Porting a 85cc 064

[jmssaws]

Got a really nice original 064.
Stock it's got 175lb of compression
Ports @ 102 125 73

 

[jmssaws]

That's no good

 

[jmssaws]

Cut 030 from the base and 020 from the chamber,now it's 105 130 76
I'm going to 102 123.5 76

 

[jmssaws]

Some pics of the finished cylinder

 

[jmssaws]

Couple more

 

[jmssaws]

Lot of work on the piston

 

[jmssaws]

I'm sure most people know but stihl has 2 different wrist pins, heavy and lite one.

 

[jmssaws]

All together @ 102 123.5 76
020 from the key and a medium muffler mod,185lbs on new rings.

 

[jmssaws]

I built the owner of this saw a 7900 last week that runs pretty good so we're trying to beat it. This is the first time the 064 has ran,it's tuned to 13.5 so it's fair to the limited dolmar.

 

[jmssaws]

Also ran it with my 066,not the same bar and chain but I filed both right before I ran them.
My 066 is a beast and the 064 ain't far behind with both at 14k the 064 will go way faster.

 

[jmssaws]

That is jb weld on the outside of the cylinder, I ground through on both transfers.

 

[drf255]

Looking great, as usual, Jason.

 

[blsnelling]

All of them sound great. However, being rev limited to 13,500 and tuning to 13,500 are two entirely different things. In theory, the 7900 could actually be tuned to 15,000 were the rev limiter not stopping it.

 

[jmssaws]

It's tuned just to the limiter.

I could turn the 064 to 15k and clobber it
That's why I tried to keep the rpm the same.

The 7900 can no matter what only turn 13500 and even if the 064 only gained a few hundred rpm in the wood at 15k it would clobber it.

 

[blsnelling]

In realty though, the tunes sound good on all of them.

 

[jmssaws]

This 7900 is my favorite sounding saw ever,love how it cackles

 

[jmssaws]

Here's the 064 with my 066.
Not the same bar and chain but just for a ear comparison.

 

[blsnelling]

Unless you're pushing quite a bit harder on the 066, I believe I like the way the 064 runs better. It's holding great RPMs in the cut.

 

[Matt B]

The 064 is a peach. It'll be interesting to see how it runs after a few tanks...

 

[jmssaws]

The 066 has a little better chain and a 9pin
064 has a 8pin and both are at 14k
In certain situations the 064 will probably be faster but I can run more chain or gear on the 066 and beat it.
Still pretty Kool for 85cc against the strongest 066 I've owned,Shaun Carr ported it. I've built a few stronger than it but not by much.
It's a insanely stout saw so for the 064 to be close is a big deal to me.
I build 064's everyday, them and a 066 is 99% of my work and I think I have built one 064 stronger. Maybe