Crankshaft

[Karl Snarl]

I was looking for a 40mm to balance myself.

Cdh is your place then. Buy in pairs for a better deal. They are advertised at the right lengths. so if you click the 38mm, you are going to get a 38mm, click the 40mm ad, you will get the 40mm throw.

 

[Karl Snarl]

Were the rods on them cranks marked ZL40 you recieved?

I can't even remember now. lol. They are in engines or I would run down stairs and look. Only free crank I have is from the case cracked engine. I have it all balanced and in a bag of parts, waiting to get a case. Not worried, I have 8 loose CG's.

 

[Karl Snarl]

Yeah it's zl40, I looked at ebay, where I get them from. CDH on amazon is good too. where I got those three engines at. One came with a damaged wire on the stator coil, no big deal. Shipping damage was all it was. They already shipped me a new coil out. Amazon wanted me to return the whole thing, lol. I was like, nah, that cost to much to do. Even though it's free for me. So I just emailed CDH directly, and gave them the info and a picture. They sent me a new one in 24 hours of my message. I can solder on a wire, lol. I just wanted to test them on amazon. It's not the same person I talk to on ebay that's for sure. They know me on ebay. lol

 

[Regalgse00]

Are you just drilling the half inch hole 15mm deep into the center to do a balance or?

 

[Karl Snarl]

Are you just drilling the half inch hole 15mm deep into the center to do a balance or?

I am balancing to around a 40% factor. It all depends on what size is my piston. If I do the same for my 100cc, as my 66cc, my 66cc get around 45-48%, so they actually get less drilling than the 49-50mm pistons. what size piston?

 

[Regalgse00]

I am balancing to around a 40% factor. It all depends on what size is my piston. If I do the same for my 100cc, as my 66cc, my 66cc get around 45-48%, so they actually get less drilling than the 49-50mm pistons. what size piston?

I’m making a 49mm case reed engine. I already have the case machined for the reed and the port work on the case done and the cylinder. So now I just need to balance the crank. I can true it myself. I already have a stand made already to hold the crank.

 

[Cannonball3]

Rod length is important also.

 

[Regalgse00]

Rod length is important also.

If you read the other posts. That was already mentioned

 

[Karl Snarl]

I’m making a 49mm case reed engine. I already have the case machined for the reed and the port work on the case done and the cylinder. So now I just need to balance the crank. I can true it myself. I already have a stand made already to hold the crank.

I drill 3 12mm wide by 15mm deep holes for a 100cc. If I'm thinking I want a little more, I will go all the way through and use my angled pencil grinder to bevel the holes. One in middle and one on back side of each existing hole. I just eyeball enough meat between holes.

 

[Cannonball3]

Sorry didnt see rod lengths mentioned must have missed it. Only saw stroke discussed. There is a 5mm difference between the rods regardless of stroke. Smolik sells a Zl40 crank thats 38mm long rod. If you want a Zeda type crank
better be sure what you are getting is a 40mm long rod. Makes a real difference on some build geometries. I found this out building a Minarelli. The 40mm Pk crank was 5 mm in the hole where the Zeda fit perfectly.