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Author Topic: CR750-ish Replica Build  (Read 4590 times)

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Offline Reasonably Fast Zack

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CR750-ish Replica Build
« on: April 29, 2012, 06:57:35 PM »
So I've nearly completed a CR750ish-replica, and I'd figured I post start to finish photos to encourage anyone else considering this project. I've derived much information and inspiration from the forum here, thanks to all who have contributed knowledge for the consumption of new-comers like me!

So....here we go. She started out as a very dirty 1977 CB750F2.


Yuck.


Uh, yea, that's a car muffler clamped on there...


Mocking up the tank and tail from airtech kept me motivated though.


Then it was a matter of taking it all apart...


...sandblasting and cutting (my neighbors love when I do this on my front porch)...


...cut off the posts for the handlebars (went with clip ons)


...polishing...


...and setting up a paint booth in the garage....


(a gluten for punishment, I was painting and working on a Kawaski H1 at the same time, seen in the background in some pics)


Post paint, mocked up again...


Mounting the bodywork was less than scientific...


Had to weld a bracket up for the front mount.  I needed to add material to the steering stops (that triangle shape) otherwise the clip-ons would hit the tank.


I got creative and bent some aluminum to make a bracket off the head.


Ended up trimming more than I planned, the airtech bodywork is a tight fit, so I cut around the ignition and magneto.




Refaced the gauges (removing the needles were a ridiculous pain. Broke the two tachometers before finally getting it right).


Then I had the tank and tail painted. Also swapped the comstars for wire wheels. Found a F1 spoked rear hub with the disc brake, and I laced it onto a set of CB650 rims I bought.


Final pics in next post!
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Offline Reasonably Fast Zack

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CR750-ish Replica Build Final
« Reply #1 on: April 29, 2012, 07:05:46 PM »
And then I painted the fairing myself


And started to decal her up


To end with this!















All told it, took about 2 summers to get everything to where it is now. There's lots of other work that went into it, but not worth photographing. I hit a ton of snags along the way, but got through most of them after taking copious notes from the postings here. Thanks for hosting such a great site! Hope you all have the best of luck with your projects!
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Offline Steve_K

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Re: CR750-ish Replica Build
« Reply #2 on: April 30, 2012, 04:47:36 PM »
Nice bike and I do like the paint colors!
Steve
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Steve_K

76 CB 550, 73CB750, 86 GSX-R750, 16 Slingshot
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Offline cmonSTART

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Re: CR750-ish Replica Build
« Reply #3 on: April 30, 2012, 05:51:07 PM »
Very cool!  I love that look!

Did you reuse the stock headers?
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Offline CBGhia

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Re: CR750-ish Replica Build
« Reply #4 on: May 01, 2012, 08:06:25 AM »
I love this.  One day I would like to build one like it...  one day.
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Offline Reasonably Fast Zack

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Re: CR750-ish Replica Build
« Reply #5 on: May 02, 2012, 06:06:48 PM »
Thanks for the compliments. Yes, I used the stock headers, I had to trim the fairing  a bit to accommodate it, as I was quite brave enough to try and bend the pipes in...
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Offline FrankenFrankenstuff

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Re: CR750-ish Replica Build
« Reply #6 on: May 02, 2012, 07:13:50 PM »
This was such a satisfying thread to scroll through. If there was any BS, I didnt see it. Great job with all of your hard work and fitting. Just let me know when I can come by for a whip on that thing.
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Offline Toxic

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Re: CR750-ish Replica Build
« Reply #7 on: May 03, 2012, 08:20:12 AM »
Stunning bike.

On both sides of the fairing , are they not too close to the header pipe?  They look like they are almost touching. 

Great fitment of that fairing
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Offline Mugen_Stumpo

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Re: CR750-ish Replica Build
« Reply #8 on: May 03, 2012, 11:52:40 AM »
i like everything minus the rear light/plate holder, side marker combo... looks really out of place


the bike is fantastic nevertheless
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Offline lucky

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Re: CR750-ish Replica Build
« Reply #9 on: May 03, 2012, 06:14:59 PM »
Great job!!! What a transformation. I would seal up the ends of those rear frame rails.
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Offline andy750

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Re: CR750-ish Replica Build
« Reply #10 on: May 03, 2012, 09:54:14 PM »
Very good detail on the photos and great finish. Looks really good! How does it ride with the fairing? Does it help with the wind?

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1. CB750K4: Long distance bike, 17 countries and counting...2001 - Trans-USA-Mexico, 2003 - European Tour, 2004 - SOHC Easy Rider Trip , 2008 - Adirondack Tour 2-up , 2013 - Tail of the Dragon Tour , 2017: 836 kit install and bottom end rebuild. And rebirth: http://forums.sohc4.net/index.php/topic,173213.msg2029836.html#msg2029836
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Offline Retro Rocket

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Re: CR750-ish Replica Build
« Reply #11 on: May 03, 2012, 10:08:28 PM »
Very nice bike, the only thing i don't like is the fairing is crooked on the left hand side looking from the front, look where the fork tube meets the fairing and you can see it is pulled inward, pr4obably where it is joined to the bracket, it pulls everything out of square. Yea, i am anal retentive, it would annoy the hell out of me.... :o
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Offline knowsnothing

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Re: CR750-ish Replica Build
« Reply #12 on: May 04, 2012, 06:36:11 AM »
Quote from: Retro Rocket on May 03, 2012, 10:08:28 PM
Very nice bike, the only thing i don't like is the fairing is crooked on the left hand side looking from the front, look where the fork tube meets the fairing and you can see it is pulled inward, pr4obably where it is joined to the bracket, it pulls everything out of square. Yea, i am anal retentive, it would annoy the hell out of me.... :o

I noticed it too Retro, but I didn't want to hurt anyone's feelings  ;)

I was thinking the headlight might be off center, but I think you are right about the bracket.
« Last Edit: May 04, 2012, 06:37:48 AM by knowsnothing »
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Offline FrankenFrankenstuff

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Re: CR750-ish Replica Build
« Reply #13 on: May 04, 2012, 07:17:21 AM »
Quote from: knowsnothing on May 04, 2012, 06:36:11 AM
Quote from: Retro Rocket on May 03, 2012, 10:08:28 PM
Very nice bike, the only thing i don't like is the fairing is crooked on the left hand side looking from the front, look where the fork tube meets the fairing and you can see it is pulled inward, pr4obably where it is joined to the bracket, it pulls everything out of square. Yea, i am anal retentive, it would annoy the hell out of me.... :o

I noticed it too Retro, but I didn't want to hurt anyone's feelings  ;)

I was thinking the headlight might be off center, but I think you are right about the bracket.

I think it looks very race specific. Somone dig up a pic of a back in the day racer from the front. I am digging the whole package. No BS polishing and extra add on. Even the tail light I didnt notice until it was pointed out. Just looks to me like it needs to pass inspection to be road legal. Its funny, I think it would be even better to ride the thing dirty in the rain. Ride on some fresh pavement and get some dare I say "patina", or even some bumps and scratches from being used. I have seen some CR750 bikes...they are always a frigging virgin looking trophy wife...I want to see the bike that just wants to go and get stinky nasty on some sideroad...put it away wet. Dang now my heart is racing.
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Offline Reasonably Fast Zack

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Re: CR750-ish Replica Build
« Reply #14 on: May 04, 2012, 08:22:12 AM »
Yes the headers do touch the fairing a bit, I tried trimming around them, but the more I do that the more the fairing relaxes and squishes up against the pipes again anyways. I presume the actual CR750's pipes would tuck in tighter than the CB750F's.

The fit of the Airtech CR750 fairing is not the best, or at least the one I received didn't fit perfect. The warping on the right side of bike (left if looking at the front) isn't due to the bracket, its because the fit is so tight. It could be remedied, but it would require taking off a lot of material, particularly around where the fairing folds in towards the steering stem. It got to the point where I just didnt want to trim anymore off.

Lol, yea the tail light set-up was temporary so I wouldnt get pulled over while riding. I bent a bunch of pieces of aluminum to build that, but that was before I had a welder, so I'll come up with something cleaner later on.

As far as the fairing and wind protection goes, its doesnt make a big difference. In fact, with the fairing on, the clip ons have to be put on quite low, so the stretch to reach the clip ons is ridiculously long. Without the fairing, you could move the clip ons up, which would be much more comfortable in general.
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Offline DORIGTT

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Re: CR750-ish Replica Build
« Reply #15 on: May 05, 2012, 10:06:40 PM »
Anything to be concerned about with the Airtech tank and crashing or fuel eating through the tank at all?  I'd like to do a similar build up, but am concerned about tank issues and most aluminum tanks I've found are only $1,000,000.
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Offline Reasonably Fast Zack

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Re: CR750-ish Replica Build
« Reply #16 on: May 06, 2012, 07:18:53 AM »
Yes on all the above. Its certainly possible that a low side crash could jam one of the clipons into the tank, rupture the fiberglass, and spill fuel everywhere, possible catching fire....

Airtech recommends using 100 octane plus fuel (I dont know the chemistry behind it, but they say 100 plus won't eat away the fiberglass). If using pump-gas, then you're supposed to coat the tank with an epoxy. I coated it with Caswell Coatings, but for some reason the coating delaminated over the past winter when the tank was empty, so that needs to be redone.

For safety sake, I'm thinking of cutting out the bottom of the fiberglass tank, and having it sit over a smaller metal tank. The outside look should end up being the same, but I'll just have a smaller, ugly, metal tank inside it.
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