What's the Dope on 372 52mm setups??

[mixxer]

I've had my 372xp for quite a while and it's the only saw I have never modded....

I have 3 of the poulan 2300 top handle saws... self made custom fiber reeds (gotta love Case Reed setups for torque!!) ... Exhaust port raised 1mm .. Base gaskets eliminated... Mufflers ported to match.... These little monsters sound like a pissed off giant wasp when they are lit... Everyone gets a kick out of how nasty good theese lightweight saws really run... Friends over for bonfire cut duty are always letting out a laugh and saying " Ha!! I forget how nasty these little saws are! Funny!"

Most underrated top handle ever! Respond so very well to those simple mods...!!

1 poulan pro 330 that I bought about 10 years ago at TSC... Wasn't even looking for a saw that day... Saw a stack by the checkout line for some ridiculously cheap blowout price... Impulse buy... " Honey I know I went to TSC to get gate hinges, but they made me buy this saw"... Wish I would have bought the whole stack of them now...

330 was an immediate disappointing over baffled turd of a saw... Bogged hard on simple 10" diameter wood with it's 22" out of the box bar... Stunningly limp saw out of the box...

Cut overly restrictive bsfgling plates leading to air filter and turned the choked up muffler into a short / straight through glass pack... Much like a chode of a mx bike silencer... Swapped 22" bar for 20"... Re- tuned the carb to match...
Dr Jekyll and MR FREAKIN HYDE!!
amazing performance light middleweight saw!! Lots of stock compression too...
Now after recently looking up posts about 330s on this site after recently joining.... The 330 has even more potential than I was ever going to bother looking for.... Almost 10 flawless years under it's belt now... I'm going to go back in for more... Soon...

Recently made an inappropriately under researched purchase of a lightly used 3.3 Craftsman thinking it would be a pp330 clone I could let my Sons use to keep them from abusing the 330 and 373xp... I bought it knowing I would mod it up a bit... Now not sure how long I will want it after knowing it isn't what i thought it would be...

Now.. the 372xp was bought new and has been with me quite some time... I picked it based on power to weight ratio... And it has run so well , right out of the box as my bigger saw, that I have never thought about modding it ... Until now....
I have read in here that base gasket elimination can produce an overly tight squish band....
I have also read the wonderful modded 268/670 piston thread where it makes for a great high compression setup when properly cut for use as a pop up dome piston in a 372... But I also see that the OEM piston prices are pretty darn high... And I know from past experience in my area that asking any machinist locally about a simple circular dome cut of a piston is met with the same enthusiasm and confidence as if I asked them could they machine me a space station from billet...

Next I have noticed how inexpensive plated knock off 372 50mm stock bore cylinders are ... And plenty in big bore 52mm also

And I have also found HyWay brand piston kits in high comp pop up style .. but not in stock bore 50mm... Only in big bore 52mm....

And now the questions I hope some of you long time members here will have the straight dope on ....

How well are these plated aftermarket 52mm cylinders made??

How well does the 52mm pop up work? Quality? Longevity??

Does anyone offer machining services on the 268 style pistons??

I would like to mod a piston for use in stock 50mm bore... I don't need a new cylinder... Port the cylinder with slightly wider / taller intake port ... And a little wider and maybe a 1mm or so higher exhaust port...
Turn the muffler into a straight glasspack silencer (moose racing dirt bike silencer packing is excellent)... And re-tune it all in...

But if the 52mm stuff works well... Or can be made to work well.. I'm ok with that too...

So whats the straight dope on all that stuff?? I KNOW some of you guys KNOW.... Be a brother and share some info please...

 

[mixxer]

All apologies for the multiple thread postings of this... Perhaps poor satellite signal delay where I live in the boonies is part of it...

Sorry I don't really know how to delete the duplicate threads.. site moderator help would be greatly appreciated...

 

[Fordhook]

I have done a few of these aftermarket cylinders now for the 372 including the 52mm kit that just retired it's self.
I raised the EX to 180 duration Transfers to to 124 and Intake at 160. I decked the cylinder 1.6mm and cut the cylinder squish to increase compression while still using a base gasket.
It run very strong and would hold rpm in the cut with a 30" bar. On 20" bar it was fun to say the least.

Unfortunately there were a few issues with the build. The casting was not thick enough in the top of the transfers and on one side I actually cut through. The stock porting is ridiculously low in timing. It was easy to repair and the repair out lasted the chrome plating in the bore.

I have just completed a build with a Meteor kit (50mm) I set it up with near the same port timings and had no problem with the casting and I was able to leave the transfer tunnels a little tighter as the casting was consistent and tidy. In fact I did little more than cleanup the surfaces and radius all internal corners. I did buy the 670 piston as per the other thread but unfortunately I had already cut the cylinder base and my intake duration was 186 so had to use the stock piston which I did my best to modify. I'm about to do another one so I'll use that piston on that build.

Stock porting was also low in the Meteor kit. Timing with base gasket totally stock EX 156 Transfers 90 (I kid you not!) Intake 150. I ran it before I did any work and it was SLOW! Pathetic might be a better word.

Since I ported it I have not had a chance to cut wood but it feels fresh a lively. Not as responsive off the bottom as I had hoped despite Decking the cylinder and cutting the squish 1mm. That was not fun to do I might add and took a few different grinds to get my boring bar to cut the nickel silicon carbides coating in the squish band. Meteors are not chrome they are generously coated and far superior to chrome. The coating also takes the edge of my very expensive cutters. I use stones were I can to grind away the coating but inevitably you cut away a lot of the nickel silicon carbides coating.

I will not do another chrome cylinder. I have had 4 fail on me now in quick time. One did not last the first day after porting. I'm sure left stock they last well but once you cut the ports you expose that edge and the ring just strips it off. The last one I could blow the plating off with the air compressor after it failed. My days of just hacking away at these cylinders are long gone the last 4 saws I have done all cut extremely well so it's time to expect them to last at least a season or 2.

I have changed the shape and direction of the transfers this time to hopefully get a cleaner burn. I have found this stuff makes a difference and my 52mm was getting 1/3 more run time on a tank of gas compared to my mates saw that I did which had a 50mm kit and I was getting far more power out of the 52mm also. It's a shame the chrome let go as it really did go well. I may get the cylinder re-coated but I can buy 2.4 Meteor kits for the same price.

I have done a lot more work on this build than the 52mm build and look forward to seeing how it cuts in comparison. This build should breath far better with the 390 intake and carburetor and make more power in the top end during the cut or at least that's my theory, here's hoping.

 

[cuinrearview]

@huskihl

 

[mixxer]

Fordhook,

I can't thank you enough for taking the time to share all of that info...

More insight than I could have hoped for... Incredibly helpful and informative...!

Flaking chrome is all I needed to hear .. curiosity cured on the cheap cylinders...

I wonder if the meteor kits do nikasil like the dirt bike world or if they are a ceramic composite...

Maybe I will do the modded 268 piston with the OEM quality 50mm cylinder...

I feel the draw for the bigger intake and carb via the 385/390 setup... And one can argue that a saw is either at idle, or cutting speeds... So it isn't really a dirt bike throttle response sensitive thing... But large carbs can have a throttle delay by running lean until rpm can rise enough to effectively activate the high speed jetting circuit... Not that that would happen, or have any real bearing on use in saw conditions... But it could possibly add a throttle lag time....

Great stuff to think about...

 

[mixxer]

I just re read your post Mr Firdhook...

Nikasil /Nicasil... the meteor brand cylinders coating would be first rate.... Glad to know that

 

[huskihl]

I'd leave the am stuff alone due to port shapes and sizes. If you were porting an AM cylinder, that may change, as shapes and sizes can be altered as long as there is material that can be removed in the right places. There are am options with superior plating.
For what it costs, and with negligible gains, I wouldn't mess with the 268 popup idea. All it does is add a little compression and intake duration. If you'd like your 372 ported I can assist with that. I can also add a larger carb. Send me a pm if I can help

 

[huskihl]

@huskihl

Thanks for the nod, Tim

 

[mixxer]

I'd leave the am stuff alone due to port shapes and sizes. If you were porting an AM cylinder, that may change, as shapes and sizes can be altered as long as there is material that can be removed in the right places. There are am options with superior plating.
For what it costs, and with negligible gains, I wouldn't mess with the 268 popup idea. All it does is add a little compression and intake duration. If you'd like your 372 ported I can assist with that. I can also add a larger carb. Send me a pm if I can help

Thanks very much for the info/ input... Much appreciated....

I have lifetimes of experience in porting for the dirt bike world... 2 stroke and 4 stroke... Dyno shops... Professionally... For race teams and engineering college competitions... Lots of stuff over about 4 decades...
Port work is where all the fun is ..

I just never went all in for modding my saws beyond quick and simple... But right now it really seems like an excellent extension of my lifetime addiction of modifying everything...

What I don't know is all the stuff that people know when they are already into a sport/ hobby... What parts interchange... What is a quality piece and what to avoid...

I was hoping to tap into the deep talent pool here... To get a crib note / fast forward/ skip ahead 10 spaces sort of education on the saw world so I can get past my saw trial and error newbie status in short order....

 

[huskihl]

Thanks very much for the info/ input... Much appreciated....

I have lifetimes of experience in porting for the dirt bike world... 2 stroke and 4 stroke... Dyno shops... Professionally... For race teams and engineering college competitions... Lots of stuff over about 4 decades...
Port work is where all the fun is ..

I just never went all in for modding my saws beyond quick and simple... But right now it really seems like an excellent extension of my lifetime addiction of modifying everything...

What I don't know is all the stuff that people know when they are already into a sport/ hobby... What parts interchange... What is a quality piece and what to avoid...

I was hoping to tap into the deep talent pool here... To get a crib note / fast forward/ skip ahead 10 spaces sort of education on the saw world so I can get past my saw trial and error newbie status in short order....

Well, there is lots of info here in the archives. Sadly, most of the pics more than 4 years old, which includes most of the good stuff, are gone.

 

[mixxer]

Well, there is lots of info here in the archives. Sadly, most of the pics more than 4 years old, which includes most of the good stuff, are gone.

That really is a bummer...

Your signature line is pretty damn funny... I enjoyed it...lol

 

[Fordhook]

Thanks very much for the info/ input... Much appreciated....

I have lifetimes of experience in porting for the dirt bike world... 2 stroke and 4 stroke... Dyno shops... Professionally... For race teams and engineering college competitions... Lots of stuff over about 4 decades...
Port work is where all the fun is ..

I just never went all in for modding my saws beyond quick and simple... But right now it really seems like an excellent extension of my lifetime addiction of modifying everything...

What I don't know is all the stuff that people know when they are already into a sport/ hobby... What parts interchange... What is a quality piece and what to avoid...

I was hoping to tap into the deep talent pool here... To get a crib note / fast forward/ skip ahead 10 spaces sort of education on the saw world so I can get past my saw trial and error newbie status in short order....

We are on exactly the same page.

I come here several years ago and trolled through old posts looking for a recipe to start and found nothing of great interest. So I buggered off and made rookie mistakes and destroyed several cylinders working it out till I learnt how to make power.

The advantage you and I have is time! As I stated above it takes possibly 16-20 hours to do all the work I do as I agonies over minor details and get everything exactly how I want it. I have the best gear on the market with no expense spared on CC Specialty tooling and cutters etc and boy does it make a huge difference. I can removed huge amounts of bulk in no time flat and when working with these AM cylinders you need to remove quite a bit of material in places. That said this Meteor build I just did was no where near as bad as some. I cut the intake and matched the 390 carb boot in maybe 15 minuets with 1/4 inch cutters. but I guess I poured at least 4 hours into the transfers and another 4 hours into the exhaust port. I hit exactly the numbers I want and get exactly the shape I want. That takes time with cutting, cleaning, assembly and checking the numbers. A trick I found is to fit the ring in the cylinder then drop your cylinder on and run the piston up till the degree wheel hits your number then when you remove the cylinder you can see exactly how the port is coming along. No lights shinning giving you errors by as much as 2 degrees I might add. Absolutely perfect!

If I charged $50.00 per hour it would cost $1000.00 plus parts to do the job. I found a YT video of a guy running back to back Tree Monkey saw and a Schnellerized saw whoever that is. He had a 28" bar and it was mostly buried in the log. The TM saw actually sounded pretty stock where the other saw sounded more like my port numbers. Both saws as it turned out they were near as dam the same in speed. I just did a speed test with my saw a week earlier using my 30" bar mostly buried and it was about 2 seconds faster and that was as the chrome was stripping off the bore as it turns out. I stopped the saw and as soon as I pulled the cord I realized it had no compression at all and I couldn't start it again. Now there are a whole lot of variables here but it's fair to say I'm in the ball park with what I'm doing and possibly ahead. My point is we have the time to do it better, we are not on the clock trying to make money.

I think it's time for us to share our success and failures so everyone can learn how to make these things go. Share details about port timing and shapes so we can all enjoy the hobby of cutting cylinders. Collectively we might even advance the power and reliability of these saws beyond our current understanding.

With all due respect guy's you have not been overly helpful at all. Tappermike has opened up but the rest of you are a closed shop. It's ok to disagree with ideas but say why. I shot F Class for years and went to our local shooting forum to help the longrange guys and gave up pretty quickly as it was clear it was a popularity contest and I was not popular destroying their myths with some of the ridicules case prep I proved makes no difference at all. I fear the same thing happens here and the site grinds to a halt as no one wants to help in a meaningful way. I personally could careless. If I'm wrong tell me why. That way we can all learn to do it better.

It sounds like you have far more experience than me and you will possibly build a faster saw the me. GREAT! go for it. Just come back and tell me how you beat me . That's all I ask.

The caveat here is the gear you need to do it well. Most guys aren't prepared to buy the gear and so they cant get the results. Also if you are like me you will need to build a jig to hold the cylinder in the lath as you cut the squish and base. I'm pretty happy with my port numbers and now experimenting with transfer roof angle. I have left some material behind this time giving me a little upward slope to see how that feels then I might go back in and cut them square again. I'll happily share my thought's as I go along with this experiment. And let's face it here guys every saw is a bit of an experiment. Some work some don't. We can argue and theorize all we like on here but in the wood is were it counts.

 

[Fordhook]

Oh one more thing. Your 372 jug is likely in good condition. I would not cut that first time around. The chrome cylinders do not last once cut but they last long enough to determine if your porting is working. But Meteor kits are about the same price so it's a bit of a no brainer really. All my cutters are about done now having done 2 Meteor kits. In all truth I think I only used about 6 cutters this time. I have a handful that look good on the screen as you push buy now but in reality I never use. I do the line share of all my work with 2 of my 1/4" cutters. I brought a cheap kit of diamond cutters and they are great for finishing ports with some rubberized polishing bits as well. They come up looking like a work of art if you put the time into them.

 

[Yotaismygame]

Plenty of guys will knock AM anything but have very little knowledge them selves and will regurgitate what they read and hear. All AM parts are not made equal. If you're not a professional AM parts will be fine as long as you're not out there buying the cheapest knock off you can find. Talking with professional fallers and buying there used up saws I definitely can see why OEM is best for them.

I've had a Hyway BB with their popup in my 372 for about ten tanks now. With no base gasket my squish was around .025 and makes 180psi. Saw cuts pretty good, but its not some crazy beast saw. I need to go back in and woods port plus raise the exhaust some, runs at a lower rpm then I would like. This is also coupled with a modded muffler and caber rings.

My next 372 that i'm gathering parts for now is going to be an OEM 50mm cylinder with 268 popup, woods ported, and possibly a carb swap or modded carb.

 

[Yotaismygame]

 

[Yotaismygame]

For what it costs, and with negligible gains, I wouldn't mess with the 268 popup idea. All it does is add a little compression and intake duration.

Interesting you would say that. The research and conversations I've had with people on the subject suggest the opposite. Bump in compression, added intake, and a lighter piston. I generally hear it'll make a strong saw without any port work done.

I personally have not done the 268 mod myself as of yet.

 

[Fordhook]

That runs surprisingly strong given how little was done. I wonder what the stock port timing numbers are? It sounds like the exhaust is about 100 ATDC. I'd laugh if you measure it and it was. It has the flat sound to it. At 90 ATDC they sound more lively and at 80 ATDC they sound hot. But no real guts to them or at least not with how I did the transfers. That one had a short life and went in the bin lol. It's all fun. Although it was a huge job building that cylinder trying to maintain compression ratio while raising the ports so high. Yes it was fun but pretty disappointing to invest all that time to get no real speed at all. On the bright side I learnt from it and now so did the rest of you. I have learnt a bit more since then and can feel another radical experiment coming on. I'm not yet happy with what I'm getting out of these 372's.

 

[Fordhook]

H

Interesting you would say that. The research and conversations I've had with people on the subject suggest the opposite. Bump in compression, added intake, and a lighter piston. I generally hear it'll make a strong saw without any port work done.

I personally have not done the 268 mod myself as of yet.

Having just gone through this exercise everything you stated checks out on my degree wheel (will likely be different from kit to kit). I'm not a fan of pop up pistons and I have little good reason for that other than I can get more compression by cutting the cylinder roof. That said I'm about to do one with the 268 piston and run it back to back with the build I just completed. I see a lot of merit in the additional flow through the bottom end over a full circle piston. I bet in the end it works well. Tappermike doesn't come across as someone to lead you astray. He is at least sharing his knowledge which is greatly appreciated.

 

[mixxer]

Fordhook... I really like your style...
We are likely brothers of different mother's... Lol....
Yota... Thank you so much for joining in...! Awesome adds...!
The cylinders or heads I have worked on in the dirt bike world all have easier access to ports and timing measuring than do the saws with the head casting being part of the cylinder...
As I read Fordhook's statement about pushing a free ring in the cylinder to mark port timing , I immediately thought " brilliant! "
I have used CC specialty for port tools since the 70's... I think I'm quoted as one of the builders commending their service all through the years on their site still... Very good people ... Happy to give them my business...
People who compete, or make a living from saw building like to guard their build information because it is their livelihood...
I have shared so much info over the years... And have seriously pissed off a lot of race shops in the dirt bike world... I treasure info.. and enjoy sharing it as much as getting it... Some shops act like it is akin to stealing their soul to share info, but most people aren't going to port things themselves anyway, even if they enjoy the tech reading... I have told shops offended by my info sharing:
" If it's for sale with a phone call and a debit card... It isn't any more "top secret" than a pizza " lol.. somehow that doesn't calm them down any...
I'm sure this trick is also used in the saw world ... And being a newbie here I haven't read it yet... So I'm going to mention it anyways...
Before cutting heights into the ports of a cylinder, you can mark out areas on piston domes or intake skirt areas and cut differing degree patterns into them (within limits of course) and try out cheaper piston degree cuts before deciding to cut the pattern into a more expensive cylinder... It isn't perfectly 1:1 with the cylinder cutting due to limitations of material and a bit of lost compression... But it still can be useful...

 

[mixxer]

You guys are going to likely be bored with the level I find satisfying on my 372....
Where I used to live in Michigan , there weren't too many trees that would make it struggle cutting with a 24" bar... I was impressed with it's tune for straight out of the box, never having bought a saw over 60cc before...
But I have found some oddly tough trees in Tennessee... The 372 actually has barely enough nuts on some of them with the 24" bar...
My goal is to turn the mid-range into a mid-RAGE .... Enough to make it haul through 24" cuts it struggles with down here...
Not interested in chasing power peak that revs impressively while unloaded.... I want to have it settle into a full cut and be aggressive in the meat of it's cutting rpm...
That would make me puff out my chest and walk around like I've got apples in my armpits... Oh yeah...