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My plan was to tear the engine apart this winter to at least replace all the leaking gaskets. Today I noticed the leaks around the base of the cylinders have gotten worse. The right side is lightly spraying my boot and that side of the bike. I also noticed some light wisps of smoke around the right cylinder base when idling, although I couldn't see exactly where it's coming from. It could be oil burning off the outside. I revved it up good but didn't actually see oil or smoke spurting out.

I'm inclined to go with my original plan and wait until this winter, making sure to keep the oil topped off and not flogging her hard. Is this a bad idea? Should I bite the bullet and lose part of this riding season in order to avoid some unforeseen but possible catastrophe? I mean, if it gets much worse I'm sure I'd give in and do it now.

I will be doing the work myself, although I don't know everything that's involved with this engine. I've got manuals and tools. I tore down dirt bike engines a long time ago and managed to get them running again, so I think I'm competent to figure it out, although it may take me a while longer than some of the experts on this board.
 

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I would check the cylinder base nuts before riding again. The leak is likely to be the O rings on the tappet block. The pushrod tube bottom seals, or the base gasket. When you do look into this, be prepared to change the piston rings as worn rings will help to increase crankcase pressure and this forces oil past seals.
 

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A quick top end job should be a weekends work. Take it apart with a view to fixing leaks only, whilst it's apart you can assess condition of bores, valve guides, seats etc and make a list for your winter strip down. A vintage Triumph should not have to suffer the indignity of oil leaks!

Rod
 

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I'm inclined to go with my original plan and wait until this winter, making sure to keep the oil topped off and not flogging her hard. Is this a bad idea? Should I bite the bullet and lose part of this riding season in order to avoid some unforeseen but possible catastrophe? I mean, if it gets much worse I'm sure I'd give in and do it now
Difficult to say really, depends how bad the leaks are I think. My bike developed oil seeps from the cylinder base and rocker boxes once I started using it properly. They're not bad and they're not getting worse so I'm happy to wait until winter, that's why I recently bought the gasket set. I think if your boot and other parts of the bike are being oiled it sounds bad enough to do now, you might not damage the engine if you keep riding but it'll always be in the back of your mind.

Yes, I think I'd do it now.
 

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just nip up all the nuts and bolts - keep it topped up with oil and keep riding it --( treat the leak as an oil change)

time to stop is when your feet slide off the footrests
 

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Discussion Starter #7
Thanks for the input. I'm on the fence but I think I'm just going to tighten everything up and keep an eye on it. If it keeps getting worse I'll do a quick top end job.

...but it'll always be in the back of your mind.
I hear you. I'm probably more anxious than I need be just because I don't know enough yet. So even a "quick top end job" is somewhat off putting. But I've managed to do a lot of work I didn't know how to do before so I bet I can figure it out. I just don't like the idea of an unknown quantity of down time because I ride just about every day and enjoy it so much.

When you do look into this, be prepared to change the piston rings as worn rings will help to increase crankcase pressure and this forces oil past seals.
That makes sense to me.

A vintage Triumph should not have to suffer the indignity of oil leaks!
Good one! :laugh2:

...time to stop is when your feet slide off the footrests
:laugh2:
 

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I have had success with a base gasket leak using a silastic and a feeler gauge to push it in. If you do this use something like brake cleaner or carbie cleaner and get the area as oil free as you can then smear some silastic in the area and push it into the gap with a feeler gauge [find one the right size]. Allow it to cure then ride a check. I've done this a few times on peoples bikes where they really didn't want to disassemble [till later] and it has worked every time so far.
 

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I have had susses with a base gasket leak using a silastic and a feeler gauge to push it in. If you do this use something like brake cleaner or carbie cleaner and get the area as oil free as you can then smear some silastic in the area and push it into the gap with a feeler gauge [find one the right size]. Allow it to cure then ride a check. I've done this a few times on peoples bikes where they really didn't want to disassemble [till later] and it has worked every time so far.
Yes, maybe...Just loosen the cylinder base nuts slightly to raise the cylinder up maybe .020" so you dont have the pushrods getting out place...Of course an old paper gasket may break up and the cylinder may not seat down squarely. So maybe better to treat it like a sore dick, don't screw with it..
 

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Yes, maybe...Just loosen the cylinder base nuts slightly to raise the cylinder up maybe .020" so you dont have the pushrods getting out place...Of course an old paper gasket may break up and the cylinder may not seat down squarely. So maybe better to treat it like a sore dick, don't screw with it..

If you first take off the rocker inspection caps, then hold up the rocker arms with elastic bands, it will be less likely that you dislodge the pushrods. Check the clearances after you retighten to make sure they have not altered.

Regards
Peg
 

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Well I hope you have better luck than me on a "quick" top end job. I had the same problem as you - every gasket on the top end leaked. So I pulled that apart and found some indications the bottom end also needed work. Terrible play in the valve sleeves too. If you have an issue, you will not be inclined to put it back together until it is properly fixed. Then again, you will know about any serious issues rather than worrying.
 

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Hi Eric, How did the tightening of bolts work?

Generally what JiminyCricket said turns out to be the case. Turns into at least a rebore, with valve guides & valves. That's often at least a month of down time. More often 2!

However... If no smoke from exhaust, no oil crust on spark plugs, not using oil, good compression. Just have oil leaks, you can remove head, cly block & replace only seals & gaskets. Don't remove pistons or rings, don't hone cyl. Just clean piston tops. Blow rings clean with compressed air or parts cleaner in spray can. Oil rings & wrist pins, bores well, line up rings in 3rds & reinstall cyl. The rings will find their old places & be as they were before. If you remove rings from pistons, they will not seal again. Then you must at least hone & replace. So if you just want a reseal don't touch rings.

The valves & seats wear slightly oval. If you remove them to check guides or for some other reason, they will need to be lapped. So again decide on doing nothing with valves, or at least lapping them. Even if guides are very worn, you can usually get away with just lapping them. Motor will run how it did before. Don't worry about seat width or any thing like that. Seats will be worn curved. That is not a problem. Don't grind valves & lap unless you actually are doing a complete head overhaul. But for just a reseal to get some more miles, I recommend what I suggested. I've done this on several machines, including my own & have covered an additional 20k miles so far with no leaks.

It is not a dumb idea to just so a reseal. Depends on the condition of hard parts of motor. If motor is not worn out, just repair the leaks.

On the other hand, if you can get away with just tightening nuts & bolts, why not ride it until winter. Then take off top end & evaluate it. Do proper repairs, which may be just reseal or a real overhaul.

In the end of the day, the condition of the hard parts of motor determines what it takes to get a good running, long life overhaul. You cannot wish a ring job will work if bore is tapered or out of round. Any parts even close to being on the border of bad must be repaired or replaced. Triumphs are not forgiving. If it's not right, it won't work right.
Don
 

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Discussion Starter #14
Hi Eric, How did the tightening of bolts work?
It did the trick, Don. The worst leak went away. Still some on the other side.

I feel good about waiting. It burns a little oil but not enough to concern me. I think it leaks more than burns.

So the plan is to rebuild this winter. Thanks to everyone for the helpful input.
 

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Go to the Dodge dealer and get a tube of Transmission Sealer with Silicone. You can clean the spots that leak with brake cleaner and many times this will slow down or stop the leak, at least temporarily. I’ve been using on a leaking push rod seal for years. Each application lasts a year or two. If clean it will stick to anything.
 

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In my experience there's no such thing as a quick top-end job. In recent months I have faced this sequence of events:

- oil leak at base gasket fast getting worse only 12 months since last top-end job
- quick strip down, but broke a ring on re-assembly so start again... this time with a search for new rings
- got hold of a set of Hastings rings with one-piece oil ring and reinstalled, this time with a copper base gasket treated with copper-kote. That
was a disaster, it leaked again at base gasket immediately and oil rings were completely ineffective (blowing smoke profusely). Mind you I
didn't do a proper hone (my bad)
- Strip again, (this time under guidance form some more experienced vintage bike specialists from my club) installed new tappet guide-block O-
rings from a specialised O-ring supplier (not a vintage Triumph parts supplier), fitted new Emgo pistons with Hastings compression rings and a
metric 3 piece oil ring (new piston ring groove machined to fit the metric sized 3 piece oil ring). Also head stripped and fitted with new valves
and valve guides. Also barrel professionally honed.
- on advice from said experts reassembled under Loctite 518 on base gasket, used a 80 thou copper head gasket to get the right amount of
crush on the pushrod tubes, grease on copper head gasket

FINALLY, the bike (1973 Bonneville) is running perfectly, no oil leaks now, no smoke, heaps opf compression

So, there you have it, a quick top-end overhaul....

My lessons learnt are: avoid trusting vintage parts suppliers unless you are ABSOLUTELY confident that they aren't just selling the cheapest **** quality parts (especially O-rings), get assistance from vintage bike club members (if you are a member of a club) or someone who doesn't have a vested interest in just selling you new parts over and over again...They know the machine shops that can do critical machining and head work
 
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