Author Topic: 67.5 mm =cc??  (Read 5099 times)

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Offline lash

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67.5 mm =cc??
« on: November 24, 2019, 03:37:43 PM »
836 is 65.5 so what would 67.5 be?
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Offline 754

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Re: 67.5 mm =cc??
« Reply #1 on: November 24, 2019, 05:35:58 PM »
836 Is 65mm  I think.  67 .5 is around 890 or 915 ish.  And will require sleeves, and maybe case boring.
Maker of the WELDLESS 750 Frame Kit
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Kelowna B.C.       Canada

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

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

Offline Terry in Australia

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I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline lash

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Re: 67.5 mm =cc??
« Reply #3 on: November 24, 2019, 05:48:50 PM »
I picked up a bunch of engine parts last year and there was a box with cylinders and brand new pistons and rings. Just finally looked at it today and the ring boxes are labelled 67.5. Bore measures the same. Pics tomorrow, maybe somebody  an identify the pistons..
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Offline 754

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Re: 67.5 mm =cc??
« Reply #4 on: November 24, 2019, 05:52:21 PM »
Better tell us if cases are bored, if they are not its step sleeves, probably a Henry Abe kit.
 If sleeve bottoms are same diameter as stock, I will guess Henry Abe with cast pistons.
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 lash

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Re: 67.5 mm =cc??
« Reply #5 on: November 24, 2019, 05:58:56 PM »
I’ll post the pics tomorrow :)
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Offline Terry in Australia

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Re: 67.5 mm =cc??
« Reply #6 on: November 24, 2019, 07:33:30 PM »
I'm betting Henry Abe too. ;D
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline Tracksnblades1

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Re: 67.5 mm =cc??
« Reply #7 on: November 24, 2019, 09:19:42 PM »
836 is 65.5 so what would 67.5 be?

Quicker....?

😎
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Offline PeWe

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Re: 67.5 mm =cc??
« Reply #8 on: November 25, 2019, 12:05:51 AM »
Important to be aware of the reall cc when ordering rings from CycleX to their "915cc" kit that use 67.5mm pistons. It should be called 900cc.

Dynoman sell a real 915cc kit, 68 mm pistons and sleeves that must have case bore.
« Last Edit: November 25, 2019, 12:08:39 AM by PeWe »
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline PeWe

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Re: 67.5 mm =cc??
« Reply #9 on: November 25, 2019, 12:07:05 AM »
836 is 65.5 so what would 67.5 be?
65.5 is 849cc
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline lash

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Re: 67.5 mm =cc??
« Reply #10 on: November 25, 2019, 08:08:32 AM »
Here are the pics.
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Offline PeWe

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Re: 67.5 mm =cc??
« Reply #11 on: November 25, 2019, 10:47:56 AM »
Im sure other guys soon will chime in with exact description of those pistons that look like old design.

You will need better rods if using that kit ;)
Like APEs rods.
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: 67.5 mm =cc??
« Reply #12 on: November 25, 2019, 02:06:06 PM »
What makings are inside the pistons. HAINST is Henry Abe. They made 2 different pistons in their kits.
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline lash

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Re: 67.5 mm =cc??
« Reply #13 on: November 25, 2019, 02:47:00 PM »
Only markings I could find...
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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: 67.5 mm =cc??
« Reply #14 on: November 25, 2019, 03:23:41 PM »
I think that pic eliminates it as a Henry Abe. Possibly a CycleX? Can't say as mine are inside my engine. I do have the ring box at home.
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline 754

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Re: 67.5 mm =cc??
« Reply #15 on: November 25, 2019, 08:22:57 PM »
There is a W on the pin boss, looks like maybe Wiseco..
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 lash

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Re: 67.5 mm =cc??
« Reply #16 on: November 27, 2019, 02:10:33 PM »
Any idea on what this would be worth? I dont really want to get into big power parts, the engine I’m building is going into a bike for my wife..
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Offline Terry in Australia

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Re: 67.5 mm =cc??
« Reply #17 on: November 27, 2019, 05:05:27 PM »
It looks like they've installed bigger sleeves so whoever buys it will have to have their top case machined to accept them, plus heavy duty rods etc. Because of this they won't be of interest to someone looking for a cheap HP gain, when an 836cc kit will give them almost as much grunt without the big increase in cost.

If someone is going the high HP route they might prefer a more modern kit (I could be wrong but the ring lands look like they're set up for 1 piece oil rings, which are not ideal) but for someone not as picky, that is still a good kit, so maybe 200-300 bucks? ;D
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline lash

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Re: 67.5 mm =cc??
« Reply #18 on: November 27, 2019, 05:13:34 PM »
I have the head for this but didnt check it to see if it has been machined. Will do that tomorrow.
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Offline Terry in Australia

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Re: 67.5 mm =cc??
« Reply #19 on: November 27, 2019, 05:17:43 PM »
No worries, take a look at the ports too, if it's been ported nicely, it may be of more interest than the big bore kit. ;D
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline BPellerine

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Re: 67.5 mm =cc??
« Reply #20 on: November 27, 2019, 05:24:33 PM »
xc rings are weisco,and not 1 pc oil rings so modern pistons,put a bigger base gasket on and use as a template and grind away.bill
1978 CB 750K ard and webers
another anfob

Offline lash

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Re: 67.5 mm =cc??
« Reply #21 on: November 27, 2019, 05:56:43 PM »
Not sure what you mean about bigger base gasket and grind away?
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Offline Terry in Australia

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Re: 67.5 mm =cc??
« Reply #22 on: November 27, 2019, 06:54:06 PM »
Not sure what you mean about bigger base gasket and grind away?

The "Blue Ridge Mountain engineer" method of boring each cylinder hole in your top case is to put the oversize base gasket in place, mark the cases tracing the bigger holes, remove the gasket and get stuck into it with a die grinder or dremel tool, File, Bowie Knife,  or whatever cutting instrument you have available, usually conducted while drinking moonshine and wearing Dickies overalls and a straw hat. ;D
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline PeWe

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Re: 67.5 mm =cc??
« Reply #23 on: November 27, 2019, 08:55:43 PM »
Sure case need to be opened up for sleeves? The sleeves look thin as the tapered sleeves look like with 67.5mm bore.
My K6 needed a little Dremel massage while my K2 did not.
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline 754

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Re: 67.5 mm =cc??
« Reply #24 on: November 27, 2019, 09:59:38 PM »
I told him, measure or compare to stock sleeves..
 Or look at holes in the case, stock I believe are unmachined..
 Am I the only one that sees the W ?
 I might be interested in them , I would have stock parts to trade towards.   And I am in Canada.
« Last Edit: November 27, 2019, 10:02:29 PM by 754 »
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