Husky 162/272--Jonny 630/670 project thread.

[Stump Shot]

For starters, 272xp cylinders are not scarce as hens teethe. You can order new ones all day long from any Husqvarna dealer. So I fail to see the "MacGyver/Mad Max" type of necessity here.
Ever notice that there's not a big bore kit available for a 272xp? That's because it's already a factory big bore on a 60cc frame. At some point you just start running out of huff and puff.
@Spike60 Popping bases is a real thing, base strength is always a fairly high thing on the list of consideration when modding. Plus what happened to the cylinder extension, that's part of the strength. What piston was used will have some bearing on the overall height. I don't know what it could be with the differences in bore diameter and pin diameter.
There's no explanation and I can't see the pictures good and there's no vidja of it running to say much about it, who knows, might be the next great hybrid build out there? After all someone has to be the first to try such things out, so at the very least he gets an E for effort.

 

[davidwyby]

Yes?

Thinking about being a Guinea pig

 

[Mastermind]

Thinking about being a Guinea pig

I looked back and saw that a post linked to Arboristsite. I'm banned from there.

 

[Stump Shot]

I looked back and saw that a post linked to Arboristsite. I'm banned from there.

 

[huskihl]

Depends on how much of the stroke is in the case versus how much of the stroke is in the cylinder. I don’t know enough about either model to have any idea.

 

[Maintenance Chief]

I have ideas.


Maybe good? Maybe bad?

 

[Stump Shot]

Depends on how much of the stroke is in the case versus how much of the stroke is in the cylinder. I don’t know enough about either model to have any idea.

I was thinking diameter wise. There should be some interesting goings on.

 

[Spike60]

I was thinking diameter wise. There should be some interesting goings on.

Yes, they would need to turn down the cylinder extension to fit it in the case. The 288's little brother, the 281 is also a 52mm top end just like a 272. I'll get out in the shop tomorrow and compare gaskets/bolt locations. I know they are at least close. All the intake stuff is also other than bolt diameter? I shouldn't be guessing like this with the answers just out back, but I've been out in the rain enough today.

 

[srcarr52]

Hmmmmmm. Take a look at how thin the cylinder base is. 272 stroke is 4mm less than a 288. Did they just take that 4mm off the base to address that? Way too much if that's the case. Saw will never hold up like that. Fun idea to do it yourself just for kicks. But that could be a $500 grenade right there.

You’d only have to take 2mm off the base to account for the 4mm difference in stroke. But depending on the part line and rod length it might not take much at all.

 

[slackinoff]

Not sure I understand this. Are you saying the location is different? I've never run into that, and not sure it's possible. There are 2 different diameter posts, 10 and 14 mm.

Hey Spike, apologies for the late reply back. I meant two different diameter posts.

 

[davidwyby]

How does a 272 bottom end compare to 372 or others in the class?

 

[cus_deluxe]

How does a 272 bottom end compare to 372 or others in the class?

in terms of what?

 

[cus_deluxe]

same main bearings, 372 must be slightly longer stroke. also outie vs innie.

 

[davidwyby]

in terms of what?

Whether it will hold up to the big bore

 

[cus_deluxe]

Whether it will hold up to the big bore

one way to find out brother…lol.

 

[cus_deluxe]

i wouldnt worry too much about a 272 crank.

 

[mrxlh]

Being the 272 is already “over square” and isn’t really prone to crank failures, I doubt it’s much to worry about. Being that it will turn up a tad faster with a short stroke, I’d go with the absolute highest class main bearings I could. Probably try to get the piston weight in the same zip code as the stock one.

 

[mrxlh]

The 6202 (depending on mfg.) is rated to 20k plus, choose your oil viscosity accordingly.

 

[davidwyby]

In case it ain’t here already - from @82f100swb :

 

[Czed]

Had a odd one on my 5 year old stumpshot ported 266xp
It has countless hour's on it and I haven't done anything at all to it just check tune occasionally.
I pulled it out to get ready for some cutting and the throttle rod was missing
I guess it wore down the metal and fell out the plastic on the throttle arm is still tight
It wasn't anywhere in the topend or recoil.
I figured it would jam up in the recoil.
I replaced it and got my zoo city 272 ready also.