Valve Check and Adjustment

2007 DL-650 Valve Check and Adjustment

March 15, 2010

I really can’t improve upon what the Suzuki Service Manual explains as, how to perform a valve check, and valve adjustment on the DL-650.  However, my situation is a little different then the average DL-650 owner.  That’s because I don’t have any fairings on my bike anymore.  If I want to check my valves, I just drop the radiator, remove the fuel tank, and I am ready to go.

But, I had to gather up quite a bit of confidence to get myself to the point of, removing the front and rear cylinder covers!  I had never done a job as technical as this before, and admittedly, I was fearful of what problems I would encounter, and also what possible damage that I might do to my motorcycle’s motor.

In contemplating doing this work, had to inventory the tools that I had on hand, and I purchased a few others to ensure that the project went smoothly.  For the brunt of the work, I used a simple set of mechanic wrenches, and a 3/8″ drive, “hobbyist”, metric socket set, (They are “Husky” brand.  I bought them at Home Depot.).

Additional tools that were beneficial to have on hand, were a metric set of Allen/socket wrenches, a 3/8″ drive torque wrench, a set of feeler gauges, a 3/8″ drive “universal joint adaptor”…..

……a micrometer, or something like this device that I purchased at Home Depot for about $36.  It worked surprisingly well!!!

First, I removed the spark plugs, the PAIR valves and the three allen bolts that hold the cylinder covers to the motor.  I was careful when I gently removed the rubber gasket that sits between the cylinder cover, and the motor.  Of course, the Service Manual is going to recommend that, “Always use new gaskets when reinstalling the cylinder covers”.  My cylinder covers have been removed three times, and I am still using the original gaskets; no leaks!  (I WILL replace the gaskets during my next valve check.).

This is what the front cylinder/cam journal area looks like, (the cam chain guide is on the right in the photo; or left side of the bike.)

Here is the rear cylinder/cam journal area exposed.

I believe the Service Manual suggests that the valves be checked at the 600 mile service and then every 15,000 miles thereafter.  My dealership recommended skipping the 600 mile valve check, but doing a check at the 15,000 mile service.  I didn’t get to the first valve check until March of 2008 at 22,000 miles………

Back in 2008, I started to do the first valve check myself.  When I determined that the valves did indeed need to be adjusted, I got scared because it was more work then I felt capable of doing.  I had never done work like a valve adjustment before, and I didn’t have anyone close by to show me how to do it.  I ended up taking the bike to my local dealer and had them finish the job for me.

BUT!!!  I knew that eventually, I was going to get up the courage to do the job myself, so I wanted to “track” what work was being done to the valves, whether I did it, or not.  When I took my bike to the dealership, I also took along the below chart I made up:

I asked the technician to please fill out the spaces for me so that I could keep a record of what work he had done.  Below is what the chart looked like after it was filled out.

At 63,000, (40,000 miles since the last valve check….), I decided to give a valve check/adjustment a go by myself.  Using the instructions in the “Periodic Maintenance” section of the Suzuki Service Manual, (Pages 2-8 thru 2-12 in my manual), I set the front cylinder to, “Top Dead Center”.  I made sure that the “F” was lined up properly on the generator rotor….

….and that the cam “lobes” were pointing according to the diagram on page 2 – 8 of the manual.

The specified valve clearances for the intake valves are:  [B]0.004 – 0.008 [/B]inches.

The specified valve clearances for the exhaust valves are: [B]0.008 – 0.012[/B] inches.

I measured the four valve clearances on the front cylinder and then I rotated the motor, (Using a 17mm socket on the generator rotor nut), to get the rear cylinder to TDC as per the diagram of the lobe positions in the Service Manual, [page 2 – 8], and measured the rear cylinder valve clearances.

This is what I found for my valve clearance measurements:

The front cylinder intake valves were too tight and the rear exhaust valves were too loose.

I would like to share some thoughts about the experience I had in using the feeler gauges to check the valve clearances.

1 – When using my feeler gauges to measure the valve clearances, I found it easiest to slide the feeler gauge, underneath the cam lobe, by working from the center of the cylinder, pushing “out” towards the edge of the motor case.

2 – It does take some “pressure” to push the feeler gauge underneath the cam lobe.

3 – Because the intake tolerances are so small, the feeler gauge for the intakes is quite thin; it can bend easily under the pressure necessary to slide it into position.  I had to go slowly and smoothly.

4 – If you look carefully at my chart, you will see that the spaces, to be filled out, for the valves are in different locations for each cylinder.  Here is why: To me, the left side of the bike is the “left side” as you face forward.  The same is true for the right side.  However, when working on the front cylinder, I was sitting on the floor, (I don’t have a lift……..), facing “aft”; looking at the front cylinder.  I decided to set up my chart with the locations of the left and right, “intake” and “exhaust” valve measurements as exactly as I am looking at the cylinder and the paper chart.  This is why the front cylinder and rear cylinder labels are in the positions that they are.  They are set up on paper exactly the same way as how I look at the actual cylinder.

I needed to loosen up, (use a thinner shim), on the front intake valves and I needed to tighten up, (use a thicker shim), on the rear exhaust valves.

I decided to start with the front cylinder because there is so much room to work around, (which eased my mind because I was scaring the crap out of myself because I have never done work like this before!).

I removed the three bolts that fasten down cam chain guide.

I also removed the cam chain tension bolt from the “top” side of the cylinder.  The assembly is actually, a bolt, washer and spring.  It looks like this:

Other then the actual journal cover, there is nothing else to remove, to get the cam shaft out.

Because I was nervous as all get out at doing what I was doing, I kept photographs to a minimum on the front cylinder while doing the work there so that I could maintain “focus”.

However, the following photographs illustrate how I released the tension on the cam chain so that I could remove the cam shaft.  These photographs areALLfrom the rear cylinder.  They are applicable to the front cylinder.

First, I would like to explain something.

The cam chain tensioner works much like a jackstand.  The only difference is, the jackstand isn’t “spring-loaded”, but the cam chain tensioner is.  There are “notches” and “pawls” involved in both.

Here is a jackstand fully extended:

If I lift up on the handle, the “pawl” disengages from the “notches” and gravity causes the stand to drop down, (and taking a chunk of skin off of a finger if you aren’t careful!!!).

To get a cam shaft out, I needed to release the “pawl” from the “notches” in the motor case.

Looking down inside, near the cam sprocket, that is closest to where I removed the cam tensioner bolt, I was just able to make out the “pawl” that I was looking for.  This is what the pawl looks like, with the cam shaft removed, and a screwdriver in the proper position, to be able to release the tension of the pawl, from the notches in the side of the motor case.

With one hand, I slid a long, slotted screwdriver down to the pawl.  With your other hand, I pulled upward on the cam chain giving it some firm tension.  Like the photo below.

With one hand applying tension to the cam chain, (pulling upward), I pressed downward with the screwdriver on the part of the pawl that is closest to the motor case.


I now had enough slack….

…to remove the journal cover…

….. and to slide the camshaft out of the journals.

Here it is!

Slick, huh?

I slid a screwdriver through the cam chain, and across the subframe, so that the cam chain wouldn’t slide back down into the case.

To remove the “bucket” from the tappet sleeve, I used a “magnetic wand” and withdrew the bucket.

Underneath the bucket, is where the shim is located.

And, here is what a shim looks like removed from the bucket.

This is why this system is called, “Shim Under Bucket”, style valve adjustment.

I am not going to bore you with how many trips I made to my local dealership to obtain, (they swapped shims with me), the proper sized shims I needed.  I can tell you that the chart in the Service Manual is to be used as a guide only!!!

An example of this is, my original front intake valve shims were labled, “175”, (or 1.75mm thick).  Using my measurements of .004 and .003, the chart suggested that I needed 165 shims.  I made the trip to my dealership to swap my 175 shims for new 165 shims and came back home and installed them……  Only to find that the 165 shims put me right at the other end of the recommended specification!  I made a trip back to the dealership to pick up 170 shims.  I installed them and they put me right at a .006″ clearance; perfect.

Here is a sidebar note about something I learned:  When selecting shims, from whatever source, MEASURE them to make sure they are the right thickness that you need.  Swapped shims often have the printed numbers worn off of their faces.  Don’t take it for granted that shims coming out of the “170” section of the shim box are actually “170” shims!

That’s where the digital calipers came in handy.  I took them with me to my dealership to ensure I was picking up the right shims.

When I installed the new shims, I gave them a light coat of oil and set them in the matching sized “divot” in the head of the tappet.

Here is a shim installed into its proper place with the Service Manual recommended, “numbers faced down”, position.

Sliding the bucket back over the shim.

I reinstalled the cam shaft, as per the alignment instructions on page 3-100 of the Suzuki Service Manual.

Here is what the markings of the cam sprockets looked like for the front cylinder.

This is the exhaust cam sprocket:

This is the intake cam sprocket:

I took plenty of time with this!  The diagram that is on page 3-100, of the Service Manual, has to be followed to a “T”.  I discovered, when installing the cam shafts and the cam chain is not aligning correctly with the cam sprocket teeth, something is wrong.  I was smart about this, and did not turn the motor!

When the cams were installed correctly, I installed the journal cover, and torqued the bolts to 7ft lbs.

Then, I rotated the motor a couple of times to set the shim and squeeze out excess oil, then set the motor back up to TDC, and I checked my measurements again.

When the measurements were good, I moved to the rear cylinder.

If by chance, someone else is attempting to do their own valve adjustments, on their own DL-650, and using this journal entry as a rough guide, I would like to offer up a few comments that I learned through my experiences:

1- Work on the front cylinder first.

2- Follow the photographs above, (even though they are from the Rear Cylinder), to make your valve adjustment.

3-  When the valve adjustment is complete, LEAVE THE CYLINDER COVER OFF.

You will need to see the front cylinder cam shaft lobes for reference in regards to the Rear Cylinder.

That is how I messed up my valve adjustment!  No damage was done, I just lost a bunch of time because of the following facts:

The front cylinder measurement is taken at TDC.  The realignment of the front cylinder cam sprockets, (using the markings on the cam sprockets in conjunction with the Service Manual diagram), is  ALSO done at TDC.

The rear cylinder isn’t done that way……  That was how I made my mistake.

I completed the front cylinder job fairly quickly.  I figured that I would blow through the rear cylinder and go for a ride.  I spun the motor so the rear cylinder was at TDC, just like the front cylinder.  I quadruple checked my measurements on the rear exhaust valves, then released the pawl on the cam tensioner, removed the journal cover, removed the cam shaft, withdrew the buckets, pulled the old shims, measured them, made a trip to my dealer to swap for new shims……..

…..installed the new shims, installed the buckets, installed the cam shafts……..


Guess what, the rear cylinder cam shafts are not installed at TDC like the front cylinder cam shafts are installed!

[At this point, I strung together a whole new set of swear words that I have never used before.]

I returned to the Service Manual, (Page 3-103), and studied the diagram on that page.  I discovered that, the lobes of the rear cam shafts are NOT installed with them set at TDC.

The rear valve clearances are measured at TDC, but I had to rotate the motor so that the cam sprocket markings were aligned for installation, (like the diagram on page 3-103 of the Service Manual), before I removed them.

So, (This is the, “Important Step”), the front cylinder valves are measured and adjusted at TDC.  The rear cylinder valves are measured at TDC but adjusted at, (I haven’t a friggin’ clue), just use the diagram on page 3-103.

I got out of my mess by studying the diagrams in the Service Manual, (Pages 3-100, 3-103, and 3-105), and by looking at the positions of the lobes of the front cylinder, (that’s why you shouldn’t install the cylinder cover.  You may need to see the cam lobe positions for reference.), and by carefully spinning the motor until I could tell that the rear cams were back in sync with each other and with the front cams.

The bike runs fine.

A couple of final notes:

I could not find a torque specification for the cam chain guide in the Service Manual.  However, there is a “torque guide” on page 9 – 43 in the manual.  I measured the diameter of one of the chain guide bolts; 5.86mm, using my digital calipers.  I rounded that size up to 6mm and, using the chart, that led me to a torque specification of 7ft lbs for the cam chain guide bolts.  That is also the same torque specification for the journal cover bolts.  I felt okay about that.

Here was my method of getting to the, “all-hard-to-get-at” the rear cylinder, cam tensioner bolt for removal.

Here is the head of the tensioner bolt as seen by sighting down the right side of my motorcycle’s swingarm.

I did not remove my exhaust.

I did not remove my rear tire.

The dealership never installed the plastic “mud flap” that some of you riders have installed on the swingarm.

I do not have anABSbike.

Because I had previously replaced my worn out OEM rear shock, with a HyperPro shock, with NO remote preload valve installed, I could……

….remove the right rear passenger footrest bracket…..

…then I reached in with my 6″ long ratchet extension, equipped with the 3/8″ universal adaptor….

….and easily removed the tensioner bolt.

Piece of cake!

It is now late Winter 2012.  I need to do this job again; to check the valve clearances before I start another season.  If I learn anything new and exciting, I will update this post with that information!

Barry B.

“Black Lab”

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