Author Topic: 69.75mm Pistons :)  (Read 3842 times)

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Offline imabass

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69.75mm Pistons :)
« on: June 13, 2010, 12:23:58 PM »
I acquired some 69.75 mm pistions and forged alum rods.  I need rings, and gasket to complete the set.  I also got the jugs already bored w/ big sleeves.  Anyone know the make of the pistons?  I have ID the rods as the cheapo ebay rods for less than $200.

That other piston that is in the pics is a new +1mm piston.



Offline Steel Dragon Performance

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Re: 69.75mm Pistons :)
« Reply #1 on: June 13, 2010, 08:57:27 PM »
They look like mtc's . I have mtc's that look like them, except you have two more rings on the bottom of the skirt.

Offline 754

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Re: 69.75mm Pistons :)
« Reply #2 on: June 13, 2010, 09:01:34 PM »
I have ones like that , that i am pretty sure are MTC

 Have those been run? ..if so they may be on the loose side..
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Offline the technological J

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Re: 69.75mm Pistons :)
« Reply #3 on: June 13, 2010, 09:24:41 PM »
cycle x has some great stuff if you explore around i think i saw some over sized stuff there
70 KO...sold to fund the ST http://forums.sohc4.net/index.php?topic=88800.0(Alpha)
74 Kaw 250 Enduro http://forums.sohc4.net/index.php?topic=124278.0
K4 added to collection! http://forums.sohc4.net/index.php?topic=104784.0
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Offline BLUE71TURBO

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Re: 69.75mm Pistons :)
« Reply #4 on: June 13, 2010, 09:37:12 PM »
  I have a new set of MTC's 67mm with sleeve's. On the inside under the dome is is cast MTC and ALCOLA . Also on the top of the pistons the surface is polished smooth not rough cast like those other pistons.  I have never seen any MTC pistons with rough surfaces.

                   
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Offline BLUE71TURBO

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Re: 69.75mm Pistons :)
« Reply #5 on: June 13, 2010, 09:43:00 PM »
  Whatta ya think BIG JAY ?   ???   ;D
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Offline the technological J

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Re: 69.75mm Pistons :)
« Reply #6 on: June 13, 2010, 09:45:47 PM »
  Whatta ya think BIG JAY ?   ???   ;D
am i the jay your referencing? they look freaking sweet... you taking bids?
70 KO...sold to fund the ST http://forums.sohc4.net/index.php?topic=88800.0(Alpha)
74 Kaw 250 Enduro http://forums.sohc4.net/index.php?topic=124278.0
K4 added to collection! http://forums.sohc4.net/index.php?topic=104784.0
78 750K... http://forums.sohc4.net/index.php?topic=60257.0 (Omega)sold to fund the K4
94 ST1100..Gone
72 750 K2 Stay tuned!

Offline imabass

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Re: 69.75mm Pistons :)
« Reply #7 on: June 13, 2010, 09:49:52 PM »
They are new. 

Not taking bids but I am trying to figure out ball park the value.  I am doing some trading for a new frame.  I dont personally want to run them because I dont want the expense of all the other upgrades that are necessary.

Offline BLUE71TURBO

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Re: 69.75mm Pistons :)
« Reply #8 on: June 13, 2010, 09:51:41 PM »
 I was refering to THE BIG JAY at A.P.E.   in regards to this subject of who manufactured those rough topped pistons.  ;D
Remember; Before you can be old and wise, you must first be young and stupid !

Offline the technological J

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Re: 69.75mm Pistons :)
« Reply #9 on: June 13, 2010, 09:53:18 PM »
so not taking bids?
70 KO...sold to fund the ST http://forums.sohc4.net/index.php?topic=88800.0(Alpha)
74 Kaw 250 Enduro http://forums.sohc4.net/index.php?topic=124278.0
K4 added to collection! http://forums.sohc4.net/index.php?topic=104784.0
78 750K... http://forums.sohc4.net/index.php?topic=60257.0 (Omega)sold to fund the K4
94 ST1100..Gone
72 750 K2 Stay tuned!

Offline BLUE71TURBO

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Re: 69.75mm Pistons :)
« Reply #10 on: June 13, 2010, 09:55:11 PM »
 IMABASS , I think THEGABRIELJ  was asking me if i was taking bids on my new set of pistons and cylinders.  ;D

 As of this time i'm not selling my set of 67mm pistons.  Maybe in the future as i'm gathering parts for a kz bigblock turbo engine i'm gonna build.   ;D
« Last Edit: June 13, 2010, 09:58:27 PM by BLUE71TURBO »
Remember; Before you can be old and wise, you must first be young and stupid !

Offline 754

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Re: 69.75mm Pistons :)
« Reply #11 on: June 13, 2010, 10:08:05 PM »
Tops look buffed or wire-wheeled..

 Measurement to me indicates they may be worn..
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline imabass

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Re: 69.75mm Pistons :)
« Reply #12 on: June 14, 2010, 08:53:32 AM »
These things are brand new. Never installed.  I think that makes it a 970cc.

At 1000cc, doesnt that require welding the fins up? 

Offline 754

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Re: 69.75mm Pistons :)
« Reply #13 on: June 14, 2010, 08:59:14 AM »
 970 and 1000 should be same sleeves. Bigger than that you will have to weld.
 If you need rings, you need fairly accurate groove measurements.
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline Big Jay

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Re: 69.75mm Pistons :)
« Reply #14 on: June 14, 2010, 08:45:48 PM »

The skirts look like MTC, but not the domes. They never had a cast piston.  Does it say anything inside?

The ring groovers look wide. Good luck finding rings.

The rods were made offshore and imported by MC Supply in L.A. We sold hundreds of them. Funky rod bolts. After tightening the nuts, you had to bend the steel tab down to keep it locked.

Offline BLUE71TURBO

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Re: 69.75mm Pistons :)
« Reply #15 on: June 14, 2010, 09:10:02 PM »
 Jay, are those chinese aluminum rods any good for a street engine or should someone stick with a reworked stock cb750 rod
  that's on a budget ?   ???
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Offline imabass

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Re: 69.75mm Pistons :)
« Reply #16 on: June 14, 2010, 09:20:41 PM »

The skirts look like MTC, but not the domes. They never had a cast piston.  Does it say anything inside?

The ring groovers look wide. Good luck finding rings.


The ring grooves were the same width as the +1mm pistons that I have.

As for ID inside the pistons, I don't recall.  I don't have them in my possession right now.  In process of working trade.

Offline scottly

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Re: 69.75mm Pistons :)
« Reply #17 on: June 14, 2010, 10:58:22 PM »
These things are brand new. Never installed. 
Never installed? What are the vertical scuff marks?
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Offline scottly

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Re: 69.75mm Pistons :)
« Reply #18 on: June 14, 2010, 11:02:42 PM »
Tops look buffed or wire-wheeled..
1+
Don't fix it if it ain't broke!
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Offline junkyardjon

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Re: 69.75mm Pistons :)
« Reply #19 on: June 15, 2010, 03:48:07 AM »
i bet i know who your trading with LOL

Offline Big Jay

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Re: 69.75mm Pistons :)
« Reply #20 on: June 15, 2010, 02:22:31 PM »
Jay, are those chinese aluminum rods any good for a street engine or should someone stick with a reworked stock cb750 rod
  that's on a budget ?   ???

I think the MC rods were Japanese. They were done almost 30 years ago, and China was not yet in the picture.  Anything would be better than "reworked stock rods"

Offline buttcan

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Re: 69.75mm Pistons :)
« Reply #21 on: June 16, 2010, 09:35:17 PM »
Hey Bass, Whadda ya think about those rods ? You had anyone look at them closely ? I'd be interested in what an engine builder would say after looking at them closely.

Jay you have any more thoughts on the rods ? I've kept away from them due to the recent Chineese parts boom and low quality thing. If these are old Japanees parts I'd thing the quality would be superior.

I did some digging and evidently the rods are old stock that have been in a warehouse since the 70's. Made in Japan by the now defunct MC company.

Sorry for hijackin the thread Bass.
« Last Edit: June 17, 2010, 06:47:21 AM by buttcan »
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Offline imabass

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Re: 69.75mm Pistons :)
« Reply #22 on: June 17, 2010, 04:20:47 PM »
Someone has looked at them and was impressed with them.  We compared them to a set of golden rods.  If i had the choice i would go with the golden rods but I would not be afraid to run the rods in a engine.  Lets face it... they gotta be better than stock but likely not as good as golden rods. 

Offline buttcan

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Re: 69.75mm Pistons :)
« Reply #23 on: June 17, 2010, 09:26:44 PM »
If you decide to sell em holler at me. I'm interested.
Inevitability: The realization that no matter how hard you try you'll never be as cool as a bull riding monkey...