Oil leak from front cylinder head/barrel

danno

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Non-VOC Member
Hi
I have oil seeping from the front cylinder head/barrel join on my series C Rapide.
Have recently returned this bike to the road after eight years and it's only done
5600 miles siince full restoration.
Is it a fairly easy job to re-torque the cylinder head bolts?
I see the frame backbone is bolted to the front two.
Any help appreciated.
Dan
 

Bracker1

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VOC Member
It's easy to overtighten the cylinder bolts and distort the head. Oil is probably coming from the oil feed at top of cylinder or the inspection caps and dripping into joint. I have heard you can back the upper nut off and tightening the 2nd nut but have no idea how you could accurately torque the nut. I would think the compression would be low of the joint is open enough to leak oil. Good luck, Dan
 

danno

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Non-VOC Member
Thanks for the reply.
Will check those places. Also notice there's a fair bit on the bottom of the exhaust nut and
it also trickles onto the alloy oil filter cover.
Mostly though you can see it on the cylinder fins around the join.
Dan
 

Hugo Myatt

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VOC Member
Before you do anything drastic try swapping the front exhaust rocker inspection cap for one of the others, plus a new washer of course. I don't know why it should make a difference but it did on mine when I had a similar problem. Curiously the cap did not leak in it's new position (inlet rocker - different bike).
 

david bowen

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Non-VOC Member
I think you will find that your bike is sumping ( the oil from the tank is slowly draining in to the sump? drain sump before starting up also put a cap full of oil down the front inspection cap push rod tube hole then start)
 

deejay499

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VOC Member
Also check the rear rocker feed bolt and the oil return banjo, as if either leak, it will run down the fins to the front.
Good luck. DJ
 

Mark Fisher

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Non-VOC Member
Danno, before dismantling anything try the following:
1. Make sure oil tank (UFM) wasn't overfilled, this happens when the engine has a lot of oil in the sump making the level in the UFM look low so you end up topping up by mistake..I know because I've done it! Some bikes wet-sump quickly and some don't. If there is too much oil it comes down the filler neck and finds its way to the top of the motor.
2. Clean top of engine and UFM thoroughly, use gunk or maybe jizer.
3. Run the bike and watch for leaks (make sure there is airflow to the engine, maybe a fan, so things don't get too hot). Depending on the severity of the leak this may take a little while.
4. Look for leaks in the following areas:
oil return banjo on underside of UFM
all rocker feed unions
cyliner head studs
valve and rocker caps
flexible hose to solid pipe joints (some hoses go hard with age and leak and they are only a push fit on a vincent, unless its been modified of course)
Unless you find a banjo/union that is actually loose don't just tighten them more, fit new seals (usually copper or aluminium washers). If its the hoses I think the club shop can supply the correct hoses.
good luck
mark
 

mercurycrest

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VOC Member
Danno,
A Vincent will play all sorts of mind games with you when it comes to the source of an oil leak. I remember, a number of years back, of a 100 point Show Rapide from the Mid-West, USA that suddenly developed a puddle that even ran down the front forks. The finicky owner almost was commited from the stress of trying to find where it was coming from. Finally, to all our relief, some kind soul pointed out to him that it acturally wasn't oil but, Preparation H.
Cheers, John
 

Albervin

Well Known and Active Forum User
VOC Member
Danno,
A Vincent will play all sorts of mind games with you when it comes to the source of an oil leak. I remember, a number of years back, of a 100 point Show Rapide from the Mid-West, USA that suddenly developed a puddle that even ran down the front forks. The finicky owner almost was commited from the stress of trying to find where it was coming from. Finally, to all our relief, some kind soul pointed out to him that it acturally wasn't oil but, Preparation H.
Cheers, John
Now that would be a pain in the arse!
 

ClassicBiker

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VOC Member
I've retorqued my head by backing off the top nut and attaching a crows foot to my torque wrench. The change in the leverage is not that significant, particularly if using a beam type torque wrench you're are making an educated guess rather than a dialed in value as you would with a "clicker" type torque wrench. Though it wouldn't be that hard to measure how far you had extended you torque wrench and reduce the reading or setting by the correct amount.
Good luck
 
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