OzVMX Forum
Clubroom => Tech Talk => Topic started by: Boyracer on September 09, 2010, 01:47:05 pm
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I recently asked for a YZ barrel reco in nicasil or chrome and the guy gave my barrel back with an iron re sleeve telling me Im better off with a re sleeve.
Does a nicasil bore make more power than an iron bore or is it about the same?
Any info appreciated, thanks.
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Boy I would have the s@&ts if somebody did that to me!! if you ask for nicasil or chrome that's what you should get!! If there is a problem in supplying what you asked for you should have been told before he took it upon himself to modify your cylinder.
Nicasil or chrome don't inherently make more power than an iron bore. You can run closer piston/bore tolerances which could make a bit more power, but the main difference is in the heat transfer.
Nicasil or chrome transfer heat from the bore more quickly than does an iron sleeve and as such reduce the drop off in power associated with aircooled engines in long motos.
Will you notice the difference, probably not. But I would be cranky all the same [and looking for a new cylinder tech guy who understood how to communicate with the customer].
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I don't know much about the stuff but I think u need different type of rings for bores other than the standard iron, correct me if I'm wrong.
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are we a talking modern barrel ? or an old barrell that was already chromed or nika ?
Where does the dude get off fitting a sleeve without telling you.
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i have had one done on one of my CR250's (watercooled) in the early days before they were available to be re-coated in OZ i had serco fit a sleeve to my 86' CR250RG and i could notice the loss of power.
later on i had another cylinder nickasiled in Vic years later (same bike) and it was much better i still have both cylinders for the same bike and the nikasil liner makes a noticeable difference on my bike.
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I don't know much about the stuff but I think u need different type of rings for bores other than the standard iron, correct me if I'm wrong.
Chrome bores needs a special ring, but iron/electrofusion/nikasil will all take the same rings.
Plus what vmx42 said.
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This is my pet hate. I would be demanding he restore the cylinder back to original condition or finding you another one. If it's a water cooled cylinder that originaly had a nikasil coating it will ping it's head off any time it gets hot.As the cylinder was never designed to cope with that amount heat.
Nikasil will handle higher compression so there's the performance advantage as well as less friction.
There is be a considerable loss in the heat transfer properties between the liner and the cylinder, most liners are cast in and have internal ribs to increase surface area for that reason.
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;D Yeehah, he said he would get me a brand spanker replacement, top bloke after all.
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So if i want to convert my cast iron bore to a 'coated' finish and still use the original suzuki rings or wiseco rings, does that mean i have to get Electrofusion or Nickasil coating only and not chrome? Can the coating be aplied to the sleeve already inside the barrel because im sure the suzuki ones only come out if you machine them out.
Who in Australia does the best job of Electrofusion or Nikasil? i dont care if its expensive, i just prefer a good job and dont want them screwing around with the port windows etc.
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So if i want to convert my cast iron bore to a 'coated' finish and still use the original suzuki rings or wiseco rings, does that mean i have to get Electrofusion or Nickasil coating only and not chrome? Can the coating be aplied to the sleeve already inside the barrel because im sure the suzuki ones only come out if you machine them out.
Who in Australia does the best job of Electrofusion or Nikasil? i dont care if its expensive, i just prefer a good job and dont want them screwing around with the port windows etc.
No good coating work done here. End of. Any ring that is good for cast iron is good for Nikasil. Rings for 'chrome' bores (actualy same as hard chrome on forks) has a grey ring with no coating on the ring face.
Here is an example of good plating ie you can clearly see the bridge has been relieved BEFORE coating. The post plating honing has not touched the bridge(you can still see the machining marks) and the port windows have been correctly chamfered again before plating.
Try NZ CYLINDERS (http://www.nzcylinders.com/)(use the UK Langcourts process) Grant over there does very good work is a little on the expensive side. They have excellent customer service and will accomodate 'hot potato' jobs for customers here.
(http://i155.photobucket.com/albums/s297/Lozza85_2007/006.jpg)
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No one in Australia hey, well im happy to send it anywhere. So are these mobs that do the whole job and are good at doing everything and not just the plaing part? eg
Do you send your slightly worn cylinder and new piston to them and then they bore to suit the new piston, chamfer ports and plate etc?
or is the area of expertise these places have solely in the plating and they are not experienced cylinder borers knowledgeable on 2 stroke ports, pistons etc? What im getting at, are these places just glorified everday electroplaters that decided to one day plate cylinders or are they a bit more than that and are actually clued up on engine cylinders too?
I have never looked into this so dont know if i need to get the cylinder bored to suit new piston and have ports chamfered by someone specilized in that and then send the the platers who are specialzed in that field, or if the platers know what they are doing when they measure up your piston to do the boring.
And the liners dont have to be removed?
When boring first, do you have to bore it a bit bigger than the normal size for running cast iron bore to allow for the extra thickness of the nikasil?
Any idea how much it cost because i have no idea if it costs $200 or $1000 ???
Ok i had a quick look at that site and they seem to be talking about plating directly onto the alloy and that if you have any steel parts they get eaten by a chemical.
They say that if you have a cast iron sleeve it has to be Nickel/silicone carbide plated. is Nickel/silicone carbide plated just the same as Nikasil? Can normal rings ment for cast iron bores be used in the Nickel/silicone carbide plated bores?
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Just ring the 1800 toll free number about 5.30Am your time and speak to Grant.
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Leith,
i have been told that coating will not apply to cast iron only alloy. i took a cast iron sleeved cylinder to be done only to be told its a no go.
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Hoony that's sort of bullshit is why I never have plating work undertaken here. Sorry but I hate when plater's here lie. From NZ cylinder website
My cylinder already has a cast iron sleeve installed, but it's worn past it's biggest piston. Can you help me?
Yes, Langcourt were the first to introduce nickel/silicon carbide plating onto cast iron many years ago. We can probably help solve your problem - just contact us for more information.
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They say that if you have a cast iron sleeve it has to be Nickel/silicone carbide plated. is Nickel/silicone carbide plated just the same as Nikasil? Can normal rings ment for cast iron bores be used in the Nickel/silicone carbide plated bores?
Nikasil is the commonly used name for nickel silicon carbide plating, basically a shortened version
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Ok so the facts are
1 - you can get iron bores coated but it has to be done in Nickel silicone carbide
2 - Nickel silicone carbide is the same as Nikasil
Has anyone here had a cast iron barrel done and was happy withe the results?
Is there a place in USA that does a good job?
Its no more of a hassle for me to send a barrel to US then is is to NZ
My main reason for looking into it is if it makes the bore last longer and you dont need to get re-bores so often
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Thats the idea of plating you no longer need to rebore.....ever the piston wears NOT the bore. US companies have dropped the ball some what lately. You can try Millenium.
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Aluminium cylinders are too soft as standard to cope as a cylinder which is why they need to be hardened.
I think a lot of cheap lawn mowers used to run non hardened alloy cylinders as they weren’t meant to last very long.
I don’t think chrome bores were very successful, Honda only tried them for one model I think, maybe Yamaha too??
Electrofusion is a Kawasaki thing, I read somewhere they explode carbon rods inside the cylinder with several thousand volts to harden the Aluminium
They’ve been using them since around mid seventies.
Nicasil is probably the most common as several makes use it these days.
Not sure about the worth of applying Nicasil to a cast iron sleeve,
You would get longer wear but all the other benefits of less weight and heat transfer would be lost with the cast iron sleeve.
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No good coating work done here. End of. Any ring that is good for cast iron is good for Nikasil. Rings for 'chrome' bores (actualy same as hard chrome on forks) has a grey ring with no coating on the ring face.
Here is an example of good plating ie you can clearly see the bridge has been relieved BEFORE coating. The post plating honing has not touched the bridge(you can still see the machining marks) and the port windows have been correctly chamfered again before plating.
Try NZ CYLINDERS (http://www.nzcylinders.com/)(use the UK Langcourts process) Grant over there does very good work is a little on the expensive side. They have excellent customer service and will accomodate 'hot potato' jobs for customers here.
(http://i155.photobucket.com/albums/s297/Lozza85_2007/006.jpg)
Hey Lozza, you've caught my interest with that photo, why do they have to releave the bridge? Its interesting because I had a KX500 cylinder plated by Mahle back in the late eighties and it seized within a few laps on the bridge :( it all measured fine prior to instillation and I could never get my head around why it had seized ???
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Aluminium cylinders are too soft as standard to cope as a cylinder which is why they need to be hardened.
I think a lot of cheap lawn mowers used to run non hardened alloy cylinders as they weren’t meant to last very long.
A bit of trivia on aluminium cylinders, A friend of mine worked on a project for Alcoa in victoria a while back on a new aluminium alloy casting material. It was to be used for casting motorbike & car aluminium cylinders / blocks that could be direct bored without a sleeve or liner. It worked! they had engines running on dyno's for years on end and worked well. Like a lot of tech out there it worked well but obviously didn't work out on some bean counters calculator ;D
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I remember a Motorcycle News project bike - 900cc Honda Fireblade from memory - and the story said that it's cylinders were not plated. Could have been a typo, but they made a bit of a fuss about it.
Seemed strange at the time.
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The exhaust side of the motor is the hottest...That little bridge in the exhaust port heats up way quicker than the rest of the cylinder & expands faster, grabbing the piston...Commonly called a "cold seizure" because it happens soon after fired up.That is why the bridge port should be relieved when rebores are done.Pretty common on Kawasakis.You can also drill 3 small holes in the piston in line with the bridge to help too.
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So does a nikasil bore make it more likely to occur? or is it mainly a Kawasaki thing?
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Mainly kwaka thing (from my experience) but can happen to any 2 stroke with a bridge port exhaust...Using hi quality oil helps prevent these nasty problems too.
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So does a nikasil bore make it more likely to occur? or is it mainly a Kawasaki thing?
happens on all bikes with exhaust bridge
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Geoff most cast in iron sleeves have quite good heat transfer, the sleeve is very rough and has ribs on the outside of the sleeve. Then the cylinder is cast around that, it gives superior heat transfer to a press in sleeve. Yamaha were the first to perfect the process.
Other Jeff yes I remember that project it had 'a coating' on the bore but was not Nikasil, the rings also had a special coating on them also.
Bridges that grab have not been relieved or they have been thinned to much.
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I just blew up my mculloch chain saw, i pullled it down ( probally only 10 hours since new and the piston is rooted on the ex side and has dragged the barrell with gouges. What i cant see is any sleeve or lining in the barrell, it looks to be just stright alloy, not even a coating? im wondering if they just missed mine on the production line or what. the mower man says it has one, but yet he cant show it too me so i think he fishing on what hes seen previously not what he can see, if it has any kind of coating its in the material as there is nothing on the top surface.
The barrell looks like it was made out of ali cans, and the pistons not much better, havent got back to me with price of a barrell yet, but me tinks its all over red rover, and be cheaper to buy one of them china copies and save me dough...... :'(
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Freaky - I'm sorry mate - your avatar is doing my head in - can you get rid of it ;D