Author Topic: spark plugs don't stay tight  (Read 1396 times)

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Offline dhall57

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spark plugs don't stay tight
« on: October 30, 2010, 05:11:54 AM »
On my 750 K6 the plugs seem to always loosen up some what. Is this a common thing ,does anyone else run in to this? After a good day of riding I almost always have to tighten up all plugs. Should I torque the plugs  down by specs per honda 8.6-11.6 lbs-ft.  All I ever do is snug them down to what feels good to me. I've heard horror stories about people that tighten up plugs to much and strip the threads.I surley don't won't to do this .
1970 CB750KO
1971 CB500KO-project bike
1973 CB350G- project bike
1974 CB750K4-project bike
1974 CB750K4
1976 CB750K6
1977 GL1000
1997 Harley Wideglide

Offline dave500

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Re: spark plugs don't stay tight
« Reply #1 on: October 30, 2010, 05:24:45 AM »
no,you dont want to strip the threads,torque them i think if you cant judge it by feel,they aint wheel nuts,once the plug bottoms an 1/8 of a turn is all it needs.if you have an air compressor,just loosen the plugs a turn,then blow any crud out of the seating area,these are old bikes now and might have gathered some crap,its hard to see down there so even a spray of carb cleaner or similar to make sure first then blow away any shyte.

Offline MoMo

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Re: spark plugs don't stay tight
« Reply #2 on: October 30, 2010, 05:25:34 AM »
Plugs should never come loose, anything properly tightened  should never come loose, unless it's an old Harley.   I tighten the plug till I feel the compression rings collapse, back off a bit and then retighten, never had a plug or anything come loose, only use a torque wrench on motors.  People strip plug threads by wrenching the plug in when it is off center. If the plug is started by hand and goes in smoothly, it would be very difficult to ruin the threads unless you put a 1/2 breaker bar on it.  Good luck, Larry