How do I stop oil leak from the chain tensioner (1980 XS1100 SG)
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"C" is correct. I have edited my post to reflect that.
TDC versus C had already been corrected before I posted but I see where the confusion could come from. I should have made the note that while agreeing with the process, C is correct with respect to the manual.Last edited by Bonz; 04-18-2026, 07:17 PM.Howard
ZRX1200
Seca 750Comment
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I stand corrected, use C for the install of the ACCT,, according to the manuals,,however I have used TDC for a few
ACCT installs and zero issues, I just make sure the engine does not rotate as the cam chain is corrected to exact tension by the ACCT.....have fun,,,,Mike in S.Diego and Pa
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It has been reported that the OEM tensioner is prone to slipping out of adjustment during heavy engine braking. The ACCT can not do this because of its one way ratchet mechanism.2H7 (79) owned since '89
3H3 owned since '06
07 Triumph Tiger 1050 (night rider)
"If it ain't broke, modify it"
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Being completely honest, I don't know what the difference would be in C or TDC with respect to removing a tensioner and replacing it now that it has come up. Can one of the collective share the mechanical importance/difference with respect to a tensioner replacement?
Top dead center on compression or C on the exhaust stroke at the top, should make no difference. They are both the same relative positions in a static state. At least that's how I see it. However, I have used C like the manual calls for. Quite honestly, why would it matter at all? The chain runs on sprockets that are fixed. Nothing with respect to the rest of the engine would affect that.Last edited by Bonz; 04-18-2026, 07:44 PM.Howard
ZRX1200
Seca 750Comment
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My take on it is the C position keeps all the slack out of the rear of the chain (keeps it taut) via the position of the cam lobes on the springs. That way when the tensioner is installed, everything is nice and tight. Now who knows, it may do the same in the TDC position. The smart Yamaha engineers I'm sure had a good reason (sweet spot) regarding utalizing the C position.Last edited by bikerphil; 04-18-2026, 08:34 PM.2H7 (79) owned since '89
3H3 owned since '06
07 Triumph Tiger 1050 (night rider)
"If it ain't broke, modify it"
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To try to add AI's two cents to this. The C alignment mark is where the cam chain has the most slack. Thinking about the original cam chain adjuster it would make sense so that when the adjustment bolt release was loosened the pad would be released and with the chain being at the most slack point it would allow for the most adjustment. The TDC as we all know is primarily geared for timing etc.. Meaning if the TDC is used instead of the C you would not be getting the maximum adjustment.2 - 80 LGs bought one new
81 LH
02 FXSTB Nighttrain
22 FLTRK Road Glide Limited
JimComment
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So... Slack is the enemy of the timing chain, keeping in mind we do not want slack when removing the adjuster but we do want slack if we are doing a manual adjustment. Would TDC be a better option based on that? Keep in mind, with the rotation of our engine, the front is the slack side as has been pointed out. Slack is the main issue we are debating.To try to add AI's two cents to this. The C alignment mark is where the cam chain has the most slack. Thinking about the original cam chain adjuster it would make sense so that when the adjustment bolt release was loosened the pad would be released and with the chain being at the most slack point it would allow for the most adjustment. The TDC as we all know is primarily geared for timing etc.. Meaning if the TDC is used instead of the C you would not be getting the maximum adjustment.Last edited by Bonz; Yesterday, 06:16 PM.Howard
ZRX1200
Seca 750👍 1Comment
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If you go back and read the OEM service manual pertaining to the section on engine assembly and adjustment it states that when installing the cam chain tensioner after reassembly that the engine should be rotated around to the C mark and then the cam chain tensioner is installed and released. Based on that it would be the same for installing the "ACT".
So... Slack is the enemy of the timing chain, keeping in mind we do not want slack when removing the adjuster but we do want slack if we are doing a manual adjustment. Would TDC be a better option based on that? Keep in mind, with the rotation of our engine, the front is the slack side as has been pointed out. Slack is the main issue we are debating.2 - 80 LGs bought one new
81 LH
02 FXSTB Nighttrain
22 FLTRK Road Glide Limited
Jim☕ 1Comment
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You're almost there... ( •_•)
If you go back and read the OEM service manual pertaining to the section on engine assembly and adjustment it states that when installing the cam chain tensioner after reassembly that the engine should be rotated around to the C mark and then the cam chain tensioner is installed and released. Based on that it would be the same for installing the "ACT".
Consider that during this "engine assembly" section in the repair manual, one should presume that any/all worn or defective parts have been identified and being Replaced with NEW. Just as say, part of a "refresh/repair" cycle intended to get another 100K mile out of the motor? (O_O)
Therefore... the cam chain that was JUST installed ain't the ratty and stretched out one which had 75 thousand miles on it, right? (O_o)
Nope. It's a brand NEW cam chain with ZERO miles on it. When installed, it won't be Bowstring taut unless something's way off. It will have exactly the right amount of length to fit around all the sprockets and with the MINIMUM slack as determined by the Yammy engineers. VIRGIN my lads! \(^_^)/
You could spin that new chain round by hand with no CCT installed at ALL till the cows come home and NEVER have it slip a tooth. Slack just ain't there to begin with. (^_^)
Install of the CCT is so it can respond to the slack that WILL develop. But at the point of all this "turn CW to reach C" and install the CCT in the repair manual? (O_o)
Assumes the chain is new, minimum slack, and so will NOT drop down/off the lower sprocket or jump a tooth. ٩(^◡^)۶
50 thousand or mOaR miles later? (O_o)
If "X" equals the amount of slack needed to drop off the lower sprocket and jump a tooth? (•﹏•)
Then when one yoinks out the CCT which has one job.... ONLY one job.... and suddenly it just ain't there to take up the slack that developed over the many years/miles? ᕙ(⇀‸↼‶)ᕗ
Then one better hope that the amount of slack in the old/stretched/installed chain is NOT equal to or greater than "X". (-‸ ლ)
Keep going gentlemen. Given the "Brain Trust" here on da-club.... someone should be able to resolve this the RIGHT way. (^_^)Comment
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Concerning replacing the tensioner with an AUTOMATIC CCT: I have experienced chain slipping on the crank sprocket while the tensioner is out. With that in mind, I was thinking that if the position on the timing wheel is on the T mark when replacing, the slack might not be perfect for maximum tensioner plunger depth, however it might be better for keeping it on the sprocket. So, after installing and releasing the the action on the ACCT, it should ratchet as needed when rotating the timing wheel to the C mark (automatically
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Last edited by skids; Today, 06:13 AM. Reason: additional concern. When finishing slowly and carefully rotate the timing wheel a couple of turns to ensure there is no valve/piston contact.Skids (Sid Hansen)
Down to one 1978 E. Stock air box with K&N filter, 81H pipes and carbs, 8500 feet elevation.Comment
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If you Choose to use the original tensioner, be acutely aware of the torque requirement for that little stopper bolt. I didn't have a baby torque wrench at the time. I felt a bit of give and just tightened the keeper nut. That was the stupidest thing I could have done because the threads had stripped and the stopper bolt allowed slippage. Yeah...that is when I learned all about reconditioning the head. That was a lesson learned long ago.Skids (Sid Hansen)
Down to one 1978 E. Stock air box with K&N filter, 81H pipes and carbs, 8500 feet elevation.Comment
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I have over 100,000 miles on my bike. Somewhere along the way I replaced the tensioner and the chain. I don’t remember at how many miles, but I think it was over ten years ago and likely documented here. I very recently did a valve clearance check. That chain is still banjo tight.Marty (in Mississippi)
XS1100SG
XS650SK
XS650SH
XS650G
XS6502F
XS650EComment
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