Morgan is most definitely talented! Im pretty sure when dyno joe tested those for him the ufo made an 11.5% gain on a 372, thats amazing for a custom pipe that fits into the stock space!
Hi Tinman, you might want to try a standard 372 piston in the cylinder in question. In MHOP the intake timing is a little to long and you will loose a lot of case compression with the windowed 272 piston. The combination of those to items might be the source of you issues. On a side note I have had what I thought was ignition break up on one of my 372's, I changed the ignition coil and replaced the spark plug with new NGK BPMR7a. Still the same issue, then replaced the spark plug again with an NGK BPMR7y. The ignition break up issue was gone! The NGK BPMR7y plug has a different center electrode, just food for thought. I have also used the NGK BPMR8y as a second test in a different heat range and that worked also. Good luck!
I guess where I was going with this is that windowed pistons and long intake durations don't generally work out as well as the non windowed pistons the saw was designed with.@@Witschor
@@wayneanderson991 thats right the casecompression is lower with the windowed piston. When you look at charly Brisco‘s echo 4910s and their Construction with a bottom fed Transferdesign and windowed Pistons, you can see that they have decent Power on high rpm. I think the 372 has that closed Piston design for midrange Torque and efficiency .
I have the 372 pop up from hyway on my clone saw with some mild porting oem bearings, oem crank, oem carb, and oem I take boot and a muffler mod and it works beautifully
Yah win some yah lose some.... I guess. I'm very interested in this one as my next project is a 371xpg. Timing of this content is perfect. I could hear it burbulling in the cut on that video. Strange, will be interesting to see the results of the new top end. If it doesn't solve the issue then it must be electrical, maybe a wire grounding out somewhere... check them out to see if it wore through somewhere, maybe the wire that runs under the top. On another point with this saw how do you change the springs on the handle for the anti-vib. My saw has two broken springs on the handle mounts. The one on the wrap was good. TC Mahalo Tinman 🤙🤙🤙
Interesting project you have going keep us informed. Sometimes you take a break from troubleshooting then come back later and a new Idea may surface leading to a fix. Has worked for me many times in appliance repair. Hang in there my friend. 👍
Great video come to the 709 Newfoundland show you the 100 mile wind 🌬 in the wreck house up 🔝 268 km 2 yrs ago . Good weather for dry clothes Tinman. 😊
Morning Tinman ! Having built 3 of these myself i am hoping you stick with the 272 piston and look to correct the undesirable traits . I will be going back into mine and finishing the job i started now that i have experienced the builds in a few different number sets . Ie. Intake duration correction and compression /pop up reduction
Hey Tinman , let us know about the issue. I don’t think its gone with the new Topend. Mine runs at 80 on the Intake with 220psi compression . I would go back to 76- maybe 78 but not higher and run 120 on the Trans. 99 on Ex, but not higher than stock exaust. Tuned at 14000rpm it has decent Power with 044 Pistonbolt. Cant wait to see the solve of this Problem. Try bpmr8y Plug . Its colder for high compression builts.
I think the exhaust port is too wide for this piston, it draws gas into the crankcase. The problem appeared when the piston gained play during break-in. the wear at the bottom of the skirt highlights this problem. I think it will run good with the 372 piston. I Hope you will excuse my Bad english... Thank you very much for this experience!
Can you recommend a kit for porting burrs? I sent an email a few weeks ago but I'm sure you're busy, or maybe i messed up the address or something. Thanks
Your transfers arnt totally open. Youd have marks from the ring below the transfer port. Ive found that big bores equal big junk. Stock bore seems to be the beat way to go. Its also been proven on the dyno that big bores actually lose power. Modify that 372 piston to have windows like the 272 youll lose the weight you wanna lose.
If you go back and read my email I sent you about the problem months ago you'll figure it out.....hint it has to do with the coil I have about 6 of them same coils for 372
Intake at 80 shouldn't be too bad. If you rework that jug with epoxy and it works I would be shocked. One of my MS360s runs ok with a crazy 83 intake timing. It was very hard to tune. Next time you're explaining intake timing can you cover effects of too much timing and if some saws can get away with bad timing more than others. I wonder if the MS360 is more forgiving and why.
Morgan is most definitely talented! Im pretty sure when dyno joe tested those for him the ufo made an 11.5% gain on a 372, thats amazing for a custom pipe that fits into the stock space!
Hi Tinman, you might want to try a standard 372 piston in the cylinder in question. In MHOP the intake timing is a little to long and you will loose a lot of case compression with the windowed 272 piston. The combination of those to items might be the source of you issues. On a side note I have had what I thought was ignition break up on one of my 372's, I changed the ignition coil and replaced the spark plug with new NGK BPMR7a. Still the same issue, then replaced the spark plug again with an NGK BPMR7y. The ignition break up issue was gone! The NGK BPMR7y plug has a different center electrode, just food for thought. I have also used the NGK BPMR8y as a second test in a different heat range and that worked also. Good luck!
You wouldn't be the first one to waste a lot of time troubleshooting erratic running issues over a $3 spark plug.
272 has 52mm and give more cc on a 372 Bottomend. Stock 372 is 50mm
I guess where I was going with this is that windowed pistons and long intake durations don't generally work out as well as the non windowed pistons the saw was designed with.@@Witschor
@@wayneanderson991 thats right the casecompression is lower with the windowed piston. When you look at charly Brisco‘s echo 4910s and their Construction with a bottom fed Transferdesign and windowed Pistons, you can see that they have decent Power on high rpm. I think the 372 has that closed Piston design for midrange Torque and efficiency .
I have the 372 pop up from hyway on my clone saw with some mild porting oem bearings, oem crank, oem carb, and oem I take boot and a muffler mod and it works beautifully
Yah win some yah lose some.... I guess. I'm very interested in this one as my next project is a 371xpg. Timing of this content is perfect.
I could hear it burbulling in the cut on that video. Strange, will be interesting to see the results of the new top end. If it doesn't solve the issue then it must be electrical, maybe a wire grounding out somewhere... check them out to see if it wore through somewhere, maybe the wire that runs under the top.
On another point with this saw how do you change the springs on the handle for the anti-vib. My saw has two broken springs on the handle mounts. The one on the wrap was good. TC Mahalo Tinman 🤙🤙🤙
Does look good. Trial and error is how winning formulas are discovered👍🏻
Interesting project you have going keep us informed. Sometimes you take a break from troubleshooting then come back later and a new Idea may surface leading to a fix. Has worked for me many times in appliance repair. Hang in there my friend. 👍
Great video come to the 709 Newfoundland show you the 100 mile wind 🌬 in the wreck house up 🔝 268 km 2 yrs ago . Good weather for dry clothes Tinman. 😊
Donnie Walker, Richard Flagg and Tinman keep me chainsaw educated and Buckin has me filing like a beast. My saws are very happy 🙂.
Keep on trucking friend, gotta love it❤🌲🪵🔥
Hey buddy thanks for your support!!
Morning Tinman ! Having built 3 of these myself i am hoping you stick with the 272 piston and look to correct the undesirable traits .
I will be going back into mine and finishing the job i started now that i have experienced the builds in a few different number sets . Ie. Intake duration correction and compression /pop up reduction
My thought is that single ring pistons will have more piston swing in cylinder sleeve which I believe will cause wear at bottom of the piston sooner.
Maybe a timing advance but switching the top end will certainly give you more answers
Hey Tinman, trial and error that's how I learn 😊. Hope you're all well. 👍
Does it have a oem ignition
Yes
Hey Tinman , let us know about the issue. I don’t think its gone with the new Topend.
Mine runs at 80 on the Intake with 220psi compression . I would go back to 76- maybe 78 but not higher and run 120 on the Trans.
99 on Ex, but not higher than stock exaust. Tuned at 14000rpm it has decent Power with 044 Pistonbolt. Cant wait to see the solve of this Problem. Try bpmr8y Plug . Its colder for high compression builts.
What your describing sounds like a electrical issue , I would try changing the magneto , or maybe it’s out of adjustment . 👍🇨🇦
I swapped the ignition already, but it didn't work.
@@tinmanssaws yah I made my comment early , it’s always a mystery when it comes to engines . 👍🇨🇦
I think the exhaust port is too wide for this piston, it draws gas into the crankcase.
The problem appeared when the piston gained play during break-in.
the wear at the bottom of the skirt highlights this problem.
I think it will run good with the 372 piston.
I Hope you will excuse my Bad english...
Thank you very much for this experience!
Tinman, is that the saw you built with the 268 piston and made a thick base gasket for it to work ?
You will figure it out
Can you recommend a kit for porting burrs? I sent an email a few weeks ago but I'm sure you're busy, or maybe i messed up the address or something. Thanks
Was the coil going bad or is the screen in the carb or fuel filter plugging up?
Your transfers arnt totally open. Youd have marks from the ring below the transfer port. Ive found that big bores equal big junk. Stock bore seems to be the beat way to go. Its also been proven on the dyno that big bores actually lose power. Modify that 372 piston to have windows like the 272 youll lose the weight you wanna lose.
Why the notches on cylinder cooling fins?
Give it to me
So when we going fishin
I never cared forthe 272 piston combo. It stared good, needs a windowless piston my theory
How's the Tinman and family?
If you go back and read my email I sent you about the problem months ago you'll figure it out.....hint it has to do with the coil I have about 6 of them same coils for 372
Hey Kevin I mentioned in the video I've already swapped the ignition..
@tinmanssaws I'm going to send you another email what I believe is going on try it before you go to deep
Intake at 80 shouldn't be too bad. If you rework that jug with epoxy and it works I would be shocked. One of my MS360s runs ok with a crazy 83 intake timing. It was very hard to tune. Next time you're explaining intake timing can you cover effects of too much timing and if some saws can get away with bad timing more than others. I wonder if the MS360 is more forgiving and why.