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Author Topic: 1979 CB750 DOHC Monoshock Build  (Read 76963 times)

Offline bananas

  • Posts: 159
1979 CB750 DOHC Monoshock Build
« on: Dec 19, 2013, 08:25:23 »
Hello DTT! Long time lurker on the forums. You guys have been a huge inspiration for starting a build.

I've been meaning to post a build thread for my 1979 Honda CB 750 Limited. Picked her up two years ago for $200. She was abandoned outside of a building downtown and sat for 4 years.

My original intention was to convert her into a very clean Cafe Racer but during the course of the build it has progressed into more of a cafe-inspired muscle bike. Much of the build is designed to focus its visuality around the prominent air cooled Inline 4. In the handling department, she'll receive a ton of weight reduction, a bit of frame strengthening, modern forks, swingarm, brakes, wheels and a custom rear monoshock suspension. Next I'd like to do race carbs, a front-mount oil cooler setup and custom GP exhaust system.

A full build write-up will be posted here as she gets nearer to completion. Don't want to spoil the suspense :)

I'll include a list of parts/modifications for reference (and for my own inventory). This will be updated as the thread goes along. The list includes both installed and acquired parts.

Performance

-Freshly Rebuilt Motor
-K&N RC-0790 Air Filters
-K&N Vent Filters
-Honda RSC (Racing Service Center) Carb Modification (Coming next)
-1992 Honda CBR 600 F2 Coils
-NGK Sparkplugs
-Moto Guzzi V11 Sport 9-Row Oil Cooler
-Custom 16T Off-set Front Sprocket/ Driven 42T 530 Power-Up Sprocket Conversion
-4-1 2.5" Exhaust System (Temporary Setup)
-2" DEI Exhaust Wrap, Graphite-Black
-Shorai LFX14L5-BS12

Suspension/Handling
-2001 GSXR 600 Front Forks, Racetech Springs and Emulators
-2001 GSXR 600 Triples with 1979 CB750 Stem
-2004 GSXR 750 Front Wheel/ Rotors
-2001 GSXR 750 Stabilizer, Pro-Tek Fork Mount, Custom Frame Mount, Fork Oil Mod
-2001 GSXR 750 Front Calipers/ Master Cylinder
-2001 GSXR 750 Swingarm, Custom Strengthening, Custom Shock Mount
-2006 Ducati SuperSport 800 Rear Shock, Heavy-duty Spring, Custom Mounting
-2004 GSXR 750 Rear Shock. OEM Mounting.
-2004 GSXR 750 180 Rear Wheel, Rotor, Custom Races and Axle
-2001 GSXR 750 Rear Caliper/ Master Cylinder/ Reservoir/ Brackets
-All Balls Racing Steering Bearings
-EBC HH Brake Pads
-K&L 90° Valve Stems
-Michelin Pilot Power 3 Tires

Controls
-Trailtech Vapor Stealth Gauge/ Indicator Dashboard, Custom Housing
-Tarozzi Rearsets, Custom Mount and Brackets
-2001 GSXR 600 Brake and Clutch Perches
-CRG RC2 Levers
-Renthal Ultra-low 7/8" Superbike Bar
-7/8 Tag Metal Bar Risers, 1" Rise
-Domino Racing Push/Pull Throttle
-ProGrip 780 Sportbike Grips
-Low-Profile Minimal Left Switch
-POSH Factory 7/8" Dual "Cap" Switch
-Marine Turn-Key Ignition Switch

Misc
-1980 Honda CB 750F Tank
-LSL Clubman Ø6.5" Headlight
-LSL Headlight Brackets
-Radiantz 8.2" LED Turn/Brake Z-Flex Array
-LED Front Signals
-Motogadget M-Unit V.2 Electric Control Unit W/ Custom Wiring Harness
-Stainless Engine Bolt Conversion
-Adjustable Anti-Vibration Longstem 4" Mirrors
-7/8" Universal Mirror Mounts
-Shinyribs DOHC Tach-Plug "Flat-Top"
-Custom Lightened Subframe

Missing/ To-do
-Stainless Brake Lines, Front
-Front Reservoir
-Seat Pan & Alcantara Upholstery
-Battery/Electronics Box
-Rear Brake Pads
-Front Fender
-Rear Hugger
-Exhaust

I've never actually built anything before so it's a learn as I go process. For now I'll be outsourcing anything that's too difficult.

This is a picture from the day I picked her up. (Yes, I now know that's not the way to tow a bike)



Full engine rebuild performed by Cypress Motorbike in Delta, BC. After four years of sitting we pretty much had to replace everything. Clubman bars installed (and now removed). It's at this point I realize a cafe-racer is not for me. Way too uncomfortable (I'm 5'6) -- especially for a 566lb monster of a bike! Rode around the parking lot and realize I'm unhappy with the suspension and braking system. Also she desperately needs rear-sets.



Bike sitting in my garage (excuse the mess!). Seat, fender and hugger removed. Temporary bracket and Tarozzi rearsets installed. Time to detab and cut the rear frame.



Mostly de-tabbed bike and rear frame has been cut off. Test fitting of the new rear loop and taillight. The shin destroyer engine guards will be removed a little later but for now they are great in case the bike falls over.



The frame is feeling a bit long. To achieve the look I'm going for I think it should end exactly above the rear axle. More cutting to do!



Applied first layer of paint remover to the tank. Test fit back on the bike. Metal tank on black motor, frame and wheels?



Another View.



Obligatory ass shot.



A couple more applications of paint remover and about an hour of sanding with an orbital. The frame has been cut shorter and the battery box and wiring harness are now removed. Test fit of a new Shorai LI battery.



Another shot. I'm liking the stance but still unsure about that tank. Too fat?



Front end, carbs, airbox mostly removed. Curious how the new tri-spoke wheels will look on the bike. 2001 GSXR 750 rear wheel on Michelin 2CT tires.



New front end installed. New tank from a 1981 CB750F. Had the original steering stem pressed into the modern lower triple. The entire front end comes off a 2001 GSXR 600 for ease of installation. The forks are off a totaled race bike and have Racetech springs and emulators installed. Originally I had wanted to do a USD fork setup but I think these forks match the style of the frame a bit better. Sanded a bit of the old paint off the motor. Currently deciding whether to go with a Rental Super-bike bar or clip-ons. The bike sits about 1.5-2 inches lower with the new front end so it looks like I'll need a custom exhaust setup sooner than later. In the background is a buddy's 197- KZ200 build.



New LSL headlight and mounting ears. Trail Tech Vapor Stealth gauge and indicator dashboard.



Tested my luck purchasing a set of Ebay Pazzo-style levers. They fit. Unfortunately they also pre-load my brakes. $40 in the garbage. Oh well, lesson learned. Purchased a set of CRG RC2 levers instead.



The bike is off at a machine shop getting a modern swingarm (2001 GSXR-750) and rear monoshock (2004 Ducati 900SS) installed.



That's it for now!
« Last Edit: Oct 17, 2016, 01:06:54 by bananas »
'79 Honda CB750 L Monoshock Build
'07 Ducati SportClassic SE
'72 Yamaha GT80

Offline Zoopants

  • Posts: 48
Re: 1979 Honda CB750 DOHC
« Reply #1 on: Dec 19, 2013, 09:31:06 »
Looks great so far!

Offline cliffno350

  • Posts: 12
Re: 1979 Honda CB750 DOHC
« Reply #2 on: Dec 19, 2013, 14:35:57 »
Yup looking good, a way lot better than inferior bike Chris so and so tried to pass off as a build

Offline SaltCityCafe

  • Posts: 388
Re: 1979 Honda CB750 DOHC
« Reply #3 on: Dec 19, 2013, 16:45:17 »
I'm in I like new meets old

Offline M.B Co

  • Posts: 614
Re: 1979 Honda CB750 DOHC
« Reply #4 on: Dec 19, 2013, 18:52:56 »
Hot damn this will be rad.

Offline Bunz

  • Posts: 12
Re: 1979 Honda CB750 DOHC
« Reply #5 on: Dec 24, 2013, 23:36:28 »
Nice build so far. Waiting for updates.

Offline Hoosier Daddy

  • DTT SUPPORTER
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  • Posts: 4748
  • Earache my eye...
Re: 1979 Honda CB750 DOHC
« Reply #6 on: Dec 25, 2013, 05:24:37 »
Nice that you are bringing her back from the slow death outside. Interesting stuff so far! Can't wait to see the monoshock swinger when it gets back.
Soooo... You striped the factory LTD tank and then didn't use it? Hope it wasn't as nice as it looked in the pics.  :( That and the side covers would have fetched a pretty penny on ebay.
 
« Last Edit: Dec 25, 2013, 05:29:26 by Hoosier Daddy »
“Before you diagnose yourself with depression or low self esteem, why don’t you just make sure that you’re just not in fact surrounded by a bunch of assholes, alright?”


JAILBAIT '67 BSA 441 Victor Roadster
STAY CLEAN '67 BSA Spitfire
ROCK-IT '81 CB750C
BOMBER '81 GL1100
OVERKILL '80 GS750
NO CLASS '72 CB450 K5

Offline bananas

  • Posts: 159
Re: 1979 Honda CB750 DOHC
« Reply #7 on: Jan 06, 2014, 23:03:12 »
Nice that you are bringing her back from the slow death outside. Interesting stuff so far! Can't wait to see the monoshock swinger when it gets back.
Soooo... You striped the factory LTD tank and then didn't use it? Hope it wasn't as nice as it looked in the pics.  :( That and the side covers would have fetched a pretty penny on ebay.

Unfortunately the paint on the tank was pretty evenly pitted all around. Early on I contemplated doing a resto but decided against it.. Recently I saw a showroom condition LTD sell on ebay for $6500 -- kind of regretting it now haha. The side covers are sitting in a bin of parts which will be listed for sale once I take pictures of everything :)

Minor update for today:

Swinger is attached. Was able to use the original Honda swingarm pivot and axle. Still missing a couple of parts before she can be a roller. At the moment the rear wheel is a bit off center -- I'll be looking for an offset front sprocket.. anyone have any advice?


Next up is fabricating shock mounts for the Ducati 900SS shock. Currently deciding whether or not to cut and fab a new rear subframe. Also, hydraulic rear brakes :)
« Last Edit: Jan 07, 2014, 14:34:05 by bananas »
'79 Honda CB750 L Monoshock Build
'07 Ducati SportClassic SE
'72 Yamaha GT80

Offline SaltCityCafe

  • Posts: 388
Re: 1979 Honda CB750 DOHC
« Reply #8 on: Jan 06, 2014, 23:31:42 »
Yup I'm digging that rearend...my next project is going to get crazier buy since my current 750 is my first build I'm not getting to nuts

Offline vbtravisd

  • Posts: 106
Re: 1979 Honda CB750 DOHC
« Reply #9 on: Jan 07, 2014, 08:35:34 »
Nice!  I have this bikes older brother!  I just fitted up my 08 gsxr swingarm on my 78 last night.  Looking good man...
There is a great need for a sarcasm font...