61 to 272 mod

[hudsn63]

I know I just posted about a 51 but I also have another project I am working on. I have a 61 that toasted the top end and from what I understand the 61 66 268 and 272 all have the same bottom end so I ordered a new jug and piston for a 272 and am working on acquiring the rest of the parts (carb, air horn, air filter, muffler, intake, all gaskets and cover) But being I have never done this before I am hoping I can find someone who has. I have a few questions about this mod before I start
1. is there a heavy duty air filter kit for a 272
2. does anyone see any other parts I need or problem I may run into (I have a greytop 61 so its a one piece coil)
3. as long as im in there what other mods can I perform and what is the best ay to do them (exhaust and I have heard guys drill out the cover around the air filter to increase airflow)
4. I understand how to perform a squish check but am unsure with what to do with the numbers and how to calculate them to aquire the correct gasket
5. is the 61 carb the same as the 272 I see carbs listed on ebay and they are listed as compatible with the 61 66 268 and 272
6. where can I get a woods port done when I get to that point
thanks for any help I cut roughly 25 cord a year for my house so if I can make my saw faster and save time I would love it

 

[hudsn63]

also can I just put a 272 cover on the 61 lower unit rather then messing around with the greytop to get it to fit I found one online for 15 bucks and would rather just bolt on the 272 top cover unless for some reason that wont work

 

[huskihl]

Grey 61 cover fits the cylinder with the small air filter. Not sure if the 272 tall orange cover fits that saw. Spike60 or wiemedog will know

 

[hudsn63]

do you see any problem with running that air filter flow wise? I think there is a high flow kit for the 272 floating around and if there is that's theoretically what I would like to run

 

[huskihl]

If you're gonna port it, the squish will be taken care of. If not, and you want some added compression, install the cylinder without the gasket and check squish with electronics solder. If squish is more than .019" get some case sealant like threebond, yamabond, or motoseal (designed to be used with gasoline, don't use silicone) and install the jug without the gasket. If less than .019, you can just put the gasket in.

 

[hudsn63]

so what your saying is I need a minimum of .019 to run safely?

 

[huskihl]

so what your saying is I need a minimum of .019 to run safely?

Correct

 

[hudsn63]

well I thank you for the help so say im at .015 would you run a thinner gasket

 

[huskihl]

Many on here have cut one from a pop can. And seal both sides with sealant. It's a bit thinner than an actual gasket. I've never done it but I'm relatively certain it works

 

[huskihl]

"Usually" you end up with about .020- .023". At least that's been common on the ones I've done.

 

[hudsn63]

well I guess id rather have something that works and loose a little compression over introducing mr piston to the spark plug hey just a thought on the cover issue. I noticed on spike60s page there is a saw with an external filter it would be really easy to make something up for that 272 air horn do you see a downside to going outa the cover other then its bulky

 

[hudsn63]

I see echo now uses a circular style automotive filter but that's under the cover with a little pipe and a hole in the top it would be easy enough to go external

 

[huskihl]

Nah. Whatever you like. Jonsered 670 west coast options came with it. Looks kinda cool. Should be relatively simple to do

 

[hudsn63]

that's kinda what im thinking as long as it seals good I don't see an issue and that is the big clearance issue with this swap from what I have heard that and the sparkplug hole not sure how that matches up on the greytop yet

 

[huskihl]

On the ones I've read about, the Grey top fits fine. The white top has issues

 

[Gypo Logger]

I think there are at least 3 different type tops that fit the 61/266/630 and 272. Some have the idle adjustment on the carb and some in the casing although they are interchangeable as are the carbs.
Some covers have different alignment on the two rear retaining screws.
I prefer the idle screw in the casing as opposed to on the carb.
Sometime a good 266 is faster than the 272, although most of the 272's Ive seen had the governed carb.

 

[SawTroll]

.....
5. is the 61 carb the same as the 272 I see carbs listed on ebay and they are listed as compatible with the 61 66 268 and 272
....

The originals are not the same, and the carbs of the white and gray top 61s have a smaller venturi (15.9mm vs 17.5), and likely other differenses as well. From around 1991 the venturis were the same on the 61 - but it still was a different carb.

The 162se and the 266se up to some time in 1985 usually had the same smaller carbs. Then you will of course need an intake that fits both the cylinder and the carb - I don'r remember the details there....

 

[hudsn63]

Anyone know where I can buy a non governed carb for a 272

 

[hudsn63]

Also I'm looking at mufflers and again I'm running into the "this muffler fits models 61 66 268 272 and 272xp" anyone know if the mufflers and brackets are the same on both saws?

 

[Gypo Logger]

Also I'm looking at mufflers and again I'm running into the "this muffler fits models 61 66 268 272 and 272xp" anyone know if the mufflers and brackets are the same on both saws?

This is where it starts to get fun. Some of these models have two different size muffler studs and 3 or 4 different muffler configurations.
You can defeat your governed carb by removing the brass plug and putting in some jb weld. To get the plug out you may have to move the choke shaft to one side.