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Offline tadrich

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CRAFE build
« on: January 01, 2018, 10:13:02 AM »
CRAFE Project Bike   

By Tad Richardson   1/7/2018

Preface

My father had always ridden Harley’s.  We have great pictures of him and a buddy in 1948 riding red 45 flatheads around the Superstitious Mountains in Arizona while attending Army Air Corps Lockheed P-80s jet school (with no trainers yet) and diving off canyon bridges.  At six years old I was scared witless on the back of a very loud ElectraGlide that emanated that luscious old Castrol(?) smell.  In the early 1960s our local Western auto dealer started selling Hondas.  Soon thereafter a white ladies step through automatic, silver CL160 scrambler and white 305 Dream arrived at the house.  At 11 years old I was allowed to buy a black CB50 not being able to afford a Super 90.  They were built and finished like swiss watches.  The owner manuals were funny to read.  No more Harleys.

We bored and stroked my 50 to 90ccs, added a road racing seat, instruments and a knobby; my first rather unusual blended bike styles custom.  We held time trials in the hay fields and have 8mm home movies of those.  Summer of 70 I got my road license was allowed to ride the rocket fast CL160.  In 1970 I bought a beat Norton Atlas for $165 and fixed it up.  It vibrated so badly I was numb all over after only an hour or riding.  It was heavy and handled like a pickup truck.  The brakes were scary. 

Dad had heard about some exciting new Honda that had just come out so we went in on a new CB750 with my getting $550 trade in on the Norton while he traded in the Dream and paid the rest.  I recall it cost around $1,600.  We missed getting the 1970 K0 and took delivery on a newly released 1971 metallic orange K1.  I had been shocked on how fast the CL160 was compared to my 50/90.  The CB750 was shocking, insanely fast.  When my father rode it I could hear what sounded like a F1 GP car approaching from ½ mile away.  What a song from the first Superbike.  A favorite stunt to impress friends on rides was to pop the front end up about a foot starting across intersections when hitting 2nd gear at 5,000 RPM, like a racing start.

1971 CB750K1 at Ford Museum, Detroit; same year, model and color we owned.

 
Cycle and Cycle World magazines had pictures of GP racing bikes and exotica like Dunstall parts which neither I nor my friends could afford.  While attending college my working friends making the holy grail pay rate of $5 per hour were buying stereos, cars, beer and weed, and nice bikes; Norton 750 Commando Combats, Ducati 750s, Bonnies, BSAs, and many CB350s plus one Yamaha Bonnie knockoff.  I fantasized about adding cafe parts to my CB750 and read about the Daytona racing accomplishments of the CR750s built from the racing kits.  I moved away from home in 1975 after college to my first job as an underpaid salary slave engineer and left the bike with my father who sold it when they moved in 1978.  I soon heard Norton was going out of business and got a loan for one of the last 850 commandos, bought from the infamous Ghost Motorcycles in NYC, and kept in in the living room of my apartment on Oyster Bay, LI, NY.

So the years pass.  I sold the Norton after 10 years because I had a child and riding motorcycles would void my life insurance policy.  My son turned 16 and what does he want, a motorcycle.  So I let him buy a side of the road for sale Yamaha Virago 920 with all the wild innovations that model experimented with.  I buy a $100 Yamaha 650 to fix up at the same time.  My son has a great time beginning to disassemble the Virage and eventually realized this project is a little over his head.  But he learns how to ride my 650 and I buy a Honda 750 V twin cruiser with Honda financing for fun and we ride together until he goes off to college.

In the meantime I started seeing all the amazing café 750s on SOHC4.net and decide I want to do that, too.  So I decided to buy a CB750K and fix it up as if I had kept the 1971 and fixed it up over the years.  That was the start of this build.






Acknowledgements and Thanks

I do not have a big garage or shop.  In fact the work was mostly done in my basement.  But I was very fortunate to know the following people who are experts at their crafts.  My rebuilt engine mated with the new Keihin CR carbs starts in half a second and runs perfectly despite a move to Salt Lake City around 4,000 ft. higher.  The paint job is show quality.  The media blasting and powder coatings came out perfect even when I had them do it over because I changed my mind on the color/finishes.  They were very patient.  The custom parts and mountings are commercial quality in fit and finish.  The finishing touch done in Utah was the seat upholstery with beautiful suggestions I never imagined.   I was very lucky to find these people.

The countless posts in SOHC.NET were an invaluable source of technical knowledge, referrals and inspiration. Right, ride and write on.

Hales Motorcycle Shop, Enfield, NH

Jim and Jake are second and third generation motorcycle mechanics.  They had also raced Formula 440 cars in SCCA and qualified for the national championships so I could tell they were not your average mechanics having raced in SCCA myself.  They rebuilt my engine and installed it into the powder coated frame/rolling chassis then installed and plumbed the new fuel tank to the new carbs, connected the wiring, installed sprockets and chains.  They also started the engine without headers or mufflers to check things out, a real pain in the ears. 

Their advice and common sense was invaluable.  They emphasized that if I was going to ride the bike it needed an air cleaner if I did not want to wear out my new rebuilt engine prematurely.  We discussed fluid dynamics and air box designs leading to exhaust pulse coordination.  So I modified the stock airbox to fit the new carbs, one of my favorite projects.  We discussed the costs of engine performance modifications and how in the end I would have more power trapped in a 1971 frame and suspension technology.  So we kept the rebuild simple and sensible.  They laced and built my new Sun rimmed wheels and mounted the modern Avon rubber all in current and normal sizes.  Looks and grips great.  Working with them and discussing my choices was one of the highlights of the build.









Volusia County Customs, East Unity, NH


I think Volusia County is in FL but I was lucky Todd moved to NH.  Wife’s family there, I think.  He is willing to do high quality small bike parts jobs which my tank, seat, fender and headlight cowl were.  He took the time to get the colors as close to Honda racing red and silver as we could that he could actually buy and he was right on.  Prep is the key and the paint is luscious and deep.  Thanks again.

Before:



Race Metalsmiths, Wilder, VT

Mitch and son Scott, another father and son(s) operation, had the media blasting, powder coating facilities plus metal fabrication skills necessary to design and build my ingenious gas tank, seat and taillight mounting bracketry.  Then they repaired, built and installed snuffers and refinished the 1978 CB750 4 into 4 exhaust system so they could be mounted to my 1971 exhaust ports and modified rear mounts to look like CR750 pipes.  Looks very CR like and sounds fantastic.

Mitch has a ton of machine shop experience on complicated jobs and finally escaped overcrowded CT to raise his family in the Upper Valley/VT.  Good move and his parts and ideas work and look perfect.  Scott worked very hard and had excellent color and finish ideas after I made some goofy decisions at first.  These helped clean up the design a lot.  Then he guided me in how he could patch weld the rust holes in the 1978 pipes and blast the chrome so they would take a clear high temp finish.  The metal look is so different than the usual black pipes on CR750s and stands out.

They finished their work and I picked up the bike and pipes for their trip to Utah so none of the New England people have seen the bike assembled until now.

1978 exhaust pipe set before:

Custom seat and rear gas tank bracket:

Examples of cleaned and powder coated parts and frame:




Bearscar Designs, South Salt Lake City, UT

Eli is an artist who has been teaching himself leather upholstery and getting real notice.  His leather handgrips are unique and on some famous builds like the BMW Alpha radical build.  I generally knew what I wanted but his suggestions in snap count and spacing , stitching pattern and using different materials on seat vs sides made the whole thing really pop.  Good butt grip, too, on the suede like seat facing.

Before:




The build


Do not do what I did.  I stupidly bought two basket case CB750s, a ’71 K1and ‘73 K3 that were mostly disassembled and incomplete for $100.  Great price, right?  No.  Getting all the mixed K1 and K3 switchgear to work with the K3 wiring was a nightmare.  Especially after I discovered the carb return springs were too strong for my carpel tortured right wrist and arthritic thumb needed me to obtain a K1 friction throttle and get working with K3 wiring and starter button.  Ugh!  Hours wasted getting it to all work again. Anyway, buy a complete bike to start with is my strong advice.

These are very different in earlier K years.  Real PITA to adapt different years to wiring harness.


So what did I want in this bike was as if I had owned and continually modified it since 1971.  I love both café style and CR750s so I decided to build a blend of both with some current technology parts like the wheels and tires.  I also did not want nor could afford a CR750 replica which is pricey to do right.  I knew I wanted a simple metal finish theme with many metal parts to be coated with clear satin powder coating because the Honda quality and metal speaks for itself.  So is it like the car style RestoMod?  I guess so. 

Original rotor cleaned, center powder coated clear, drilled


What I did not do


I also decided not do some things.  I did not replace/move the oil tank.  Not mounting the side covers and finishing the tank in clear gave me the look I wanted.  I did not move the battery or replace with lightweight lithium type.  I did not add a second front disc.  I am not going to race the bike and I recalled one disc worked just fine.  I like the old school single disc look. I did send it out for a great looking drilled hole pattern which was not expensive.  I did not buy an aluminum gas tank.  Maybe I should have because the coated and painted fiberglass tanks cost about as much in the end.  But in the end I decided wanted a Honda racing red tank and not have a aluminum look alike tank like the excellent British cafes.  I am still worried that phase 2 with the Rickman/Metisse half fairing will create a confusing look.  I did not install clip ons nor setbacks, yet.  I am 64 and not at an age where riding in a racing crouch is comfortable.   I know you erudite readers know there was a Rickman Honda CR750 but building a replica of that bike would have frozen it in 1975.

The snotty looking original tanks that came with the bikes were not the look I wanted.



More to come...




« Last Edit: February 03, 2018, 07:35:05 AM by tadrich »

Offline SOHC4 Cafe Racer Fan

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Re: CRAFE build
« Reply #1 on: January 02, 2018, 07:47:21 AM »
Riding a motorcycle would have voided your life insurance policy???  Which insurer was that?
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 754

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Re: CRAFE build
« Reply #2 on: January 02, 2018, 09:52:01 AM »
 Great Stories and Intro..good luck with the project..and Welcome aboard..
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline tadrich

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Re: CRAFE build
« Reply #3 on: January 06, 2018, 07:26:08 AM »
That was back in the mid 1980s.  Not a problem now.  Not certain when that changed.  Policies still exclude other behavior without a (insurance) rider.  I think things like skydiving, diving below certain depths, and flying experimental (homebuilt) aircraft might qualify.

Offline MCRider

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Re: CRAFE build
« Reply #4 on: January 06, 2018, 09:16:22 AM »
That was back in the mid 1980s.  Not a problem now.  Not certain when that changed.  Policies still exclude other behavior without a (insurance) rider.  I think things like skydiving, diving below certain depths, and flying experimental (homebuilt) aircraft might qualify.

Yes, known as the "hazardous avocation exclusion".  Haven't seen one for motorcycling lately, but still current, company specific.
Ride Safe:
Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."

Offline tadrich

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Re: CRAFE build
« Reply #5 on: January 06, 2018, 04:36:58 PM »
I apologize to readers for being such a posting noob.  Struggled with FTP to my hosting site all afternoon after photo file transfers looked like the worked but actually did not.

I am posting as fast as I can.  Please keep coming back.

-tadrich

Offline DV Red Herring

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Re: CRAFE build
« Reply #6 on: January 06, 2018, 05:10:18 PM »
Great intro!!! I like that airbox.

Offline 754

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Re: CRAFE build
« Reply #7 on: January 06, 2018, 05:40:12 PM »
Is that front wheel 18? How wide?  I been thinking to run 130 x 18 up front, probably with a wider fork.
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline Stev-o

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Re: CRAFE build
« Reply #8 on: January 06, 2018, 05:52:07 PM »
Good story, subscribed....
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline tadrich

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Re: CRAFE build
« Reply #9 on: January 24, 2018, 03:22:01 PM »
(finally finished this reply/post)
Excellent question because the last thing you want is something that does not fit between the forks, or tires and rims are mismatched, or worst, it looks stupid.  And you just spent A LOT of money.

I agonized over, I mean researched, rims and tires for the longest time.  I knew from the start I wanted to go -1 in front so instead of the original stock 19 inch I wanted 18 inch.  Although I modernized certain components in the build I felt adapting a cast one piece wheel, like from a rice rocket, was the wrong look.  So a rim and spoke wheel it was to be.  The original rim is chrome plated steel.  The other choice would be aluminum rims with various finish choices.  I called the folks at Buchanan’s Spoke and Rim in Cali, http://www.buchananspokes.com/ , 626-969-4655, who after blathering out what I was doing asked the simple, now obvious, question, what tires am I using?  Oh.  Hadn’t thought about that and it is the first decision, sort of.

This set me off on another research quest about tires.  A million hours later I settled on Avon RoadRider tires which are actually designed to be a “Performance upgrade for classic and vintage motorcycles”.  Their tire specs also show recommended rim widths and limits. I called and got their blessing for tire sizes and rim width requirements.  I also decided on modern sizes in order to have modern sidewall ratios.

http://www.avonmoto.com/street-tires/street/roadrider/

Perfect!  What size?  SOHC4 and other google results talked often about this topic.
 
Nice thread and chart guide here: http://forums.sohc4.net/index.php?topic=56494.0

I also measured the width between the forks to double check.  I did not want to modify the stock fork width.  I also checked on posts on how raising or lowering the CB750 front affected handling.  Lowering some in the front seemed to be a good thing.

Like many old farts who were young in the 70s I was been in love with various British and Italian café and racing exotica in my youth so originally I wanted Italian Borrani rims for the vintage look.  They are pricey.  I also had to find the right diameter and width to match the tire specifications.  Plus find them in stock somewhere.  This turned out to be very difficult because the size I needed was just not in stock anywhere nor could they be ordered because I was told a reseller had to buy lot quantities of the sizes they were offering.  Not good.  I quickly discovered that the Sun rims, manufactured by Buchanan, would work and I hoped would look fine.  They offered the size the tire needed.  I ordered the rims, with holes, stainless steel spokes and nipples for Hale to assemble.

1971 CB750K1   Stock tire and wheel sizes   
 
Front   3.25 x 19   1.85 x 19
Rear   4.00 x 18   2.15 x 18

CRAFE tire and wheel sizes

Front   Avon RoadRider    110/90V18 61V   Sun WM4.5 2.75 in x 18
Rear   Avon RoadRider    130/70V18 63V    Sun WM6 3.5 in x 18

Hale ordered the tires and when I picked up the tires mounted on the laced rims to my RaceMetalsmith cleaned and clear powder coated stock hubs I was knocked over by how perfect they looked.  18 inch front with decent size modern meat really works.  Handles so much better than the old skinny 19 inch 1970s technology rubber; or so I think.  Neither I nor the bike are track day material.  I mounted them as soon as possible so I had a rolling chassis to look at.  The wheels and tires looked awesome, or #$%*in’ as they like to say here in Salt Lake. (Velocity channel #$%*in’ Rides shop is here)

Offline slikwilli420

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Re: CRAFE build
« Reply #10 on: February 01, 2018, 07:54:14 AM »
Bummer I didn't see this sooner. I got my Borrani wheels from a US distributor and pricing was better than Sun rims from Buchanan. Oh well, the Sun rims still look killer.
All you gotta do is do what you gotta do.

Vintage Speed Parts Mashup: http://forums.sohc4.net/index.php?topic=133638.0
Rickman CR Parts Kit Refresh: http://forums.sohc4.net/index.php/topic,154837.0.html
AHRMA CB750 Racer: http://forums.sohc4.net/index.php/topic,158461.0.html
AHRMA Superbike Heavyweight Racer: http://forums.sohc4.net/index.php/topic,173120.0.html
'76F CB750 Patina Redemption: http://forums.sohc4.net/index.php/topic,174871.0.html

Offline MCRider

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Re: CRAFE build
« Reply #11 on: February 01, 2018, 08:03:14 AM »
I went the 18 front, 17 rear route myself with Excel rims from Bucky's. With the wider lower profile tires. Don't forget that your ride height will be lower. THis makes it stand up nervously vertical on the sidestand and nearly impossible to engage the centerstand.

I had this guy http://soupysperformance.com/hyosung/gt650r.html make me an adjusable sidestand and a local machine shop cut down my centerstand.
Ride Safe:
Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."

Offline tadrich

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Re: CRAFE build
« Reply #12 on: February 03, 2018, 07:33:20 AM »
Build continued

I hauled the frame with engine and other engine to Hale’s so they could look at both engines and choose which one to rebuild.  We choose the one that was mounted in the frame so that was pulled out and all the mounting hardware bagged for refinishing and reassembly.

It was easy to strip down the K1 frame I chose and shuttled it and assorted parts off to Race Metalcraft for stripping and powder coating.  Then I began refinishing all the parts I could do myself using degreaser and paint removing gel as needed in the utility sink.  My wire wheel also got a good workout.  I was continually impressed with the quality and finishes of Honda parts reviving the feelings I had as a youth working on the various Hondas we owned.

Honda metal quality and finish speak for themselves




Almost without saying I ordered new bearings and seals and upgraded some things like using a modern sealed bearing kit for the steering.  More no brainer items were stainless steel brake hoses to replace the old hoses, new brakes pads and shoes, new battery; the usual items time and wear warrant replacement.

Suspension

A 1970s frame and suspension were never going to be like a modern sport bike.  I remembered the front springs being too soft.  I felt the modern tires would make the biggest difference.  I researched K suspensions and found Progressive Suspension who offer stiffer front springs with spacers and rear shocks, too.  I chose their front spring kit to install in my new fork tubes.  Installing the springs was a major hassle because I did not have any kind of tool rig to compress then whilst screwing the nut on.  I finally Macgivered something that compressed everything, and the pressure required was quite high, and cautiously threaded the nuts in.  I did not take a photo of this mess.



Ohlins were not in my budget.  The Progressive rear shocks did not have the shock and spring finish I wanted.  So I went cheap and bought generis boy racer Asian shocks with adjustable springs and air cylinder damping.  They look great.  The performance will be described in the sorting out section of the build.



Wheels and Tires

I agonized over, I mean researched, rims and tires for the longest time.  I knew from the start I wanted to go -1 in front so instead of the original stock 19 inch I wanted 18 inch.  Although I modernized certain components in the build I felt adapting a cast one piece wheel, like from a rice rocket, was the wrong look.  So a rim and spoke wheel it was to be.  The original rim is chrome plated steel.  The other choice would be aluminum rims with various finish choices.  I called the folks at Buchanan’s Spoke and Rim in Cali, http://www.buchananspokes.com/ , 626-969-4655, who after blathering out what I was doing asked the simple, now obvious, question, what tires am I using?  Oh.  Hadn’t thought about that and it is the first decision, sort of.

This set me off on another research quest about tires.  A million hours later I settled on Avon RoadRider tires which are actually designed to be a “Performance upgrade for classic and vintage motorcycles”.  Their tire specs also show recommended rim widths and limits. I called and got their blessing for tire sizes and rim width requirements.  I also decided on modern sizes in order to have modern sidewall ratios.

 http://www.avonmoto.com/street-tires/street/roadrider/

Perfect!  What size?  SOHC4 and other google results talked often about this topic. 
Nice thread and chart guide here: http://forums.sohc4.net/index.php?topic=56494.0
I also measured the width between the forks to double check.  I did not want to modify the stock fork width.  I also checked on posts on how raising or lowering the CB750 front affected handling.  Lowering some in the front seemed to be a good thing.
Like many old farts who were young in the 70s I was been in love with various British and Italian café and racing exotica in my youth so originally I wanted Italian Borrani rims for the vintage look.  They are pricey.  I also had to find the right diameter and width to match the tire specifications.  Plus find them in stock somewhere.  This turned out to be very difficult because the size I needed was just not in stock anywhere nor could they be ordered because I was told a reseller had to buy lot quantities of the sizes they were offering.  Not good.  I quickly discovered that the Sun rims, manufactured by Buchanan, would work and I hoped would look fine.  They offered the size the tire needed.  I ordered the rims, with holes, stainless steel spokes and nipples for Hale to assemble.

1971 CB750K1   Stock tire and wheel sizes   
Front   3.25 x 19   1.85 x 19
Rear   4.00 x 18   2.15 x 18

CRAFE tire and wheel sizes
Front   Avon RoadRider    110/90V18 61V   Sun WM4.5 2.75 in x 18
Rear   Avon RoadRider    130/70V18 63V    Sun WM6 3.5 in x 18

Hale ordered the tires and when I picked up the tires mounted on the laced rims to my RaceMetalsmith cleaned and clear powder coated stock hubs. I was knocked over by how perfect they looked.  18 inch front with decent size modern meat really works.  Handles so much better than the old skinny 19 inch 1970s technology rubber; or so I think.  Neither I nor the bike are track day material.  I mounted them as soon as possible so I had a rolling chassis to look at.  The wheels and tires looked awesome, or #$%*in’ as they like to say here in Salt Lake. (Velocity channel #$%*in’ Rides shop is here)




Engine and Fuel System

The engine rebuild plan was to keep it stock.  More power in a 70s suspension did not make sense.  Speed costs money.  I was 63 years old when it was rideable and not the same rider I was as in my teens and twenties when we said we would go so fast the cars we blew past would not see us.  I can buy a used modern sport bike if I wanted to go really fast and scare myself which I did at times when renting bikes while visiting my son out west on our epic rides canyon carving around the high deserts.  He let me ride his Honda Super Hawk and Aprilia sport touring liter bike which is insanely, scary fast and reminded me how painful my worn out shoulders, wrists and fingers quickly became in a sport bike crouch.
The Airtech CR750 fiberglass tank along with seat and front fender solved the fuel issue with RaceMetalsmith’s designing and building the rear mounting bracket and Hale plumbing it.
 


So what about carbs?  My junkers came with what looked like around 50% of various disassembled stock carb parts and we all know about the limitations of the stock carbs.  So I found the beautiful Keihin CR carb sets and Hale convinced me they could make them work and they would give acceptable performance on the street not requiring wide open throttle to make the bike run.  See results in sorting out section that follows.  They also cost only around $200 more than a rebuilt/restored stock set so I saved up $800 and bought them. 
They have exactly the look I want, have CR in large letters in red on the side which fit right in with my CRAFE name, and have warning stickers that state “Motorcycle Race Use Only” which are uber cool.  They came with velocity stacks which look great but Hale convinced I would harm my engine without using air cleaners and educated me about the benefits airbox fluid flow dynamics.




Airbox project

OK, I bought into needing air filtering preferably using an airbox.  I researched both and did not find anything I liked or could easily be adapted.  I knew a custom designed and built airbox would cost a lot $$$$.  So I looked at my stock airbox which is kind of a butt ugly blocky plastic lump I’d find under the hood of any modern econobox.  With a velocity stack next to the airbox openings I saw some potential for somehow getting the velocity stacks into the holes and somehow sealing those up with PVC cement.  I measured the IDs and ODs so I knew they would fit in without having to enlarge the holes.  Then I saw where the stack OD met the airbox ID measuring the length sticking out.  The problem was without the engine in the frame with the carbs mounted I could not measure the distance from the back of the carbs to the front of the airbox.

I drew up some sketches of the airbox with various mods to make it look better.  I also discovered the original OEM Honda air filter was also available as NOS, New Old Stock, and used yellow filter paper vs reddish paper on all the aftermarket filters.  So I bought the NOS one and the yellow color worked vs the red clashing with the Honda racing red that was to be the tank color.  My brain boluntary blanked out on exactly how I would seal the stacks to the opening either before or after mounting and pressed on regardless.
I cut the bottom of on hole in the airbox which allowed bending apart the sides and forcing the stack inside and flop around.  I then verified I could cut off the covering of the bottom of the airbox leaving the air filter attachment and mounting plate intact.  To get the dull, even finish I tried various steel wool and sandpaper and found the one that gave it the look I wanted.

I will describe how I got the thing mounted in the final assembly section to follow.









Offline SOHC4 Cafe Racer Fan

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Re: CRAFE build
« Reply #13 on: February 03, 2018, 01:29:00 PM »
Nice progress.

Don't forget to coat the inside of the fiberglass gas tank with Caswell epoxy liner.  Otherwise, the ethanol-based gasoline with break down the resin in your tank and you'll have a leaky tank.
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