ms660 question on exhaust port

[outdoorfan]

This is a new farmertec big bore p&c on a huztl ms660. Question is, what happens with that free porting on exhaust port (pic) when piston is at tdc? Will it be detrimental? Opening is at most .050.

The standard 54mm piston that came with the saw has a longer skirt and doesn't free port like this.

Wondering if it will be a waste of time to install it.

Thanks.

 

[redbull660]

get what you pay for. anyone want to take bets on how many tanks it lasts?

 

[outdoorfan]

Do all the a/m 660 big bore pistons have this free port issue, and will .050 (approx) be a big deal. I want to do a mild port job on it, but am afraid it will be a waste of time.

 

[cus_deluxe]

Put a little epoxy in there and run the piss out of it

 

[outdoorfan]

I apologize that I don't know how epoxy will safely and effectively fix this issue.

 

[cus_deluxe]

I apologize that I don't know how epoxy will safely and effectively fix this issue.

Using epoxy in ported saws to raise or lower port opening to solve problems like this is common. I guess im not sure about in exhaust ports, hence my suggestion to try it and run the piss out of it. Make sure to report back

 

[outdoorfan]

I see. I think I'm too chicken to try that.

 

[pioneerguy600]

You will loose some case compression ans a bit of fuel/air mix out from under the piston as it starts its down stroke but the saw will run, it won`t make anywhere near the power a OEM piston and cylinder does but it will run. Porting, I wouldn`t bother as it won`t help that P&C set.

 

[outdoorfan]

Well, I decided to go ahead and install and port it anyway, even though I'm sure you're correct that it will be a waste of time. But I figured I could use the practice on a mild port job, so I went ahead and did it. No epoxy, though.

I've got my eye on the cross performance 660 piston and cylinder kit. But I'll see how this runs for now compared to the 54 millimeter farmer Tech version which was in it previously.

 

[jmssaws]

Free port ain't necessarily a bad thing, there's lots of good running saws that free port,I'm not saying it helps but I don't think it's detrimental.

It's not going to hurt it as far as longevity, the piston skirt passes over the intake without issue so I can't see why the exhaust would cause a problem.

You can machine a 395 piston and fix the free port but you won't gain anything from it.

 

[outdoorfan]

I see. Thanks for the reply. Once I leaned the carb out a bit, it started to cut nicely. Probably have some more leaning out to go, but want to play it a bit conservatively. Put 1.5 tanks thru it today.

It idles nicely and runs well, so far...

 

[outdoorfan]

I set the squish tight to compensate for the stepped squish area of the cylinder combustion chamber. My cheap compression gauge said 145, and it's usually off by a factor of 1- 1.4 or so. So, looks to be pushing 200 psi.

 

[outdoorfan]

Btw, the elasto- start handles from huztl are completely useless. Sometimes won't even last their first startup.