Topic: Timing marks on crank and end of cam line up but not punch marks on cam sprocket

[juntjoo]

This doesn't matter right? I think those punch marks are just additional marks to line up but the parts that NEED to line up are the crank(t 1-4)and cam shafts which is confirmed by their respective marks. Correct? I think making the sprocket marks line up would just be a matter of rotating the sprocket 180 degrees which by itself wouldn't change a thing. Confirmation pls.

[juntjoo]

OMG, I just noticed that I missed one of the springs which is still upside down. I'm not going back in. I barely Rev this engine. Dang! All that time and I missed one. How?? Maybe I'll order one of those tools to get get it out with the head on. Maybe I need to get my own head on. Maybe it's a message from above I need a tool.

[BomberMann650]

Ummm...you lined up the cam on the wrong mark.

If ------ is the surface of the head.  And O• is the cam with it's timing mark.

Tdc would appear as -----O•-----

And you are currently at -------.O--------

Do overs are in order

[bryanj]

Please read the manual again, and again

[juntjoo]

Please read the manual again, and again

Nice illustrations there. Okay, I'll check the book again. I could have sworn I'd done that before, lined up the mark with that gulley down there. Not home now. On my bicycle earning my gas. Thanks!

[Scott S]

 That "gulley" is for oil feed. The notch on the end of the crank should be at 3 or 9 o'clock, with the edge of the head.

 You ran it like that before?

[juntjoo]

I see now in the book how it's supposed to line up. That little groove threw me off.

[kerryb]

Seeking clarification...  I'm studying the manual right now, and I can't find a reference to the punch marks in the cam chain sprocket.  Is this because I'm dealing with a 550 and juntjoo is working on a 650?
I studied the cam sprocket and can find no marks besides the shape and orientation of the mickey mouse ears.  After assembly, the correct valves were closed for each piston at tdc, but how am I sure?  Sorry for the thread jack.

[juntjoo]

I see now in the book how it's supposed to line up. That little groove threw me off.

No, I def didn't. After jogging my memory a bit I remember how I did it correctly b4. This time my mind somehow sent me off in a different direction. False confidence

[juntjoo]

I see now in the book how it's supposed to line up. That little groove threw me off.

No, I def didn't. After jogging my memory a bit I remember how I did it correctly b4. This time my mind somehow sent me off in a different direction. False confidence

Interesting you should ask. I was just reading some thread(s) in here off a Google search regarding your bike. Lemme see if I can find the threads in my history. I think I googled "cam sprocket punch or timing marks cb650 or cb650"...

I do think it doesn't matter. Though. I think all that matters to set the timing is the crank at the t1-4 mark and cam shaft mark level with the head surface. I mean, do that then imagine magically rotating the sprocket without moving the chain. What would change? I did mine stupidly wrong though

... Idk where I saw what I thought I saw about your 550 if I even did. The guys in here will set you straight though.

[754]

 I think that gash on end of cam is in the open on a 750. I always thought it was to drive the cam while grinding the lobes. I.e. prevent cam from spinning.
 In your first pic the valve spring on left looks like its compressed, i.e. coils close together. But cam is not pushing it down.. strange like valve is bent and sticking or something.
 Did you turn it over with timing off, and feel resistance and keep turning it ?

 You can hold the valves up to remove springs, by pushing a small rope thru plug hole. 

[dave500]

that "gash"(slot)on the end of the cam is the timing mark!!!set it level with the head either to the front or rear with the 1/4 ignition timing mark set at "T"once set turn the crank 360,if that cam notch was set front itll now be rear and visa versa,check it again,be sure that you have the correct 1/4 mark on T,the notch should be level with the gasket surface front or rear,if not,alter it so it does,that slot in the actuall head is an oil flow gallery!!!!!#$%* how many times has this #$%* been gone through?

[kerryb]

I'm with 754, that gash on the end of the cam is much bigger than it needs to be just to be a timing mark.  It makes sense to use it as a timing mark too, just put it at the correct orientation to serve both purposes.

Now, now Dave...one of the great parts of this forum is the collective membership's willingness to answer the same        (dumb) questions for every newbie that decides to join in the fun.  ( I was a middle school teacher, so I got to answer the same questions over and over and over...all day long)  it would be a shame to lose the vast collective knowledge because folks got tired of answering the same question.  We need and appreciate your knowledge, don't let us upset you.  Maybe try like TT to slip in a vieled insinuation, those are fun too.

[juntjoo]

It's been months since I last did the timing. Excuse me! That little oil gulley seduced me into the idea they were meant to match up. I shall never make that mistake again I promise. I'll make others though, just be warned. Thanks all

I'll point out as 754 alluded to I didn't feel much resistance rotating the CS which worried me but now is reassuring and will mean something to me in the future. But back to my original point which I got confirmation elsewhere on: those marks on the sprocket don't matter, but if you get them right I guess they can make you feel good.

[dave500]

don't panic Kerry,i like to add a few choice words from time to time to keep the place alive,#$%*en hell ive really toned it down lately.

[754]

As long as people are new to these bikes, the question will be asked..

[MauiK3]

When I was a supervisor machinist building nuclear submarines we would always get new apprentices. I answered a lot of questions. The stakes were high so good answers well delivered were important.
Everyone has their “first day on the job”
I only get annoyed when someone just won’t do any research and goes the lazy way. I always learn better when I’ve delved into something and then still have questions for the gurus.

[johans]

My first boss said " it's better to ask a stupid question than make a stupid mistake "