Author Topic: CB750 F Word 3  (Read 10679 times)

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Offline seanbarney41

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Re: CB750 F Word 3
« Reply #50 on: March 31, 2014, 05:25:42 PM »
Is the head toast, too or just the camshaft up?  If it's just the camshaft, why replace the entire motor?
I have not been in there yet, and quite possibly will just get rid of the whole bike as is.  This motor was stuck, and had been abused when I got the bike.  I am guessing once I get in there, I am gonna find a whole world of hurt.  Slappin' the k in there, would allow me to ride and enjoy the bike while the f motor gets done up proper as time and small budget allows.
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Offline 70CB750

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Re: CB750 F Word 3
« Reply #51 on: March 31, 2014, 05:44:34 PM »
Oil passage clogged?
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Offline SOHC4 Cafe Racer Fan

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Re: CB750 F Word 3
« Reply #52 on: March 31, 2014, 05:59:06 PM »
Is the head toast, too or just the camshaft up?  If it's just the camshaft, why replace the entire motor?
I have not been in there yet, and quite possibly will just get rid of the whole bike as is.  This motor was stuck, and had been abused when I got the bike.  I am guessing once I get in there, I am gonna find a whole world of hurt.  Slappin' the k in there, would allow me to ride and enjoy the bike while the f motor gets done up proper as time and small budget allows.

Gotcha.  That makes sense.
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)

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

Offline seanbarney41

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Re: CB750 F Word 3
« Reply #53 on: March 31, 2014, 06:05:38 PM »
Oil passage clogged?
that is my guess.  Plenty of oil pressure, main gallery is literally gushing, a look see through the valve caps shows slightly less oil on the rh side of the engine.  I had checked this before starting the bike months ago and oil quantity seemed ok.
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Offline ekpent

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Re: CB750 F Word 3
« Reply #54 on: March 31, 2014, 07:22:37 PM »
Sorry to hear that Sean, you have been tinkering on that for quite awhile. Wonder if some old sludge and rust might have broken up in the engine and possibly plugged up an oil jet ? Bummer.

Offline seanbarney41

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Re: CB750 F Word 3
« Reply #55 on: May 16, 2014, 11:38:14 PM »
Sorry to hear that Sean, you have been tinkering on that for quite awhile. Wonder if some old sludge and rust might have broken up in the engine and possibly plugged up an oil jet ? Bummer.
turns out that is exactly what happenened...and here are the results...




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Offline seanbarney41

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Re: CB750 F Word 3
« Reply #56 on: May 16, 2014, 11:45:25 PM »
so I cleaned out the oil jet, plopped a k6 cam and towers in there, runs a little noisy cus the goddamn f3 valve tips are thrashed...no leaks, no smoke...and it will spank any "k" I have ever ridden...




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Offline mrbreeze

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Re: CB750 F Word 3
« Reply #57 on: May 16, 2014, 11:48:14 PM »
That cam was doing some hopping up in there!! Gonna have to do some major flushing in that engine.
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Offline seanbarney41

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Re: CB750 F Word 3
« Reply #58 on: May 16, 2014, 11:50:25 PM »
...but this #$%* is still fighting...ate up two brand new Daichi condensers within 50 miles of each other(note to self: don't buy that Daichi crap anymore), and now the ignition key switch is on the fritz...
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Offline seanbarney41

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Re: CB750 F Word 3
« Reply #59 on: May 16, 2014, 11:53:55 PM »
That cam was doing some hopping up in there!! Gonna have to do some major flushing in that engine.
yeah it hopped around so much that it dropped two cylinders from the valve clarances going away, and nope, I blasted out what ever oil passages I could get at with compressed air, and have done two oil changes in 800 miles...all looks better and better
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Offline seanbarney41

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Re: CB750 F Word 3
« Reply #60 on: May 17, 2014, 12:01:59 AM »
top secret new exhaust pipe finish... :P

I got this pipe for cheap from Tews a couple years ago, we both thought it was a MAC, wrong, it's a Jardine
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Offline Stev-o

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Re: CB750 F Word 3
« Reply #61 on: May 17, 2014, 05:20:02 AM »
What are ya gonna do with the F bike Sean?   Sold mine and never looked back.
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline seanbarney41

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Re: CB750 F Word 3
« Reply #62 on: May 17, 2014, 07:08:35 AM »
Now that I've had a couple good rides on it, I've kinda fallen in love.  That seat that is on it is super comfortable.  The wide and low Renthal bars give me the leverage to really throw this thing around, and this motor is now relatively oil tight and will put a hurtin' on any stock k bike I have ever ridden, even with the k6 camshaft in there.  Oh, and the brakes are much better than what I am used to!  I am going to ride this until I got my gold cafe bike back together.
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Offline seanbarney41

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Re: CB750 F Word 3
« Reply #63 on: January 21, 2016, 07:53:55 PM »
The saga continues :o...Actually this bike has turned out to be a pretty trusty rider and it's still goin'.  Odo is at 27,000 miles now, and it has developed a healthy thirst for oil...dang valve guides is my guess.  Also, the valve tips are pitted and cupped and noisy, another common F2/3 malady...requires frequent and careful valve adjustment.
DSCN0738 by Sean Barney, on Flickr
added some 900f shocks and the extra length really sharpens up the steering on these
DSCN0791 by Sean Barney, on Flickr
beauty and the beast, with EdwardMorris' K2
DSCN0815 by Sean Barney, on Flickr
I put 2500 miles on this thing between September and end of December...then winter set in.
Here it is in Milwaukee...
DSCN0837 by Sean Barney, on Flickr
If it works good, it looks good...

Offline seanbarney41

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Re: CB750 F Word 3
« Reply #64 on: January 21, 2016, 08:06:43 PM »
Last thing done...new chain and sprockets, converted to 530.  The original 630 parts lasted nearly 38 years and 27,000 miles...
DSCN0943 by Sean Barney, on Flickr
After all the initial grief, this bike has been there for me when all others are not running and will continue to do so while patiently waiting its turn to get done up right.
If it works good, it looks good...

Offline Stev-o

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Re: CB750 F Word 3
« Reply #65 on: January 21, 2016, 08:50:51 PM »
It's good to have at least one good trusty steed.  Looks super clean in that last pic, Sean.
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline MoMo

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Re: CB750 F Word 3
« Reply #66 on: January 21, 2016, 08:53:19 PM »
It's good to have at least one good trusty steed.  Looks super clean in that last pic, Sean.


agree with that, looks real good sb41...Larry

Offline seanbarney41

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Re: CB750 F Word 3
« Reply #67 on: January 21, 2016, 08:56:42 PM »
It's good to have at least one good trusty steed.  Looks super clean in that last pic, Sean.
lol...its not...really needs everything cosmetically, well I guess the wheels are still very nice
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Offline Don R

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Re: CB750 F Word 3
« Reply #68 on: January 22, 2016, 10:30:59 PM »
 Nice bike, glad to see you kept at it. I love the F's, I had a triple disc F1 that I loved.  I needed cash for a sandcast 750 I bought and wanted to keep so I sold it. I don't regret that but do miss the F1.
 Mine seemed so much bigger than any of my K bikes, I guess it was the differences in offset of the triples, I dropped the front a bit but didn't notice much change. The Avon roadriders were wonderful on it too, just a good match for me. I cupped a front tire practicing stopping with the double discs.
 
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Offline seanbarney41

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Re: CB750 F Word 3
« Reply #69 on: January 22, 2016, 10:59:52 PM »
yup, all my cb750 front tires end up cuppped...just too much weight on the front
If it works good, it looks good...