Husqvarna 61 to 272xp conversion

[peter92]

Is there any diff between the 1981 and later model 61,s , white top and later were orange , just want to make sure the 272 cylinder will fit the earlier case , so if any one has a stuffed 272 cylinder please let me know , rather find out now before i buy new parts, pics have been added in the first post
mine is a 1981 model
heres the pics , of my saw , wanting to change my 61 to 272

 

[Dub11]

Is there any diff between the 1991 and later model 61,s , white top and later were orange , just want to make sure the 272 cylinder will fit the earlier case , so if any one has a stuffed 272 cylinder please let me know , rather find out now before i buy new parts, pics have been added in the first post
mine is a 1991 model
heres the pics , of my saw , wanting to change my 61 to 272

IIRC a 272 with the whole intake set up is a tight fit with the white tops.

 

[Dub11]

Is there any diff between the 1991 and later model 61,s , white top and later were orange , just want to make sure the 272 cylinder will fit the earlier case , so if any one has a stuffed 272 cylinder please let me know , rather find out now before i buy new parts, pics have been added in the first post
mine is a 1991 model
heres the pics , of my saw , wanting to change my 61 to 272

 

[Ronie]

Is there any diff between the 1991 and later model 61,s , white top and later were orange , just want to make sure the 272 cylinder will fit the earlier case , so if any one has a stuffed 272 cylinder please let me know , rather find out now before i buy new parts, pics have been added in the first post
mine is a 1991 model
heres the pics , of my saw , wanting to change my 61 to 272

I put an aftermarket one on an older 61 with the two piece coil and the flange was a little to wide to fit in the case. I had sand the outside of the flange to get it to fit. Don't forget to get the 272 carb bolts and if you use the 61 airfilter and elbow you might need to shorten the bolts, I did. Some pics of the one I did. Also the plug wire was a little tight. I also put the newer plastics on it. it's the one on the left.

 

[GoBigBlue1984]

Got any video Ronie? Saw looks nice.

 

[Ronie]

Got any video Ronie? Saw looks nice.

No, sorry. I sold it and deleted the videos.

 

[KYsawman]

Is there any diff between the 1991 and later model 61,s , white top and later were orange , just want to make sure the 272 cylinder will fit the earlier case , so if any one has a stuffed 272 cylinder please let me know , rather find out now before i buy new parts, pics have been added in the first post
mine is a 1991 model
heres the pics , of my saw , wanting to change my 61 to 272

Peter , your saw is a 1981 model, it is the first generation 61, it has the very shortest top cover and two piece muffler, when going to the 272 cylinder spark plug clearances is going to be your problem, the mid production gray top cover saws can fit a OEM 272 cylinder with no problem. Some aftermarket 272 kits have a taller spark plug angle and will hit the top cover. The last generation of the 61 where one piece coils and had the orange top. These saws have no trouble clearing any jug. The are even taller top cover and muffler than the gray ones. You will need to get the bolts and intake block and gaskets for the 272 cylinder also.

 

[peter92]

Peter , your saw is a 1981 model, it is the first generation 61, it has the very shortest top cover and two piece muffler, when going to the 272 cylinder spark plug clearances is going to be your problem, the mid production gray top cover saws can fit a OEM 272 cylinder with no problem. Some aftermarket 272 kits have a taller spark plug angle and will hit the top cover. The last generation of the 61 where one piece coils and had the orange top. These saws have no trouble clearing any jug. The are even taller top cover and muffler than the gray ones. You will need to get the bolts and intake block and gaskets for the 272 cylinder also.

Thanks for that info , much app it
so if i got another cylinder weather OEM or after market would the 272 cylinder fit my case , seeing mine is the first generation of the 61 , what else would i need to complete the saw and get it running

 

[KYsawman]

If you got the gray top from a mid production 61 it will clear a oem cylinder fine. The muffler is not a problem. A top from a 66 or 266 will bolt on too and be fine. There is a change in the cases when they went to the one piece coil and orange top. The bolt holes for the top cover moved slightly on one hole. The later style tall orange cover will only bolt in two spots if used on the early model cases. Some guys have tapped a new hole in the case to make it work, only the last generation orange style covers are available oem and aftermarket new.

 

[KYsawman]

So a total list would be
Gray cover from 61 or 66 266xp orange one will work fine too,
272 top end kit
272 intake block and gaskets
272 intake bolts
There are a few things that may need looked at depending on what cylinder kit you get, some of the aftermarket ones the spark plug angle is taller and will hit the top cover. Sometimes the flywheel needed to be clearanced to not rub on the bottom of the transfer port on the cylinder. I have done several of these saws and have always used oem cylinder kits and had no problem with any clearance issues. Good luck with the building! Hope this helps, post up pictures as you go.

 

[peter92]

So a total list would be
Gray cover from 61 or 66 266xp orange one will work fine too,
272 top end kit
272 intake block and gaskets
272 intake bolts
There are a few things that may need looked at depending on what cylinder kit you get, some of the aftermarket ones the spark plug angle is taller and will hit the top cover. Sometimes the flywheel needed to be clearanced to not rub on the bottom of the transfer port on the cylinder. I have done several of these saws and have always used oem cylinder kits and had no problem with any clearance issues. Good luck with the building! Hope this helps, post up pictures as you go.

Thanks for helping out by post things i need , you wouldnt have any of these things i need there would you
and price please , need posting to Australia
Peter

 

[KYsawman]

Here is a top cover on eBay
https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/323997476791
I don’t have any extra parts for the 61 right now.

 

[drf256]

I’ve got a 272 top end with piston somewhere if anyone needs.

Bought in attempt to fit on a 262, it’s a no-go.

 

[peter92]

I’ve got a 272 top end with piston somewhere if anyone needs.

Bought in attempt to fit on a 262, it’s a no-go.

any ideas on how much you want for it, and will you post it to Aust for me please
Peter

 

[peter92]

one guy said this to me "why make it overbore with a small case that cant feed the larger top end properly?
you need to look at more than just the CC of the cylinder.
The case volume and carb designed for a much smaller saw is not going to work well"
whats your thoughts
Peter

 

[XP_Slinger]

one guy said this to me "why make it overbore with a small case that cant feed the larger top end properly?
you need to look at more than just the CC of the cylinder.
The case volume and carb designed for a much smaller saw is not going to work well"
whats your thoughts
Peter

Tighter cases typically work very well in situations like this. Now, does that guarantee that this particular build will run like a scalded dog? No. But, you never know til you try, and I think what he’s doing is worth the effort. Have to remember that the increased displaced volume (area under piston) with the larger bore will have less space to get lazy in the crank case as the piston forces it to the transfers. At least that’s how I see it. Aside from the great porting, I believe that’s why hybrids such as the 044/460 run so strong.

And he may find that he needs a bigger carb. But all that will come in time with methodical testing and only changing one thing at a time.

another member here put a 272 top end on a 357xp, runs like an animal, and I believe he left the crank stuffers in place. It’s never about just one aspect of the build, it’s everything together.

 

[Ronie]

posted in the wrong thread

 

[Dub11]

one guy said this to me "why make it overbore with a small case that cant feed the larger top end properly?
you need to look at more than just the CC of the cylinder.
The case volume and carb designed for a much smaller saw is not going to work well"
whats your thoughts
Peter

If he's talktal about the 272 head on the 61 chassis they share the same cases so it won't be a problem.


Hopefully I read your original post right.

 

[Spike60]

If you got the gray top from a mid production 61 it will clear a oem cylinder fine. The muffler is not a problem. A top from a 66 or 266 will bolt on too and be fine. There is a change in the cases when they went to the one piece coil and orange top. The bolt holes for the top cover moved slightly on one hole. The later style tall orange cover will only bolt in two spots if used on the early model cases. Some guys have tapped a new hole in the case to make it work, only the last generation orange style covers are available oem and aftermarket new.

This is all correct.

Other consideration with the white top 61's and 162SE's is the length of the plug wire. The early plug wire is too short to properly clear the fins on the taller 272 cylinder and it will rub and wear/ground out at some point. Some extra insulation can do the trick, but it's something to keep an eye on.

 

[drf256]

one guy said this to me "why make it overbore with a small case that cant feed the larger top end properly?
you need to look at more than just the CC of the cylinder.
The case volume and carb designed for a much smaller saw is not going to work well"
whats your thoughts
Peter

You are correct.

It all has to work together. It’s along the lines of adding a full circle crank to a saw, the timing would have to be different to take advantage of the mismatch in case to cylinder volume.