Routine Valve Check, Possible Timing Issue

Been a long time since Ive asked yall for help!
But I always like to consult my superiors before I do anything major.

Taking the XJ700 apart to check valves
No biggy, done it a million times on my old XJ with no issues. (Most of my experience now from working in a Honda shop is with tappets and those are almost never out of time.)
SO, like a good tech ive always got my manual in front of me.
"Rotate CCW and place "T" on stationary for TDC for CYL 1 or 4"
The pic shows the tip of the lobe at a 90 with the pad, then measure with feeler gauges.

So when I put mine on "T" the lobe was about a 1/4 turn (on the intake) from being at a 90 with the valve and pad.....
So I didnt continue.
And yes I rotated the engine a few times (since engines have an exhaust stroke and intake stroke) just to be sure and same results on 1 and 4.


<b> T on the Stationary Mark </b>


<b> Cyl 1 Exhuast and Intake on "T" </b>


<b> Cyl 1 on T from the top </b>


<b> Cyl 4 on T from the top. This are very close but not a full 90 </b>


<b> Where I set the timing to get CYL 1 INTAKE on a 90 with the pad </b>


<b> CYL 1 at a 90 with the pad with timing slightly off </b>




SO!
Any thoughts? Should I go ahead and measure clearances, at least while I get this sorted out?
I cant remember if my old maxim was off a hair or not.. I jsut remember turning the lobes to 90 and rolling with it.
That cam chain is super tight I cant imagine it skipped a tooth unless the PO messed with it.
4000 miles I cant imagine he would

-Chris

 

Ummm... where does it say to check them with the piston at TDC? Factory book?

If that's what the book says, then check them that way, and yes the cam lobes WILL be pointing off semi-horizontally like that.

My Clymer book shows the later ('84 ~on) 550/600 being checked with the cylinders at TDC and the lobes pointing off to the horizon like that; but I can't corroborate that from a factory book.

Factory books for the early bikes show the lobes at 90 degrees to the shims. I don't know what changed cam-wise, or maybe they decided to change the procedure.

But it's OK for them to not be pointing straight up at 90 degrees when the piston is at TDC; they won't be.

 

As Per "Star Genuine Yamaha Service Manual"

Vague as usual, but just enough info to interpret.

Just checking. I cant remember where the T was on my old Maxim with the lobes at 90. I think yall had just told me to check them that way and I always have since then.
But when I get a doubt in my head I like to get a second opinion

 

The 3rd picture in your original post is where the cams will be at TDC on the compression stroke. That's where you measure them.

Picture #2 is TDC on the exhaust stroke. Exhaust lobe has just lifted off and intake lobe just about to touch down. This is the wrong position to measure.

The sketch in the book is just that - a sketch. It's exaggerated for clarity.

If it'll help you sleep better check the timing according to the marks on the camshafts, not how the lobes look.

 

On the compression stroke both the cams are barely touching the valve pads. It's impossible to get a reading from the front cause nothing will slide in between and from the back you hit the tip of the lobe.

 

I'm pretty sure that the manual wants you to read the lobe at a 90 degree angle from the pad, on the compression stroke.
The manual says TDC is 0 degrees. The next measure is at between 180 and 360.
So I can only assume that I must measure the lobe in between 0 and 180 degrees. And with the lobe at a 90 degree from the pad the exhaust lobe is still not touching the pad, meaning the valves are still at rest

 

I do not know where you keep coming up with this 90 degree thing. The directions are on the page you posted and there is nothing about 90 degrees.

You set the timing mark to "T". If the #1 cylinder lobes are pointing toward each other rotate the crank one full turn. The lobes should point away from each other (similar to picture #3). Measure cylinder 1 clearances.

Rotate the crankshaft 180 degrees. Measure cylinder 2.

Rotate the crankshaft 180 degrees (You are back to "T"). Measure cylinder 4.

Rotate the crankshaft 180 degrees. Measure cylinder 3.

 

Thats what I was thinking cause when the face toward each other I cannot get an accurate reading.
But if they face away from each other I can with the valves at rest.

I ran it my way and got 1 tight exhaust and one loose exhaust with the rest in spec.
I'll run it the book way tomorrow morning and post both results.
Its always frustrating when I get things confused or backwards. I miss being able to turn directly to my master tech or the guy that always works on antiques for advice.

Honestly I just wish the manuals were a bit more descriptive in most procedures.

-Chris

 

Oh and BTW

THIS is why I do it like that

AIRHEAD VALVE ADJUSTMENT
http://xjbikes.com/Forums/viewtopic/t=14827.html

I remember pouring over this for DAYS in the beginning of my mechanical days and committed it to memory.
Thanks BigFitz

 

how can you tell the lobe is 180 from the shim anyway, it's like balancing a egg on a crooked table

 

truth be told, i never read that but the 90 degree it mentions should be 180