Husky 575xp max bar length.

[Spike60]

Got ya. Is all the linkage for the Throttle and choke different to?

Use the same choke lever and throttle link from the 630. All of these links "work", but a 272 link is slightly longer and results in a crazy high idle. These saws already spin up pretty quick on high idle as it is, but the 272 link is like 3/4 throttle or more. Scary!

One other item on sticking with the 630 carb is that you will still have a fast idle. 272 carb will not have one at all on a Jonsered. Reason is all Jonnys in this family had the fast idle set with the choke lever, and all Huskys had it set with the thumb latch on the fuel tank. So, only the Jonsered carbs had the fast idle cam that can be set with the choke lever.

Edit: The insane fast idle problem is not really an issue on the Jonnys, due to the choke lever idle set. I was thinking of a 61 to 272 build that I recently did, and that is where you want to be careful mixing up the throttle links.

 

[huskihl]

On a 630, the 272 conversion is quite a bit simpler than turning it into a 670. All that is needed in addition to the top end is the 272 intake block and carb bolts. Plus there are both OEM and aftermarket 272 kits still available. Going the 670 route would require changing the carb to the separate impulse line, and finding a decent used 670 top end and intake boot/clamp

True. I was thinking 625, not 630, as the 625 and 670 share the same boot

 

[Spike60]

True. I was thinking 625, not 630, as the 625 and 670 share the same boot

And the separate impulse line too. Those boots are short and very rarely failed, but they are impossible to find. Other thing to be aware of is that there were early and late boots. Early boots had the wire clamp and later boots had the band clamp. And to make it even more fun, the cylinders also changed when they changed the boots. The neck on which the boots were fastened was extended to accommodate the new boots. You can use the new boot on an early cylinder, but you have to retain the wire clamp. Bottom line I guess is to make sure any used 625 or 670 cylinder has the intake boot still on it.

Unless............the earliest 670's had an intake block and were internally pulsed. Very rare saw. Not certain, but I'm pretty sure it was the same top end as the Husky 266.

 

[Boomer 87]

Mine is a two thin ring type

 

[Dub11]

And the separate impulse line too. Those boots are short and very rarely failed, but they are impossible to find. Other thing to be aware of is that there were early and late boots. Early boots had the wire clamp and later boots had the band clamp. And to make it even more fun, the cylinders also changed when they changed the boots. The neck on which the boots were fastened was extended to accommodate the new boots. You can use the new boot on an early cylinder, but you have to retain the wire clamp. Bottom line I guess is to make sure any used 625 or 670 cylinder has the intake boot still on it.

Unless............the earliest 670's had an intake block and were internally pulsed. Very rare saw. Not certain, but I'm pretty sure it was the same top end as the Husky 266.

And thanks for the info again. I know it was listed in the video you and Walt made but it was really hard to pay attention with all them saws setting there.