Let's build me a red head 670!

[Johnmn]

No need to go larger duration on the intake than on the exhaust. It's only going to reduce your crankcase compression.

So just raise the exhaust?

 

[srcarr52]

So just raise the exhaust?

No, grind on the intake too, just don't go crazy on it. I'd say 76 max with the exhaust at 103.

 

[Johnmn]

So this cylinder has a huge taper on the exhaust roof as pictured below. When I check timing to the exhaust roof I get 107 but when I check through the spark plug hole with a light I get 103 1/2. Which one should a guy go by? I'm sure with that taper it's letting exhaust out at the 103 1/2.
Thoughts?

 

[Johnmn]

Carb rebuilt

 

[Johnmn]

Oh intakes are big on these babies

And the factory exhaust is 60% of bore

 

[Johnmn]

I like a saw I can push on so I took the exhaust to 103 I left the transfers alone at 123 and the intake is at 75 we shall see.
Squish .019 and .025 off the key.

New fuel line and filter, impulse line, spark plug. Carb, muffler, intake installed.
I think I'm going to do a v-stack on this one!

 

[Johnmn]

I'm waiting for my dealer to get in more o-rings for the oiler and an outer bar plate. I hate waiting for parts!

 

[Johnmn]

It lives!

 

[Johnmn]

@Dub11 is going to post a video of it for me, cuz he's a nice guy! Wood is a chunk of maple about 20x26 tree was dead and it's harder than a wedding day prick!

 

[Johnmn]

Saw is tuned FAT and only has about 1/2 tank ran through it. Chain is off the roll Oregon square.
Numbers ended up at
103
123
75
I wonder if it will liven up more with the trans at 121ish?

 

[Dub11]

@Dub11 is going to post a video of it for me, cuz he's a nice guy! Wood is a chunk of maple about 20x26 tree was dead and it's harder than a wedding day prick!

Get to filming!

 

[Dub11]

Here she is boys.

 

[Spike60]

I'm also thinking about a 266 p&c in my 630 just because it's a direct swap

I did one of those myself. I call it a "Jonsered 636". Built it on a kind of ratty blown up 630, and I've actually used it quite a bit. Not all that different from a 630 in performance in this case. I cleaned up a used 266 jug, popped in an aftermarket piston, no gasket. Mixing and matching things like this, everyone's results can be a little different. But they're always fun.

 

[smokey7]

That 670 runs pretty nice. I love these 6xx series saws. I got 1 more to build.... Cant deside weather to build it as a 625 630 266 268 or wait to find a 272 topend for it. I have 1 625 i went nutty on porting since it had damage above the transfers and exhaust. Its at 98 118 80. It would be good as a play or limbing saw as it lost some torque. It sure revs good. Runs up to 14500 4stroking hard. Not really my style tho as i likes the torque. Nice build thanks for the read i enjoyed it.