Honda Talk chapter 3: Pistons

3457 Views 24 Replies 8 Participants Last post by JD, Dec 23, 2004

jbranson

Discussion Starter · Dec 14, 2004

The new pistons are in for those that requested them.

56 and 57mm varieties...get'em while they are hot.

Well actually...if you haven't requested them already...it's too late. But I can order more if there is sufficient interest from the slow bikes ...errr.. people that don't have them. To tell the truth..I'd prefer it if only rich people ordered them cause so far I lose money on every set I sell. But not much, so don't go making charity offers.

Here's a pic before polishing.

Changes to the 56mm type are .015" deeper valve pockets so users should be able to use a thinner head gasket and still have .005" more valve/piston clearance. Claying is of course highly recommended before choosing your gasket thickness.

Changes to the 57mm type include .015" deeper valve pockets and setup for a thinner wiseco ring set. And of course 1mm larger for 209cc.
JohnnyB

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jbranson

Discussion Starter · #3 · Dec 14, 2004

John,
With these little 200cc twins the bore and stroke is so small that it's difficult to make compression...you have to stuff the piston way up in the head. The notches are to clear the spark plug electrode. Pete T. is I'm sure doing similar things to his Duc pistons making big compression.
The reason for the size and shape of the notch is of course one of my trade secrets.
JohnnyB

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jbranson

Discussion Starter · #5 · Dec 14, 2004

Pete T. probably only does it to his REALLY fast Ducatis. I even discussed the issue with him before I decided what to do.
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jbranson

Discussion Starter · #10 · Dec 15, 2004

Aaron,
I've got an angle grider with some 36 grit disks...I can take that notch right out the piston.

Scott,
Figured you were busy. I'll send them along after polishing.

JohnnyB

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jbranson

Discussion Starter · #11 · Dec 15, 2004

Aaron's Pistons.

Like succulent aluminum boobs.

JohnnyB

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jbranson

Discussion Starter · #13 · Dec 15, 2004

Hey... I ain't no beginner at this.
They have some CNC milling done underneath the dome to reduce weight. Even at 4mm larger than OEM pistons, and with a higher dome they are 19% lighter than stock pistons. Forged pistons evidently can be made lighter than stock cast pistons.
Damn straight walled wiseco piston pin is 6 grams heavier than the OEM tapered wall pin though. Can't get the size I need in tapered wall...and mine are a bit longer than stock.
The larger 57mm pistons at 118 grams are just a tad lighter than the 52mm stock pistons.
Of course the phase 5 piston design is floating around in my head already, more compression but probably a few grams heavier, depends on how much I can get taken off the bottom side. Might have to look into custom piston pins to get the weight down there.
JohnnyB

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jbranson

Discussion Starter · #18 · Dec 21, 2004

Scott,
No I haven't. I'm dicking around, still have to polish them.

I've been working on this:

http://www.jrbranson.com/pvl-test-1.wmv

That's a windows movie format...not sure if you can view it or not.

Here's a picture of it:

Works like a Mofo. If you can view the movie note how stable the timing is...by watching the bolt holes in the rotor while the timing light is on it. Yes that rotor is turning way fast.

I hope to obtain the parts to sell these kits in the not too distant future. This was a very preliminary test, have no idea where the timing actually was..gotta figure out a good way to do that...and the plug wires had no caps...just some of the bare wire wrapped around the end of the plug.
JohnnyB

Edited by - jbranson on Dec 21 2004 2:51:28 PM

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jbranson

Discussion Starter · #24 · Dec 22, 2004

Same here...I'm still using Media Player 7.
The new versions have to many "additions".
All kinds of copyright restriction bullshit etc.

But I gotta live with windows update telling me I need the new version every time I go to dl security updates.
JohnnyB

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