Rebore of chromed barrels - V7 S3

I have some 82.5 mm barrels for a V7 / S3 with damaged chrome on the bores,and I also have some virtually new 83mm LM1 pistons.

My question is, if I were to re-bore the 82.5 mm barrels to be suitable for the 83mm pistons, is the liner behind the chrome a suitable type of ??cast iron to use as a “new” bore or not?

Does anybody know? I realise this is a bit of a specialist (metallurgist) area, but maybe someone on here has done it?

If not, I will try selling the barrels as they are, if anybody is interested? ReggieV2013-10-14 19:31:53

I think they would need to be rebored then lined or recoated/replated in some way. I also have a set of S3 barrels with knackered chrome lining, I just bought new Gilardoni ones.italianmotor2013-10-14 19:59:57

I am no expert on this BUT I thought the cast iron is reboreable but the chrome ones not I seem to recall you can get different liners. The guy to ask may be Nigel at NBS I DO know he had some barrels a wee while ago They were becomming difficult to get , I mentioned this in passing and he had a fair few of them …

I actually sold some old scarred cast V1000 barrels to someone who was going for an o/s bore for a Le mans, worked a treat we were both happy. He saw them languishing in my shed and made me an offer for them that almost made my eyes pop.

Not totally sure but the plated ones are usually plated onto the bare aluminium and not cast iron linings if they are alli plated bores they can be bored and replated then ground to size required onething to watch is piston ring selection they are not interchangeable between bore linings

I think some relatively modern motorcrossers are the same, might be worth looking in a copy of Dirtbike etc.

Thanks for the reply’s, I’ve just gone and had another look at these barrels and the cylinder is indeed aluminium and not cast iron as ex-smokingbiker says! Doh! Why didn’t I notice that?

So I suppose my options are to;

  1. re-chrome (a friend of mine knows a place in Germany I think, who can do this).
  2. Replace with a new cast iron liner,
  3. Sell them as they are.

Thanks to all again for your help.

Plenty of places in the Uk i just done this searchhttp://www.google.co.uk/search?q=mengine+bore+re+plating&ie=utf-8&oe=utf-8&rls=org.mozilla:en-US:official&client=firefox-a&channel=fflb&gws_rd=cr&ei=qTZdUoePHrKW0QXZ1oH4CQ

Yes, I have used Langcourt, near Weston Super Mare www.langcourt.com
Used them a couple of times. Very easy to deal with and did a pretty quick turnaround both times.

I believe so, the ones with liners stand out a mile (as very obviously having a big tube [the liner] stuffed up the middle), viz Le Mans’s, Spada’s. The plated ones are straight onto the alloy. This is why you might see oversize pistons available (or mentioned in manuals) for Le Mans 850’s and the V1000’s, but NOT T3’s etc. NB: I was told (by Motomecca I think) that the later nikasil has no advantage whatsoever over chrome plate EXCEPT it’s simply more convenient or easier to apply at the factory. NB 2: piston rings for the ‘iron’ (actually steel) liners have chrome plated outer faces IIRC, obviously chrome liner ones DON’T, are just steel I think, not sure about nikasil, might just be steel again. Some oil rings are plain (sic) and simple, some (e.g. 850 Le Mans) are complex and delicate structures (means easily broken, guess how I know) and have a looped coil spring inside a hollow channel on the inside (which can be a barsteward to compress to get the ring back into the cylinder) HTH

Does the cost of resleeving or replating better the cost of new set of barrels I am wondering, if available?

Cost of reboring, replating with Nikasil was about £140 for a 100mm bore single cylinder, piston not included, about 2 years ago.

Mmm, interrsting, that was a couple of years ago, looking around, new Gilardoni Nickasil barrel including piston/rings for T3 etc around £250 for one side, maybe a bit less if you shop around. I think if it was bike I wanted to keep (like I did my S3), I’d go for the new cylinder kit complete.italianmotor2013-10-15 19:16:23

If you have a Guzziology Dave suggests new set rather than the redoing of the chrome/nikasil/nigusil. The cast iron ones are the onew well worth reboring it is relatively cheap to do the pistons are not more than others IF you can get them BUT and this is the killer blow the rings are almost £100 per set per side and break real easy.

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When I tramlined MY oem cast bores it was LESS to go buy new sets than pay for the rebore/pistons and cast rings. I sold the barrels to a mate who had them oversised to the max and they are in a real niiiice Le mans