Author Topic: 73 CB750 HURRICANE build thread (Read 8326 times)

Lefthook · « **on:** December 09, 2009, 12:14:23 PM »

As pictured in the welcome thread:

cb750k3 - runs, but is absolutely ragged out. Perfect for a ground-up cafe build, but wondering if my eyes are bigger than my wallet, lol. 62k miles, and pretty much nothing on it that isn't worn out.

Has a 4-1 pipe with some goofy slip on silencer that really was slipped on.. as in "not attached". That's it laying on the trailer. The guy I bought the bike from was pretty psyched about it and how cool it was.. I wasn't sure what to say to him. "Um.. no, dude. Just... no."

No front brake CALIPER much less working front brakes.

WHEE!! My wife made me promise not to even ride around the neighborhood. I let her think that it's because she doesn't want me to but the truth is you couldn't pay me to get on this greasy monster.

dyno and timing covers missing. Planning on going with finned covers.

Motor leaks. I'm going to split the cases and go through it, paint it and then put it back together.

So I decided the steel hoops were a little too ratty and bought a set of GL1000 aluminum wheels. I'll powdercoat them and send them off to be laced up with new stainless spokes. Stoked about a 19" front, and this works well because I want to do dual front discs anyway.

Haven't decided what to do with the forks, or even where to buy new ones. I'm pretty sure I want to go with -1 though and bring the front end down.

Pictures coming up soon....

rickmoore24 · « **Reply #1 on:** December 11, 2009, 09:36:00 AM »

Awesome LeftHook, at least it looks like it's all there. Best of luck with it, keep us posted on you progress.

Old Scrambler · « **Reply #2 on:** December 11, 2009, 05:42:17 PM »

My K3 has about the same miles and was starting to show a lot of wear around the edges. A little $$ for some new chrome bolts, a top-end rebuild, a lot of luck finding a great set of original pipes, a little motor paint and a lot of cleaning. I just rode it 2,000 miles while on a trip in Utah. I restored it because I have had it since new. I have others to make into cafe-racers. Good Luck with yours.........

Lefthook · « **Reply #3 on:** January 18, 2010, 12:25:24 PM »

So... a few updates. These are cell phone pics.. I have more on my DSLR but uploaded these while sitting in a traffic jam on my way to work this morning.

The project was on hold momentarily but I'm back on track. The steel rims were worse for wear, and so I decided to buy some aluminum GL1000 rims. Going to powdercoat them and lace them with new spokes. After much debate I've decided to stick with a single front brake on this bike.

Started stripping it down and then decided I needed a bench, so I don't have to sit on the floor to do this thing.. I think the bench weighs as much as the bike, it's decked with 2x4's laid on edge, glued and screwed together and then topped with a 3/4 sheet of plywood.

The OCD side of me wanted to top it with a sheet of stainless, but my buddy who owns a steel company told me it would be 150-ish for his cost so I decided to stick with plywood. 2 feet wide, 8 feet long, bike fits on it perfectly, and in the 4th bay of my garage.

I happened across a guy selling some Tarozzi rearsets for a good deal, so I snagged them. They are for an F1, so I would have to modify them. I may ebay them off and look for the K- compatible sets.

Lefthook · « **Reply #4 on:** January 25, 2010, 10:29:42 AM »

PROGRESS:

sitting on the bench:

the amount of wiring crammed into the headlight bucket was

check out the spiffy shocks on this bad boy:

the PO decided the way to fix an oil leak was just to smear RTV everywhere.. sort of a "shotgun" approach at maintenance:

cross-threaded bunch of mashed up mix-match holding on the bent up garbage 4-1 header, lol:

these two were so long they bottomed out in the head before they could clamp down on the flange

what was funny about that is the guy I bought it from was going on and on about the "cool" exhaust on the thing.

disassemble:

the vent line on the back of the oil tank was split. I think this is the source of 99% of the oil all over this thing, regardless of the willy-nilly applications of RTV. The snot is like 3/4" thick:

nasty:

typical of the surface rust all over. Very minor. The liberal coating of gunk all over it probably helped with preservation, lol.

airbox out of the way. It's junk, having received the "hot rod" treatment (holes drilled all over the backside). The filter hasn't been changed in well over a decade. Wow.. look at the gunk.

bars out of the way. Yes, I was watching basketball:

Believe it or not, this bike had been recently ridden. On those tires.

My dad getting ready to help me pull the motor:

pulling the motor:

Going to replace ALLL the hardware with black anno'd torx head screws and cap screws. My ARP catalog is going to get a workout.

BAM:

Now to start grinding all the unnecessary tabs off the frame, clean it all up, and start powdercoating stuff!!

Ready to split the cases and go through the motor. Debating the big bore kit.

carbs on the bench. They don't look too bad, the bike actually ran well:

Lefthook · « **Reply #5 on:** May 20, 2013, 04:03:32 PM »

So this thing got mothballed for a little while but is now in full build mode.

I toyed around with doing knee dents in the original cb750 tank, which was smashed in pretty good in the front from a laydown by the previous owner:

But ultimately I abandoned that idea.

The motor is being rebuilt at Precision Auto Machine in Ontario, OR with a stage 1 big bore kit (836) with the Super Deluxe add on from Dynoman. Wiseco pistons, Carillo rods, titanium retainers, Web cam, KPMI Black Diamond Stainless valves, DP Ampco valve guides, Dyna ignition and coils.

I bought a CBR1000rr front end, a bearing kit from All Ballz and started mocking it up.

Also ordered a set of Ohlin S36P shocks and a 7" headlight bucket from Dime City Cycles. I'm going to do the motogadget tach/speedo combo gauge, because I really wanted just one big tach with the digital speedo.

I wanted something different for the bodywork than what I could just go buy so David Lewin was tabbed to help me figure out how to redesign a cbr600 tank to work with the cb750 frame:

I chose a different graphic than this, but ultimately this is the tank and tail we are building:

David had some really cool ideas that I hadn't thought of, or figured out how to integrate - like modifying the bezel on the headlight to integrate some little pods for turn signals so that it's street legal but doesn't affect the form.

More pictures as the work is completed coming - target date to finish is before July 1.

SOHC4 Cafe Racer Fan · « **Reply #6 on:** May 20, 2013, 06:34:02 PM »

Holy crap. You hired an industrial designer (Dave Lewin). His renderings look sweet.

Lefthook · « **Reply #7 on:** May 21, 2013, 11:24:12 AM »

Quote from: CB750 Cafe Racer Fan on May 20, 2013, 06:34:02 PM

Holy crap. You hired an industrial designer (Dave Lewin). His renderings look sweet.

Yeah. David did the rendering on the Eleanor convertible that Mark Wright had done at Mayhem Customs, so when it came time to figure out some details on this thing, rather than bang my head against the wall trying to hack job the thing together I thought hiring David to help me figure out some graphics, get a game plan and run with it just made more sense.

David is an awesome guy, by the way. An absolute joy to work with.

Lefthook · « **Reply #8 on:** May 28, 2013, 09:43:37 PM »

OK - so I met with David today and went over some things. Ultimately what we decided is that it would be cool to give the bike kind of a visual reference. Retro is in.. so after sketching some things up, the thought basically was "what if the Hurricane was introduced in 1973 instead of 1987? Same designer, but no farings..."

Here's what he came up with:

and the full drawing:

So we're off and running. I'll post more pictures of the bike as we go through the assembly - goal is to have it assembled by the weekend after July 4.

rickmoore24 · « **Reply #9 on:** June 04, 2013, 09:12:38 AM »

Those renderings are awesome! I love that kind of stuff, nice work!

SOHC4 Cafe Racer Fan · « **Reply #10 on:** June 04, 2013, 04:03:42 PM »

Ditto on the renderings. I am excited to see how the 600rr tank will be fabricated/modified to fit the CB750 frame. PLEASE go into detail on that end, with LOTS and LOTS of PICTURES.

My guess is that more than one of us on the forum would be interested in having a similar tank. It reminds me of the Hondaducati project, but I like the fact that it is using a CBR600RR tank.

Lefthook · « **Reply #11 on:** June 13, 2013, 12:07:31 PM »

PARTS!

Unfortunately the Motogadget gauge is on back-order so looks like that will be the last thing that we do for this bike - delivery will be in about 4 weeks. Motor should be done in the next 2 weeks or so.

volthause · « **Reply #12 on:** June 13, 2013, 01:03:13 PM »

I'm in on this one. Looks epic.

Tews19 · « **Reply #13 on:** June 13, 2013, 05:15:21 PM »

Im hooked. I mean subscribed

Roach Carver · « **Reply #14 on:** June 13, 2013, 06:25:15 PM »

Schweet.

cheftuskey121 · « **Reply #15 on:** July 14, 2013, 09:38:58 AM »

Any updates?

Lefthook · « **Reply #16 on:** October 23, 2013, 04:26:45 PM »

Still waiting on the motor to be completed but most of the gusseting and reinforcement of the frame is done. Have the tank, but kind of need to have the motor to be able to get everything mocked up. I've been looking around for a non-running SOHC cb750 just to use the motor for mock-up purposes - but the closest one I found was a couple hours away from me and I pulled the wheels and bumpers off my truck to powdercoat them so I didn't have any way to get it anyway.

I'll be in this thread with a vengeance as soon as I have some good forward progress

70CB750 · « **Reply #17 on:** October 23, 2013, 05:54:19 PM »

That is bloody sweet!

Lefthook · « **Reply #18 on:** May 22, 2015, 02:55:20 PM »

So it has been 2 years but the motor is finally complete and together so we are finally getting on with this.

When we put all the go-fast parts in the bottom end, we looked at each other and realized the heads were not going to support the rest of the pieces going into the build, so the head went out for porting to Wes King Racing Heads. CFM's certainly improved:

Pretty stoked about those numbers. For the tank we bought a couple different ones but a late-90's CBR900rr tank was the right fit. Mocking it up, with the controls mounted:

Basically what we are doing is cutting apart both tanks and grafting the 900rr top to the base from the 750k3.

SOHC4 Cafe Racer Fan · « **Reply #19 on:** May 22, 2015, 03:17:05 PM »

Hey, I remember this build from the cool renderings. I'm glad it's moving along. The tank looks like it's a pretty tight fit using the stock triple clamps with reduced offset. Have you considered getting custom triple trees to re-obtain stock or near-stock offset? If so, I'd recommend Devin at Cognitomoto who just milled a set of custom triples for use with my 2008 CBR600RR forks:

SOHC4 Cafe Racer Fan · « **Reply #20 on:** May 22, 2015, 03:21:05 PM »

Quote from: Lefthook on May 20, 2013, 04:03:32 PM

The motor is being rebuilt at Precision Auto Machine in Ontario, OR with a stage 1 big bore kit (836) with the Super Deluxe add on from Dynoman. Wiseco pistons, Carillo rods, titanium retainers, Web cam, KPMI Black Diamond Stainless valves, DP Ampco valve guides, Dyna ignition and coils.

I bet that motor is going to pack some added punch now. What type of carburetors are you going to use? Keihin CRs, Mikuni RS34s, EFI or something else?

PGF550F · « **Reply #21 on:** May 23, 2015, 02:38:41 PM »

Man this thing is going to look and ride awesome!! Ill be along to watch this come to shape!

SOHC4 Cafe Racer Fan · « **Reply #22 on:** May 23, 2015, 03:09:49 PM »

PLEASE do not let this one go back into mothballs. It's way too cool.

Bigsam302 · « **Reply #23 on:** May 23, 2015, 03:42:48 PM »

I agree, this build is going to be beautiful. Please keep at it!

Lefthook · « **Reply #24 on:** May 29, 2015, 05:16:04 PM »

Quote from: CB750 Cafe Racer Fan on May 22, 2015, 03:17:05 PM

Hey, I remember this build from the cool renderings. I'm glad it's moving along. The tank looks like it's a pretty tight fit using the stock triple clamps with reduced offset. Have you considered getting custom triple trees to re-obtain stock or near-stock offset? If so, I'd recommend Devin at Cognitomoto who just milled a set of custom triples for use with my 2008 CBR600RR forks:

Quote from: CB750 Cafe Racer Fan on May 22, 2015, 03:21:05 PM

Quote from: Lefthook on May 20, 2013, 04:03:32 PM
The motor is being rebuilt at Precision Auto Machine in Ontario, OR with a stage 1 big bore kit (836) with the Super Deluxe add on from Dynoman. Wiseco pistons, Carillo rods, titanium retainers, Web cam, KPMI Black Diamond Stainless valves, DP Ampco valve guides, Dyna ignition and coils.

I bet that motor is going to pack some added punch now. What type of carburetors are you going to use? Keihin CRs, Mikuni RS34s, EFI or something else?

4 brand new Keihin CR29's.

And the bike has never really been mothballed, it just moved really slow trying to get the motor done the right way. Still have some small pieces to track down and side covers and stuff to make, but the motor was the rock in the river. It's out of the stream.

Those forks are really pretty. I may consider it rather than adapting it with the bearing and race set from All Ballz.

News:

Author Topic: 73 CB750 HURRICANE build thread (Read 8326 times)