Author Topic: 650 heads  (Read 2963 times)

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Offline bwaller

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650 heads
« on: March 05, 2017, 12:04:47 PM »
Are there different inlet port spacings between CB650 heads. I know carbs changed but wonder about casting changes?

Thanks

Offline 754

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Re: 650 heads
« Reply #1 on: March 05, 2017, 12:20:41 PM »
Yep, port spacing changed when they went to CV carbs.
 I have an NOS bare head to sell..I think its the later type have to check..
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Offline bwaller

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Re: 650 heads
« Reply #2 on: March 05, 2017, 12:47:34 PM »
If anyone has both model heads I sure would appreciate a picture of both heads together intake ports up.

Not asking much huh?  ;D

Offline Camrector

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Re: 650 heads
« Reply #3 on: March 05, 2017, 01:40:53 PM »


PD50A stock '79cb650 carbs:
Type of carb                  - Mechanical linkage
depth (front to back)       -99.8mm
OD (motor side)              -35.4mm
OD (airbox side)              -45.8mm
#1&2 and 3&4 (c to c)     -76mm
between2&3  (c to c)      -80.9mm


VB44a stock '81 cb650 carbs:
Type of carb                  - CV
depth (front to back)       -122.1mm
OD (motor side)              -39.8mm
OD (airbox side)              -53.8mm
#1&2 and 3&4 (c to c)     -66.3mm
between2&3  (c to c)      -92.7mm



Offline cb650

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Re: 650 heads
« Reply #4 on: March 05, 2017, 05:07:26 PM »
Yes 81 / 2 went with a wider spacing on the head to accommodate the carbs. I was told the DOHC 750 uses the same carb with diff jets.    Some one years ago did some work to find how to make them interchange.  seemed like a lot of work to not get the right carbs
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Offline GV1390

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Re: 650 heads
« Reply #5 on: March 06, 2017, 06:49:17 AM »
If anyone has both model heads I sure would appreciate a picture of both heads together intake ports up.

Not asking much huh?  ;D



You're welcome.

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Offline MRieck

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Re: 650 heads
« Reply #6 on: March 06, 2017, 06:52:50 AM »
That looks familiar ;D
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Offline bwaller

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Re: 650 heads
« Reply #7 on: March 06, 2017, 01:16:19 PM »
Thanks guys, that works.

Offline BLAC

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Re: 650 heads
« Reply #8 on: March 07, 2017, 02:21:08 PM »
That looks familiar ;D

You've been to GV's shop?  jk :P
If you can't fix it with a hammer, it's an electrical problem... If it's an electrical problem, it's Cal's problem.

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Offline SOHC4 Cafe Racer Fan

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Re: 650 heads
« Reply #9 on: March 07, 2017, 04:15:13 PM »
That looks familiar ;D

You've been to GV's shop?  jk :P

Oh!
I think your head is going to take a little longer now! ;)
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Offline BLAC

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Re: 650 heads
« Reply #10 on: March 08, 2017, 08:16:56 AM »
That looks familiar ;D

You've been to GV's shop?  jk :P

Oh!
I think your head is going to take a little longer now! ;)

I KID I KID!!!!  ;D
If you can't fix it with a hammer, it's an electrical problem... If it's an electrical problem, it's Cal's problem.

*2005 Yamaha R6 (sold)
*2014 Ducati Streetfighter 848 (sold)
*2014 BMW S1000RR (sold)
*2010 Ducati Streetfighter S
*1978 CB550 Restomod Build
*1974 CB550 Monoshock build
http://forums.sohc4.net/index.php/topic,154614.0.html

Offline bwaller

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Re: 650 heads
« Reply #11 on: March 08, 2017, 09:28:28 AM »
Someone helped Mike get the pics up for me. You're not in hot water!