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Author Topic: will a 650 swap in place of a 76 550?  (Read 1194 times)

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Offline Mercuno

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will a 650 swap in place of a 76 550?
« on: September 23, 2011, 11:10:25 PM »
Just wondering? Looking on ebay and around here and I definitely would like more bang for the buck. I see so many head swaps and cam swaps but why all the hassle. why cant we just swap in a 650? &50 would be nice but seems like it isnt even close. I am beating around this bush because I am planning to rebuild something this winter so if your gonna be a monkey be a gorilla lol..... I even wondered if i won the lottery I would pay someone to put a big cbr engine in there with cdi and fuel injection and all that...oh well enough rambling at 1 am.
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Offline cameron

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Re: will a 650 swap in place of a 76 550?
« Reply #1 on: September 24, 2011, 01:34:52 AM »
Ive considered trying to put a modern engine on a CB550. Just for funsies.
That would be interesting.

Still in dream-stage.
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Offline Hush

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Re: will a 650 swap in place of a 76 550?
« Reply #2 on: September 24, 2011, 01:45:50 AM »
Mounting points would be all wrong and swing arm in wrong place, motor probably too high to fit under the top of frame.
Better to maybe get a rolling 650 frame and stick all the 550 bits on it, no that would be wrong too......basically any engine can be shoe horned into any frame, the balance is making it structurally sound and safe to ride.
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Offline classic bike tuner

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Re: will a 650 swap in place of a 76 550?
« Reply #3 on: September 24, 2011, 02:42:23 AM »
it will swap in place only small propblem is the wiring of the alternator and ignition
and the 650 alternator is not as reliable as the 550 one 
and maybe the 550 exhaust wont fit and the 550 carbs
oil pan of a 650 is higher use the 550 one
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Offline Gordon

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Re: will a 650 swap in place of a 76 550?
« Reply #4 on: September 24, 2011, 09:25:24 AM »
Probably end up being less trouble doing some top end work to the 550 engine and boring for bigger pistons.  Plus you'll keep the kick-start that the 650 doesn't have. 
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Offline Jon

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Re: will a 650 swap in place of a 76 550?
« Reply #5 on: September 24, 2011, 01:40:37 PM »
The cb650 SOHC motor will bolt straight in.

Yow will need to swap the ignition & charge circuits from the 650 over.

You will need to use the 650 exhaust or a kmac 650 exhaust.

Airbox will need to be made as they are a fair bit different.
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Offline babyfood1217

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Re: will a 650 swap in place of a 76 550?
« Reply #6 on: September 24, 2011, 02:59:06 PM »
Quote from: cameron on September 24, 2011, 01:34:52 AM
Ive considered trying to put a modern engine on a CB550. Just for funsies.
That would be interesting.

Still in dream-stage.

Check this out http://forums.sohc4.net/index.php?topic=87305.0.  I like it.  A bit different, but inteeresting.  It seems to have gone stagnant for a little while, but I'm gonna assume he's just up to his neck wrenching and fabbing it all together...



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Offline Scott S

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Re: will a 650 swap in place of a 76 550?
« Reply #7 on: September 25, 2011, 05:32:06 AM »
Quote from: Jon on September 24, 2011, 01:40:37 PM
The cb650 SOHC motor will bolt straight in.

Yow will need to swap the ignition & charge circuits from the 650 over.


 What do you mean by this? Aren't the stator/rotor/alternator and the starter all part of the engine? Or, are you referring to starter solenoid, fuse panel, regulator/rectifier, etc.?
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Offline Mercuno

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Re: will a 650 swap in place of a 76 550?
« Reply #8 on: October 05, 2011, 03:20:53 PM »
+1  Wiring is no problem to do. Are you speaking of the components involved with the wiring?  I have found a good 650 engine but would like to pin this theory down before I go and buy it.

So, given it will swap right in..( I could even massage some new brackets to the frame with my welding expertise ;)  )

I need to make sure the angle of the chain will still be copacetic with the frame and rear sprocket.

I need to cross / swap some wires to the reg/rec.   -----   solenoid?

What about carbs. I have kehein carbs on there now  due for a rebuilt or replace for what?(I sure would like that single carb kit that works for 750's)

Im surprised this has not ever been done before?

thanks for the replies
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Offline Mercuno

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Re: will a 650 swap in place of a 76 550?
« Reply #9 on: October 05, 2011, 03:23:52 PM »
saw in another post that only the first two years of 650 have same style carbs...good to know.

I can modify the exhaust I have to get the right geometry pretty easily and have the correct diameter to fit the head.
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