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DRZ Cam/Valves

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I searched, but did not find.

 

The valves on my 2004 DR-Z400S are tight (< .08 clearance).  When I removed the CCT and cam covers, with the piston at TDC (IN lobe at 2:00PM and EX lobe at 10:00AM), then the cam chain was too tight to allow the cams to be removed.  At that time, the cam sprocket markings were lined up as prescribed at http://www.thumpertalk.com/topic/718276-drz-valve-clearance-check-and-adjustment-plus-cam-timing/.  I rotated the piston to the next time the mark came  up, with the IN lobe at 8AM and the EX lobe at 4PM, and the cam chain was then sufficiently loose to allow the cams to be removed.  I did not check the sprocket markings again, but the cam lobes were clearly not at 10 and 2 at that point.  I've yet to pull the valve buckets.

 

Feedback?  Seems like something is a bit off.  I did have someone else adjust the valves a few years ago, and soon after the bike stopped starting due to the tight valves.

 

Thanks in advance!

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Were your cam caps off when you tried to remove the chain from the sprockets the first time?

The cam caps that are held on by the allen bolts?  Yes, they were, and when they were taken off then the cams were perfectly seated.  I followed the precise directions as in the link posted above.

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The cam caps that are held on by the allen bolts?  Yes, they were, and when they were taken off then the cams were perfectly seated.  I followed the precise directions as in the link posted above.

 

Don't know what the problem was then, you should have had no problem popping the cam out of place and removing the chain from the sprocket.

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Yes don't remove anything till you get the timing back correctly , assuming that you had the cct removed, the cams have to be kinda tilted in to get the chain on and off. but I hope you didn't turn the motor over with no cct tension.

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Yes don't remove anything till you get the timing back correctly , assuming that you had the cct removed, the cams have to be kinda tilted in to get the chain on and off. but I hope you didn't turn the motor over with no cct tension.

The cam chain did have tension when the motor was turned over.  No skipping teeth, etc.

 

At this point I will adjust the valves, put the cams back in, and then turn back to TDC and check for correct alignment.  If it's not correct per the original marks/chain spacing between marks, then I will have to take notes, turn back/adjust the cams until its right.  It was just a bit of a boggle that the cams absolutely did not want to come out when the engine was clearly at TDC with the sprockets lined up as shown in the instructional link above.

 

Any additional feedback is welcome, thanks.

Edited by bluesurf

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>.08 inch is at the tighter end of spec, but in spec, and valves will go tighter than that without issue, like to zero. So I don't see valve lash of your exhaust as the problem at hand. just an FYI. I wouldnt adjust anything till you get back to proper TDC.

Edited by Spud786

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>.08 inch is at the tighter end of spec, but in spec, and valves will go tighter than that without issue, like to zero. So I don't see valve lash of your exhaust as the problem at hand. just an FYI

 

.08 inches is way out of spec, like 10 times beyond spec  :smirk:

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08 inch is 2mm, spec is 2 to 3mm so no its not way out of spec

 

The OEM service limits for clearance are:

Intake 0.10mm ~ 0.20mm

Exhaust 0.20 ~ 0.30mm

 

Edit: I'm sure his measurement was in millimeters, .08mm is too tight for both intake and exhaust.

Edited by Wisconsinite762

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Okay you are correct, its .2 mm , my mistake. .008 would be the equivalent

Edited by Spud786

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I fit the cams/sprockets back in at 10 and 2, ensuring that the engine timing mark remained centered on the line just to the left of the T for TDC and the sprocket marks lined up correctly per the previously-referenced link.

 

One thing that I immediately noticed is that there was a bit more slack in the cam chain.  I counted the chain rivets from a picture taken prior to disassembly, and realized that the picture had only 13+ rivets in between the 2 of the EX and the 3 of the IN.  With my fitment then there were 14+ rivets in between, which appears to be correct.  Seems like there was some slack underneath one of the cam sprockets.

 

So, multiple issues....am glad that I now live ~1500 miles away from the guy who last worked on this bike.  Tomorrow, I will track down some shims (have heard H-D carries them???) and get this particular beast up and running again.  Thanks everyone for chiming in.

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S

 

I searched, but did not find.

 

The valves on my 2004 DR-Z400S are tight (< .08 clearance).  When I removed the CCT and cam covers, with the piston at TDC (IN lobe at 2:00PM and EX lobe at 10:00AM), then the cam chain was too tight to allow the cams to be removed.  At that time, the cam sprocket markings were lined up as prescribed at http://www.thumpertalk.com/topic/718276-drz-valve-clearance-check-and-adjustment-plus-cam-timing/.  I rotated the piston to the next time the mark came  up, with the IN lobe at 8AM and the EX lobe at 4PM, and the cam chain was then sufficiently loose to allow the cams to be removed.  I did not check the sprocket markings again, but the cam lobes were clearly not at 10 and 2 at that point.  I've yet to pull the valve buckets.

 

Feedback?  Seems like something is a bit off.  I did have someone else adjust the valves a few years ago, and soon after the bike stopped starting due to the tight valves.

 

Thanks in advance!

Most likely you balled up the chain at the crank.

 

If you had followed the procedure in the article...as written, that would not have happened..

"Setting Timing and Checking the valves

Set the motor to Top Dead Center (TDC) on the compression stroke. The timing index mark on the flywheel will be in the center of the sight window (Note your looking to align the index line NOT the T next to it center of the sight window)

TDC_mark.jpg

Looking at the cams from the side the lobes should be pointed at 10 and 2 O’clock
If not and the index line is in the center of the window, you're not on the compression stroke. Try again; turn the motor in the normal forward direction, until the index line is centered.
Cam sprockets.jpg
The cam sprockets will look like this if you’re using OEM cams.
The #3 and #2 should be straight up. The other index lines even with the top flat surface of the head."

 

and later

 

"In order to remove the cams to gain access to the valve bucket and below it the shim, you will need to make sure the cams are at TDC (or close) then remove the cam chain tensioner (CCT)."

 

So rotate the engine forward,,till cams are at 10 & 2 plus timing marks aligned. BEFORE removing the CCT and cam caps would have left all the chain slack on the CCT side and available to remove the cams when you needed. 

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The cam caps that are held on by the allen bolts?  Yes, they were, and when they were taken off then the cams were perfectly seated.  I followed the precise directions as in the link posted above.

If the caps were off, then no sir you did not follow the procedures as suggested. 

If you can detail how you misunderstood the article I may be able to add some clarification that will keep others from making your same mistake.

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At this point I will adjust the valves, put the cams back in, and then turn back to TDC and check for correct alignment.  I

I would suggest...

 

 

 Holding the cam chain UP with your fingers.. Rotate the motor till the flywheel timing mark is centered in the sight window.. The CRANK is now set to TDC and you held the chain up so it is not balled up at the crank which can lead to damaged chain guide mounts.

 

 

NOW install the cams one at a time and then adjust cam rotation to align timing marks and if OEM go ahead and count pins .. Remember to push in on the rear chain guide with a finger or tool to take up slack as you check cam position each time... 

 

DO NOT ROTATE the motor with the  cams in and the cam caps off.... 

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