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Author Topic: cb500 vs CB750 frame  (Read 5955 times)

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Offline oldhondarider

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cb500 vs CB750 frame
« on: November 04, 2008, 08:43:30 AM »
Don't know the answer... i've looked...but can't find it...   Is there any fundamental differences between the 70's cb750 and 70's cb500 frame?- Specifically... could a 500 engine fit into a 750 with the existing hole pattern, etc...  I'm thinking the engine is smaller ( with more room at the head and front to back.... but I'm not sure about the hole pattern....

any help would be appreciated... 

MANY THANKS O' WISE ONES!
« Last Edit: November 04, 2008, 08:46:31 AM by oldhondarider »
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Offline TwoTired

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Re: cb500 vs CB750 frame
« Reply #1 on: November 04, 2008, 09:19:41 AM »
750 Engine is bigger than the 500, has different mount points.  There is room, though.  But, expect to make brackets for the adaptation.

Cheers,
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Offline Geeto67

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Re: cb500 vs CB750 frame
« Reply #2 on: November 04, 2008, 11:07:10 AM »
There isn't room for a 750 engine in a 550 frame, the motor is too tall. There is also not enough front to back room in the cradle.

I am shocked you didn't find this in your search as it is one of the more commonly asked questions here.

While not internally the same the 500,550, and 650 will all bolt into each other's frames. these are your only bolt in options. Personally I have always wanted to build a cb500 with a slightly modded650 motor in it

for the record the 350F and the 400 four engines are interchangible in the frames as well, and while I completely understand why you would put a 400 in a a 350F frame (extra cc's, 6th gear) I don't know why anybody would put a 350 F engine into anything other than a trashcan.
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Offline oldhondarider

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Re: cb500 vs CB750 frame
« Reply #3 on: November 04, 2008, 12:01:08 PM »
Quote from: Geeto67 on November 04, 2008, 11:07:10 AM
There isn't room for a 750 engine in a 550 frame, the motor is too tall. There is also not enough front to back room in the cradle.

I am shocked you didn't find this in your search as it is one of the more commonly asked questions here.

While not internally the same the 500,550, and 650 will all bolt into each other's frames. these are your only bolt in options. Personally I have always wanted to build a cb500 with a slightly modded650 motor in it

for the record the 350F and the 400 four engines are interchangible in the frames as well, and while I completely understand why you would put a 400 in a a 350F frame (extra cc's, 6th gear) I don't know why anybody would put a 350 F engine into anything other than a trashcan.



Thank you.....  the question was..... "could a 500 engine fit into a 750...."
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Welsh Customs, Tacoma Washington

Offline oldhondarider

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Re: cb500 vs CB750 frame
« Reply #4 on: November 04, 2008, 12:02:24 PM »
Quote from: TwoTired on November 04, 2008, 09:19:41 AM
750 Engine is bigger than the 500, has different mount points.  There is room, though.  But, expect to make brackets for the adaptation.

Cheers,

Thanks TT...  much appreciated.
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Offline cafe750

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Re: cb500 vs CB750 frame
« Reply #5 on: November 04, 2008, 12:31:02 PM »
Beyond the basic size, the construction of the frame is different.
The 550 has stamped pieces forming the backbone, where the 750 has a gusseted tube frame...there are other differences as well.... ;)
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Offline Geeto67

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Re: cb500 vs CB750 frame
« Reply #6 on: November 04, 2008, 01:15:09 PM »
sorry, mis-read it...Well one thing I can tell you about the 750 frame tubes is that the down tubes are in a different location from 550 down tubes and can possibly block the exhaust outlet on the head.

I have a new question, why on earth would you want to put a 500 engine (that is just about 10 hp less) in a bike that weighs a lot more?
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Offline oldhondarider

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Re: cb500 vs CB750 frame
« Reply #7 on: November 04, 2008, 01:20:49 PM »
Quote from: Geeto67 on November 04, 2008, 01:15:09 PM
sorry, mis-read it...Well one thing I can tell you about the 750 frame tubes is that the down tubes are in a different location from 550 down tubes and can possibly block the exhaust outlet on the head.

I have a new question, why on earth would you want to put a 500 engine (that is just about 10 hp less) in a bike that weighs a lot more?



Good question...  Well...I have an "extra" 500 motor...and I was looking at a guy who has a 750 frame for sale....  thought I could do some misc bracketing..squeezin...and make it work....  I'm having a little difficulty finding a titled frame around here...without somebody asking for it's weight in gold....
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Offline cafe750

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Re: cb500 vs CB750 frame
« Reply #8 on: November 04, 2008, 01:37:34 PM »
I've got a spare titled 550 frame...... ;)
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Offline mlinder

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Re: cb500 vs CB750 frame
« Reply #9 on: November 04, 2008, 01:50:46 PM »
Quote from: Geeto67 on November 04, 2008, 01:15:09 PM
sorry, mis-read it...Well one thing I can tell you about the 750 frame tubes is that the down tubes are in a different location from 550 down tubes and can possibly block the exhaust outlet on the head.

I have a new question, why on earth would you want to put a 500 engine (that is just about 10 hp less) in a bike that weighs a lot more?


Closer to 15 or more on a well tuned 750.
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Offline oldhondarider

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Re: cb500 vs CB750 frame
« Reply #10 on: November 04, 2008, 02:41:22 PM »
Quote from: cafe750 on November 04, 2008, 01:37:34 PM
I've got a spare titled 550 frame...... ;)

how much..how much...how much?  ;D ;D
« Last Edit: November 04, 2008, 02:45:26 PM by oldhondarider »
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"I have never seen a wild thing feel sorry for itself. A little bird will fall dead, frozen from a bough, without ever having felt sorry for itself."   D. H. Lawrence

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Offline Johnnie

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Re: cb500 vs CB750 frame
« Reply #11 on: November 13, 2012, 05:20:56 AM »
Quote from: Geeto67 on November 04, 2008, 01:15:09 PM
sorry, mis-read it...Well one thing I can tell you about the 750 frame tubes is that the down tubes are in a different location from 550 down tubes and can possibly block the exhaust outlet on the head.

I have a new question, why on earth would you want to put a 500 engine (that is just about 10 hp less) in a bike that weighs a lot more?


Thanks for the info that's my next build as I have a cb500 frame and cb650 motor!!
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Offline Johnnie

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Re: cb500 vs CB750 frame
« Reply #12 on: November 13, 2012, 05:23:29 AM »
Quote from: Geeto67 on November 04, 2008, 11:07:10 AM
There isn't room for a 750 engine in a 550 frame, the motor is too tall. There is also not enough front to back room in the cradle.

I am shocked you didn't find this in your search as it is one of the more commonly asked questions here.

While not internally the same the 500,550, and 650 will all bolt into each other's frames. these are your only bolt in options. Personally I have always wanted to build a cb500 with a slightly modded650 motor in it

for the record the 350F and the 400 four engines are interchangible in the frames as well, and while I completely understand why you would put a 400 in a a 350F frame (extra cc's, 6th gear) I don't know why anybody would put a 350 F engine into anything other than a trashcan.


Thanks!!
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