Need a little porting help with a Hyway 272 cylinder.

[Ronie]

Before you mess with any of the porting... have you tried advancing the ignition timing a bit?

It seems a little lazy upon spool up which is normally be an indicator of too much intake duration... but it can also be lack of timing.

I didn't change the timing. I should have tried before I pulled the cylinder. When I put the 670 cylinder on it I'll advance it a little.

 

[huskihl]

I didn't change the timing. I should have tried before I pulled the cylinder. When I put the 670 cylinder on it I'll advance it a little.

I’ve only done a few of this series of saws, maybe a dozen or so. But mine really liked the timing advance. I didn’t put a wheel on it to check the degrees, but I worked in approximately .010 increments and stopped at around half the key. It wasn’t popping yet, but it just seemed to run really well there and I was satisfied

 

[Ronie]

I’ve only done a few of this series of saws, maybe a dozen or so. But mine really liked the timing advance. I didn’t put a wheel on it to check the degrees, but I worked in approximately .010 increments and stopped at around half the key. It wasn’t popping yet, but it just seemed to run really well there and I was satisfied

I have a 630 with an OEM 272 cylinder on it it that I'll try advancing the timing on after I get this one done. It runs good but maybe I can get a little more out of it. Here's a video of it and the timing numbers. The chain acts like the rakers are to low but it's a new LGX chain.

EX 102 TR 122 IN 78 .020 SQUISH .040 POP UP 13,950 wot

 

[srcarr52]

That one is much better!

 

[Agent Smith]

I like it. Good job so far

 

[huskyboy]

I have a 630 with an OEM 272 cylinder on it it that I'll try advancing the timing on after I get this one done. It runs good but maybe I can get a little more out of it. Here's a video of it and the timing numbers. The chain acts like the rakers are to low but it a new LGX chain.

EX 102 TR 122 IN 78 .020 SQUISH .040 POP UP 13,950 wot

Much better! Oem cylinders are hard to beat with am.

 

[drf256]

The AM cylinders are hit and miss. You may get a unicorn that runs well every now and then.

The power and black magic in a 2 stroke jug is in the transfer ports. They may look identical to OEM designs, but there is nearly always a substandard design in the AM reproductions. The AM jugs generally lack the finesse of the OEM in terms of angles and direction in the tunnels and uppers. It’s something that one can’t always see.

I’d love to see the ports on the oem vs hyway. Generally in the dual port jugs I see the upper sitting almost vertically over the lower on AM jugs. On the OEM, the upper is always moved over towards the intake in relation to the lower opening.

If the AM goes through the trouble of ripping off someone else’s R&D, I’m not sure why they can’t just truly make a reproduction in every way.

Advancing the ignition timing should help a lot. The low compression will need more advance to have the extra time to burn the charge completely.

 

[drf256]

I still have the 272 P&C if you need it Ronie

 

[Ronie]

I still have the 272 P&C if you need it Ronie

Thanks, at the moment I'm in the process of trying to buy a house and had to pay for a VA inspection and the earnest payment so I'm pretty much broke. I'll get with you next month and see if you still have it.

 

[XP_Slinger]

I have a 630 with an OEM 272 cylinder on it it that I'll try advancing the timing on after I get this one done. It runs good but maybe I can get a little more out of it. Here's a video of it and the timing numbers. The chain acts like the rakers are to low but it a new LGX chain.

EX 102 TR 122 IN 78 .020 SQUISH .040 POP UP 13,950 wot

That is much better. Great thread gents, I just put a 268 together with a 272 top end and I’m learning a lot of good stuff about that saw in here. Mine is stock for now, even has a BG because it was a head slapper without it...OEM jug and slug

First cuts, bone stock.

 

[Ronie]

Got the 670 cylinder on it and I think it runs much better. I still need to put a longer bar on it and get a good tune in some bigger wood.