whats the first steps toward more performance

[Street Ryderz]

Jaycee604 where in Canada are you?

 

[DieselTech]

The total thickness and weight is not really an issue because you are balancing rotating mass vs the reciprocating mass and want it to statically balance, as long as you didn't nick the rod your fine!

Thanks @Street Ryderz I'm trying to help him out & trying not to give any false or wrong advice. What's a 2 stroke crankcase pressure called? Is it blow down pressure? I know it's best to stuff the crank to restore it, whatever it is called.

 

[Street Ryderz]

Thanks @Street Ryderz I'm trying to help him out & trying not to give any false or wrong advice. What's a 2 stroke crankcase pressure called? Is it blow down pressure? I know it's best to stuff the crank to restore it, whatever it is called.

Crank case pressure is CCR, Crank case compression ratio, now a day's the case volume/pressure is thought of as being more for the pipe to pull on if there is more volume/lower pressure but this is only true with a true tuned pipe that will do so.
A CCR of 1.4 is the norm for a performance 2t and ours is only 1.1 and as pressure goes that's less than half of the 1.4 norm, stuffing the crank holes or the case will not bring it up to the 1.4 normally used it will get you to maybe 1.2 at best which is exactly half the pressure of 1.4 and with this known I wouldn't worry to much about it as no one else does!

 

[DieselTech]

Crank case pressure is CCR, Crank case compression ratio, now a day's the case volume/pressure is thought of as being more for the pipe to pull on if there is more volume/lower pressure but this is only true with a true tuned pipe that will do so.
A CCR of 1.4 is the norm for a performance 2t and ours is only 1.1 and as pressure goes that's less than half of the 1.4 norm, stuffing the crank holes or the case will not bring it up to the 1.4 normally used it will get you to maybe 1.2 at best which is exactly half the pressure of 1.4 and with this known I wouldn't worry to much about it as no one else does!

Ok thanks @Street Ryderz so basically the only way to increase CCR is to stuff the crank & decrease the inside case volume. With 1.4 being optimal on performance 2 strokes. Basically theres not enough physical room inside the case to get our CG to 1.4CCR Right? That's what you are saying in a nutshell. Lol or simple/laymen terms in my case.

 

[Street Ryderz]

Ok thanks @Street Ryderz so basically the only way to increase CCR is to stuff the crank & decrease the inside case volume. With 1.4 being optimal on performance 2 strokes. Basically theres not enough physical room inside the case to get our CG to 1.4CCR Right? That's what you are saying in a nutshell. Lol or simple/laymen terms in my case.

Exactly right! Our case volume is well over 600 cc's and compared to say a Minarelli case volume it's around 200 cc's less than ours, that's alot to try to fill in and as stated not enough room to do so!

 

[Karl Snarl]

I ll use a carbide dremel bit if i have to

Cobalt bit is what you want to use. Hard as can be an takes a lot to dull. Nitride can't compare to a ColBalt bit. I use the colbalt bit at work when I need to drill hard stuff or 10000 holes. The bit doesn't bevel the sides. You will still need to bevel the edges of the hole. If you go through, you need to bevel the back side of the hole too.

 

[Karl Snarl]

Wouldn't holes in the crank like that cause disturbances with airflow mixture?

Crank is moving to fast to cause any probs with the holes there. It will lower your primary compression slightly though.

 

[Street Ryderz]

Cobalt bit is what you want to use. Hard as can be an takes a lot to dull. Nitride can't compare to a ColBalt bit. I use the colbalt bit at work when I need to drill hard stuff or 10000 holes. The bit doesn't bevel the sides. You will still need to bevel the edges of the hole. If you go through, you need to bevel the back side of the hole too.

Cobalt bit's are the way to go for sure that's what I use as well, I don't chamfer the edges of the holes though because the chamfering actually aids in the charge being pulled into the holes and creating more turbulence in the case/charge, sharp edges there are better at cutting through the charge cleanly and the worst culprit of turbulence in the case is the rod's edges, this helps with that!

 

[Karl Snarl]

Cobalt bit's are the way to go for sure that's what I use as well, I don't chamfer the edges of the holes though because the chamfering actually aids in the charge being pulled into the holes and creating more turbulence in the case/charge, sharp edges there are better at cutting through the charge cleanly and the worst culprit of turbulence in the case is the rod's edges, this helps with that!View attachment 164123

It prevents crack out. A non smoothed hole will eventually crack and start walking. Same with the Pistons, bevel the edges. Piston is more likely to crack, for obvious reasons.


Don't have to be a big bevel, just enough to knock the edge smooth.

 

[DieselTech]

Cobalt bit's are the way to go for sure that's what I use as well, I don't chamfer the edges of the holes though because the chamfering actually aids in the charge being pulled into the holes and creating more turbulence in the case/charge, sharp edges there are better at cutting through the charge cleanly and the worst culprit of turbulence in the case is the rod's edges, this helps with that!View attachment 164123

Street Ryderz did you just take the casting line off your rod? Or is your connecting rod actually knife edged? Your pic look like its knife edged.