Camshaft Installation

[kh99]

Ok, so I took the cylinder heads off (for no good reason it turns out, but that's another story), and I'm putting them back together. I had marked the timing chains and camshaft sprockets, but by the time I had everything back together the marks on the chains apparently got rubbed off. No problem, there's a line drawn across the sprocket which is supposed to line up with the cylinder head wall, so set it to TDC, line that up, put everything back together and it all looks good. So I go to do the front cylinder. When I took that one apart there was no line so I drew one with a marker. But after taking it apart I found that the front sprocket did have a line etched in it, and it's exactly parallel to the one I drew but on the other side (180 degrees away, I mean). So the question is do I use my line or the etched one? Did I maybe forget to set the front cylider to TDC before drawing my line? Or maybe it's like that so in the factory they can put both cylinders together when it's a TDC for the rear? Anyone know, or at least know how I can tell which way it goes by looking at the cams?

[rick]

With that piston on top of the compression stroke, both valves on that cylinder should be fully closed. Can be 180 out if the piston is on the exhaust stroke and cam on compression stroke. Really advise you to find the correct timing diagram and go by that. Either buy or borrow a manuel, unless you can find a diagram on line maybe?

[mapletree]

http://www.google.com/url?sa=t&rct=j...7Z8JeOs7P94GGQ

By the process used to set the valve lash, the line on the cam sprocket should be parallel with the top of the jug when at TDC. Look at the link above, scroll down to the photo on page 8 and consider.

[kh99]

Originally Posted by rick

With that piston on top of the compression stroke, both valves on that cylinder should be fully closed. Can be 180 out if the piston is on the exhaust stroke and cam on compression stroke. Really advise you to find the correct timing diagram and go by that. Either buy or borrow a manuel, unless you can find a diagram on line maybe?

Thanks for the reply. I have a Haynes manual but it only says to use the line method, so it isn't clear. I suppose I could look in other places in the manual to see if anything else helps. (Edit: but you probaly mean the real manual - yeah, I'll look around online for that).

But I guess if TDC is the compression stroke, then if I can figure out which way the engine turns, the exhaust valve should open next - does that sound right? Edit: ...I think I figured it out below).

[kh99]

Originally Posted by mapletree

http://www.google.com/url?sa=t&rct=j...7Z8JeOs7P94GGQ

By the process used to set the valve lash, the line on the cam sprocket should be parallel with the top of the jug when at TDC. Look at the link above, scroll down to the photo on page 8 and consider.

That's some good info, thanks. Confusing though - since TDC on the two cylinders aren't 180 degrees apart I don't understand how I could have ended up drawing my line 180 out of phase. If I'm understanding it right, even if I left it at TDC for the rear cylinder it shouldn't have ended up that way.


Also the description in that picture of how to set TDC isn't the same as my manual. My manual says you want to align with the mark above the T, not the top of the T.



But now that I looked at the manual again I figured it out - the mark sets it to TDC for either stroke, so I had it on the exhaust stroke when I took it apart and drew my line. So what I have to do is figure out how to know if the front cylinder is on the compression stroke.


Edit: OK, I found the manual online. First, the service manual says use the top of the T, so the Haynes manual is wrong.

Second, in case anyone needs to know in the future, the procedure to get the camshafts installed correctly is to set TDC on the front cylinder, install the front camshaft using the line on the sprocket, then turn the crankshaft 305 degrees counterclockwise to the TDC mark for the rear and install the rear camshaft the same way.

Thanks again guys.

[pacomutt]

To clarify it even more, the engine turns counter-clockwise when viewed from the left side. OR, the engine turns the same as the wheels!

[Drewcifer]

Thanks!
Marked my front before removal but not the rear...can't believe the answer was this readily available...

Drewcifer