Enfield help needed

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Greenbat
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Enfield help needed

Unread post by Greenbat » Sat Mar 23, 2013 4:09 pm

Morning,

I had a look in the cylinder and bottom end of the knackered enfield...oh dear! It appears the valves have walloped the piston, presumeably due to being fitted the wrong way round. Pictures and description here: http://oldnailsandswarf.blogspot.co.uk/ ... d-joy.html" onclick="window.open(this.href);return false;
I'm guessing the piston and conrod are scrap, but I thought I'd best check. I really don't want to do a full strip! What do you reckon?

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Hooli
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Location: Doncaster

Re: Enfield help needed

Unread post by Hooli » Sat Mar 23, 2013 6:23 pm

That much silicon in the wrong places reminds me of Stroppy when I got her. Enjoy.
Classics ain't built in Metric

Velton
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Location: London, England

Re: Enfield help needed

Unread post by Velton » Sat Mar 23, 2013 6:38 pm

That looks as if a total strip down would be very wise!

The con-rod is likely to be scrap and, given the level of"expertise" shown by that quantity of sealant and the likelihood of some of it getting into the lubrication system, you would always be waiting for it to go BANG!
On the bright side, you probably would not have to wait long! :lol:

I bought a B25SS off an acquaintance at work many years ago.
He assured me that the engine had been totally overhauled by himself but he could not get it to start.
When I dismantled it, not one of the nuts, bolts etc. was more than finger tight!
If if had started at all it would have flown apart like a grenade. :o

The previous owner of the Enfield is not called Denis, is he? :lol:
Just being old doesn't make it a "Classic."

Aaaah! Nostalgia is not what it used to be!

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Greenbat
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Re: Enfield help needed

Unread post by Greenbat » Sat Mar 23, 2013 6:50 pm

I think you (and 3 other websites) are right. When I took it on it was only a quick recommision...
I'm seriously thinking of naming and shaming the twat who did it (got receipts with his address), or at least ringing up to provide an ear bashing. Moral of the story is, don't buy rebuilds!

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johnr
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Re: Enfield help needed

Unread post by johnr » Sun Mar 24, 2013 11:32 am

surely when the valves have clobbered the piston the weak link in the whole chain would have been the pushrods not the conrod? surely the impact of the valve onto the piston, obviously not both at once, is nothing compared to the stresses of the bike every time it fires.

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Greenbat
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Re: Enfield help needed

Unread post by Greenbat » Mon Mar 25, 2013 2:38 am

johnr wrote:surely when the valves have clobbered the piston the weak link in the whole chain would have been the pushrods not the conrod? surely the impact of the valve onto the piston, obviously not both at once, is nothing compared to the stresses of the bike every time it fires.
True, but the rod itself has damage-it looks like maybe something got caught between it and the cases. Pic isn't too clear but it is a fairly deep gouge.
More horrors here: http://oldnailsandswarf.blogspot.co.uk" onclick="window.open(this.href);return false;

Pete R
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Re: Enfield help needed

Unread post by Pete R » Mon Mar 25, 2013 6:19 pm

The piston looks good enough.I doubt that it's been hit hard enough to jam the rings in their grooves.Even that might not be a big problem.Just tidy up the sharp edges on the valve pockets.It wouldn't hurt to put a 1/8" radius on the top edges of pockets too.

It would still be a good idea to check valve-to-piston clearance with plasticene or clay before it goes back together.
No doubt the intake valve would be bent,but it's probably worn anyway and the valve-tips didn't look too flat.I'd throw away the aluminium valve spring collars before you get some real engine damage.

It's hard to tell about the conrod from the picture.Any scratches running across the rod should be polished out vertically (180 grit paper will do;polish it finer if you like).If it's taken a lot off the web thickness of the rod,then it could be a different story.
If the rod eyes are round within 0.001" when the cap is torqued,and the eyes are parallel within about 0.002" in 6",it's usually a good sign.It still never hurts to crack-test an old aluminium rod,even if you only do it with hot kerosene and talcum powder.

You wouldn't trust much in this engine,without building it all again.

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Greenbat
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Re: Enfield help needed

Unread post by Greenbat » Tue Mar 26, 2013 1:01 am

Owner says go with a new rod. Bloke at work has a GS750 triple after No.1 rod went, flymoing the cylinder off and spraying oil everywhere at 125+mph...

Good news on the piston-the bike came with a spare barrel and piston, which I got given today. Only +30 bore and hardly used (no wear lip), plus it's the right barrel with extra bolt holes on the head. No idea why it wasn't fitted, other than a cracked fin! Other barrel is on top size and knackered.

So, full strip it is! Got a few other jobs to catch up on, then hopefully get cracking after easter. BTW, spoke to someone who seems to think people often put a rod in the 250s out of one of the RE twins, any idea what he might be on about?

Triton Thrasher
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Re: Enfield help needed

Unread post by Triton Thrasher » Tue Mar 26, 2013 8:21 pm

Greenbat wrote:BTW, spoke to someone who seems to think people often put a rod in the 250s out of one of the RE twins, any idea what he might be on about?
It may use the same rod as some twins. One piston fits the 250, the 350, the 500 twin and possibly the 700 (I can't remember).

sbsbsa
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Re: Enfield help needed

Unread post by sbsbsa » Thu Mar 28, 2013 12:39 am

Greenbat, you might want to contact Tollgate Classics (use Google). They predominantly deal with Bullets ( & big bore kits for) but they may be able to give some advice.
Steve :)

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