Mastermind
Work Saw Specialist
Notice the divider in the filter base? Get that out.
372 xpw cylinder?
- Thread starter idiotwithasaw
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idiotwithasaw
another row to hoe
The whole thing or just the bottom. What aboutthe divider in the carb?
RIDE-RED 350r
No wing, no prayer
IDK how I have missed this thread till today!
I have an XPW that I will be doing a base gasket delete on soon. Lots of helpful info here and the Spike60 vid showed me a couple of things I didn't know could be done. I have very limited experience modifying cylinders.
Awhile back I did a base gasket delete, muff mod, port match and cleanup on my 357. These things made a positive difference... But I did not trim down the cylinder skirt or the intake side of the piston skirt... Might be pulling that top end again to do those!!
After reading this thread and watching the vids, I'm planning to do the cylinder skirt trim and piston skirt trim on my XPW along with the gasket delete and lower transfer port matching.
So to make sure I understand, I should be able to trim .030" from the intake side of the piston skirt without worrying about taking it too far, correct? The cylinder skirt trimming I fully understand. Just want to be sure on the piston skirt trimming.
I have an XPW that I will be doing a base gasket delete on soon. Lots of helpful info here and the Spike60 vid showed me a couple of things I didn't know could be done. I have very limited experience modifying cylinders.
Awhile back I did a base gasket delete, muff mod, port match and cleanup on my 357. These things made a positive difference... But I did not trim down the cylinder skirt or the intake side of the piston skirt... Might be pulling that top end again to do those!!
After reading this thread and watching the vids, I'm planning to do the cylinder skirt trim and piston skirt trim on my XPW along with the gasket delete and lower transfer port matching.
So to make sure I understand, I should be able to trim .030" from the intake side of the piston skirt without worrying about taking it too far, correct? The cylinder skirt trimming I fully understand. Just want to be sure on the piston skirt trimming.
Mastermind
Work Saw Specialist
idiotwithasaw
another row to hoe
Ok I will gut it.
In the trimming of the piston skirt on the intake side that spike60 talks about in the video. What are the advantages of that. And would it be recommended on a 51.4 mm cylinder. I want to know too.
In the trimming of the piston skirt on the intake side that spike60 talks about in the video. What are the advantages of that. And would it be recommended on a 51.4 mm cylinder. I want to know too.
RIDE-RED 350r
No wing, no prayer
Restore/increase intake duration...
If I understand it correctly, we could trim as much as .050" off the intake side of the piston skirt if doing a base gasket delete... This would account for the loss in duration due to the base gasket delete which drops the cylinder (and consequently the ports) by about .020". So trimming .020" from the piston skirt should effectively restore OEM spec for the intake. Going to .050" after a gasket delete would take you .030" beyond OEM. And in the vid if I understand it correct, they say you can usually go as much as .030" beyond OEM spec pretty safely.
Someone please correct me if I am not understanding this correctly.
Mastermind
Work Saw Specialist
You are looking at it backward.
Lowering the jug adds intake duration. Cutting off the piston skirt adds even more.
Personally, I try to keep intake duration short, but I do other mods that make that work well for me.
Lowering the jug adds intake duration. Cutting off the piston skirt adds even more.
Personally, I try to keep intake duration short, but I do other mods that make that work well for me.
RIDE-RED 350r
No wing, no prayer
Thanks Mr. Mastermind...after you posted that I got to thinking about it more... I get it now.
idiotwithasaw
another row to hoe
What's the other things can you do to wake one of these 51.4 cylinders up. I'm not sure I'm confident enough to adjust port timing, or grind anymore than I already have. Im not looking for trade secrets, just some tips.
as long as the ring lands are not all beat to death (too much clearance) the pin bores aren't blown out and the skirts still have some taper left...all day o that piston...
Mastermind
Work Saw Specialist
Good sir, I don't have any secrets.
When I do a XPW jug it takes me about 6 hours just to do the grinding.
If you can look at a 50mm jug next to the XPW jug, you can see that the transfer ports are far smaller on the 51.4mm jug.
It's actually designed for a cut off saw instead of a chainsaw.
When I do a XPW jug it takes me about 6 hours just to do the grinding.
If you can look at a 50mm jug next to the XPW jug, you can see that the transfer ports are far smaller on the 51.4mm jug.
It's actually designed for a cut off saw instead of a chainsaw.
idiotwithasaw
another row to hoe
what i meant was, I don't expect you to give away what you work so hard for and spend so much to gain for free. So you are saying to get more gains I should widen and shape the transfers.
Mastermind
Work Saw Specialist
The whole thing works together. I'm not sure just opening up the transfers would get any serious gain.
idiotwithasaw
another row to hoe
I get it, change one thing you have to change something else. I really need to read up on how to port. Try to understand how to read a degree wheel. What are desirable numbers, And why. Also learn the terminology. Like blowdown for example, what is it and why is it important. I see a lot of timing numbers thrown around on this site without a lot of explanation.
I understand that alot of port work is trial and error and varies by person. What one is looking for and satisfied in gains with could be completely different to someone else.
I understand that alot of port work is trial and error and varies by person. What one is looking for and satisfied in gains with could be completely different to someone else.
Mastermind
Work Saw Specialist
I got on the PC so I could give you better and more complete answers. There's just so much I can do from a cell phone.
I was right where you are a few short tears ago. Wondering what these guys were talking about, how to set up a degree wheel, etc.
Here's a few pics of the 50mm VS the 51.4mm jugs......
50mm on the left, 51.4mm or the right. See the difference in the transfer tunnels?
Now, here is a 50mm jug. The passage on the right is the main transfer port for this side of the engine. Notice it's width.
Then look at the 51.4mm jug. See how much smaller the main transfer passage is?
Mastermind
Work Saw Specialist
This is where I start grinding.....
Mastermind
Work Saw Specialist
And this is where I end up.
Mastermind
Work Saw Specialist
On the left is the amount of aluminum chips that came for the 50mm jug, and on the right is the amount from the 51.4mm jug.
idiotwithasaw
another row to hoe
I see that you also narrowed the divider I was afraid to take too much out, being my first attempt and all. And before I do much more may try on something a little smaller, like an ms250. Lol. What you see I'm my pictures is all I have done.
And @Mastermind I really appreciate you making the effort to teach a cull like me. I know it was a typo but I'm sure you have been tempted to shed a few tears over the years
And @Mastermind I really appreciate you making the effort to teach a cull like me. I know it was a typo but I'm sure you have been tempted to shed a few tears over the years
Mastermind
Work Saw Specialist
LOL
I see my typo now.
You can get good gains from widening the ports (careful not to overdo it, and be sure you have a nice little bevel when you are finished), doing a good open muffler mod (on that saw a hole right on the brace on the bottom of the muffler is very effective), and most of all, learning to make a really good chain.
I see my typo now.
You can get good gains from widening the ports (careful not to overdo it, and be sure you have a nice little bevel when you are finished), doing a good open muffler mod (on that saw a hole right on the brace on the bottom of the muffler is very effective), and most of all, learning to make a really good chain.
