Engine timing

[John o keeffe]

Hi all,
     I need some advice about setting up the timing
on the valves/cams. I installed the buckets and shims , but I cant fix the exhaust cam onto the journal because the valve keeps it off the journal.  If I tighten the cam caps to set the cam the rt mark wont line up.Its a 1993 gs500e.
I've rebuilt the engine   and am on the home straight after  ONLY  2 years of very valuable experience. Hope someone can talk me through this part. I have the Haynes manual by the way.

[chris900f]

I did this job last summer when I replaced my cams. I watched the BaltimoreGS videos on YouTube but they didn't show the exact problem.
I found the work around in the 2006 service bulletin re: cam walk/replacing cams. Suzuki recommends NOT trying to use the cam-cap to force
against the valve-spring pressure, as it can damage the bearing surface.

1)set up timing, count the pins, rt mark etc. When setting up the initial cam timing, be sure to draw to chain taught to the exhaust cam.
   After timing, any slack in the chain should be at the backside/tensioner side of the engine.

2) Install cam caps on the intake.

3) Very carefully rotate the engine backwards, if your wrench is pointing straight up on the timing bolt, it needs to go 90 degrees to the left.
     You can watch and just rotate enough that your left exhaust lobe releases the bucket. Install exhaust cam-caps.

4) ***********Stop!!, do not attempt any more rotation of the engine until you install your cam chain tensioner****************

5) With the Cam-chain tensioner installed, there should be good tension on the chain and it's safe to slowly rotate the engine forward to RT. Now re-check your timing, pins etc
     before rotating through a full cycle.

Here's a pic of the Suzuki doc, hope this helps.

[John o keeffe]

Thanks very much Chris,
 I will try this out over the next few days.
I have only two thin washers on the left of both cam shafts , o mention of wave washers on the right hand side. (That's according to the Haynes manual), will let you know how I get on .
  Thanks again.

[Bluesmudge]

Thanks very much Chris,
 I will try this out over the next few days.
I have only two thin washers on the left of both cam shafts , o mention of wave washers on the right hand side. (That's according to the Haynes manual), will let you know how I get on .
  Thanks again.

Those wave washers were only on 2006+ model years to stop the cam walking noise. Its correct for your 1993 engine to not have those.

[John o keeffe]

 

[chris900f]

Sorry, I should have pointed out the differences between the cams. I think the procedure from the Suzuki update
is better/safer for your parts, since it doesn't put huge stress on the aluminum cam-cap threads in the cyl head.

I probably don't need to stress the point of making sure your timing is perfect before that first rotation. One thing
to add is that if your are turning the engine via the timing rotor bolt, use a wrench, and not a socket. The socket
will only give you forward direction of control and valve spring pressure will cause the engine to rotate by itself though
parts of the cycle. If you use a solid wrench, you can control rotation throughout the cycle. So rotate very slowly: if the
worst happens and you feel contact, you can get someone to hold the engine steady, while you remove the cam-chain tensioner
and the cam-caps to close all the valves.

Good luck, let us know how it goes

[John o keeffe]

Chris,  I did what you suggested and it worked out fine, I can turn over the engine multiple times and the rt mark and cam sprockets are all bang on time.,, but when I bring the rt mark to the line , it kicks back a little bit,  would this be normal ?

[chris900f]

Yes, I think that what your describing has to do with valve-spring pressure since at RT your #1 exhaust valve is full open.
Check the tension on your cam-chain too (just in case), it doesn't need to be really tight, but there shouldn't be any sag between the sprockets

If all your timing marks/arrows on sprockets/pin-count are good when you hold the engine at RT using the wrench then you should be OK.

If you were out even 1 tooth, I think you would have clipped a valve during rotation. So if your getting compression on both cylinders, the
valve-train is working as is should. Just install one plug and rotate the engine, you should be able to feel more resistance than with no plug,
now remove that plug and repeat the process on the other cylinder. If compression checks out, I would go ahead and check/set valve-clearances
and put the cover back on.

 

[John o keeffe]

Chris, thanks very much for your very clear and informative advice. Much appreciated,  will continue with the project during the week. I must pick up three shims and I can close up the engine. Thanks again
      for the prompt reply.

[chris900f]

No problem John, keep us posted on your progress.

[Trolleywire]

Good information! I was sent this link in a post as I had the same issue with cam timing. I followed everything in your instructions and when lined up the RT mark they were slightly out is that a problem?

[chris900f]

It's hard to say what "slightly out" means without a pic. If you are "out" you are out by a whole pin, so triple-check
all your alignment points/arrows, and recount the number of pins between the arrows on the cam sprockets.
If you are out, you won't be able to turn the motor without clipping a valve.

[Trolleywire]

It's hard to say what "slightly out" means without a pic. If you are "out" you are out by a whole pin, so triple-check
all your alignment points/arrows, and recount the number of pins between the arrows on the cam sprockets.
If you are out, you won't be able to turn the motor without clipping a valve.

If I turned the motor over (with wrench) and clipped a valve, would I know that it clipped one? I will try again and post a picture - thanks for your input.

[chris900f]

Basically, if you turned over the motor and you still have compression you didn't hurt the valves.

It's critical to set everything to the timing marks: the RT sets your crankshaft position, and the
camshaft and sprocket markings set your valve timing.

From the diagram pg 2.14 of the Haynes manual. the arrow marked #3 on the intake is the 18th pin
which is the left side of that link. The arrow marked #2 on the exhaust cam is the 1st pin which is on the right side
of that link. The notches on the camshafts will be facing each other if the position is correct.