I Ported my 346XP

[MattyF]

Your bored aren't you steve.....will try and drop that piston and pot for the h's 80 off soon and the 357 you love so much!!!! The 346 sounds like it's going to be a ripper ! You want to sell?

[Paul Smith]

Matty, did you get Pete to port a saw for you?

[spudulike]

Your bored aren't you steve.....will try and drop that piston and pot for the h's 80 off soon and the 357 you love so much!!!! The 346 sounds like it's going to be a ripper ! You want to sell?

 

Be about time - the wife keeps falling over the parts:001_rolleyes: I am guessing the decomp valve wasn't the issue with the 357 - still dont know what the issue is....perhaps the Altitude difference:lol:

 

The 346 is my project to see what is possible, fixed up so many saws and don't do much for myself so I took about the fastest saw around and am attempting to get even more out of it. Hopefully it will fly, my 345 was great after I modded the muffler so have high expectations!! So - not for sale but if it all works and I am happy........can do saws for others.

[spudulike]

It started 4th pull and revs really nice - have set the carb rich and will tune at the weekend when I have more time - will fit the black unlimited coil before doing this so the rev limiter doesn't effect the tach giving spurious max rev readings.

 

All looking good so far:thumbup:

[ben lightfoot]

Take the day off tomorrow and tweak her then i cant wait to see it, as you said already a really fast saw. Bring on the vid

[spudulike]

Got the saw running on the blue limited coil and have now swapped it out for the unlimited black one - hope to get it tached on Sunday but need a new chain for it - only got a semi chisel on a 17" bar and am thinking a 15" bar full chisel will be faster!

 

All sounds good, lots of noise and revs cleanly but only tuned by ear!

[MattyF]

Matty, did you get Pete to port a saw for you?

Never did in the end to be honest I can't really be bothered with the 338 it's currently in bottom of lock up with a broken handle!

 

I might well have a 325 15" chain in full chisel steve, roll have a look for you.

[spudulike]

Never did in the end to be honest I can't really be bothered with the 338 it's currently in bottom of lock up with a broken handle!

 

I might well have a 325 15" chain in full chisel steve, roll have a look for you.

 

Cheers Matty, will probably tach the saw tomorrow and see what I can get out of it - got a 17" and a Stihl semi chisel on it at the moment but reckon the 15" bar I have will be the one to go for - better balance and speed.

[JSFGreig]

looks good spud i had a go with an 021 and fear i may have over done it

 

 

what do you reckon? ive never done it before so i just got the dremmel out and had at it!

 

i dropped the old piston inside the over day just to see and noticed theres a slight lip over hanging the cylinder plating on the inside of the exhaust port and its definately hitting it(if any of that makes sense) is there any way to get rid of the lip? dont trust my dremmeling hand close to the cylinder plating

[spudulike]

Unfortunately there is more to porting than just taking a dremmel to the cylinder and hoping it will work. On the exhaust port, you can make the port wider but are limited by the wall thickness and also the piston design.

You can raise the top of the port but this will change the power band and may lessen the compression. There are specs that should be adhered to when widening the port.

 

The inlet port can be widened but are again limited by the piston and the design of the port - there are magical figures on the % of bore size that the ports should be! You can have a go at the lower edge of the port to lengthen inlet duration and also have a go at the transfer ports or take a little off the piston skirt. The squish can be adjusted for optimal - manufacturers rarely dive in to this grey area plus you have the muffler opening that again has a magical % of exhaust port sizing tolerance!

 

Very difficult to see what you have done and if it will work - if the ring is catching then that is bad - the edges of a ported port need taking down with a dull dremmel bit or as I did with a diamond file followed by semi fine wet and dry paper - if you have made them too wide then hope you are happy with your new ash tray:thumbdown:

 

If you put the piston in the bore as it would normally sit then draw the outline of the port on the piston and post this image - it will tell me if the port is too wide - also, if you have raised the port by more than circa 1mm then you may have gone too far!

 

I am no expert but have spent many hours gathering information on this tech and did what I did with a wealth of knowledge and a sound experience of saw maintenance - mistakes can be costly!