Author Topic: CB750 F Word 3  (Read 10682 times)

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Online seanbarney41

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Re: CB750 F Word 3
« Reply #25 on: January 29, 2014, 06:38:14 PM »
I've never used one like that, Steve-O.   I did bust out the vacuum pump for a while and it didn't seem to help.  It seems like, with your link, unless you got a pretty bulletproof conection to the caliper, that thing could get real messy.  Let me know how it works.
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Offline MoMo

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Re: CB750 F Word 3
« Reply #26 on: January 29, 2014, 06:52:47 PM »
Have you used the strap the brake lever a finger length from the grip trick?  When I have trouble getting the last bit of air out that trick never fails me...LARRY

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Re: CB750 F Word 3
« Reply #27 on: January 29, 2014, 07:21:38 PM »
yea, that's really the only thing that has worked significantly at all
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Offline SOHC Digger

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Re: CB750 F Word 3
« Reply #28 on: January 29, 2014, 08:12:21 PM »
The master on the F has a different piston diameter than the K's.
That's what I figured on the master, but what diameter piston should I be using?

Piston diameter should be 11/16"

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Re: CB750 F Word 3
« Reply #29 on: February 16, 2014, 03:54:01 PM »
Fixed the headlight dimmer switch.  It turned out that the problem was this little metal bracket that holds the switch in and clamps it all together wasn't clamping tightly enough.

So I slightly modified the bend in it so it would clamp everything together tightly, achieving good contact.
Checked with the multi-meter before re-assembling and re-installing.


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Re: CB750 F Word 3
« Reply #30 on: February 16, 2014, 04:07:05 PM »
Cleaned up the lh switch as best I could.  I was just too lazy to paint or polish the faded anodizing.

had to dig up a good hoodlight.  I had two sealed beams laying around in which the low beam was burned out.  Dug up this h4 conversion.  Pretty nice piece that I bought here on the forum a while back.

This one works!

Did some cleaning on the mounting and trim rings.  This stuff all cleaned up pretty nice.


« Last Edit: February 16, 2014, 04:12:26 PM by seanbarney41 »
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Re: CB750 F Word 3
« Reply #31 on: February 16, 2014, 04:26:19 PM »
Started working my way to the back...fiddled the rear brake pedal adjustment just to make sure all was well using the gl1000 rear master.  Everything seems to be working good back here.

Pulled off the crusty rear shocks.  They look like they might clean up ok if I pull 'em apart, and if they do, I might try them on my 550.

 Decided to try these old S&W rear shocks.  Kinda hate the blue though, so eventually, the blue will get painted black.

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Offline Stev-o

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Re: CB750 F Word 3
« Reply #32 on: February 16, 2014, 08:54:39 PM »
Good progress. Agree, shocks would look better black.
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

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Re: CB750 F Word 3
« Reply #33 on: March 27, 2014, 09:30:12 PM »
A lot more struggling, and a little progress...Put some more work into the pd42's.  The choke would not close.  Thought the shaft might be bent, so I swapped the one from from some 41a's I had.

 It didn't help much, but in the process discovered that the throttle slide was sticking above half throttle on carb #4.  Turns out, carb body #4 was warped or bent.  Replaced it with #4 from the 41a's.

Here is my trick little tool for fishing the washer and o-rings out of mixture screw hole.
 Got it all back together and the accelerator pump was no longer working.  Fixed that with the actuator spring from the 41a's.  I am not allowed to tell you how that #$%*ed up spring got in there and it wasn't me who put it there.

Here is the #$%*ed up spring...

and what it is supposed to look like on the 41a's...




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Re: CB750 F Word 3
« Reply #34 on: March 27, 2014, 09:48:29 PM »
So I mount up the pd42's once again...and...absolutely no improvement.  Still only runs on full choke, won't take any throttle, and won't idle below 2500rpm.  The only thing I can figure now is the boots and clamps are shot. 

They are pretty hard but I have never had problems with hard boots on the older style carbs.  Maybe someday I will fork out $90 for the vintage cb750 repros, but for now these "pumper" carbs can suck my dick.  They sure are not any good at sucking air and fuel.  Cleaned up the airbox, even bought oem airbox boots and clamps(anybody want 'em? my originals are fine now that I found them again).

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Re: CB750 F Word 3
« Reply #35 on: March 27, 2014, 09:53:36 PM »
So hosed down the roundtops a little and put them back on.  I figured out a fuel line routing that works decent with the roundtops and f tank.


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Re: CB750 F Word 3
« Reply #36 on: March 27, 2014, 10:02:35 PM »
Crusty back end...

better...

crusty back wheel...

quite a bit better...

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Re: CB750 F Word 3
« Reply #37 on: March 27, 2014, 10:14:11 PM »
decided I better take a peep at the front sprocket and got in a tangle with one of the cover screws...impact driver won


even after getting the cover off the sucker was still stuck in there.  Pulled it out with vice grips and found myself a new old one.


I am probably crazy but I am gonna use this chain and sprockets for at least the first couple rides.  The chain is not as bad as it looks and will be cleaned and lubed.
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Re: CB750 F Word 3
« Reply #38 on: March 27, 2014, 10:23:41 PM »
crusty footpeg bracket...

not much photographic evidence of improvement...ideally they go in the bin anyway and I get rearsets, but not until this thing proves it self worthy of the money and time

dingy sidecovers...

shiny sidecovers...
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Re: CB750 F Word 3
« Reply #39 on: March 27, 2014, 10:27:49 PM »
New tires are here.  Should get them mounted tomorrow.  All I need now is some barely acceptable riding weather...that might be too much to ask
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Offline Stev-o

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Re: CB750 F Word 3
« Reply #40 on: March 28, 2014, 03:49:11 AM »
Good progress on the effen F. What tires you get?
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline ekpent

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Re: CB750 F Word 3
« Reply #41 on: March 28, 2014, 04:44:05 AM »
New tires are here.  Should get them mounted tomorrow.  All I need now is some barely acceptable riding weather...that might be too much to ask
Get em' on by Sunday and Monday. Supposed to maybe hit 60----Whoooo-Heeeeeee

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Re: CB750 F Word 3
« Reply #42 on: March 28, 2014, 05:13:51 AM »
New tires are here.  Should get them mounted tomorrow.  All I need now is some barely acceptable riding weather...that might be too much to ask
Get em' on by Sunday and Monday. Supposed to maybe hit 60----Whoooo-Heeeeeee
...and I don't have to work Monday!----Whoooo-Haaaaaa.  Steve-O, I bought cheap ass Shinko 712's 'cuz I still don't really trust this thing.
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Offline 70CB750

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Re: CB750 F Word 3
« Reply #43 on: March 28, 2014, 05:20:17 AM »
My eFing comstars for K3F have old Dunlops 404 I am going to start with but I got a Shinko for the sidecar wheel.

But this page scares me, I just put on all the brakes, all lines are empty and if it's gonna be a major effort to bleed it I will not be happy camper :(
Prokop
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I love it when parts come together.

Dorothy - my CB750
CB750K3F - The Red
Sidecar


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Re: CB750 F Word 3
« Reply #44 on: March 28, 2014, 05:23:52 AM »
My eFing comstars for K3F have old Dunlops 404 I am going to start with but I got a Shinko for the sidecar wheel.

But this page scares me, I just put on all the brakes, all lines are empty and if it's gonna be a major effort to bleed it I will not be happy camper :(
I am hoping all my brake bleeding troubles are due to the non-original master cylinder, so if you have a good one, it might not be so bad.
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Re: CB750 F Word 3
« Reply #45 on: March 30, 2014, 07:53:53 PM »
...#$%* this thing, mounted brand new rubber friday, took it out for a spin, ran like a beast for about ten minutes, and then it ate it's camshaft. >:( >:( >:( >:( :'(
...I got a line on a 77k motor
...or someone show up at my shop with a love for eff's, an aptitude for engine rebuilding, and some cash :-\
If it works good, it looks good...

Offline SOHC4 Cafe Racer Fan

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Re: CB750 F Word 3
« Reply #46 on: March 30, 2014, 10:38:25 PM »
...#$%* this thing, mounted brand new rubber friday, took it out for a spin, ran like a beast for about ten minutes, and then it ate it's camshaft. >:( >:( >:( >:( :'(
...I got a line on a 77k motor
...or someone show up at my shop with a love for eff's, an aptitude for engine rebuilding, and some cash :-\

That seriously blows.  Sorry to hear about the camshaft fail.
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2008 Triumph Thruxton (http://forums.sohc4.net/index.php/topic,190956.0.html)
2014 MV Agusta Brutale Dragster 800
2015 Yamaha FZ-09 (http://forums.sohc4.net/index.php/topic,186861.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html and https://magazine.cycleworld.com/article/1995/3/1/song-of-the-sausage-creature)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html) - Sold

Offline Stev-o

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Re: CB750 F Word 3
« Reply #47 on: March 31, 2014, 05:37:12 AM »
Effin F's.  Glad I sold mine. 
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline SOHC Digger

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Re: CB750 F Word 3
« Reply #48 on: March 31, 2014, 03:43:32 PM »
Mine ate it's camshaft too. Must be an appetizer for them. I replaced my camshaft and cam towers and it's been good since.
« Last Edit: April 01, 2014, 04:12:51 AM by SOHC Digger »

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Re: CB750 F Word 3
« Reply #49 on: March 31, 2014, 04:08:08 PM »
Is the head toast, too or just the camshaft up?  If it's just the camshaft, why replace the entire motor?
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2008 Triumph Thruxton (http://forums.sohc4.net/index.php/topic,190956.0.html)
2014 MV Agusta Brutale Dragster 800
2015 Yamaha FZ-09 (http://forums.sohc4.net/index.php/topic,186861.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html and https://magazine.cycleworld.com/article/1995/3/1/song-of-the-sausage-creature)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html) - Sold