Two stroke theory question

[rd400pi]

Brian,
  Interesting topic as I had just talked with Forest Stahl Wed am about the '83 175 piston.  He confirmed what you are saying when he said he didn't have any of them.  Let me know what direction you are going with the pistons if you get a chance.  Cheers.

  Mike H.
  Tulsa
  [email protected]

[auto]

I got my 82 125wr from Stan Beni.He gave me a 175 kit cylinder and piston with it.The piston is a Wiseco.There is no casting ID on it,but it is a wiseco P40.Contact Wiseco,they can locate inventory sometimes with their dealers.

[brian kirby]

Mike,

Do you have an 82-83 175 Husky? I am going to have Diamond Racing reproduce some pistons, if they are $100-150 each with a minimum of 4 I will buy that many just for myself. My cylinder is std bore too, so I will probably have std size pistons made and have my cylinder nicasil plated that size. Let me know if you want some, and what sizes you think I should have made.

Brian

[Knute]

Hey Brian,

Several things...Kevin had told me that the 1981 125's did NOT have a windowed piston, but that the team bikes used pistons modified to include a window.

I wasn't aware that Diamond would do "one-off" pistons, but I spoke with JE Pistons several years ago at the Dealer Show and they were willing to make me affordable one-off's with no minimum.  In fact, they were even advertising this service.  JE is a very high quality piston and, if Al had not started offering Wiseco Sachs pistons, I was going to have JE make them for me.

As far as Nikasil goes, I'm not sure I understand your theory.  Nikasil plating was developed as a coating that is directly applied to the aluminum cylinder and offers several advantages over an iron liner.  For one, the main problem with an iron liner is that it expands at a different rate than the aluminum piston, thus requiring larger tolerances.  This becomes especially problematic with larger bore sizes.  By coating an aluminum cylinder with Nikasil, you've gained a hard, low wear surface for the piston to be run against, as well as expansion properties that are similar to the piston, allowing tighter tolerances.  An added benefit is the cylinder also has better heat conductivity, which has aided in the development of engines with higher specific output. I'm not aware of Nikasil being applied to an iron liner, but perhaps it could be done...I just don't see why you would do it.

Kent

TEAM PENTOVARNA
Kent Knudson
Kevin Brown
Gary & Toni Roach
James & Adam Giddings
Dennis & Cory Buttrick

[brian kirby]

Kent,

Thats odd that all the 76-78 and 82-83 pistons have an oval window but apparently the 79-81 dont? I thought all cylinder reed pistons had windows, but I guess they dont. The case reed piston on my 84 KTM 125 has no window, but the case reed piston on my '99 YZ125 does. Go figure. [?]

You can apply nikasil to an iron liner just as well as aluminum. You obviously dont get the thermal advantages because you are plating over a liner, but you get the wear advantages, once plated it will basically last forever provided you keep the air filter clean and dont snag a ring or something like that. If applied to a cylinder like mine you never have to get oversize pistons made, you just get one size made and reapply the plating if/when it wears out. Larry Stahl told me he does that with 360 Huskys, those pistons are hard to find, but a 2mm over is the same size as a std 390 which is easy to find so he overbores then has it plated to fit the std 390 piston.

Brian

[rd400pi]

Brian,
  Can you email me directly at [email protected]?  I can't find your email address.  I have a bunch of questions concerning the Huskys'.  Cheers.

  Mike H.

[Dwight Rudder]

The piston from the 1975-76 GP175 Husky would have to be 64mm not 62mm. That is if the stroke was 54mm.

[brian kirby]

I dont know what the stroke is on the 76 Husky, but I know the standard piston is 62mm. You are right though, the Can-Am 175 has a bore of 62 and a stroke of 57.5 so the Husky cant have a stroke of 54, it would have to be longer. The 125s all had a 52 stroke.

Brian