Is my Enfield cylinder head scrap?

[stinkwheel]

Had a problem on my '07 plate 350 bullet classic where it's been losing compression, burning more oil and popping from the exhaust on the overrun.

Oil consumption has always been a problem and popping on the overrun has been an intermittant problem I put down to a poor exhaust seal. These have sort of gradually crept up on me getting worse and worse until compression was so low I could push it over TDC with a hand on the kickstart and it was popping every time I closed the throttle. Tappets have been regularly checked and fine throughout.

I decided enough is enough and pulled the head off. It was immediately apparent from the mark on the piston crown that it's dinged the exhaust valve at some point so I'm calling the piston scrap and the valve bent even if they're not. Bore looks, feels and measures up as fine though.

Oops!
https://i48.photobucket.com/albums/f216/stinkwheel/enfield%20head%20231010/dscn1421.jpg

Whoopsie!
https://i48.photobucket.com/albums/f216/stinkwheel/enfield%20head%20231010/dscn1423.jpg

I just took the valves out and I think I have a more fundamental problem. As I wiped a finger round the exhaust valve seat, it dropped out and is totally loose in the head, it can be pushed in and out with light finger pressure. There is no apparent visual damage to the seat itself but the alloy under it looks none too clever.

Some images.

Valve seat in place:https://i48.photobucket.com/albums/f216/stinkwheel/enfield%20head%20231010/dscn1424.jpg

Valve seat removed: https://i48.photobucket.com/albums/f216/stinkwheel/enfield%20head%20231010/dscn1425.jpg

Extreme close-up of head under valve seat: https://i48.photobucket.com/albums/f216/stinkwheel/enfield%20head%20231010/dscn1428.jpg

So. Scrap and new head? Or ream out and fit bigger valve seat (if I can find one that suits).

I'm at pains to point out that the loss of compression and popping was already happening BEFORE I drag raced it.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Kickstart]

Hi

Thought Enfield spares were reasonably cheap, in which case it is probably financially scrap.

Difficult to tell how much damage there is there under the seat.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Lone-Wolf]

Wotcha.

You ain't the first to have a valve seat fall out on an Enfield. I know to at least another two. Luckily it's a relatively cheap fix - if push comes to shove, a new head is cheap compared to "modern" bikes. . . . . I paid less than £350 for a gas flowed head with big valves - like almost 2" dia exhaust valve.
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Cheers.
^..^
L.W. - www.moonshiners.org.uk

[Ariel Badger]

That is dead, how much for a new head?
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Bikers make great organ donors, get 115 on your licence today.

[stinkwheel]

[stinkwheel]

On a closer look. Does it look to anyone else like a circular defect/drilling has been filled in with a plug or weld that has partially melted?

I wonder if it was like this from new (or somewhat like this then exascerbated by the hot gasses).
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[temeluchus]

Looks like a repair if a faulty casting repair that's given out.

Poke at it a bit, see if there is a larger cavity behind there!
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Some shite cruiser. Now with guns and FREEDOM!

[Martay]

Id say that looks like poor casting thats been repaired. Send them pics, you may get lucky??
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Eat well, poo hard
Drives: Cavalier 2.0 16v
Rides: Slightly ratted Honda City Express

[The Shaggy D.A.]

That does look suspiciously round.
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Chances are quite high you are not in my Monkeysphere, and I don't care about you. Don't take it personally.
Currently : Royal Enfield 350 Meteor
Previously : CB100N > CB250RS > XJ900F > GT550 > GPZ750R/1000RX > AJS M16 > R100RT > Bullet 500 > CB500 > LS650P > Bullet Electra X & YBR125 > Bullet 350 "Superstar" & YBR125 Custom > Royal Enfield Classic 500 Despatch Limited Edition (28 of 200) & CB Two-Fifty Nighthawk > ER5

[stinkwheel]

I think this says someting interesting about the price of labour and materials where the bike is manufactured.

In Japan, a flawed casting coming off the production line would be chucked directly into the scrap bin. If there were two, the person responsible for making them would ritually disembowel themself.

In Germany it would be chucked directly into the scrap bin and its presence noted. If the level of casting flaws exceeds their previously stated efficiency target, an internal review as to the cause would be triggered.

In India, a good casting is sent down the line. A flawed casting gets put to one side and sent to the welding wallah in the next village who fills it in with a mixture of donkey poo and elephant snot then sends it back.

In Britain it would depend who noticed. If it was the guy whos job it is to make them, he'd chuck it in a disused corner of the factory where nobody could see it until such time as that corner of the factory was overflowing onto the shop floor. If it was anyone further down the line, they'd fit it anyway and wait for the warranty claim. This would continue until the factory went bust.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[MarJay]

[bwprice100]

.
As others say cheaper to get a new head.

Brian
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www.eBolt.co.uk www.ToolRoomChucks.co.uk
My bikes 1956 BMW R26 250cc, !981 BMW R80 (was a TIC ex plod), 1994 R100RT, sold my 1981 Yam XS 250

[jimspeed]

Also it looks like the piston has slightly melted in that pic, around the 4 Oclock position ? or it could just be the pic making it look like that, It all seems pretty oily in there tho.
It almost looks like the head has a drilling that has gone too far and been poorly welded back up which is a bit poor really considering where it is .
scrap I would say unless you can find a bigger seat (and maybe valve too) and someone good enough to repair the head and fit the seat.
The guy that does all the rally engines here would possibly be able to fix it but he is slow
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Hyosung cruise 125(passed test on, sold) Kawasaki el 252 (better than expected but sold on) Kawasaki GPZ500S first "big"bike.(sold) ZZR600 E5..Z750 2007,ER5, currently on a 2008 Enfield bullet electra x and loving it..
,"Alpha-9: Is there any correlation between dyno rod and dyno kits?"

[Robby]

New head. Even if you fixed that one up (costing most of the £300 for a new one) you would never trust it. Every little problem with the bike would have you suspecting the head as the cause.

The new tuned heads - have they been tuned by an old school engineer with a beard in his shed on a housing estate in the midlands? If so, you can trust it. If they have been tuned by the Indian factory, I would be getting a normal one and sending it to the aformentioned beared engineer to have new seats and valves fitted.

Sodium filled exhaust valves are always nice to have, too.

[stinkwheel]

[Lone-Wolf]

[Kickstart]

Hi

Looking at those heads, and Stinkwheels earlier pics, it looks like they were set up for twin plugs. Is this common on them.

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[bikenut]

:karma: hi dude never heard of desmodromic BSA but have Norton.

royal oilfield ( cruel i know as usually oiltight ) you drag raced it you naughty boy ( valve bounce bent push rod?? )

However, lookin at pics the hole does seem round!! the blow hole i mean.

head scrap, is small round thing opposite plug a decompressor?

[stinkwheel]

[temeluchus]

[Pete.]

Bloody hell have you ordered a new head? I would fix that sooner than pay £350. I'd weld it up, indicate off the guide and bore a new pocket with a 2 thou interference for the seat.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[Walloper]

J.B. Weld and a Dremmel.
Sorted.



Excellent pics by the way.

That's the standard everyone should be aiming for.
Some of the photographs folk post are appalling.
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W-ireless A-rtificial L-ifeform L-imited to O-bservation P-eacekeeping and E-fficient R-epair

[Pete.]

By the way there's nowt wrong with the piston I'd say, but if it's a shell-bearing crank you better pop off the big end and see if there's any damage from pounding on the crooked valve seat.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[sickpup]

That does look like a faulty casting that has been drilled, welded and re-profiled prior to having a seat fitted. If the seat had been a tight fit it would probably never have been noticed as combustion spreading the seat would have sealed it just as it seals the valve in position.
It is repairable and I would have thought it was doable for less than £100. I know the company that does diesel head repairs for Citroen and Peugeot and have seen a lot worse than that repaired like a crack between the inlet and exhaust valve machined out, filled with weld and machined back to shape ready for a new seat to be fitted.
The chap that does the work is an old Irish man but sadly he has no beard, can PM you his details if you want them?

[Lone-Wolf]