Author Topic: 1977 CB750F "El Moto"  (Read 18846 times)

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Offline Roland

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Re: 1977 CB750F "El Moto"
« Reply #75 on: June 23, 2014, 05:02:38 PM »
Damn, it has been a long time since I updated this.  Summer hits and I am so busy I cant get anything done!  I have been breaking in the motor and working out all the kinks.  I think I am pretty close though.  I just started playing around with new exhaust.  Here are a few pictures...




Offline Roland

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Re: 1977 CB750F "El Moto"
« Reply #76 on: June 23, 2014, 05:16:00 PM »
Frank (754) build some sweet adapters so us F guys could run Pingel fuel valves.  Here are a few pics of the adapter and new Pingel.  Works perfect and looks real clean!




Offline Freaky1

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Re: 1977 CB750F "El Moto"
« Reply #77 on: June 23, 2014, 10:09:28 PM »
Very nice! I dig the engine color accents, gives it some nice pop. Nice to see a few more F bikes here in Colorado.
That which does not kill you leaves cool scabs which turn into awesome scars.

'77 CB750F Come on...were almost there!

Offline SOHC4 Cafe Racer Fan

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Re: 1977 CB750F "El Moto"
« Reply #78 on: June 23, 2014, 11:52:32 PM »
The powdercoated motor, the Mikuni RS34s and the custom-convertible cowl seat are BAD-A$$! 

How's the tuning on the RS34s?  I've head some criticism that the spring on the RS34 is so tense that it is almost an on/off, making it difficult to roll on the throttle.  What has your experience been?  I'm very curious as I am still on the fence about choosing between RS34s and CR29 for my next 750 build.
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 Roland

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Re: 1977 CB750F "El Moto"
« Reply #79 on: June 24, 2014, 01:20:57 PM »
Thanks for the complements!  I have had some issues with the new set up but mostly because of the way I originally routed the fuel line.  I was getting an air lock in the fuel line that was making my bike run lean.  Now that I got that sorted out its much better.  I live at 6000' so I have been playing a lot with my jetting to get it dialed in.  The spring is stiff but I have no issues with it, I put an Venhill throttle assembly with the short pull cam on it so throttle control is a must but it isn't just on or off.  I did notice when my jetting was off it made my bike feel like the throttle was an on/off switch.  Now that I have the jetting closer it is very smooth and consistent.  My biggest gripe with the RS34's is the lack of float bowl drain screw (I don't think the CR's have one either).  It really sucks to not be able to drain the bowls without getting gas everywhere.

The powdercoated motor, the Mikuni RS34s and the custom-convertible cowl seat are BAD-A$$! 

How's the tuning on the RS34s?  I've head some criticism that the spring on the RS34 is so tense that it is almost an on/off, making it difficult to roll on the throttle.  What has your experience been?  I'm very curious as I am still on the fence about choosing between RS34s and CR29 for my next 750 build.

Offline Stev-o

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Re: 1977 CB750F "El Moto"
« Reply #80 on: June 26, 2014, 07:43:36 PM »
Bike looks fantastic!   What muffler is that?  Like the sound??
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline SOHC4 Cafe Racer Fan

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Re: 1977 CB750F "El Moto"
« Reply #81 on: June 26, 2014, 08:58:50 PM »
Nice Leo Vince can. What type of header are you using?
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 Roland

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Re: 1977 CB750F "El Moto"
« Reply #82 on: June 28, 2014, 06:39:09 AM »
Nice Leo Vince can. What type of header are you using?

The header is the sidewinder from Cycle X.  This is his new one made specifically for the SOHC.  The old version of this was designed for the DOHC Honda's and didn't fit quite as well.  It was about 1/2" lower and stuck out about a 1/2" more from the frame on the right side.  I would always drag it in right handers.  This one tucks in just enough so it doesn't drag as easily.  The Leo Vince sounds great, nice deep growl.  I did have to re-jet for it though, it creates some back pressure so I instantly fouled my plugs.

Offline Roland

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Re: 1977 CB750F "El Moto"
« Reply #83 on: October 04, 2014, 08:32:37 AM »
The bike is fully broken in now and that motor really screams!  While on a Colorado 500 mile loop this summer I was riding with my buddy on a Aprilia Tuono.  I could stay right on him up to about 95 then he would start pulling away. 





While in Estes Park we had to get wood to our campsite...2 miles up a dirt road.





Offline SOHC4 Cafe Racer Fan

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Re: 1977 CB750F "El Moto"
« Reply #84 on: October 04, 2014, 10:50:08 AM »
The bike is fully broken in now and that motor really screams!  While on a Colorado 500 mile loop this summer I was riding with my buddy on a Aprilia Tuono.  I could stay right on him up to about 95 then he would start pulling away. 





While in Estes Park we had to get wood to our campsite...2 miles up a dirt road.






Way to get out there on it, Roland.
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 Roland

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Re: 1977 CB750F "El Moto"
« Reply #85 on: September 12, 2015, 07:54:18 AM »
Here are some pics of this years 2015 CO500 weekend trip we did.  Spending the night in Redstone, CO.









« Last Edit: September 12, 2015, 07:56:35 AM by Roland »

Offline Roland

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Re: 1977 CB750F "El Moto"
« Reply #86 on: September 12, 2015, 08:23:40 AM »
It was a great ride but somewhere along the way I possibly pushed it a little hard as by the time I got home I was losing a lot of oil through my head gasket.  I pulled the motor apart to find that I had pulled the threads on 3 cylinder studs and warped my head pretty bad.  The 3 that pulled were 3 of the 4 problem studs that you find with 77-78 F motors.  The ones that are exposed through the cooling fins on the motor.  When I originally built the motor those 4 were rusted in and a real bear to remove.  I guess I should have know this would happen...  I Time Serted all 4 now so I should be good.  Just picked up my head from the machinist so now it is time to re-assemble!



Head is assembled




Offline Roland

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Re: 1977 CB750F "El Moto"
« Reply #87 on: November 26, 2015, 08:13:26 AM »
I got the motor back in and have been trying to get it broken in before the snow flies.  One thing I have never messed with much was the wire harness...until now.  Couple of weeks ago I decided to design and build a new wire harness and get rid of the plastic controls on the handlebars.  I replaced all the controls with just 1 control on the left side.  I built a completely new harness, upgraded to a Motogadget M-Switch 3 button, and used the Motogadget M-Relay+ to control the signals.  I really like how clean the new setup is and the M-Relay+ is really trick.

Before:




Before and after of the wire harness:


After:





Also switched to a Shorai battery so my battery box now has a ton of extra room in it.  You can see how small the M-Relay+ is, it's above the fuse block.


This is the wire diagram that I designed and used:


Maybe someday I'll stop modifying this bike, I keep playing with the idea of an custom oil tank.  That might happen this winter...
« Last Edit: November 26, 2015, 10:57:03 AM by Roland »

Offline SOHC4 Cafe Racer Fan

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Re: 1977 CB750F "El Moto"
« Reply #88 on: November 26, 2015, 11:32:07 AM »
Pretty slick wiring.  Nice work.
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 calj737

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Re: 1977 CB750F "El Moto"
« Reply #89 on: November 26, 2015, 04:46:21 PM »
Interesting approach to use M-Relay. Why not the M-Unit and ditch the relay? I don't see a horn circuit in your diagram? Curious what functions you have wired into your M-Switch?
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline Roland

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Re: 1977 CB750F "El Moto"
« Reply #90 on: November 27, 2015, 07:22:31 AM »
Interesting approach to use M-Relay. Why not the M-Unit and ditch the relay? I don't see a horn circuit in your diagram? Curious what functions you have wired into your M-Switch?

I looked at the M-Unit but didn't really need all the extra functions that it had, all I was looking to do was clean up my handlebars by eliminating the bulky plastic switches that I had.  I was able to buy the relay, switch, and all the materials for the new wire harness for the same cost as the M-Unit.  My M-Switch has 3 buttons, left signal, right signal, starter.  No horn, headlight is always on.  I am using the led headlight bulb that Cognito sells, it is super bright and I have it wired so the high beam is always on.  I pointed the headlight so it isn't blinding people but it really lights the road up nicely.
« Last Edit: November 27, 2015, 02:06:59 PM by Roland »

Offline SOHC4 Cafe Racer Fan

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Re: 1977 CB750F "El Moto"
« Reply #91 on: November 27, 2015, 10:07:03 AM »
Roland,

Are you using the Truck-lite headlight (housing and "bulb") or just a LED plug in bulb?
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 Roland

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Re: 1977 CB750F "El Moto"
« Reply #92 on: November 27, 2015, 02:06:05 PM »
Roland,

Are you using the Truck-lite headlight (housing and "bulb") or just a LED plug in bulb?

It is just the plug in bulb from Cognito Moto. 

http://cognitomoto.com/collections/lighting/products/h7-led