Cam chain tensioner gasket leak...
Posted October 21, 2008 - 03:10 PM
This leak can often be confused for a base gasket leak, but since 2004, DR650s have had a metal base gasket, which was a huge improvement. The cam chain tensioner gasket was not upgraded with the base gasket. I overfilled my oil which increased the oil pressure enough to blow out this gasket.
This oil leak can look like this : Oil at the arrows and even in the Suzuki lettering of the oil filter cover. Oil can also be seen on the lower 3 or 4 cooling fins.
The most effective way to find the exact leak is by :
1) Thoroughly cleaning the engine area.
2) Putting talcum powder around the suspect area.
3) Running the engine and watch for the powder to absorb the oil.
Note: My gasket only leaked at high rpm on the highway.
In case anyone doesn't know what the tensioner is, it is outlined in red and the gasket is outlined in yellow :
In order to replace the gasket, do the following :
1) Remove the clutch cable mount shown here :
(This should give you enough room to slide out the tensioner...You might need to loosen the clutch cable further)
2) Remove the two hex bolts at the left and right of the tensioner.
3) Slide out the tensioner. The tensioner is self adjusting, so it should extend as you remove it.
WARNING!!! Do not insert the tensioner fully extended! You can stretch/break the cam chain. You must retract the shaft of the tensioner before replacing. In order to do this, you must:
I) Remove the bolt at the end of the tensioner. This will give you access to a small screw which you can use to retract and lock the tensioner.
II) Using a small flat screwdriver, retract the tensioner by turning the screw.
III) Turn the screw the opposite direction to lock it in place.
IV) Remember to unlock the shaft after you replace the tensioner.
(Just mess with the tensioner a little bit. Its easy to figure out how it works.)
4) Replace the tensioner with the stock OEM gasket or silicone.
5) Extend the tensioner shaft with the adjustment screw.
6) Replace the adjustment screw cap.
7) Replace the clutch cable mount and everything else you took off.
Tell me what you guys think...
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Posted October 21, 2008 - 04:22 PM
How does the oil pump put out more pressure because of more oil? I can see too much oil hitting the crank and causing splashing.
I overfilled my oil which increased the oil pressure enough to blow out this gasket.
At high RPM there would be more crankcase pressure (blow-by) and aggravate a weak gasket. Breather somewhere clogged?
Posted October 21, 2008 - 04:50 PM
Here it is...http://www.thumperta...ll oil pressure
A clogged breather might do the same thing...I would guess it would have to be clogged pretty tight though.
Posted March 06, 2009 - 05:04 AM
Nice write up jmc, thanks!
Posted March 06, 2009 - 04:59 PM
If I inspected the bike closely I probably would have spotted it earlier as the gasket protrudes a little, but in this area it disappeared into the engine. Might be worth checking the edge of your side cover gaskets. This is a freak occurance for any motorbike let alone a DR650, but could prove to be fatal so worth a check
Posted March 13, 2009 - 03:40 AM
Posted March 13, 2009 - 01:32 PM
Posted August 21, 2009 - 06:52 PM
Posted July 10, 2012 - 06:35 PM
I mainly added the silicone dur to the factory gasket being "glued" to the cylinder..... what a pain in the ass.... It took me atleast an hour of careful scraping, and I still did not get it off 100%. So the silicone will take up any irregularities in the mating surfaces, and make it easier to remove.... if I ever have to.
I did remove the exhaust, header, and removed the hard oil lines from the top of the head, and the top-right side of the engine case.....this allowed me to pull the oil line back, and gave me alot more room to pull the tensioner out and work on that gasket.
Edited by crooks420, July 10, 2012 - 06:38 PM.
Posted July 21, 2012 - 09:08 AM
Posted July 22, 2012 - 05:53 AM
Posted August 14, 2012 - 06:23 PM
Posted August 14, 2012 - 08:01 PM
Clue #1, don't go postal when you don't understand something. We all started somewhere. The instructions at the top of the page are exceptionally well done, kudos to jmc1583.
Rant - Is this a joke or am I a dumbass - or both? I finally tried to fix the leak after reading numerous posts on the "simple" fix and feeling confident I could do it. Following the manual on removing the CCT and other posts, I attempted to find TDC by turning the crankshaft - but before I could access the crankshaft, I stripped out the Allen wrench hole on the cap covering the crankshaft (supposedly a common occurrence). So I have read you dont need to remove the cap, just turn the rear wheel to find TDC. Well how do you turn the wheel while you are looking in the hole to see if you are at TDC? I never even got to trying to remove the CCT because I could not find TDC, which I have read can be critical (dont believe everything you read?) I do not see how the simplified instructions at the top of this thread could enable a non-mechanic type to do this fix. I'll just live with a little oil leak.
I suggest hosing the bike off before you start, paying close attention to the head and under the tank (if it's still on). You don't want dirt falling into an open rocker arm cavity. Remove a plug, stick a straw in the hole, rotate the wheel, watch the straw rise with the piston. The plug hole is at a sharp angle to the piston travel and the straw will bind/bend, so bump the tire, watch the straw, wiggle the straw, bump the tire, etc. When the straw stops, you're at one TDC.
Remember that there are TWO TDCs, one with both valves completely closed. This is the one you want. On the second TDC both valves are slightly open (called 'overlap'), the one you don't want. Remove both valve covers (they have reuseable o-rings). Wiggle both the intake and exhaust rocker arms. At one TDC, both rockers will be immoveable, solid. This is where you don't want to be. Rotate the engine another revolution, watching and wiggling the straw. Now try to wiggle the rocker arms again, side to side; there should be slight movement. It's unlikely you'll feel .004 with your fingers with oil damping the clearance but side to side is more obvious (larger clearance). This is where you want to be. Rotate the engine watching/wiggling the straw, two or three times. Somewhere in here, you're going to have the 'Aha' moment. Now ya got it. Wiggly rocker arms are the correct TDC.
The piston is at the same TDC both times. The cam, rockers, and valves are not.
This next tidbit is going to take a leap of faith. It doesn't matter where the 'T' is in the little window. Since both valves are closed for almost 360* (BDC of the compression stroke, TDC of the compression stroke, spark, BDC of the power stroke), the straw is more than close enough. When it stops and the rocker arms wiggle, you're at the mysterious, coveted TDC.
Don't chop up your gasket surface with anything harder than alum, no steel (razor blades for instance). An old credit card has been mentioned. Leave your impatience in the house, relax, enjoy the project, even if it takes all weekend.
Edited by Craig in Denver, August 14, 2012 - 08:09 PM.
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