Optical illusion. It's the edge of where the coating that comes on them had rubbed off on the thrust face.
Considering I don't EVER warm that engine up, it wouldn't be surprising if it was a little scuffed anyway, though.
Piston Boost Port
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Optical illusion. It's the edge of where the coating that comes on them had rubbed off on the thrust face.
Considering I don't EVER warm that engine up, it wouldn't be surprising if it was a little scuffed anyway, though.
That's def a big ol boost port I had cut into the piston.
To be completly honest I really didn't notice too much of a difference.
I always had scuffing like that on the intake side. Thats a well used piston just it was on meth so it doesn't build varnish or carbon.
To be completly honest I really didn't notice too much of a difference.
I always had scuffing like that on the intake side. Thats a well used piston just it was on meth so it doesn't build varnish or carbon.
Results will be in tomorrow ill be installin the piston if best didnt already tomorrow after work an taking the old girl for a test run. I have much more seat time on the bike then best an will give my honest opinion on the mod. Im also looking forward to this test
Stay tuneddd!!
Stay tuneddd!!
Cant wait to hear the results. This looks like a easy knee mill mod. Where is the piston exactly (related tot he cylinder) when you scribed that line? Was it exactly at BDC or what....
Time to do some experimenting.
Damn it Joe... Cut the sh*t and get working on that radius tool! lol
This guy made a radius tool to cut his own tube bending dies.
This link might help you out. lots of pictures...
A homemade radius cutter. - Pirate4x4.Com : 4x4 and Off-Road Forum
This link might help you out. lots of pictures...
A homemade radius cutter. - Pirate4x4.Com : 4x4 and Off-Road Forum
Looks a bit too bulky. Ive been looking at some on youtube and seen some I like. I more just waiting for you to make one of those amazing how to you like to make!!
There's alot of good "how too" in that link. all you have to do is shrink it down to your needs. You'll have a bit of a wait,because I have lots of irons in the fire at the moment.
OK, Blaster has been running but New Years has a way of bringing a lot of socializing and other interruptions to serious Blaster testing.
I have more pictures, piston cleaned up:
The secret cleaner? Big Orange hand cleaner. Smells nice too.
Here is the scuffed bit on the exhaust side. No cause found, bore good in this area:
Where the triangle is is the exhaust side of the piston and where detonation damage normally starts.
Hard to tell if this is micro pits from detonation (don't think so) or baked on carbon (likely).
One issue that bothered me was the side clearance on the pin to the clips.
It has held together this long...
Here is a last shot up the intakes into the epoxy stuffed reedbox.
So, how does it work?
Well, I was sorry that I didn't take it for a ride just before we did this.
I don't have anything to compare to if it got better or worse.
My comparison is with a full on motocross engine only slightly mellowed with a slightly lengthened pipe.
Neil's Blaster works well, good start away torque, better than my KTM. Noticeable "on pipe" very low in the rpm range (that occurred with the reedbox stuffing), and strong power into the high revs. Not as strong or as high revving as the KTM yet plenty peppy. His engine starts with one kick, still idles well and at a surprising low rpm. Lower and smoother idle than my KTM. Also noticably less vibration than my KTM too. Still a harsh little screamer, great power but more refined and better gearing than my KTM. Fun ride.
Now just waiting for Triplecrown to get over here and pronounce judgement, better or worse.
Steve
I have more pictures, piston cleaned up:
The secret cleaner? Big Orange hand cleaner. Smells nice too.
Here is the scuffed bit on the exhaust side. No cause found, bore good in this area:
Where the triangle is is the exhaust side of the piston and where detonation damage normally starts.
Hard to tell if this is micro pits from detonation (don't think so) or baked on carbon (likely).
One issue that bothered me was the side clearance on the pin to the clips.
It has held together this long...
Here is a last shot up the intakes into the epoxy stuffed reedbox.
So, how does it work?
Well, I was sorry that I didn't take it for a ride just before we did this.
I don't have anything to compare to if it got better or worse.
My comparison is with a full on motocross engine only slightly mellowed with a slightly lengthened pipe.
Neil's Blaster works well, good start away torque, better than my KTM. Noticeable "on pipe" very low in the rpm range (that occurred with the reedbox stuffing), and strong power into the high revs. Not as strong or as high revving as the KTM yet plenty peppy. His engine starts with one kick, still idles well and at a surprising low rpm. Lower and smoother idle than my KTM. Also noticably less vibration than my KTM too. Still a harsh little screamer, great power but more refined and better gearing than my KTM. Fun ride.
Now just waiting for Triplecrown to get over here and pronounce judgement, better or worse.
Steve
OK, the results are in!
Neil pronounces no change in bottom end power, definite increase on top end.
He says powerband comes on stronger but at about the same rpm.
Here is the piston after 1/2 to 1 hour (we lost track of time!) of steady hard running:
So, we are ready to put Joe's cylinder on, right?
Hang on just a bit, we gotta crazy experiment to do with the last life of this piston.
Old man grabs the piston from the clutches of the young feller, snaps a couple punch marks on it, and drills...
Then he drills again!
BWAaaaaa Ha Ha Ha!
Then he files like a crazy man:
Cleaned her up a bit:
and shoved her back into the Blaster:
Whole operation took less than half an hour with 2 wildmen going at it.
Bigger, better than before... MORE HOLE!
How does it work now?
Neil pronounces no change in bottom end power, definite increase on top end.
He says powerband comes on stronger but at about the same rpm.
Here is the piston after 1/2 to 1 hour (we lost track of time!) of steady hard running:
So, we are ready to put Joe's cylinder on, right?
Hang on just a bit, we gotta crazy experiment to do with the last life of this piston.
Old man grabs the piston from the clutches of the young feller, snaps a couple punch marks on it, and drills...
Then he drills again!
BWAaaaaa Ha Ha Ha!
Then he files like a crazy man:
Cleaned her up a bit:
and shoved her back into the Blaster:
Whole operation took less than half an hour with 2 wildmen going at it.
Bigger, better than before... MORE HOLE!
How does it work now?
You guys are nuts and I LOVE IT!!!!!!!!!!!! Tarmo and I would have had a long discussion about this, thought about it, talked again and then started milling. Way to jump in and see what happens!!!!!!!!!! Here’s my thoughts ……and they’re just thoughts. I’m wondering how the piston will react with the huge boost port when it gets hot. I’m referring to the expansion of the piston. Pistons are cam ground / machined so the top of the piston is smaller than the bottom @ the skirts. I’m curious to see if the huge boost port will affect the natural way the top of the piston expands when it gets hot. The cylinder should tell the story with some different wear lines. Great job guys and I’m tuned in!
Yeah Ken, we are no different.
We can talk something to death, but it doesn't prove anything until we try it does it?
Neil and I came back excited and determined to find out "if a little works well, how does a lot do?"
I didn't feel the little slot was risky, it is in the "meat" of the piston, but my crazy holes probably do represent a walk away from reliability.
It is all a balance isn't it?
That piston is done its useful life. Neil runs her wide open thru mud and sand and 'til she is too hot to touch.
Piston is sloppy in the bore, funny wear grooves aplenty already, there will be no long term test of this piston.
It was just one last hurrah before retiring a good old workhorse!
SO, HOW DID THE BIG SLOT WORK?
Funny thing, on first start the idle was lower. We were concerned we had a leak or something wrong.
It cleared up as the Blaster warmed up, but the idle was not as steady to my ear.
I think I feel a slight loss of low end torque, and the powerband kicks in a bit higher.
But it does kick in! Power in all the powerband seems up a bit, not huge but noticeable right up to peak.
Seemed like more intake noise out of it too, a throaty growl.
I felt it lost a bit on the low end, just under the powerband but distinctly gained a slight bit all through the powerband.
Incidentally this was all with a toroidal head which favours mid-range.
The boost port may even work better with a hemi which favours top end?
Steve
We can talk something to death, but it doesn't prove anything until we try it does it?
Neil and I came back excited and determined to find out "if a little works well, how does a lot do?"
I didn't feel the little slot was risky, it is in the "meat" of the piston, but my crazy holes probably do represent a walk away from reliability.
It is all a balance isn't it?
That piston is done its useful life. Neil runs her wide open thru mud and sand and 'til she is too hot to touch.
Piston is sloppy in the bore, funny wear grooves aplenty already, there will be no long term test of this piston.
It was just one last hurrah before retiring a good old workhorse!
SO, HOW DID THE BIG SLOT WORK?
Funny thing, on first start the idle was lower. We were concerned we had a leak or something wrong.
It cleared up as the Blaster warmed up, but the idle was not as steady to my ear.
I think I feel a slight loss of low end torque, and the powerband kicks in a bit higher.
But it does kick in! Power in all the powerband seems up a bit, not huge but noticeable right up to peak.
Seemed like more intake noise out of it too, a throaty growl.
I felt it lost a bit on the low end, just under the powerband but distinctly gained a slight bit all through the powerband.
Incidentally this was all with a toroidal head which favours mid-range.
The boost port may even work better with a hemi which favours top end?
Steve
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