Author Topic: What do you see in this photo?  (Read 1281 times)

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Offline 3000 FPS

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Re: What do you see in this photo?
« Reply #10 on: January 08, 2019, 11:14:31 pm »
Nice trick someone made there.
PP 505, 475, 445.

Offline trappermike

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Re: What do you see in this photo?
« Reply #11 on: January 09, 2019, 08:20:32 am »
I 100% designed it,an excellent machinist friend did all the machining,I built 2 of them.
Experience builds real horsepower...
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Offline Cut4fun .

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Re: What do you see in this photo?
« Reply #12 on: January 09, 2019, 08:34:33 am »
Found the one MVP did for a partner 5000 3ci. I ended up trading it to a guy in IN.  He put it in one.





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Offline trappermike

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Re: What do you see in this photo?
« Reply #13 on: January 09, 2019, 08:51:07 am »
I see it has no counterbalance holes(Like modern Japanese cranks) on the crankpin side,so I'm assuming it is balanced with heavy metal on the opposite side,such as full circle McCulloch cranks were made.
I used the modern Japanese method,but it took some real trickery to make the whole thing lighter than stock. I have another photo from the side but I think it's too blurry to see any detail,such as the stuffed counterbalance holes on each side of the big-end rod pin.

In the end both style cranks create much higher vacuum and pressure in the crankcase which really increases power. I conducted a bunch of test on hotsaw engines,charting pressure and vacuum in running engines from idle to WOT,the full circle crank motor had much higher readings.I still have the test charts,quite interesting.
Experience builds real horsepower...
When the hammer drops the BS stops:Loggers sports competition!
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Offline trappermike

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Re: What do you see in this photo?
« Reply #14 on: January 09, 2019, 08:55:58 am »
I see your crank doesn't have any holes that need stuffing,,that's good.
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Offline Cut4fun .

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Re: What do you see in this photo?
« Reply #15 on: January 09, 2019, 12:16:38 pm »
Send me pic and I will see what I can do for it.

I am sure you heard of Marcel Vincent back in the day from Canada too.  = MVP

Offline Cut4fun .

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Re: What do you see in this photo?
« Reply #16 on: January 09, 2019, 12:20:35 pm »
Reason never putting the full crank in the little 3ci 49cc. Talking with a  builder, we didnt think the full would be good for cold start racing in the small saw.  Coming up from cold start to hitting wood. Thought it would have been better in a over the wood saw where it was already up to rpm. Being I was cold start racing at the time. Traded it off.

Partner 5000 49cc with MVP 272 alky carb.  Stock crank.


Offline trappermike

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Re: What do you see in this photo?
« Reply #17 on: January 09, 2019, 05:07:30 pm »
That's why I designed these cranks to be light,a stock crank is about 1/3 circle,I figured a full circle could be 2-3 times as heavy,and would take more HP to spin,not to mention getting quick revs on a cold start. I was actually quite surprised when the crank weighed slightly less than stock. I also completely polished the crank counter weights as I'd seen some race bikes done,modified the big and small rod ends for better oiling,the rod is slightly knife-edged too which you can see.
I sent you the side image if you can post it thanks.
I never heard of Marcel,but I really only knew people in my area,I was never a serious competitor on the circuit,I only entered local competitions that weren't too far.
I sold all my hotsaws to a serious competitor in the U.S.A.
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Offline Cut4fun .

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Re: What do you see in this photo?
« Reply #18 on: January 10, 2019, 12:17:23 pm »
Best I could do.  I can make out the holes though.  Both of these pics redone.

You in pic?




Offline trappermike

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Re: What do you see in this photo?
« Reply #19 on: January 10, 2019, 12:25:46 pm »
Thanks for posting it but the photo is illegible,some photos kept on my computer for years seem to turn very dark.Maybe I'll try to find and scan the original photo and send it to you,in it you can see details quite well. Sorry...
Experience builds real horsepower...
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