Cylinder Replate v Liner

[stirlinggaz]

REPLATE v LINER

Hi all,
following a convo with another fb/2t enthusiast, I thought I would get some other opinions.
it seems pjme is not offering re-plating of nicosil cylinders currently & are only offering to press in a new liner, which can then be bored out a couple of times.
I reckon this is a backward step, in terms of technology, performance etc.
I know there is only 1 or 2 places that can actually do the re-plating & most places just send cylinders to langcourts.
but im of the opinion, it would be better to send a cylinder direct to langcourts & iF it can be re-plated to original specs, it SHOULD be .
I will stick this post in a couple of different groups/ forums & hopefully it will attract a few knowledgeable repplies..
cheers,
GAZ

[stevo as b4]

It's an interesting and can of worms debate.

My rebuilt KMX125 has been fitted with a liner by PJME, and all I can say is that it runs well. Have I lost any power over a std plated bore?
Well it's impossible to tell or measure really, and I suspect that 90% of how a sleeved originally plated cylinder performs is down to how well the liner was fitted and the port matching etc.

It's said to reduce heat transfer and cooling ability having a liner, but in the real world on a road engine I don't think it's going to matter worth spit really. Yes if your 125cc is 40bhp+ then there might be a performance or reliability issue, but as long as a bike runs well and is reliable I doubt you'd ever tell the difference performance wise, all things being equal (fresh bore/piston etc)

Cost wise there does not seem much in it really between re-plating or sleeving a cylinder, so id say it's down to preference more than anything.

I've had a KMX 200 cylinder re-plated and tuned along with the head too, and this was about £460. It's sat on a shelf waiting for when I get bored of 125cc, or cant get anymore out of it.

[redeem ouzzer]

Remember a liner is heavier. Surely part of the appeal of more modern strokers is lightness?
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[Pete.]

Probably a whole 50 grams heavier. More weight in a clump of mud.
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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

[Fidge]

why get it bored and plated to original spec when you can give them a +2mm piston and they will get it to fit.

[redeem ouzzer]

[Shaft]

Makes you wonder why they've stopped offering re-plating.

First thoughts are, either A/ they've fallen out with their supplier, or B/ they've had one too many warranty claims, which might take us back to A.
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[Kickstart]

Hi

Putting a liner in has never sat well with me. Although partly that is having had a barrel with a liner fitted fobbed off on me under warranty on my Aprilia AF1 Futura many years ago. We gave it a try but the piston slap on it was awful. I only dared ride it about 300 yards. Lousy job (and the matching of the liner to the ports was pretty dire).

As far as I know there are potentially different rings for cast iron and plated bores. And a bore you can rebore is of no use if you can't get over size pistons.

You can always log a liner into a trashed bore but you can't replate a barrel once you have lobed in a liner.

Personally a replated bore would be my first option.

That said I am probably going to get a liner put in to a spare barrel for the Gilera NGR250 soon. But that barrel will need some mods to work with the pistons that are available (KTM 300 piston is the closest match).

[Vincent]

[bladerunner]

^^^^^ have seen that done a few times ^^^^^
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Current bikes...cbr929, KDX200's, Rd125lc mk2, RGV250's

[saikouslx]

i've always had my rs 125 replated rather than sleeved. If you want to tune your cylinder such as porting i believe you cannot do that with a liner.