Questions about ported saws...

[Jason280]

I have been looking for a saw to replace a 575XP, and came across a potential deal on a 272XP. The plan is to primarily run a 20" bar, or occasionally up to a 24". The saw looks solid, and is in excellent condition, but was ported/polished by the previous owner. Specifically, the ports have been opened and polished, with the skirts cut off the piston.

My concern is whether the work was done correctly, is there any real way to check other than pulling the head and piston? What potential issues are there regarding longevity? I feel reasonably good that the work is solid, just don't want to end up with a saw that grenades on the 2nd tank of fuel.

 

[cuinrearview]

You'll get a few opinions on this. You're putting trust in a stranger anytime you buy something used. A lot of guys here do work on cylinders with varying results. I suspect the same is true everywhere. There are so many variables to consider that I would suggest that if you have any trepidation just keep looking.

 

[Jason280]

That's kind of my thinking. I've found a replacement cylinder/piston kit for around $130, worst case is I can try to get it cheap enough {and still be OK if I have to replace the top end).

 

[Jacob J.]

The fact that the piston has been fiddled with would be enough to scare me off. Most of the guys here that are porting saws and doing good work that's been verified, are not modifying the pistons that much.

 

[Jason280]

So, what is the potential issue with too much of the skirt removed?

 

[Ketchup]

Weak transfer, carb flooding and spitback are the most common issues with trimmed piston skirts. The saw may be sluggish, hard to start, or have idling issues.

If a saw has been modified it needs to come with some guarantee. If you can't bring it back, don't take it home.

 

[Jason280]

I guess my next question is, wouldn't all these symptoms manifest fairly quickly? As in, wouldn't they show up within the first few cuts with the saw?

 

[Ketchup]

The worse the job, the sooner you will notice. If you run it hard and get it hot you should have a feel for its reliability. If it pulls hard, idles well and starts easily during hard use, the piston timing probably hasn't been badly altered.

But there's more too it. You might get 5 tanks of hard charging 272, then your saw hangs a ring from inadequate chamfering. Or the saw might run like a scalded dog until it dies from the air leak that was left over from sloppy reassembly. I'm not saying that's going to happen, but it might. You need a guarantee that you can bring it back if there is a legit problem. Or, you need to be ready to fix it yourself.

 

[drf255]

Ask the seller how many tanks he has put through it, then go run the saw.

Most porting defects occur within the first few cuts. If it’s gonna happen, it’s gonna happen then.

I’ve never had any issue that didn’t manifest itself in the first few cuts. That’s why I generally beat the piss out of a saw for at least 1/2 tank before it leaves here, never had an issue that didn’t happen then, but maybe I’ve been lucky.

Trimming the intake side skirt is a reliable way to increase intake duration without touching the port. I’m not sure why that was done if the seller knows what they are doing. Especially on a 272 which is a simple saw to grind on.

Most try not touch a piston so that a replacement is easy someday for the new owner. That’s why I rarely touch a piston and if I do, it’s fully disclosed and a replacement will be available for cost with no machining charge in the future.

I’d say go there, ask the guy to see the piston (if he ported it that should take him under 5 min to reveal and reassemble) and go make some cuts before you hand any cash over. If it puts a smile on your face and runs well/doesn’t grenade, buy the saw. Keep in mind (as you did) that the model in question is a simple beast with many cheaply available parts.

 

[blsnelling]

In short...no.

 

[Jason280]

Thanks for the responses.

I may make an offer in the saw, with the idea of potentially having to replace the top end. I think ill be OK if I can get it under $250, still be in less than $400 with a new piston and cylinder.