Recoating nikasil cylinder

[Beamishnz]

I have a '97 KX250 that has nikasil plated cylinder that is ready for a replate. I know that guys used to send their cylinders to US, Oz and UK ... but heard today that someone is doing the plating here in NZ .... anyone know who's offering this service? Many thanks Paul

[onearmedbandit]

Someone correct me if I'm wrong but don't HPC do them?

[Ixion]

Te Puke Farm and Trail advertise 'Electrosil' cylinder recoating service. They claim to be "the cylinder coating experts". 18 day turnround claimed. I am unsure if they do it themselves, or send it overseas and are just agents.

Ph 075733999 Fax 07 5733998 2103 Main Highway Te Puke. Kerry Vercoe

[Motu]

There have been a couple of threads recently...

http://www.kiwibiker.co.nz/forums/showthread.php?t=25795

[Kickaha]

Someone correct me if I'm wrong but don't HPC do them?

No they don't unless they are agent for someone, and with my experience with HPC it would take months to get them anyway

[Beamishnz]

Yep found the old threads. Useful stuff. USChrome seem like a safe bet at US$165-200 but shipping will add another US$40 to that ... would have been good to keep the business in NZ if someone was actually doing it here. Brent at Spectrum Motorcycles was telling me it was being done now but was unsure who was doing it.

[umka]

i have heard some bad reports about us chrome have a look at this forms posts.

http://www.nsr250.net/forums/viewtopic.php?t=2056&highlight=chrome

dont wnt to scare u off but just making u aware that a safe bet may not be as safe as u think.

[Beamishnz]

Hey .. that makes sober reading! Anyone know of a replating out fit with a GOOD reputation! Are Aussie crowd any good?

[sugilite]

I'm sad to say I have a lot of experience getting this done. Forget the aussies, the UK mob (wales) are by far the best, I got dicked somthing chronic by the others.
Robert Taylor from Hawera Motorcycles is one of the UK agents.

[Beamishnz]

mmmm... thanks for that! Do you know the name of the outfit in Wales?

[Ixion]

Just send it to Jones the Replating. That should get there :rofl:

Or, ask Biff. He's Welch, so he'll know.

[scott411]

I ahev used L M electrol=plating is Australia for barryls from 85cc to 500, they are very good, we have never had a problem with them, Farm and Trail te puke are an agent fro them but you can deal direct as well, the are in Victoria and their phone number is 0061 3 94357029

[NZCYL]

Hi NZ Cylinders in Ashburton New Zealand do the repairs and replating of Nikasil (TM), Chrome or electrofusion (TM) cylinder bores. Type NZ Cylinders on google and you will find them.<_<

[CRF119]

My CR125 one was done many years ago in aus Electrisil plating very nice job. Get some mods done while you are at it :)

[tommorth]

I had my ktm cyl welded and replated by dg engine sevices second half of last year not cheap but great sevice and it was back in under a week

http://www.engineservices.co.nz/cylinder%20plating.htm

[The Stranger]

Hi NZ Cylinders in Ashburton New Zealand do the repairs and replating of Nikasil

Can you give an indication of price please?

[jt119]

the price NZ Cylinders gave me to weild and replate mine was 570 + post the guy was really helpful

[flyingcr250]

I had my ktm cyl welded and replated by dg engine sevices second half of last year not cheap but great sevice and it was back in under a week

http://www.engineservices.co.nz/cylinder%20plating.htm

theres an old guy in the south island that does it, does real beautiful work, just trying to find his card

[camchain]

Here's a link I found was a good place to start for some basic quick info on Nikasil coatings that most will probably find very useful to know: http://www.electrosil.com.au/news1.htm

Apologies for this lengthy post but I hope it might save someone else a very frustrating experience. Been doing some reading up on this subject and it's something I wish I'd known a bit more about earlier. Personal impressions at this point would be to go with an outfit that has a lot of experience doing the job. The reports of coatings ending up wrong final size/too soft are a bit of a worry.

Nikasil (and other) surface coating is high tech stuff and you're dealing with extremely fine tolerances - a very different kettle of kezzafish to the old days of air cooled engines, sleeves and boring for oversize etc. It's now a real mix of science and engineering.

My own basic top end refresh has proven to be far from straightforward. After cleaning my glazed up bore with a scotch brite pad/CRC then hot soapy water, put my vernier across it - seemed OK for size. Bore surface had some fine lines where rings had caught carbon buildup on end of power valve (previous owner a slob) but nothing major I figured. Vernier not the best instrument for measuring a bore so I took cylinder in to shop for inspection/measure before ordering piston.
It wasn't measured but eyeballed and pronounced OK, just needing a 'light hone' and standard piston. I wasn't keen about this as I'd heard not to hone nikasil, but Fizz - Whizz - bore now looks very pretty, almost like new in fact. Hmmm. Ordered standard size piston and later found ring end gaps to be suspiciously over spec. After already waiting a month for piston, temptation to just re-assemble and ride was hard to resist but took cylinder to engine reconditioner and he very accurately measured with bore guage and DTI. (Charged me nothing but I gave him a ten pesos anyway)

Despite bike being only 2 years old, cylinder found to be bang on max size limit and therefore in need of max oversize piston for correct clearances. My cylinder wasn't perfect to begin with and now there's no way of knowing how much material was removed with the hone but I certainly wish I'd measured it properly first.

Here's the real important stuff to keep in mind when cleaning your airfilter and/or thinking about trying to get a few more hours out of a tired sloppy piston: The standard coatings are apparently only about 0.1mm (tenth of a mm) thick, maybe even less. The standard bore size for my cylinder is 64.000mm and wear limit is only 64.025! that's almost nothing. A sharp, well directed fart could easily shave off 0.01 I'd say, let alone what a hone might do.

To put it in perspective, I remember from my apprentice days that the average human hair is 0.05mm or about 0.002 of an inch.
So the coating is only about 2 hairs thick and bore wear tolerance is only a thou of an inch, or half a the thickness of a hair! The piston oversizes come in tiny 0.01mm increments so I figure piston/bore clearance must be extremely critical.

Hey Tommorth - I'd wondered how you got on after your bad luck with the new bike. Did you ever figure out what caused it?

[crazyxr250rider]

Very accurate info camchain,as for the kx250 barrel i find the only reliable easy solution to aquire is a new barrel....very expensive,but your safest bet.
Try trade me,ebay,ect... for a NOS barrel.

[kezzafish]

lol, my name is mud. I looked at re-plating my (4T) after i lunched it (you may remember the thread about my motor running water lube instead of oil). I'd heard that Nicasil plating could be dodgy and there was no one doing it here so it turned out to be only slightly more expensive to just buy a new barrel from the states (KTM) forget buying a new barrel from KTM NZ.

[tommorth]

camchain general consenus on the ktm talk foum is its standard practice to change to b size piston on the 200 on first piston ring swap but you cant believe everything you read
I never found out what caused my bike to go but suspect that it may have just been due and after my rattley kdx I didnt notice the noise till it was to late

havent even done 10 hours on it since i fixed it which is pretty slack hoping to get out this weekend fiddled with the clickers last time and it made a world of difference its amzing how big a change small adjustments make

[camchain]

Cheers crazyXR. The coatings are obviously very tough but I still can't get over the miniscule wear tolerance of these bores, and with mass production processes being what they are, it'd be very interesting to know what sort of bore size variations (and coating thicknesses) you get from bike to bike. I'm guessing the factory teams probably get their pick from the parts bin so they can start with a blue-printed engine. For some reason KTM only offer 2 Vertex piston sizes yet Vertex makes 4 sizes. My jug has a '1' cast on the side of it. Possibly something to check when buying a bike? Anyone shed some more light on this?

Heh heh. No mud intended on your name Kezzafish. Just thought the two words sounded nice together and I like a little alliteration. Yeah, now that you mention it I remember your post on the KTM submarine testing (I felt your pain). Retail for the 200 jug aint cheap at $1200, guessing possibly dearer than a 4t due to complex casting for 2t ports? Is your top end still spinning OK?

Thanks tommorth. I'll have a dig into that. I've read some very strange stuff on KTMtalk, but certainly also has a lot of good info. I'd wondered if maybe your bike had been re-ringed and a too thin base gasket used? Sounds sorted now though.

[Reckless]

Hey Cam I think you should send the bill for the re coat and your time to the guy that put the Hone into it!!!
Cam how did you judge that the bore was Glazed? They are often very shiny, completely different to a steel bore. They very seldom need any doctoring unless they have worn through which almost never happens to a bike less than 2 years old. Also quite often there's the odd light scratch down the bore from foreign matter that makes little or no difference to power output. As long as your not using very high fuel/oil ratio the 2 stroke oil will take care of minor marks and still give you just as good ring seal and therefore compression. Especially on a non race bike. I've seen some really shit bores go really fast. It sounds to me like you've been the victim of bad advice all the way through. You should have just replaced the piston with the same A or B and run it in as described under!

Read this mate re running in- http://www.mototuneusa.com/break_in_secrets.htm.
I was doing it for years through impatience in my karts. Always wondered why my engines did quite well against all the professional tuners who practiced slow 3-5 x 20 minute run in sessions. I never had the Patience always did 10 laps then found I was flat out?? Only discovered Moto tune a few years ago.

With my MX bikes! I can't resist starting them in the garage for 10 secs just to make sure they actually go and I haven't made a stuff up! Then I take it out the sandpit or thunder, warm it up properly and just ride it, don't "run it in", don't thrash it, but ride it like I want it to go! In fact when I put my sons 200 together The slide in the carb was stuck on full throttle so when I started it, it screamed its head off until I could quickly get to the the kill switch, the thing goes like a cut cat now and I don't expect that its done any damage to it considering the generous layer of 2stroke I put around the bearings and rings when I put them together.
Also I always warm my engines before riding, always. Even if I start slowly riding I always wait till I know the cylinder and water have come up to temp before going hard. This of coarse is a must with a wiseco piston.

Secondly Re the Tommorth post. I'm no expert by far! BUT going to a B size piston to early therefore making the tolerances to tight or tighter would accelerate the bore wear in my humble opinion. Its quite often the piston skirt that shows the most signs of wear/damage when you do a piston replacement (this is why you measure it there) so this practice makes no sense to me. Also a bigger or smaller, A or B piston has little or no impact on horse power, its the ring seal that is important to compression. A looser tolerance (as long as the piston isn't banging about) makes more sense.

In my humble opinion the two best pyhysical things you can do to a standard engine to improve mechanical engine performance is match the transfer ports between the the crankcase and cylinder and line bore and balance the crank. Part of the "Blueprinting" process in Karting. Of coarse the engine has to come completly to bits to do this!
Anyway enough of my raving. Feel free to disagree KB!!:whocares:

[Reckless]

For some reason KTM only offer 2 Vertex piston sizes yet Vertex makes 4 sizes. My jug has a '1' cast on the side of it. Possibly something to check when buying a bike? Anyone shed some more light on this?

My guess is Ktm only need 2 sizes. Manufacturing processes are so good now the bore and Nikasil coating is very much the same each time so its measured and a piston size chosen to fit the bore, "usually for its life". The coating is so hard it usually out lasts the bike or should if its looked after. Its the piston and ring that are deliberately made of softer metals, to wear first, as they are cheaper to buy and easy to replace. Unless someone stuffs a hone down it (I'm bloody sure I've heard this stuffs the texture on a Nikasil Bore?) or never ever cleans his filter. Unfortunately both may have happened in your case?

You mentioned "blue printing" in your post while I was away typing mine.
I do know that they can line up say 100 Tillitson carbs and 5 will flow better than the rest for some reason?? The factory sells these as specials. In the karting world these cost many hundreds more in a governed/restricted class as they are better, but still standard. So maybe the same will apply to what you say about the engines. From my very small knowledge of a blue printed 2 stroke engines it is more "made" rather than produced. By crack testing, balancing, truing up the crank in the casing ie line boring, matching/polishing the transfer ports and a lot more things that each engine guy thinks works better than what the other guy is doing and thinks he won't get caught doing! LOL!! Its a very competitive world on and off the track! One look at the Karting Licence technical section (at the end of the book) on the Kartsport web site will show how very deep they go with the rules on engines and chassis! Measurement after measurement and pic after pic of the cannot do's!
Anyway enough of my opinions again. Quite like these discussions. Even if I am full of shit LOL!!!

[dammad1]

There is a lot of agrueing on the net about honeing of these bores, I gave mine a very quick going over with a diamond hone to help the rings bed in a little, and it has worked out mint. Certainly bought the power back up again.

I was told to stick with the standard size piston until it has at least 200 hrs on it.

[Reckless]

There is a lot of agrueing on the net about honeing of these bores, I gave mine a very quick going over with a diamond hone to help the rings bed in a little,

Just read the article Cam posted and it said this about Honing.

Also, many mechanics use a ball hone on cylinders before reassembling during a top-end rebuild. Ball hones are used to create fine oil retention paths on cast iron cylinders. On Nikasil cylinders, however, a ball hone won't do this. Instead, a ball hone will knock the Silicon Carbide peaks from the coating which wrecks the surface's oil retention capability. Ball hones are a bad idea for use on Nikasil coatings. LM use a special plateau hone, which they developed specifically for Electrosil. The main reason they use the hone is to aid with ring run-in more than oil retention. Nikasil cylinders should be cleaned but not ball-honed before reassembly.

Its the oil retention on the cylinder wall that creates the ring seal and therefore good compression in a 2smoker.
Camchain will have to make his own judgement as to whether or not the guy has stuffed his bore by honing it. But I've always thought it was a nono in a nikasil bore??

Secondly I personally wouldn't go up a piston size intil the measurements say you have to not because of the age or time on the engine. You may never have to! Especially if your running more oil than the minumim. Ie 40:1 instead of the factory 60:1 and your jetting has always been on the safe side!

[kezzafish]

yeah i had a reconditioned swear to me that it was fine to use a diamond hone but nothing else

[Reckless]

yeah i had a reconditioned swear to me that it was fine to use a diamond hone but nothing else

He could be correct, I'm not sure!
One thing I do think is Honing will shorten the life of a nikasil bore!

[dammad1]

yeah i had a reconditioned swear to me that it was fine to use a diamond hone but nothing else

Yeah that was my impression as well, I think if you went hard on it, it may take to much off but mine literally just had a very quick going over to scuff it slightly.

[camchain]

Uh Oh. War & Peace type length alert on post.
Feel like a thread pirate on this but relevant info to initial post and lots of very interesting comments going on here - enough for several different threads!

Although I'm pretty sure too much coating material was removed, I'm not sure I have much of a leg to stand on with any sort of claim as I didn't measure the thing first, and it was pretty tired to begin with. I see the Ashburton replate outfit refer to a specific diamond hone machine. Apparently these type machines are very expensive - like $30,000 or so. Different thing to finish honing a newly replated bore to honing a worn one though. After finding a couple of in-depth articles, conclusion is a lot more to it than meets the eye. Seems to me the real advantage of a very light hone is to create a good surface for an oil film to cling to, ie not perfectly smooth. I think a light scuff would be OK.

I can't afford a re-plate or new jug so I'll just be trying to extract the max life out of what I now have. I can still get correct 0.055mm piston/bore clearance with bigger piston.

I was told it 'needed a hone to help bed the new rings.'
Really wish I'd gone with instinct now. Although it would certainly help I don't believe this is really necessary and here's why. I hate to admit this on here, but when I did the valves and rings on the KLX I made a stuff-up with (black ring) ring order (bum steer off US site thread is my excuse) I wanted to pass the bike to new owner in proper condition so I stripped it down and re-ringed it again. I'd run it in quite hard as per Mototune advice. The new ring seal faces were quite rough to start with - they came out shiny, after only an hour's riding. Seems as long as you get enough pressure on them, they should bed in fine. Rings are soft, bores are hard.

See photo of before and after hone:

I'm getting into the habit of making notes and taking photos when doing any significant work. Unfortunately no pics of bore after cleaning. My rough guess of hours on the bike was 100-150.
Bore was pretty grubby but the marks looked worse than they really were. Rings were pretty stuffed. The odd looking diagonal smear on bore at left of the before pic is beginning of me cleaning. There was definitely some varnish type glazing that was tougher to remove than the black stuff. The WD40 solvents and scotch-brite broke it down though. I kept going until I got a clean paper towell with white spirit. Main concern was quite a pronounced ring lip.

RE. larger piston. I think changing piston sizes without very accurately measuring the bore first probably not a good idea. I'd actually priced up a telescopic guage and mic for the job but decided not worth it for amount of use (Hindsight now 20-20!). The bore guage the engine recon guys used was a very fancy thing - like a tripod with telescopic guage on the end. Another to be aware of is although my bore measured up nice and round, there is always more wear around ports. 4 strokers don't have to worry about this. There are bunch of ports all the way round my cylinder. Hardly any bore surface at all at bottom of stroke. With straight edge against the light you can see the extra wear curve at port height.

I'm big on warming up engines first too. Apparently the thermostat on the EXC opens up at 55 deg, so when you can feel heat on the radiator tops this gives you an indication of where engine temp is at. Was curious about what engine clearances might be at operating temp so doing an 'oven experiment' on this at the moment. Results pending...

Well put Reckless Re blue printing being 'made' not produced. Mass production processes and product design always involves compromises. I've found a couple of pretty big nasties on mine that weren't imediately obvious - previous owners had missed.

RE Carb slide stuck open: Ha. I had the same thing happen last time at the Sandpit carpark. Scared the shit out out of me. Not a good look.

Apologies again for the mega-post. Just hope this might save others a big pile of time and money. "Say No to Honing" 'T' shirt on order.

[Reckless]

I can see from the pic why you wanted or let it get honed mate! Heaps of blow by and shit built up on the Cylinder walls. Thats not normal. That piston and ring must have been in there for hours, or as I said before, he never cleaned his filter and completly whore the ring out!
Oh well sounds like you've slid in with the last oversize piston as long as you check it every 50 or so hours it will still last you a long time!

Good luck!!

[kezzafish]

cheers camchain and reckless, good learn for me

[Reckless]

cheers camchain and reckless, good learn for me


Just remember Kez! Don't believe anything you read on the internet!!:buggerd:

[kezzafish]

Just remember Kez! Don't believe anything you read on the internet!!:buggerd:

really? so "hot girls in my area" don't actually want to meet up?
I've often wondered if i actually am the "999 999th visitor to this website" and where the fuck is my prize?

[Reckless]

Yeh mate the girls want you BAD! Just take a hundred dollar note up Vivian street and your prize is in the mail!! :Pokey::Pokey:

[warewolf]

Cheers good info fellahs.

Watching & reading with interest, as my 200 is still in bits waiting for a rebuild. :cry:

[laserracer]

Yeh mate the girls want you BAD! Just take a hundred dollar note up Vivian street and your prize is in the mail!! :Pokey::Pokey:

YEP FREE PIZE ... A trip to the nearest std clinic :banana:

[laserracer]

really? so "hot girls in my area" don't actually want to meet up?
I've often wondered if i actually am the "999 999th visitor to this website" and where the fuck is my prize?

Hey whats going on:shit: ..you cant have hot girls in your area ..they keep telling me they are in my area..whats going on ??:confused:

[camchain]

Righto, didn't want to 'bore' anyone too much but might as well add this.

Rang the Ashburton replate outfit and spoke to Grant. He gave up quite a lot of his time as he apparently finds this stuff as interesting as I do, and was incredibly helpful.

He was understandably a bit wary about being critical of the hone but I found out some more about the plating process, eg. apparently coating tends to build higher on port bridges hence need for perfectly uniform diamond hone machine to finish. Ball, grape, 3 legged hones just aren't in the same league.

I was worried my Nikasil was now so thin it might delaminate or piston/rings suddenly go through to ali base but he reckoned I should be OK as standard coating approx *Edit dimension: 0.007 " (0.17mm) so still enough left for safety. He suggested using some bearing blue and running piston through bore for an indication of how much extra wear at port height. Price for basic recoat for mine (w no repairs) was around $560 (+ Grab,Snatch, & Take).

I checked my notes again and re-measured the old ring end-gaps.

Before hone: 0.53mm (this was a bit of a quick and dirty check as they were being binned)
After hone: 0.6mm
Which = 0.07mm loss in circumference
Divide that by mince Pi (3.1416 if I remember right) and you get 0.022mm loss on diameter (0.025mm being wear limit)

Especially hard now not to feel I may have had an accidental reaming as well as a hone.

Warewolf, I'd be very interested to know what size your bore is, are you planning to measure it? It only cost me $10 to have this done. BTW: Was thinking about sticking up a thread on this but I discovered a couple of critical things on setting 'X' and 'Z' dimensions not mentioned in manual or any forums I've seen. Found case gaskets proud at centre split where cylinder sits and also TDC not what it first looked to be due to pull of generator magnets.

Reckless, A big thanks for your input. You're a gentleman and a scholar.

* Edit dimension, I think I wrote this dimension down wrong during phone converasation, not 0.07 (mm) but 0.007" which equals 0.17mm


:::Sex is unhygenic and should be avoided:::

[Reckless]

Cam sorta depends if you have a spare $600-00 sitting around for the re-coat? But looks like you'd be OK with the present barrel for a while if your measurements are correct.

Concerning the ring end gap I wouldn't worry to much if its a bit wide you'll never notice it power wise. I've always thought the ring end gap check was mainly a safety check in case it was to small and the rings couldn't expand enough when running hot. Not so much for loss of compression or any other issues.

Concerning X and Z settings Again wouldn't worry to much about the high point at the join in the cases. The gasket crush may account for this but as long as it seals the properly it should be fine?? We always used a very light smear of silicon in our karts so we could get them apart again without tearing the gasket. If I where to guess I would say the X setting is to make sure your compression is factory and mainly to make sure there is enough squish clearance in the head so your piston doesn't top out and start smacking into the head at full revs. My 03 Engine book and 08 Manual both put 'x' at zero ie flush with the top of the barrel. So compression must be the same (as long as the head bowel is the same) for the 200 over the years. It appears that Dimension 'Z' varies 46.5 on the 03 and 48mm on the 08 and between models. This may be one of the reasons why the 08 has a softer power delivery, more enduro and less MX track?? But I'm guessing here! I've done rings on the 03 bike but managed to get everything apart without tearing any gaskets or taking the head off so didn't reset X and Z settings. Piston measured up fine looked brand new with no scuffing whatsoever so I put new rings, pin, bearing and c-clips in and left it at that for another 50 hours or so. My 08 (I've been told by the previous owner) has had a thinner base gasket put in to raise compression by the race mechanic so they do play with the 'X' dimension for performance anyway. We used to plain our heads and re-machine squish on our karts to adjust compression which essentially is the same thing as the changing base gaskets. Changes in the port heights by a small decrease in base gasket size is negligible in my opinion. I'd not notice it at my level of riding anyway!

TDC are you setting this and the advance etc with a dail guage? I have one here but we used to use a reamed out sparkplug with a bracket welded on it to mount it in the head (much quicker and more stable than the magnet stand) but I've lost it? You can borrow the guage if you need it.

[kezzafish]

1 question Reckcam (fuck, that should be my name) what is the "Y" measurement of? i figured the x from the surrounding info. Also reck you mentioned a z measurement, did you mean y?


YEP FREE PIZE ... A trip to the nearest std clinic :banana:
Nah that wasn't free not to mention the emotional cost

Hey whats going on:shit: ..you cant have hot girls in your area ..they keep telling me they are in my area..whats going on ??:confused:
Their everywhere mate... slags. I hope your not riding the same ones as me

[Reckless]

I'm typed out at the moment Kez and I gotta get some work done!!!

'Z' is the measurement of the height of the control flap (power valve) to the upper edge of the cylinder. Done before you put the barrell back on I'd guess??
'X' is the Height from the upper edge of the cylinder to the upper edge of the piston at TDC. Controlled by different base gasket thicknesses.

[tommorth]

pretty sure y dimension is clutch pushrod as there are differnt thicknes gaskets available for the slave to get clutch action correct

x dimension is different on pre o3 200s as they use a differnt head and barrel

cam if you cut the bit of gasket between the case halves off it will make life easyer , your barrel was looking pretty grotty in those pics hope you get it sorted soon

[Reckless]

oh shit your correct now I have to go back and edit all my bloody posts. Meant X and Z!
Y is the clutch push rod, Damn typo's

Edited now cheers tomo!

[camchain]

Looks like no one's keen to sell me a Nikasil recoat, so that seems good. Heard back from Electrosil (Aust) and they didn't think I had anything to worry about.

Told me standard KTM coat approx 6 thou (0.15mm). I think I made a mistake re thickness I mentioned in earlier post (0.07 probably should be 0.007"), will edit. These recoaters will know Nikasil thickness for certain as they'll be accurately measuring after removing old coating, but we were talking KTM orange flavoured so I don't know if this thickness applies to other manufacturers. They were also extremely helpful and happy to give advice.

They suggested I could even get away with a standard size piston if I couldn't find an oversize one which kind of surprised me. Manual only gives piston/bore clearance of 0.055mm. Electrosil suggested upper tolerance of 0.76mm . They also confirmed diamond hone is best but can use other hone to remove glazing but NO cylinder material should be removed. I think this would be hard to avoid so I'll be sticking with the WD40/scotchbrite pad. Slower but safer. If your cylinder measures up good after a clean, maybe a very light scuff up.

I'd downloaded Electrosil's tech data PDF. Not a huge amount of info in it but impressive as it looks like they have some fancy equipment and are able to measure/quantify what they do eg, friction coeffients, thermal expansion etc. Apparently they use a ceramic material in their recipe as well.

I picked up a 'C' piston from shop and putting that in today. Didn't do any dummy spitting over hone, and they took the 'A' piston back. Just glad I'll be rolling again after so much down time.

Probably should also mention for other KTMer peace of mind, while piston searching I spoke to NZ Vertex piston wholesaler (454 Unlimited ChCh) who also happened to be an Ex KTM dealer. Said KTM coating very good and only A and B pistons normally needed. Confirmed there are 2 bore/piston sizes to cover production variations, check for number cast on side of your cyl.

I guess moral of story is the old carpenter adage: Measure twice - cut once.

I was considering starting to do some compression testing, but told leak-down test better. Is the gear for this similar?

::::::::::::::::::::::

Copy that on the ring end gap Reckless, I was mainly noting that it was a good indication that I'd lost some bore diameter. I agree, can't see the small amount I'm over spec having any real effect on compression.

Re 'X' and 'Z' stuff, I really think starting another thread a good idea as keen to explore more. Some great points being raised and best to avoid going off topic on this Nikasil caper.

Beamish did you decide on a replater for your KX? Hope you get back on this thread with result. Me, I'd be measuring a newly replated cylinder so I knew exactly where I started.

Will start a thread out in engine section asking for ideas re my 'oven bake' engine experiment results, might as well cast the net wide.

[Reckless]

.I was considering starting to do some compression testing, but told leak-down test better. Is the gear for this similar?

"Compression/leak-down test" Don't do it mate you'll only open a whole new ball of wax. Just put it together and ride the arse off it. Your toooo fussy!
Not as if your racing and a fraction less ring seal/compression will mean second instead of first!

MY 2c and only because I've met you!

[camchain]

You've hit a significant nail on the head with a sizeable hammer there Reckmeister. Being a perfectionist can be satisfying but it's mainly a pain in the arse. Good advice re compression testing etc, so test gear crossed off shopping list. Sorry for not thanking you for the DTI offer etc, trying to cut post volume. Once I worked out the perfect way to set everything up I found perfect 'X' height measurement was 0.8 - Imperfect .75 gasket was a close as I could get!

Bike back together again and got the little bugger going again this afternoon (started SECOND kick so not overly happy about that). Put a JD jet kit in as well but is running rich on idle jet. Search is on for perfect jetting now. LOL

[NZCYL]

the price NZ Cylinders gave me to weild and replate mine was 570 + post the guy was really helpful

For a standard replate the price is $565 incl and a weld is $625 incl. The barrell once finished looks brand new with a year warrenty on coating ( conditions apply) and its cheaper to do it this way than buy a new barrell and we have a 5 working day turn around :2thumbsup
Also if you have a group of cylinders ie 4 or more then we will do a special price for those.
Any questions that you might want to know specifically flick us an email nicky-sil@nzcylinders.com:clap:
P.S Grant aint that old:headbang: