What do you think about Sleeves?
- Thread starter bobkyle2
- Start date
I would never sleeve a plated cylinder. Plating is superior in every way. It's harder and more durable, has better oil retention properties, better heat transfer rates, expands at the same rate as the cylinder casting and piston, and has better wear characteristics. Sleeves also have problems when installed in cylinders not designed for them. They create ridges and directional changes in the port tunnels because the cylinder casting has to have a larger hole punched in for the sleeve.
the main reasons to do this are cost and making a large bore out of your motor. Ive got a sleeved 250 KTm 250F to a 300F, no problems with it at all.
Unless money is a factor, go with replating. If want to go big bore now or down the road then go with a sleeve.
Good info my freinds... Roost to you all !!
I've actually had better luck with sleeves than with plating because I can run about 3-4 pistons in a sleeve before I have to bore the sleeve one size... Where as when nikasil gets screwed you get screwed also
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Agreed. Nikasil is nice and all. But at $275 for each plating?
Versus the $40 bore job, you can do it 4-5 times for the nikasil price.
2-3 weeks shipping to plate it. 1 week if you live locally. Boring takes an hour or so.
Also, if your machinist is worth his salt, the ports will be smooth and match the cylinder perfectly with the sleeve.
It's about money. Steel is cheap and proven reliable.
-BIG DAN
Versus the $40 bore job, you can do it 4-5 times for the nikasil price.
2-3 weeks shipping to plate it. 1 week if you live locally. Boring takes an hour or so.
Also, if your machinist is worth his salt, the ports will be smooth and match the cylinder perfectly with the sleeve.
It's about money. Steel is cheap and proven reliable.
-BIG DAN
Give me a 500cc aircooled two-stroke and I doubt i'll notice the 20% power loss they talk about. 
It all depends on how you are using your bike.
From an engineering perspective the plating is greatly superior. It allows for much greater heat removal. It is not a minor change with a steel sleeve. Depending on the exact alloys the aluminum has a 3 to 5 times greater thermal conductivity. Next is thermal expansion. Steel has around half the expansion of aluminum. This requires more clearance between the piston and the bore. Now for bore life. The plating is way harder than the steel sleeve. That's why you can just replace the piston on a plated cylinder. The plating does not wear at near the rate of the steel. Finally you have the ports. It's tough to get the proper shape of the ports when installing a sleeve.
What does all this mean? Well the plating has a lot of advantages. The advantage the sleeve has is reboring for a lot less then replating. If you flog your engine hard you might want to replate. That tells me that if you are racing you want a plated cylinder. If you are a trail rider and you don't flog the bike too much then a sleeve should work great.
Engine displacement also has a role. The smaller the engine the more you have to loose with a sleeve. Got a big bore like Dan? Steel is fine unless you are trying to set a land speed record or something.
From an engineering perspective the plating is greatly superior. It allows for much greater heat removal. It is not a minor change with a steel sleeve. Depending on the exact alloys the aluminum has a 3 to 5 times greater thermal conductivity. Next is thermal expansion. Steel has around half the expansion of aluminum. This requires more clearance between the piston and the bore. Now for bore life. The plating is way harder than the steel sleeve. That's why you can just replace the piston on a plated cylinder. The plating does not wear at near the rate of the steel. Finally you have the ports. It's tough to get the proper shape of the ports when installing a sleeve.
What does all this mean? Well the plating has a lot of advantages. The advantage the sleeve has is reboring for a lot less then replating. If you flog your engine hard you might want to replate. That tells me that if you are racing you want a plated cylinder. If you are a trail rider and you don't flog the bike too much then a sleeve should work great.
Engine displacement also has a role. The smaller the engine the more you have to loose with a sleeve. Got a big bore like Dan? Steel is fine unless you are trying to set a land speed record or something.
I understand what you're saying about plating vs sleeving and it's 100% as we talked about this the other day in my engineering class. But I think sleeving is the way to go for 'weekend riders'... As long as your aren't racing at a national level I imagine a sleeve will be just as fine. ALOT of non-serious racers just ride there bike until the piston skirt snaps which is one reason why i'm so in favor for sleeving, because that would generally ruin the plating where as if you running a sleeve you could just bore it over by 0.010" or so.
So what you're saying is sleeves are better for idiots. I can go with that!I understand what you're saying about plating vs sleeving and it's 100% as we talked about this the other day in my engineering class. But I think sleeving is the way to go for 'weekend riders'... As long as your aren't racing at a national level I imagine a sleeve will be just as fine. ALOT of non-serious racers just ride there bike until the piston skirt snaps which is one reason why i'm so in favor for sleeving, because that would generally ruin the plating where as if you running a sleeve you could just bore it over by 0.010" or so.
nice chokey, I'm just saying I've had better luck with sleeves and on all the cylinders I've had plated it seems like the plating always chips around the exhaust ports.