Author Topic: 76 CB750/GSX-R750/CBR600F2 Hybrid Build. (Read 20465 times)

Letze · « **on:** July 12, 2012, 07:18:40 PM »

I'm an graphic designer who is going back to school for industrial design after working full time for 2 years and deciding I didn't like the career I had gotten myself into.

I have a loving family who is supporting me in the above... they however do not support what is below. Growing like many of you I'm the kid who took everything apart to figure out how it worked and hoped it would work better than before with my own "improvements". I'm still that same little kid every time I enter my garage.

GnarlyCharlie gave me this frame back in November so I could mock up the suspension alterations while I was searching for a good donor CB750 for this project, It originally was just going to be a suspension update for a CB750 with GSX-R forks and a mono shock rear. This changed after I purchased a shifter kart with the intention of putting a CBR600 motor on it. Well after a few close calls with cars and a hand full of warnings from the police. The Final blow was VIR telling me their insurance wouldn't let me run the kart on their track (the main course not the kart track) I decided it was time to move on. So I returned the kart to stock and sold it.

Leaving me with all of this.

After moving all of my crap back to Roanoke where I had a garage (parents house

) I started test fitting the motor.

The motor almost fit! but this isn't a game of horse shoes.

Removing the CB750 motor mounts and cutting the center brace/thing gave me an extra 1cm of clearance that the motor needed to sit down all the way.

This was great, the carbs even fit although cramped as hell, then I realized something.

Well Shoot... What am I going to do? I KNOW!

MORE CUTTING!

Then i decided I'd clear out the rear motor mounts and the stock pivot mounts as the GSX-R's rear pivot bolt is 25mm in diameter it sure as hell wasn't going to fit in a 10mm hole.

And I was greeted with this and it's not the only one I put my wooden spacers back in place to see how much the tubes were flexing and I saw another fracture in the tubes, currently it looks like the tubes are cracking in various places along what looks like the seam of the tube mostly on the bends. So now I'm sunk, I wont be looking for another frame, that would be nonsense. Why? you've only done work in the area where is's broken. THAT's CORRECT! why use old metal that's potentially rusted in the same way? So now I'm either going to get myself a simple ratchet style tube bender JD Squared Model 3 Tube Bender like the guys on locostusa forums had suggested and bend replacements myself or if I can get my friends in VT's Formula Baja Team to give me a hand have them bend them on a proper machine. Do this all based on the width I'm aiming for rather than force old rusted steel to conform to my crazy demands.

Letze · « **Reply #1 on:** July 23, 2012, 08:40:59 PM »

So After a long search for a shop who might be able to help me bend some new tubes I almost forgot about a family friend and my welding instructor, who happens to be the head of our community college's SAE Baja Team (lies, I didn't forget I just didn't want to beg

)

Here's their SAE Baja Vehicle.

After bugging him a bit he got back to me that he does indeed have the dies to bend the tubing I wish to use. YAY ME!... oh crap I only have 1 8 foot section and a bunch of scraps.

So I'll be waiting a little bit till I can proceed.

Till then I sat down and did a flat drawing of what I was hoping to get out of the bike so I dont have to go "imagine (blank)" and hope people understand me.

There is a bit left for interpretation for now but it'll give you a better idea of where I'm going with it.

Retro Rocket · « **Reply #2 on:** July 23, 2012, 08:59:09 PM »

Subscribed, interesting...

afkrejci90 · « **Reply #3 on:** July 23, 2012, 11:16:52 PM »

Definitely watching this. Old school looks with modern power

Syscrush · « **Reply #4 on:** July 24, 2012, 06:39:13 AM »

Intriguing...

Good luck with this, hope it works out for you.

Tews19 · « **Reply #5 on:** July 24, 2012, 08:03:06 PM »

AWESOME! subscribed

65Ch3v3LL3 · « **Reply #6 on:** July 24, 2012, 09:28:35 PM »

Should be an interesting build. Looking forward to seeing progress.

FrankenFrankenstuff · « **Reply #7 on:** July 25, 2012, 03:51:09 AM »

HOLY COW. I like.

Letze · « **Reply #8 on:** July 25, 2012, 02:48:36 PM »

STEEL IS HERE STEEL IS HERE!

So I got really excited as my brother brought this into the garage I was working on wire wheeling the possible rust areas so I could make sure the upper half was solid before we did the new lower frame. and to my surprise the steel showed up a day early

Dom 1-1/4 x 0.95 wall 3x8' lengths (cause why not!?)

Letze · « **Reply #9 on:** August 14, 2012, 05:36:08 PM »

Things got interesting today

Been really bugged bout how long this part took to sort out, this is mainly due to access to the machine shop at VWCC, so Today I finally got a chance to meet my new team mates on the SAE Baja Team, who offered a bit of insight on tube bending before I got started

Not pictured is the one tube I royally buggered up but the second two came out just fine, I was unable to do the whole lower half in the bender against my original wishes but this will provide results still close to my original design so I'm not to bothered by it.

Here's the Tubes beside the frame, kickstand mount has it sitting so the tubes don't line up in the shot but they will work out just fine. The buggered up tubing has the sections to join the back of the lower section to the upper half of the frame. More on that when i get my tube notcher.

Till then I leave you with a shot of my clean CBR600 motor, osha would throw a fit, but kerosene in a spray bottle with a tight spray blasts dirt out of the little tight areas it's hard to get a brush or scotch bright pad.

gnarlycharlie4u · « **Reply #10 on:** August 14, 2012, 05:40:16 PM »

you make it look so easy

afkrejci90 · « **Reply #11 on:** August 14, 2012, 06:19:26 PM »

Can't wait to see the end result

Gurp · « **Reply #12 on:** August 14, 2012, 08:57:12 PM »

Its going to be a awesome bike.
Cant wait to see it done

MRieck · « **Reply #13 on:** August 14, 2012, 09:21:45 PM »

Looks good. Why is there so much oil in those exhaust ports? Valve cover leaking?

sirdaft1 · « **Reply #14 on:** August 16, 2012, 03:33:39 PM »

A) I've always wanted a GSXR/CBR swapped shifter kart after seeing this years ago... gixxer kart gsxr 1000

B) Cannot wait to see your progress on swapping the CBR engine into your CB frame. I was just wondering what kind of undertaking that would be.

Subbed.

Radam · « **Reply #15 on:** August 16, 2012, 03:55:33 PM »

Looks like a good project to follow.

SOHC4 Cafe Racer Fan · « **Reply #16 on:** August 16, 2012, 03:57:00 PM »

That is absolutely INSANE!! I want one too!!

Letze · « **Reply #17 on:** August 19, 2012, 03:42:38 PM »

Quote from: MRieck on August 14, 2012, 09:21:45 PM

Looks good. Why is there so much oil in those exhaust ports? Valve cover leaking?

Honestly what you're seeing is wetness from the tarp and trash bag getting blown off of it from a storm (yes I have a garage and I left the motor outside) and then just dirt and oil from over the years.

So here's sunday's progress, I lobbed off the lower half of the frame, finished cleaning up the tubes, and right now it still needs a little help I'm going to go over those high spots by hand with a file so I don't go through the metal and have to replace the tail too, I can joke about it now but if that happens in a couple weeks I'll be quite mad.

So a little bit of advice for any one who wishes to do the same as I've done their first time out, without a proper jig, without any real experience in the matter. You will mess something up and you wont realize it until you start putting things together. where the tubes join the neck is my real anguish for two reasons.

First issue I have is that the tubes some how even after all of my measuring I managed to make it too long. I had aimed for an extra inch to give the CBR motor more clearance but some how I over shot that by 3 inches and I'm really not happy about it but I am able to solve the issue without re bending or cutting sections out.

Second problem, when I was mocking it up at the shop I didn't have the tank with me so I wasn't sure my clearance on the front end, as a result the tank has to be moved back an inch in order to clear the new front which I'm afraid will impact my visual plans but it's almost a lucky coincidence since I'll be getting more clearance for the GSX-R Forks so wile I'm not thrilled about it something positive did come from the mistake.

So until Tuesday when start cutting more tube to finish tacking the frame together

Cheers, Letze

luap · « **Reply #18 on:** August 19, 2012, 06:32:53 PM »

Man if the cb is gonna be as fun as that cart I want both.

Letze · « **Reply #19 on:** August 21, 2012, 06:42:45 PM »

I shouldn't have bought these damned hole saws.

"bi metal, cuts through steel" the heck it will... yes it was lubricated, yes it's a harbor freight pos and I should have known better.

So... Here's the super awesome bit in question, after the first test piece. which it didn't actually finish.

Which resulted in this after I twisted the remaining pieces out.

If you can tell it's off center, that's after I corrected it with some 1/16th inch thick washers because the tubing wasn't centered in stock configuration

So since I didn't get past the test piece I technically didn't make any real progress today, Good thing I still have this reciprocating saw another day. my battery powered one is a POS and this one is bad ass!

Syscrush · « **Reply #20 on:** August 23, 2012, 07:30:18 AM »

Those things are probably OK for mild steel, but hopefully you're using cromo.

sirdaft1 · « **Reply #21 on:** August 26, 2012, 09:32:56 PM »

Ouch.

Quote from: Letze on August 21, 2012, 06:42:45 PM

I shouldn't have bought these damned hole saws.

"bi metal, cuts through steel" the heck it will... yes it was lubricated, yes it's a harbor freight pos and I should have known better.

So... Here's the super awesome bit in question, after the first test piece. which it didn't actually finish.

Which resulted in this after I twisted the remaining pieces out.

If you can tell it's off center, that's after I corrected it with some 1/16th inch thick washers because the tubing wasn't centered in stock configuration

So since I didn't get past the test piece I technically didn't make any real progress today, Good thing I still have this reciprocating saw another day. my battery powered one is a POS and this one is bad ass!

Letze · « **Reply #22 on:** August 30, 2012, 06:09:37 PM »

After buying real hole saws I have properly notched tubes, a little bit of cleanup at the bench grinder has ensured they're nice and clean.

I had hoped to be at this point on Sunday but I was busy reorganizing my garage space with a new work bench and even a garage computer since I don't enjoy going back and forth covered in metal dust to my computer in my office.

Now, It almost looks like what I started with only fatter!

Retro Rocket · « **Reply #23 on:** August 31, 2012, 12:52:37 AM »

Nice work....

Syscrush · « **Reply #24 on:** August 31, 2012, 07:34:42 AM »

Lookin' good.

Do you have a dedicated tubing notcher, or did you set something up yourself?

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Author Topic: 76 CB750/GSX-R750/CBR600F2 Hybrid Build. (Read 20465 times)