Piston type for 175 same as 90?

[duckman86]

Hello, I was wondering if I am correct in believing that 90 pistons are the same as the 175 pistons? That also goes for 100 pistons and 200 pistons. My idea was too get my 175 sleeved and bored to standard 90 iron cylinder size or .25 over because its a lot cheaper than plating and I can keep boring them over if I need to put in new pistons and rings. I've done a lot of research on this and I'm wondering other peoples input.

[william anderson]

 hi , i think the pistons are the same on the chrome plated cyclinders , i have always wondered  if you could remove the 90 cc cyclinder studs an replace them with the 100 cc engine studs an just use a 100 cyclinder , if there is enough opening for the cyclinder sleeve to fit into the cases , an the stroke on the rod was compatable , thanks  william A.

[OldSwartout]

The 90 and 175 use the same part number piston for the aluminum (chrome bore) cylinders.

The 90 cast iron cylinders used a different piston that should not be used in the aluminum cylinders, although that would work in a pinch, but you'd end up with extra operating clearance.

The 90/175 pistons for the aluminum cylinders shouldn't be used in the iron cylinder, nor an iron sleeved aluminum cylinder.  The expansion rate will tighten it up in the cylinder unless you start with excess clearance, not really a good idea. But, you're right, you could resleeve the 175 cylinders with iron and use the 90 (cast iron cylinder) pistons.

The 100 and 200 use the same pistons.  

I'm not certain about the 90/100 cylinder bases interchanging into the cases, but I would assume it is the same situation as the 175/200.  The 200 cylinders have a larger spigot than the 175s and the cases have a slightly larger opening for the cylinders, consequently they are not interchangeable.

I don't know the price for resleeving a cylinder, but it seems a professional job milling the ports and machining and installing the sleeve would be nearly the price of plating.  Once you replate one, especially if  you get it nikasiled, it will never wear out.

[old smokey]

I would think the time and money to modify that would probably be more than getting the original cylinder replated. I had my 350 cylinders replated last fall. Including welding repairs for missing corners around ports and plating and honing to match the new pistons was just about $250 per jug.
I have not assembled the motor yet, but I'd recommend the following place which happens to be in the town where I live.
http://www.mt-llc.com/

http://www.mt-llc.com/cylinder.php   this lists approximate pricing guidelines based on bore size...

If your cylinder needs no repairs before plating it's closer to $200 each.
As Karl suggests, a quality modification to bore and fit the sleeve would likely cost more. The nickasil coating by Millenium is warranted for lifetime.

[OldSwartout]

http://www.mt-llc.com/ (Millenium Technologies) is where Paul Piskor and I have been getting the bores replated on our 175 race bikes. It was about $375 for the pair for mine with no/minimal welding required.

[duckman86]

The places by me are all like 250 per jug to get plated. Also, do the older style Bridgestone pistons and rings work with the newer nikasiled plating? Price wise it's just like 250+250 plus the 175 rings and pistons seem to be going for around 180 dollars. So 680 dollars seems like a lot of money to me when I have seen decent bikes go for less than 680. When I looked at iron sleeve prices it was cheaper per jug about 105, and I can seem to find 90 cast iron pistons and rings a lot cheaper and I have two pistons for a cast iron 90. It says they don't cover wear and tear at mt llc just free from defects. I suppose I might plate a 200 engine and not do two two engines like I planned.

[duckman86]

For the people that got them re-plated how long does it last for? Has anyone had to go back I'm wondering?

[OldSwartout]

Unless you have a mechanical failure, the nikasil will effectively last forever.  It seems to be tougher than chrome. Paul and I have had mechanical failures that probably would have damaged a chrome bore, but the nikasil held up.

You can use either the normal 175 iron rings or the 90 std. chrome-faced rings with nikasil. A chrome bore can only use the 175 iron  rings.  The 90 chrome-faced rings will immediately seize to a chrome bore.

It sounds as if you have a cheaper way to go with the 90 pistons and sleeved cylinders.  That should work OK.  I sleeved a Kawasaki 175 single 25 years ago because of cost. Back then, there weren't any places to get cylinders re-nikasiled and a new cylinder was $300.  The steel sleeve, installation, piston & rings were about half that. It got a new piston and rings last year, but the bore was still useable. It had a lot of motocross & play time on it.

[duckman86]

If I have more money later this summer I should probably just sleeve the 175 and plate the 200 and I will find out which seems better and how the 175 turns out. Most likely they both would last my lifetime for how much I would ride them.