Author Topic: Oily right hand exhaust  (Read 1564 times)

Offline pdg

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Oily right hand exhaust
« on: 28.10. 2014 15:29 »
I've recently acquired an A7 Star Twin that has an oily right hand exhaust (looking from the back of the bike). The plugs are clean and both look to be in the same condition. The bike has not done many miles following a complete rebuild.

There aren't any great plumes of smoke, just a gently rolling oily vapour coming out of the right hand exhaust when the engine is switched off.

Would I be right in assuming the exhaust valve guide has mysteriously given up the ghost, or could it be a breather problem?

Many thanks.

Online Greybeard

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Re: Oily right hand exhaust
« Reply #1 on: 28.10. 2014 17:49 »
Hi and welcome. I like your avatar!  *good3*
Greybeard (Neil)
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Re: Oily right hand exhaust
« Reply #2 on: 28.10. 2014 20:02 »
G'day pdg,  *welcome* to the forum.
Yes that would be the culprit. Have the guides been replaced recently? I often have to go 1 thou bigger on the replacements. You don't say if it's a long or short stroke A7ST.
That info will cost you an introduction to us over in Bikes, Pictures & Members.  *grins*
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
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Offline duTch

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Re: Oily right hand exhaust
« Reply #3 on: 28.10. 2014 23:23 »

 G'day pdg, I reckon before you go berserk and strip the head off, give the whole exhaust a clean out- possible when the rebuild was done the oil residue which may have prompted the rebuild was overlooked..... *conf*

 You have to pull them off first anyway- and clean them out anyway also.... *whistle*
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
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Offline pdg

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Re: Oily right hand exhaust
« Reply #4 on: 29.10. 2014 09:26 »
Many thanks for your replies. A nice job for the winter!

Offline duTch

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Re: Oily right hand exhaust
« Reply #5 on: 29.10. 2014 09:54 »

  *????* *????*winter- you serious ?- It only should take a short time (<two stubbies) to flush the pipes with some kind of gasso...and go for a blast, afterburners an' all.....? Then you'll know if you need all winter to do whatever...
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Online bsa-bill

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Re: Oily right hand exhaust
« Reply #6 on: 29.10. 2014 12:34 »
Quote
.and go for a blast, afterburners an' all

Whoa that's new
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline Topdad

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Re: Oily right hand exhaust
« Reply #7 on: 30.10. 2014 10:26 »
But an interesting picture don't you think Bill regards BobH
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Offline RichardL

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Re: Oily right hand exhaust
« Reply #8 on: 19.04. 2015 22:24 »
Perfect topic for posting my questions

Just put new rings into bores 1.5-2  thou too big. Good and about even compression on both cylinders. I am pretty sure I'm looking at a valve-guide problem here. The black by the right exhaust port is wet oil. It seems to be just on the right but maybe the left piipe just fits better. Both plugs are sooty and look similar, but  the right is a bit wetter. Is there some agreement that this is guides? If my (our?) conclusion is that it's right side only, should I bother with the left guides as well, or follow the "if it ain't broke" addage?

Richard L.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020. This year it's a solo or pillion ride in dapper attire. Watch website at https://www.gentlemansride.com for details.


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Re: Oily right hand exhaust
« Reply #9 on: 20.04. 2015 10:27 »
G'day Richard.
How many miles on the new rings?
It could be the ex guide looking at the amount around the pipe. If you have to do one, I'd do the lot.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
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Online KiwiGF

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Re: Oily right hand exhaust
« Reply #10 on: 21.04. 2015 11:59 »
I think there are holes that allow oil to drain from the rocker box through the head and barrel back into the crankcase that can cause oil leaks like yours.......it might be worth a try to re torque the head bolts as that might stop the leak if the bolts are a bit loose.

https://www.draganfly.co.uk/index.php/accessories-a-misc/product/14132-

Shows the oil holes at the front of the head.....I think ..... *eek* its some since I've had the head off mine  *good3*
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Online bsa-bill

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Re: Oily right hand exhaust
« Reply #11 on: 21.04. 2015 13:15 »
agree with KiwiGF, it also important to make sure those drain holes are free (when you have the head off)
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline RichardL

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Re: Oily right hand exhaust
« Reply #12 on: 21.04. 2015 13:38 »
Kiwi,

It's a legitimate point. I wasn't really considering the injestion of oil past the gasket because the gasket was well-annealed and sprayed with copper sealer and the head had just been mounted and torqued evenly (I thought) at 32 ft.-lb. I'll test the torque on the exposed bolts, the problem being, if they move, it's basically a commitment to remove the rocker box and torque the rest. By then, the head might just as well come off so the gasket can be visually checked for leakage paths and the guides checked for tight.

I was thinking about just riding it and letting it spew for a few hundred miles to see if it cleared-up on its own by letting the rings seat. Wishful thinking, maybe, since my bores were basically oversized to the point of book-recommended re-bore before installing the new rings. Also, some folks (Muskrat, for example) have reported successful running on oversized bores. In any case, the whole deal started as a test to see if new rings would be enough to allow the oversized bores. It's too soon to declare failure on that front.

Richard L.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020. This year it's a solo or pillion ride in dapper attire. Watch website at https://www.gentlemansride.com for details.


Offline RichardL

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Re: Oily right hand exhaust
« Reply #13 on: 21.04. 2015 14:05 »
Bill,

That would be a big surprise/shock/embarrasment if the oil drains were blocked. You've made me think, this condition did not exist before I added an oil filter and  SRM pump. Maybe I should bypass the filter and check (again) the hole sizes  in the rocker feed bolts.

Richard L.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020. This year it's a solo or pillion ride in dapper attire. Watch website at https://www.gentlemansride.com for details.


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Re: Oily right hand exhaust
« Reply #14 on: 21.04. 2015 16:01 »
If it didn't do this before, then I doubt it's the drain holes unless some foreign object found it's way in there, or as you indicate over supply to the rockers, I have a filter and don't have the problem but I also don't have a SRM pump.
One filter element I bought though was too restrictive, I bought it online (it was compatible to the one I had used without problem)  gave it my customary test (blew through it) and it failed so binned it.
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco