OutdoorKing Repair Forum Forums Restoring, Customising and Modifying Small Portable Machines 088

Hi all..Dont know if this is in the right place?...Well to much time on my hands so am porting one of my saw's as ya do lol...Here are a few pics, I have to get this one right as a new cylinder is about 900 bucks! here in AU anyway we get ripped off on Stihl parts haha..And no Im no pro at porting I just have a go.Just have to use the Vernier Calipers to work out what id like to change but there is more to it than just that...Hand filing a sharp chain round or square now that I do have down pat haha ..Also in one of the pics piston wash tells you alot and yeah this saw is 121cc...I will load pics after porting Cheers Chris..

Good on ya Chris
Ya cant beat the sound of a ported two stroke. dont forget if you have ported the cylinder you might as well deck a wisker off the head as well(make sure you use 98 premium if you do) and mabey then you could go up a size on your main jet. Sometimes (depending on type of carby) you can port the throat out a wisk.
All makes for a snappy two stroke motor that will sound and hopefully go sweet.

Your right there nothing beats the sound of a strong running 2T...But sadly a saw is nothing like a bike or 2T Victa for that matter as they don't have a head that can be removed ,well some very old saw's you can but now days no...To get more compression on a saw now days they cut the squish band and drop the cylinder to up compression and this also keeps very mellow less than stock port timing numbers its very on the safe side but with a little porting they are a very strong more or less stock saw but on the very safe side as in won't blow up! lol.....Yeah an 088 has 8.7HP thats not bad I say they dont have much room to work in....

Hi chris125,
Just out of curiosity, what oil was used and how much work has the saw done?


Nice photo of the top of the piston, the books I have say misaligned transfer ports for that effect..

Edit: FYI just did a little more research on that the pattern on the top.. is called a "Jante" velocity pattern, named after Alfred Jante in about 1968, looks like an SAE Paper was written on it (Jante, 1968, SAE 680468)

Light holiday reading....

G'day FAST GRASS
This saw has done many years as a full time falling saw Aussie hard wood then downgraded to a mill saw so more or less 10 years hard work. I gave it a full Rebuild a few years ago I use it most days but the last few months I run it say 4 hrs a day(workdays)..The carbon on top of piston is from running 25:1 and its always run that I cant pinpoint one oil for more or less carbon at that mix as its run a few brands of oil lol,but the bore is still like new and bottom end is good for anuther 10 years of work...Cheers.

Yep there is always Light holiday reading FAST GRASS haha ..Its all good fun working out how things work...The way I look at it is like a river and muddy water with gold maybe? haha..Well where flow drops it give's the mud (fuel) time to drop out and settle and you can see that on the piston in two spots at the back and over time it leaves carbon...Here is a pic before I cleaned the combustion chamber and the decompression valve its open in this pic but even closed you can see it upsets the flame front and fuel will drop out settle behind it,you can clearly see the way carbon has formed behind it...

I like you river analogy works for me too!

Really its quite clean, Ive seen worse, shows that it works hard and you use good oil and fuel in it, by the looks. Yeah its leaving a pocket of combustion reside behind that valve, you might improve that with your port job though....

Make that "your" river analogy... twas late...

haha yeah I will own that one not that good of a analogy..Im still tryng to work out how fuel and air flow its just a hobby for me...lots of trial and error and reading still to do lol...

Not done yet but am happy so far still lot's to do..alot of work going into the transfer ports and when done portng I will chamfer the ports...Done alot to the carby and Muffler as well,its not race saw porting but should make a strong work saw...Cheers Chris..

Looking great Chris,

I'm not sure exactly what I'm seeing.
1. have you rounded off the 4 oval holes in the carby?
2. I see you have done the golf ball pattern, on the inlet.
3. Is that chamfer exhaust side, was this originally flat?

Very interesting, I would love to know the results.
Could you show some of the tools you use at some point?
Thanks from Mark

G'day Mark..sorry I should have named the pics top pic is piston ,then inlet port with inlet manifold on ,last pic is exhaust port..Im still working on transfer ports but wll load a pic when done...you need to chamfer ports so you dont catch a ring in the port ,some also say a port with no chamfer and just a sharp lip will wipe oil off the ring..There is lots of good stuff on the net to read if you google porting a 2T but what works on one kind of 2T does not mean it will work on every 2T thats the hard part working out what works on what lol, With the carby there is a good site on how to make a big bore carb but cant seem to find it this min...Yep i will get some pics of what tools I use.....here is a pic of carby and muff.. Cheers Chris....

That is great, I imagine you have a die grinder of some sort, I have a dremel, not sure what I could do with that.
I would like to have a go at mild porting, I have a full crank 160cc as a subject here.

It's also good to practice portng when starting out on cheap thngs like a whipper snipper,helps with getting used to the tools you are using and how they cut and best way to hold them ,one slip and you can hit the bore and thats not a good thing.Good lghting is a must also...The porting it self does not take that long its the researching and working out what and why to come up with best plan of attack for the engine your working on..With this engine Im aiming for more torque fingers crossed lol ..I will no as soon as I use it if it has worked and is pulling the chain with more authority...Cheers

yep I have air die grinder and dremel and do lots of work with the dremel they are a good thing...for me just doing this as a hobby these work fine it just take a little longer than with $700 pro porting tools....

All done and Im very happy it's alot stronger saw after mods,considering its very mild porting and I did not touch the upper transfer ports I left them for now so can see how the rest of the mods are workng....It's still running very fat on the high I will fine tune better when Ive run it in more...

Here is a vid its running round file RS .404 and 7pin cuttng hard old ironbark... [video][/video]

Great video, engine is strong and not missing a beat, what sweet tune it makes.
Nice work.

Hi all Ive had time to give the saw a goog tune am very happy with it. Here is a vid with more tune in it.. [video][/video]

I would be very happy aswell, I have a chainsaw, but nothing like your Stihl.
My eyes have been opened to the world of chainsaws.