1971-ish CB750 with GSXR Front End and other bits

I am a long time lurker and figured I'd join this site and let everyone tear me a new one. Apparently that is the reputation this site has.

I have lots of experience with removing stock parts and putting new parts on, basic bolt on performance modifications, routine maintenance, and some slight vehicle alterations from stock. I have never done something like this CB750 build. With that said being, I am completely open to criticism, advice, help or anything of the sort from everyone on the forum.

Here is the bike the way I got it. It shows 51,xxx miles. Frame/motor are 1971 but some members on this site informed me that some of the other pieces on the bike are from a 1976.


I am using a '76 CB550 swing arm. The 550 is on the right. Stock on the left.

Overall the cb550 swing arm has the same dimensions as the CB750 but the 550 is slightly longer. I switched swing arms because the tubular steel looks better and flows with the rest of the frame. The stock stamped steel swing arm doesn't fit the look of the stock tubular frame. I also wanted a slightly longer swing arm since the stock '71 CB750 swing arms are too short in my opinion.

I picked up an entire 1996 CBR600 F3 for dirt cheap. Fairings and air box pieces are in the shed. This willl end up being another project down the road but for now I am stealing the rear rim and brake setup for the CB750. THe F3 has a 170mm tire mounted which is a nightmare to shoehorn into the CB550 swing arm


I think I could have got away with a 160mm tire on the back but my fabricator and I were drinking and decided to take a shot at modifying the swing arm to accommodate the 170mm tire. We had to widen it, install some plates to hold the caliper mount, mill the hud carrier slightly and also trim the left side a bit on the swing arm.



Seat design in cad and had it made. Dave's ebay store is located here http://stores.ebay.com/hotrodmetal



Cowl and seat pan needed some expected modifications.





I also changed my mind at the last minute and decided to use an upswept rear hoop.


So we modified the seat to flow with the hoop.



Will I ever experience a tank slapper on a "butchered" CB750? Probably not but fuck it. Let's mount the stock GSXR damper on here.

Re: 1971-ish CB750 with GSXR Front End and other bits I can't really afford

welcome
gixxer front ends on a vintage bike are just plane stupid, 'specially on a sohc 750
stand out in the driveway and slam yourself in the face with a brick till the dumb goes away

Re: 1971-ish CB750 with GSXR Front End and other bits I can't really afford

xb33bsa said:

welcome
gixxer front ends on a vintage bike are just plane stupid, 'specially on a sohc 750
stand out in the driveway and slam yourself in the face with a brick till the dumb goes away

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That's really rude. I prefer to make out with a shotgun and hope it goes off before I get to third base with it

Re: 1971-ish CB750 with GSXR Front End and other bits I can't really afford

hahahahah

you will need to brace the 550 swingarm it is not up to the task as is

Re: 1971-ish CB750 with GSXR Front End and other bits I can't really afford

xb33bsa said:

hahahahah

you will need to brace the 550 swingarm it is not up to the task as is

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Probably but we will see if I survive after the first attempt at 100+mph.

Re: 1971-ish CB750 with GSXR Front End and other bits I can't really afford

I must be missing something here. Why not modify the F3 swingarm. I hear that an F3 wheel fits in there nicely. ;-) And slip on the F3 complete front end while you are there - better brakes, and suspension and matching wheels.

I like Resto Mods, but why not clean up both bikes stock and flip them? I just hate to cut up a complete bike for parts - especially when the outcome is a bike that is not actually as good as either donor. I have some frankenbikes in my garage and I'm probably an addict when it comes to modifying bikes, but some are worth more stock and some projects are interesting but only to me and have very low resale value and sometimes are not worth the effort - let alone the cost. I'm just thinking out loud again.......

Re: 1971-ish CB750 with GSXR Front End and other bits I can't really afford

I really started to dislike that fat 1976 (I think) CB gas tank. Even though I have a fat chopper like rear tire on here. The rear axle spacers have not been machined yet so the rear wheel is cock eyed.


So I picked up a '74 CB500t tank that has very subtle knee dents stock. The tank cost me $25 and was clearly used as a punching bag by a redneck which is fine. I'd rather he beat this then his dog or wife.
The CB500T tank was hammered out to clean up all the dents. The C mounts were relocated about 1/4 back. I am not sure if they are called C mounts but they are the brackets located on the front of the tank that slip over the rubber mounts located on the frame. The back of the tank had about 1-1/2 inches removed. Sand blasted the inside before tig welding it back up.





The tank came off a twin so we needed to make some space for the outer carb/throttle linkage and relocate the petcock.



Pressure testing. Hopefully won't catch on fire.

Re: 1971-ish CB750 with GSXR Front End and other bits I can't really afford

teazer said:

I must be missing something here. Why not modify the F3 swingarm. I hear that an F3 wheel fits in there nicely. ;-) And slip on the F3 complete front end while you are there - better brakes, and suspension and matching wheels.

I like Resto Mods, but why not clean up both bikes stock and flip them? I just hate to cut up a complete bike for parts - especially when the outcome is a bike that is not actually as good as either donor. I have some frankenbikes in my garage and I'm probably an addict when it comes to modifying bikes, but some are worth more stock and some projects are interesting but only to me and have very low resale value and sometimes are not worth the effort - let alone the cost. I'm just thinking out loud again.......

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The decision is purely based on looks and....ignoring common sense? I like the CB550 tubular steel look cause it goes with the rest of the frame. The F3 swing arm is a big ugly rectangular piece that would probably be stronger in my application. The stock rear swinger on the F3 will stay on the F3 since I'd like to put that bike back to stock or do a project with it. Plus a replacement wheel, tire, brake setup is cheap to put back on the F3. I also have a spare kawasaki zrx1200 swing arm that I may use on this project that would be better suited if I choose to add some bracing on the back end.
I have a ton of 06-07 GSXR750 parts due to racing my gsxr and acquiring spares so that's why this has the front end it does.
The CB750 will handle better than stock but that is open to one's own personal taste.

Re: 1971-ish CB750 with GSXR Front End and other bits I can't really afford

Rearsets and cognitomoto bracket.


Added a piece for the rear master.

Re: 1971-ish CB750 with GSXR Front End and other bits I can't really afford

Seat and the oil tank is from cognitomoto

Re: 1971-ish CB750 with GSXR Front End and other bits I can't really afford

I think the exhaust that came on the bike is a MAC 4 into 1. I'd love to have a stainless steel exhaust on this but I've already blown my initial budget out of the water.
Added some steel to the original mac exhaust to extend and angle it up. Added a mounting tab to the rearset bracket and a tab on the muffler to hold everything in place.


I took the basic Bates Style 5.75" Black Bottom Mount Headlight and replaced the H4 60/55w bulb with an LED unit.
A lot cheaper than other LED headlight units I have found.

It's rated at 3600 lumens, 5600K color temp, 20 watts on low and 30 watts on high. It is significantly brighter than the H4 bulb and half the wattage. The rest of the bike will have LED brake/running and turn signals.

All the fabrication work is complete (I think) so the bike will be stripped down soon and sent off for paint and powdercoat. I'll post up the engine build shortly. Just a basic build with electronic ignition, minor headwork and rebuilding/tuning the carbs.

Re: 1971-ish CB750 with GSXR Front End and other bits I can't really afford

you are just building a poser drag queen anyway stainless steel paint you can get in a rattle can

Re: 1971-ish CB750 with GSXR Front End and other bits I can't really afford

xb33bsa said:

you are just building a poser drag queen anyway stainless steel paint you can get in a rattle can

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Yeah but the rattle can won't get me that super duper raw metal color change to match your mom's eyeliner as she rides around on the gas tank with me.

Re: 1971-ish CB750 with GSXR Front End and other bits I can't really afford

GNGSXR said:

Yeah but the rattle can won't get me that super duper raw metal color change to match your mom's eyeliner as she rides around on the gas tank with me.

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oh thats funny,real funny

Re: 1971-ish CB750 with GSXR Front End and other bits I can't really afford

That's a nice looking build. The CB500T tank has always been my favorite. It definitely enhances the appeal.
You've got some pretty good fab skills for a poser. Rear sets look good too,

Re: 1971-ish CB750 with GSXR Front End and other bits I can't really afford

yeah, those rear shocks and anything else from cognito moto would blow my budget out of the water too. nice looking build though! good call on the last minute upswept tail decision. always looks better than flat in my opinion.

I like the whole look. Nice job, waiting to see painted.

This is a nice build, however that GN peeking out caught my attention, all stock?

erock85 said:

This is a nice build, however that GN peeking out caught my attention, all stock?

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Not stock. Just a bunch of bolt ons and built transmission at the moment. I've been too occupied with two wheeled vehicles to give it more attention.

Can you post source and further specs on the LED headlight?. I dig the bike and where you are going with it. I'll be curious to see how the 550 swinger holds up to the heavier loads of the 750.