about to open a show so I've been more or less at work 8am to 10pm... but we open Thursday

Hop Along

TLRam1 · March 01, 2014, 02:49:28 PM

You open on Thursday, what kind of event is it?

hop along · March 01, 2014, 05:41:57 PM

Terry, this a Handel opera called 'Alcina'. My job as Technical Director is ultimately to implement the scenic designs for our operas, musicals, plays, and dance shows. So 8-9 weeks a school year I get to work extra long hours. Not to be confused with other regular longer hours

In a way, the scenic designer is like an architect, describing the scenery that needs to go onstage; I'm kinda like the engineer, project manager, and construction foreman rolled into one.
As far as operas go, this design is different, not vary traditional. All sorts of curvaceous platforms and 'ice-flame-like' sculptural shapes onstage. It's pretty cool looking, and beautiful to listen to. We're in rehearsals to put all the technical elements together (orchestra, scenery, props, special effects, lighting, costumes...). It is a week long process usually.
Hop Along