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PMVERN View Drop Down
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    Posted: 02 Jan 2019 at 20:04
So, after buying my lovely 1968 V700 as a rideable classic, I started reading about the dreaded chrome bores.
To cut a long story short, it's rebore time.



I've phoned Langcourts about Nikersil coatings, seems pretty straight forward, but when I put new piston rings in, will they be compatible?
Also, has anyone on here done this? Any helpful advice will be gratefully received!

Thanks, Paul.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Glawster Quote  Post ReplyReply Direct Link To This Post Posted: 02 Jan 2019 at 20:12
Hi Paul,
I've just replaced the pistons and cylinders on my V7 Sport for the same reason.  I called Langcourt and they confirmed they could replate the bores with Nikasil, but the total cost of a Gilardoni kit with new pistons / rings / pins and cylinders was less than £600, so I went down that route instead.  If you do go the replating route I'm interested to hear how much it costs.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Paul-l Quote  Post ReplyReply Direct Link To This Post Posted: 02 Jan 2019 at 21:30
hi Paul,
I've just had mine done by langcorts, it was about £120 per side + vat. They bored the cylinders to match the Pistons and rings that I had. I put a picture of them on the head stud broke thread a week or two ago.
I read somewhere that the original rings were compatible with the new plating so didn't need changing if they were in good condition.

Paul
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Post Options Post Options   Thanks (0) Thanks(0)   Quote PMVERN Quote  Post ReplyReply Direct Link To This Post Posted: 02 Jan 2019 at 22:08
Thanks for the responses, the price on the Gilardoni kit seems reasonable,I'll post more details when I decide which way to go.
Sludge trap out next
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Post Options Post Options   Thanks (0) Thanks(0)   Quote JayDee24ca Quote  Post ReplyReply Direct Link To This Post Posted: 03 Jan 2019 at 02:52
By the looks of the chrome in that bore, you may be well advised to check the lower end of the engine for damage  as well. Chrome is well known to destroy the bearings etc. Have you ad a look at the engine oil and inside the sump, for chrome specks? 
JD
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Loopian Quote  Post ReplyReply Direct Link To This Post Posted: 03 Jan 2019 at 09:57
I’m afraid by the look of those bores, I would expect the flaked off chrome to have gone through the rest of the engine.  I’m no expert but they look worse than on my Eldorado when I got it. I ended up rebuilding the engine completely. However it’s a very easy engine to rebuild, I got Nigel of NBS to rebuild the heads and regrind the crank. I put new bearings and seals throughout plus barrels and pistons etc, I took my time and had everything scrupulously clean.  I did it all indoors in the warm over last winter and really enjoyed it. Sorry that’s probably last thing you want hear, might be worth giving Nigel a ring at NB S.
Good luck
Ian
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oscar225 Quote  Post ReplyReply Direct Link To This Post Posted: 03 Jan 2019 at 13:43
sorry to butt in on this thread, for the sake of us ignorant souls who are "NBS"?
Chris
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Barry Quote  Post ReplyReply Direct Link To This Post Posted: 03 Jan 2019 at 14:03
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Amboman Quote  Post ReplyReply Direct Link To This Post Posted: 03 Jan 2019 at 14:51
Unfortunately, there are no Gilardoni kits for V700s, haven't been for nearly a decade. Ambassador/V7 Special sets can be substituted, but their spigot needs to have the diameter reduced and there's a .5 mm difference in cylinder height as well.

For my V700 "Tutto Terrenco" project, I bought NOS piston assemblies and had Millennium Technologies replate the cylinders. Ended up costing virtually the same as what Gilardonis would.
Charlie
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Post Options Post Options   Thanks (0) Thanks(0)   Quote PMVERN Quote  Post ReplyReply Direct Link To This Post Posted: 03 Jan 2019 at 18:49
Thanks everyone. I'm doing a total rebuild. Surprisingly, everything looks good, but I've yet to check tolerances.
I've talked to Gutsibits and was assured the 750 Gilardoni kit was a straight fit (apart from bigger gaskets). Looks like I'll be going down the Langcourt route
I'll report back after I've measured up next week.
Thanks again,
Paul.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote PMVERN Quote  Post ReplyReply Direct Link To This Post Posted: 12 Jan 2019 at 16:54
Hi all,
I had the callipers out last night, everything was pretty much in spec. The old girl's going to want new big end shells, and I'm going to purchase a pair of Asso 80mm pistons because one of the old piston skirts has a chunk missing (god only know what caused this to happen).


The barrels will be sent to Langcourt next week. I'm presuming the rings will work on nikasil the same as on chrome?
The advert for the Asso asks what weight you want the pistons (choice of 3 - a, b, or c) I'm thinking, as long as they are a matched pair, all should be well?
Emptied the sludge trap, hardly anything in it, result!



Thanks in advance for any feedback, this site is proving to be invaluable.

Paul.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Dukedesmo Quote  Post ReplyReply Direct Link To This Post Posted: 12 Jan 2019 at 17:38
Currently waiting for some Ducati cylinders being replated. I'm getting them done by Poeton/Aptec as I have already had them replated twice by Langcourt only to fail both times.

That said I have had other cylinders done in the past by Langcourt without issue so maybe I was unlucky with this one...?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ken-Guzzibear Quote  Post ReplyReply Direct Link To This Post Posted: 12 Jan 2019 at 17:56
Cast rings work on all cylinders but Chrome only work with chrome therefore most aftermarket ones are Cast However one needs to run in cast rings in chrome/nigusil cylinders very carefully indeed
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Post Options Post Options   Thanks (0) Thanks(0)   Quote JayDee24ca Quote  Post ReplyReply Direct Link To This Post Posted: 12 Jan 2019 at 19:51
I hope you are planning on turning the crank as well, and not just slipping in new bearings. That crank journal in the photo looks a tad rough. 
I wonder why the trap did not have more crud in it. Was this a low mileage machine? Or is there any sign it had been torn down before with perhaps the sludge trap emptied some time in the past? 
Have you thought about flushing the casing at all, to rid yourself of loose chrome bits? I would imagine the oil pump is toast as well by now. It looks as though there are chrome flecks in the sludge you removed, although that could just be the lighting.
JD
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Amboman Quote  Post ReplyReply Direct Link To This Post Posted: 13 Jan 2019 at 14:36
The rings that come with the Asso pistons will work on either chrome or Nikasil. You'll likely find that the new pistons are 10-15 grams lighter than the originals - the two sets I've bought were. I ended up having my crankshaft balanced as a result. On the other engine, I used a thicker piston pin to bring the piston assembly weight up to the original.

A, B or C doesn't really matter, but it is best to have a matched pair.
Charlie
'69 V700, '69 Ambassador, '76 Convert, '13 V7 Stone
http://www.AntietamClassicCycle.com
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