Topic: The spoils of war - project Bugsy 78 CB750

[bigsherm]

I'm Sherm.  BigSherm.

Guess I can't wait any longer to post a build, though I've done quite a bit already.

From the beginning of this project I intended to build a street going CR750 replica.  That's where the name comes from - Dick "Bugsy" Mann who won the Daytona 200 on the original SOHC CR750 Honda racer.

I guess I wanted to wait until I had something like what I wanted before showing it around.

In late Fall of 2007 I searched for an SOHC CB750, and found a good candidate in Bettendorf, Iowa (!) quite a drive from Clarksville, Tennessee.  Oh, well, my wife (then fiancee') and I made a road trip of it and trucked to scenic Bettendorf.

$1200 dollars later I had a pretty solid running bike that looked somewhat presentable.

It came with a beat-up 750F pipe that I ditched right away.  In its place I used some stainless headers from BCR with some generic Emgo megs.

I fitted a lower handlebar and dual disks with a GSXR master caliper and braided stainless lines.  I fitted longer generic shocks.  I used a bicycle speedometer and ditched the gauges.

I installed CR carbs and K & N pod filters, bobbed both fenders, fitted fork gaitors, and cut down the seat foam.  I polished my ass off - engine covers, forks, ets.  I ventilated the drum brake cover and replaced a lot of the fasteners with stainless.

I ended up with this:

[bucky katt]

what exhaust is that? that factory or an aftermarket 4 into 4

[bigsherm]

I was then immediately off to a tour in Afghanistan.  That tour was as a scout pilot in the army flying the OH-58D in the 2-17th Cavalry.  "Scouts Out!!!"

Anyway, it was a hell of a tour, lots of excitement, lots of crazy sh*t, but there is always lots of downtime.

A dude can save some serious bank on a year long tour, and while there I schemed and planned and researched on the net and snatched up eBay parts (shipped to my home) like crazy.  Hence the "Spoils of War" nickname.

Through my research I began to question the rideability of a CR750 replica with a replica tank.  Just too stretched-out.  

Back in 1970 roadracers sat way on the back of the bike, putting lots of weight over the rear wheel and cutting graceful, smooth lines on the track.  Advances in tires, forks, and the huge power of modern bikes made the riders move toward the front of the bike.

I decided to upgrade the suspension of my CB to modern parts, and the wheels to a size that could use some better rubber.  I gathered the parts to assemble a CBR1000 front end, but with the even bigger brakes from a CBR954.  I used the CBR954 triples because that bike doesn't have a steering damper mounted on the top clamp (meaning no ugly holes on the top of the clamp). The 954 triple clamps offer the perfect amount of trail (according to my plans) with the longer shocks that steepened CB750 frame, the shorter CBR fork, and 18" wheel.

I decided to use 18" rims to retain the big-wheeled vintage look after making sure I could get decent 18" rubber.  The V-rod front tire is a 120/18 and the somewhat recent ZX-6 uses a 180/18 rear, ensuring those tire sizes will be around for a while, at least in sport-touring quality.

I'm no computer whiz, but I nugged my way through learning how to draw on Microsoft Powerpoint.  I found a Honda factory diagram (with measurements) of the CB750 frame and swingarm, and created a scale replica drawing.

I spent a lot of time building a frame, swingarms, wheels, brakes, many many tanks, fenders, headlights, oil tanks, forks, shocks, blah, blah, blah.

I came up with this:

[bigsherm]

I did find a fellow SOHC4/DoTheTon member with a CR750 replica gas tank and oil tank from TA Baker in England.  I also scored his Swarbrick's CR replica exhaust!  Woohoo!!!  His build was going in a different direction and I was happy to lighten his burden.

Still, I questioned the rideability and comfort of that loooooong CR tank.  There's no question; a CR750 is the BEST looking bike as far as I'm concerned, but I wanted to ride this thing a lot, and I wanted to be able to get my weight toward the front of the bike and feel what the front end was doing.  I scored a super-grungy but relatively dent free Suzuki GS450 tank on eBay cheap.  It had peeling paint and a huge sunoco gas sticker ruining it's good looks, so the price stayed kind of low.

I had all these parts and a lot more piling up at home.

I created a stock frame (modified with extra braces) with the CBR front, 18" wheels with the 120 and 180 tires, an aluminum front fender, and my longer shocks.  My most careful measurements predicted that the front end rake and trail would be virtually identical to the new CBR1000.  Sweet!

[bigsherm]

Here's what I came up with for my naked CR750 replica:

[odin836]

The PNGs are awesome...
You say you did them in Powerpoint?

[bigsherm]

I did so many designs, monoshock rears, dirt trackers with 4 high pipes, Manx style tanks, Rickman tanks, original '69 bodywork with modern running gear, etc.  Any tank, seat, etc. that I considered got thrown in to the design program.  Cutting and pasting and subsituting tanks, fenders, forks, seats, shocks, pipes.  It worked pretty well.

I married the best woman in the world while home on leave in July, and returned home after a year total at New Year's.

Then the fun began!

I laced the new rims and spokes from Buchanan's on to the old (but cleaned) hubs, had adapters made to fit the CBR954 discs on the CB750 hubs, installed the wheel bearings (in the sizes I had researched to fit the old hub on the CBR axle).  I sealed the wheels to run tubeless(!) with Goop household adhesive -  no sh*t.  Works like a charm once you figure out how to do it.

I made the front fender out of an aluminum blank meant to be rear fender of a Royal Enfield.  I got the stainless tube mounts into nice U-shapes by bending them around my son's junior-sized basketball.

I installed the brake calipers, lines, and master cylinder from a CBR1000 with some custom spacers so the calipers would reach the bigger CBR954 discs.

I scored a modified (lengthened) CB750 steering stem that another SOHC4 member had made for his similar front end swap.  I installed the forks, brakes, and some sweet-ass Paolo Tarozzi clipons and some new headlight brackets.

I made my own offset sprockets using 630 sprockets.  I ground down the wheel side of them to fit a narrower 530 chain, giving me 1/8th" offset to the left.  I used a gold non-o-ring (it's narrower) 530 motocross chain.

Then I ended up with this:

Sorry for the crap cellie pic.

[bigsherm]

Hey Bucky - the pipes are headers from Benjie at Benjiescaferacers.com with generic Emgo megaphones.

Odin- yep, Powerpoint.  It's all I had!

So...

The pipes look much better in a side pic than in person.  They stick out too far to the side because on the left, the outboard pipe has to run outside the kickstand.  I dragged that header in a left corner!  So I've been chomping at the bit to get the Swarbrick's pipes on.

The Army moved me to Ft irwin, California where you can lane split on a motorcycle and it's awesome!

It's the Mojave Desert, but it ain't so bad at all.  It.  Does.  Not.  Rain.

Ever.

Yes!

Being a family man with kids, I knew that this 2-month long school I am now attending at Ft Rucker, Alabama would have lots of free time and I needed to take advantage of it.  I brought my CB and lots of parts and tools with me and have been fairly thrashing my ass off in the parking lot after class most days.

I have polished, painted, and fitted the '82 Suzuki GS450 tank.  Once again - it's only painted in the black area (flat black header paint) and polished (and polished, and polished, and...) everywhere else.  I coat it with lots of wax to keep the rust away, and it barely works with frequent polishing here in ultra-humid lower Alabama.  Should be no problem at home in the ultra-dry Mojave Desert, though.

Here's what that got me:

[bigsherm]

Here's the latest-

I scored some stainless 16 gauge sheet at a local machine shop (leftover from some hospital stuff they built).  Using posterboard mockups, I designed a seat and cowl.

[bucky katt]

that black and white tank looks alot like a bmw toaster tank to me. killer look. do you mind me asking what you paid for the headers?

[bigsherm]

Bucky - I suppose you mean the Benjie's headers.  I think it was $250 or it might have been $200.  The megs were about $40 a piece, discounted from my local Clarksville shop.

I've got it all sitting right here with me - headers, megs, header clamps.  I think I'll put it up for sale.

Here's the design of the GS450 tank and my own design seat cowl with the Swarbrick's pipes:

[bigsherm]

And here is where I am today.

Couldn't be more pleased so far, especially with the stainless seat.

Waiting on sticky-backed seat foam, and the plan is to be able to switch between the solo and original seats.

I'm headed to the on post auto craft shop in the morning to weld up the pipes.  They're a little droopy until then.

Sorry, again for the cell pic, but I didn't bring a camera here with me!

[mcpuffett]

Wow Bugsy is a credit to you  , top work, look forward to more instalments  cheers Mick.

[J.Webster Designs]

what year CBR1000RR forks did you pick up? i am in the processes of planning out my build.

[bigsherm]

Midnight -

I don't remember what year, exactly, the forks are, but almost all of the recent models are the same.  I think the 2009 and on are different, but CBR's, 929's and 954's included, up to that are pretty much identical exept the brake caliper mounts, which are different for different size discs.

I searched a LOT on the stunt bike forums to see which forks people were replacing their crashed ones with.

Hope this helps.

Sherm

[yellowbirdrs]

WOW!!!
Now I want the CBR 1000 front setup 

[bigsherm]

If you want to switch forks, you've got to remember that CBR forks are much shorter than the CB750.  Unless you also want to install shocks that are quite a bit longer, your bike will ride very low in the front with the fok swap.  Other brands modern forks are practically identical in function and appearance, but may be longer.  I learned while searching the SV650 race forums that Suzuki GSXR froks are quite a bit longer.

Lowering the front and raising the rear steepens the fork angle, and decreases trail, too.  Mine turned out to have nearly identical front end geometry to a newer CBR, but the CB750 frame isn't nearly as stiff and substantial as modern sport bikes.

That could lead to problems, but so far, I haven't noticed any.  I'm extremely happy with the stability and handling of my CB750.

After I finish this stage of the build, with the much more tucked-in headers, I'll be able to lean it over much further.  I'll let you know how that goes.

Sherm

[Head]

Nice build,More pic's     Head

[andy750]

Wow really great build and equally great story to go along with it. I  think the tank was a great idea - can I ask how much modification it took to fit to the stock frame and what is the fuel capacity of the tank? Looks very good!

thanks and looking forward to seeing the bike with the new exhaust ;-)

cheers
Andy

[bigsherm]

Hey Andy-

     The tank almost fit on my '78 frame with no modifications whatsoever.  The forward mounting pins were just a little too wide.  I had to grind about 1/8" off each mount peg.

     Now, after grinding the mounts down, I could still put the rubbers back on and still use the stock tank, but to use the GS450 tank I had to also trim the rubbers down narrower.  After doing this, I could still use the stock '78 tank but it was just a little wobbly.

     For the rear tank mount, the GS450 tank just rests on the frame crossmember right ahead of the battery box.  I haven't yet figured out what I'm going to do with that but I'll post it when I do.

     The petcock on the GS450 tank is at the back left corner (same side, but farther rear than the '78 tank, opposite side from earlier CB750s).  The GS450 tank petcock location puts it too close to the CB750 frame to use a stock petcock, so I used a cheap ($20 or so) lower profile generic tap from custom chrome, and a generic Pingel adapter plate (+/-$20).

     I keep mentioning that mine is a '78 because the '76 and back CB750s use a different tank, and the rear mount may be different.

     The '82 GS450 specs say it hold 4.5 gallons, but I haven't completely filled it yet since the paint is still a little soft.

Sherm

[andy750]

Thanks Sherm, great info and I wish you luck with finishing it off.

Cheers
Andy

[bigsherm]

Well, BWC is back in business!

It's been a long time since I welded, and everyone said that MIG with argon gas would be much better than my flux core efforts before, but the results are the same.

BWC means Booger Welding Company.  I seem to be unable to weld anything but big, gloppy, boogers.  Anyway, there's no weld you can't grind away, thankfully.

Here's a pic of one of Swarbrick's pipes after my welding, and one after an eternity of grinding to clean it up.  I used a scotchbrite red paint stripping wheel on a drill to get the spun, aluminum baseball bat-like finish on the plain steel pipes.  I'm happy with the spun finish, but not so much with the appearance of my welds.

I'm considering filling the seams with amumafill or JB Weld and sanding that down.  I'm paying so much attention to the finish of the pipes because I'm going to paint them with CLEAR 2000 degree header paint.  I know the JB Weld or Alumafill will be a different color than the steel.  What do you all think?

-Sherm

[bucky katt]

are you using flux core wire? or is the pipe galvanized?

[bigsherm]

No Buck-

Just plain old untreated mild steel.  It only looks shiny because I put a spun finish on it.

I did not use flux core wire, I was welding MIG with argon shielding gas.

But, anyway, the welding is done (save touchups).  Just wondering what to do to make the seams look as good as possible.

Thanks,
Sherm

[bucky katt]

i wondered because of the white residue around the welds is all. how hard has it been to deal with those pipes? i really love the look of them but the extensive fabrication is kind of putting me off