Couple of questions, very confused!

pablohoney

Ok, so I recently put my 1979 xs650 special back together and the timing was 180 degrees off. I came to the conclusion tht I put the cam shaft on backwards, (the advance mechanism was on the left side.) So I took it out and flipped it around and the timing was perfect, but the valve timing was off. So I pulled it out again, and something caught my attention. The little alignment circle was facing backwards when the rectangle alignment thing was facing up. This is contrary to what the manual shows. SO right now, I am not sure if anything is right. Here are some pics to give you an idea of what I am talking about. Thanks a bunch. I just would hate to screw it up and have to take it out a 6th time.

gordo

Pablo, it look's good from here.Notch up, dot even with the head surface.That's the tricky part, gotta make sure that the front of the cam chain is tight. Adjusting the tensioner help's. I usually move the crank shaft back a few degree's, say 15-20, then move it forward to the TDC mark & check the alignment of the dot's.Then I know for sure.

pablohoney

I just tried it and like gordo said and it was sixty degrees off. Any guesses as to why, judging from the pics? Thanks. I promise this will be the last post I make asking for help. Smile

nj1639 · Last edited by nj1639 on October 15, 2009, 6:10 pm; edited 1 time in total

Heck, Pablo, there's a lot to learn AND remember for us 'new to these engine' folks. Think I pulled mine 3 times on my first top end rebuild and twice on my 8-1 compression change. The one good thing is - it gets easier each time, HA!
Don't worry about the questions, they help to confirm what we hope we know.

Edit to add
Watch out for slack in the timing chain, like has been said, loose in the front could have put you off. Keep the cam wheel centered in its opening, keep the cam bearings in tight towards the cam lobes. Watch out for that 10 mm headed bolt at the rear, they strip easily.

650skull · Support Staff Joined: Jul 19, 2007 Posts: 1186

have you Looked in the Vault under "Head" Here is a link that may help.
www.650rider.com/index...6352#66352

Joseph · Full Member Joined: May 22, 2007 Posts: 767 Location: NY

Here is a link labled. XS 650 Camshaft Installation TDC Index Timing
www.650motorcycles.com...iming.html

650skull · Support Staff Joined: Jul 19, 2007 Posts: 1186

You should check out the Vault some time Joseph you have posted the same info

Joseph · Full Member Joined: May 22, 2007 Posts: 767 Location: NY

pablohoney

I cannot seem to get my timing correct. If I do it anywhere near the pictures above it is like 40 degrees off.

Also the manual shows how to do it but is impossible. Below is what the manual shows to do. But this is impossible. To have the rectangular alignment mark up the circle mark must be facing backwards, or else the point will be on the wrong side. Am I wrong or is the manual?

xsjohn

My spare cams ............looking from the left side the large rectangular mark being straight up with both pistons on top dead center is correct.........looking at the small round dent in the sprocket with the large mark straight up the small dent is in the rear pointing straight back and on the opposite side of the large retangular mark.......

Looks like to me you are good to go.......paranoia does strike deep....

xsjohn

pablohoney

Ok, Thanks XSJohn, I just couldn't stand taking the engine out again.

What Happened to 650rider.com?

Yamaha xs650