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Shovelhead rocker oiling


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#1 red jonson

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Posted 27 November 2012 - 08:38 PM

I've got a 72 shovelhead ...The rear cylinder is smoking a little after the bike is run some and there is an oily film on the inside of the rear cyl exhaust...The spark plug is clean and not oily and the cylinder is clean inside so I think the oil is coming in around the exhaust valve stem...I suspect that there is too much oil building up in the rocker box and the oil is getting in around the exhaust guide/seal.....I have seen some suggestions that the oil tube leading up to the rear rocker box needs to have a restrictor put in to limit the amount of oil going in...I have also seen suggestions that the return might be plugged or restricted not allowing the oil to get back to the sump.... The valve stem seal may have come off in there as well.....I'm gonna have to pull the rocker box off and have a look.....Has anyone had this problem and found the cure?Thanks for looking....RED

Edited by red jonson, 27 November 2012 - 08:46 PM.


#2 Red Good

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Posted 27 November 2012 - 09:10 PM

Was it ok last month ? Or last year ? Just started doing this ? Has someone done the top end recently ?

Compression test says what ?

Leak down test ?

If it was ok before then it's probably not the rear oil tube needing a restrictor and it's probably not the return either . I would do those tests 1st as they won't cost money and will give you an indication of engine condition before disassembly , and help you decide what to look at as you tear it apart . Good luck ,Red

#3 red jonson

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Posted 27 November 2012 - 10:14 PM

The bike just started doing this......leakdown test shows 78 over 80....cylinder and plug burn clean....makes me think the valve stem seal has come off ....The oil is coming in downstream of the cylinder so I think it must be the guide...The Clymer manual shows a gasket under the valve guide before it is pressed into the head...I have talked to some shovel mechs who don't use these gaskets....This engine was rebuilt about 2000 mi ago and I don't have the specifics but the prev owner rattled off a list of parts like Keith black pistons, aftermarket valves, new guides, tappets, pushrods etc....I believe it was a professional job judging by the way the engine and bike look and what the guy paid it should be good...I'm going to pull the rocker cover off and have a look.......I haven't worked on a shovelhead for 25 years...

#4 red jonson

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Posted 12 March 2013 - 12:00 PM

I put the shovel in the back of the shop for winter storage...Got it out yesterday and put it on the lift....This engine was rebuilt (not by me) about 1500 miles ago... .Pulled the rear cyl head off....Nice and clean inside..cylinder walls show a nice crosshatch...Valves, Springs, retainers, all new aparts...Top of piston just a little carbon dust...I popped the valve springs off and the intake valve stem to guide fit is perfect...The exhaust stem to guide fit is sloppy at .005 + The seal is intact but worn out ...I suspect from the sloppy guide....I'm taking the head to the cyl head service tommorrow to get that sloppy guide replaced...The exhaust valve stem is straight and measures evenly at .375 diameter all the way down so I suspect the guy that rebuilt the engine just got careless on the reamer when he did the guide...

I noticed that the crankcase breather hose (vented to the atmosphere) had a kink in it.....Might not have been open all the way...I was wondering if that would keep the top end oil from returning to the sump properly....and have oil building up around that rear exhaust valve stem? This bike has a belt primary and all the chain and primary oiler stuff has been blocked off and the sump vented thru one hose..I hope to be riding this one soon...
RED

#5 Crazy Cats

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Posted 12 March 2013 - 06:20 PM

No it won't stop it from draining.

#6 Copper

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Posted 13 March 2013 - 01:30 AM

I think you found your culprit and your suspicions are most likely correct. Good luck getting her back together and on the road!

#7 insaneme371

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Posted 13 March 2013 - 08:59 PM

Valve stems on a shovel? why for put new guides in and make sure there tight no seals needed
Do you know why they call it “PMS”? Because “Mad Cow Disease” was
taken.

#8 red jonson

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Posted 20 May 2013 - 03:56 PM

Shovel is back together...New valve guides and valves...i had them put in new seats as well....valve stem to guide clearance is now .001 using modern valves and guides.....My harley overhaul manual says .003 + for stem clearance...These modern parts make tighter tolerances possible and should extend the time between top overhauls.....Runs good now...sounds like a John Deere tractor and pulls like one too!....

#9 hardrock785

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Posted 20 May 2013 - 08:29 PM

when you get the son of a gun polished up, put up some pics!

#10 red jonson

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Posted 27 August 2013 - 07:53 PM

when you get the son of a gun polished up, put up some pics!


t's dirty but I've been ridin' it...runs good now...72 FL shovel ....70 cubic inch..belt primary,the juice brakes work good, the V&H pipes are loud, 4 speed clunks a little going into second....I'm havin a ball....

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