cylinder bore question

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novack2007
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cylinder bore question

Post by novack2007 »

on my 91 kdx200 i might have to pull the cylinder. can i just rebore the cylinder over or do i have too pull the sleeve and re sleeve the cylinder? and also what would be the best just bore it over alittle or get something like the 225 big bore kit?
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Post by Julien D »

It's a plated cylinder. Best bet is to get it re-plated to spec. If it's already been sleeved, next best is to find a used cylinder and replate that. Last resort, re-sleeve it.

I don't think you can 225 the E bike without loosing the power valves.
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novack2007
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Post by novack2007 »

well i have to do more investigation on this. i could get a sleeve tho and do that if need b? i have access to all the tools to rebore the cylinder for free to install the sleeve.
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Post by Julien D »

I guess?
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Post by Fletch »

>|<>QBB<
juliend wrote:I guess?
Yes from what I hear a replate is superior to a sleeve except that a sleve can be re-bored later.

I went with a replate from cv-tech in Canada and it's awesome, better in every way to a stock job. I'd say pony up and go with the replate. I even have a spare stock cylinder i'd part with that's ready for a replate.
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novack2007
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Post by novack2007 »

if i would go with a replate could i go with an oversized piston?
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Post by Julien D »

why? Incremental oversizes are to compensate for wear in the bore, there's no performance gain. In order to see a gain in performance from an oversize, you would have to look at a big bore kit. I think the only thing you can get for the E bike is a 240 kit, and doing so sacrifices the power valves. I don't even know if that kit is still available anywhere.....

If you just really want to go with a 20 or 40 over piston, you can have it bored, plated, and matched to that piston. I don't understand why tho....
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Post by Fletch »

Uh well that's a good question... I'm not sure I have the right answer for ya. I wonder at what point the cylinder wall will just get too thin and start to crack etc. As it is the cylinders I have had (2) both had cracks in the center port with stock bores. So any thinner I think you may run into problems sooner. I suppose it would be possible but probably not warrantied or recommended.

Are you looking for more power? IMHO the 200 has plenty with other mods ie. pipe, rb stuff etc. But I'm fairly new to all this so take that with a grain.

I think the general consensus is that the plating is much stronger than stock plating, transfers heat much better and lasts much longer than a sleeve. Depending where you live you can get a re-plate for around 180-300. It has worked extremely well for me, and I can't recommend it enough.
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novack2007
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Post by novack2007 »

well the bike has a pro-circuit pipe and uni filter. the bike isnt going to get ridin hard just trail riding a few times a month. so it looks like doing a sleeve might be alittle cheaper than sending it out and getting it plated. if im wrong please let me kno. i live in fleetwood pa. so if anyone would kno anyone close too do plateing please let me kno.
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Post by Julien D »

A little cheaper, perhaps. Inferior, most definitely. Your choice.
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Post by Fletch »

Yeah it'll be cheaper. just not better
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Post by Dodger »

>|<>QBB<
juliend wrote: I think the only thing you can get for the E bike is a 240 kit, and doing so sacrifices the power valves. I don't even know if that kit is still available anywhere.....
My '89 SR model was fitted with a 240cc kit back in 1998 and it does have the powervalves. From what I remember, the front exhaust valve is machined down to provide clearance for the larger bore. The kit was installed back then by the Australian importer of Wiseco pistons, so I assume that it's a wiseco kit. It is no longer available in Oz.

Kustom Kraft in Colorado still offer a 240cc kit for the KDX: http://kustom-kraft.com I have to purchase head gaskets from them as they are no longer available here.

Here's what Kustom Kraft say about their KDX kit, which mentions mods to the exhaust valves.

"Kawasaki 2 Stroke Off Road Big Bore Kits
KDX 200 1986 - 2006 240cc Big Bore Kit
Includes sleeving or plating, piston,
rings, pin and clips, gaskets, and
exhaust valve mods. $525.00"


Being a rider who doesn't really rev his bike, I find the 240cc kit ideal for my riding style.

Cheers
I may be old, I may be slow, but hey I'm still getting my leg over - a dirt bike!
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Post by SCREAM »

So are all you guys saying that having the stock cylinder replated is superior in every way (i.e. durability, performance) to just buying a new oem cylinder? I am in the process of rebuilding my '02 200 and I'm sure that in a season or two I will be making the same decision. I'm not rich but when it comes to my bikes I will spend what I need to in order to ensure maximum performance and reliability......and I have an oem hook-up. :lol:
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Post by Julien D »

Well, aftermarket plating is generally superior to the OEM plating. As in, a better formula and better process which ends up being much more durable than the OEM nikisil coating that kawi used.

The big discussion here is around plating vs sleeving, and there is no arguing the superiority of plating from a performance and durability standpoint.
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novack2007
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Post by novack2007 »

is there any aftermarket company that makes a cylinder for these bikes?
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Post by Julien D »

Nope.
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Post by SCREAM »

In that case what are considered to be the best places to have our cylinders replated.
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Post by Fletch »

millenium, langcourt, and if in Canada cv-tech aab in montreal
they did mine and it's a great job
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Post by SCREAM »

Alright, thanks for the info. I'll check them out.
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Post by Julien D »

I use langcourt almost exclusively, however the others mentioned by fletch have a good rep, as well as powerseal. Best bet is to send a piston in with it, or purchase the piston from the company doing the re-plate. This way they can match it perfectly.
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