Topic: 1971 CB750 with GSXR Front End

[SOHC4 Cafe Racer Fan]

I bought a spare stock GSXR fender but might try a similar bobbed modification if yours goes well.

[GNGSXR]

Anyone know the length of the battery strap?

http://www.vintagecb750.com/products/5/electrical/55/wiring-harnesses-and-charging-system-parts

Trying to fab up a little section in the tail for my battery and will maybe use one of those straps to keep it held down.

[GNGSXR]

Any measurements on the rear axle spacers? I have a DOHC model but just wanted to get an idea. I have the same CBR rim with a 160 tire.

These are the custom spacers I had made.
Right rear spacer


left rear spacer


DO NOT MATCH THESE SPACER SIZES if you are doing the "same" swap as me. Yes I used a '96 CBR600F3 rear rim but It has a 170 mm tire which is larger than the stock 160 mm.  The rear swing arm (which i used a cb550 swinger) was widened with the use of a high temp blow torch and the expertise of someone who has been doing metal fabrication for 30 years.

[GNGSXR]

I took the basic Bates Style 5.75" Black Bottom Mount Headlight and replaced the H4 60/55w bulb with an LED unit. http://cognitomoto.com/collections/lighting/products/h7-led
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.

[GNGSXR]

These are the tail lights I will be using. Purchased them from revival cycles. http://store.revivalcycles.com/collections/lighting-1/products/led-light
2 reds for running/brake light duties and turn signals.
The fronts will be the motogadget mblaze



Made some frame tabs out of spare steel for them. Trying to figure out a good spot for them


They are extremely bright. Almost bright enough for me to feel bad for the people behind me. Almost.

[GNGSXR]

All the electrical devices haphazardly laid out. M-unit, battery, starter solenoid, regulator, rectifier. I wish I would have purchased a reg/rect combined unit but oh well. These have a lifetime warranty from oregon motorcycle parts.
I want a clean underside of my tail so nothing will poke threw. I'll need to weld some platforms in the rear tail section to keep all the electrical devices off the rear pan and not just bouncing around in there under the cowl.

[GNGSXR]

I am going to weld a plate in the location shown in an effort to not have an ugly license plate ruining the lines of my rear tail section. I'll install some white LEDs to light up the plate at night. I wonder if the cops will have an issue with this location.

[reedrunner23]

Any measurements on the rear axle spacers? I have a DOHC model but just wanted to get an idea. I have the same CBR rim with a 160 tire.

These are the custom spacers I had made.
Right rear spacer


left rear spacer


DO NOT MATCH THESE SPACER SIZES if you are doing the "same" swap as me. Yes I used a '96 CBR600F3 rear rim but It has a 170 mm tire which is larger than the stock 160 mm.  The rear swing arm (which i used a cb550 swinger) was widened with the use of a high temp blow torch and the expertise of someone who has been doing metal fabrication for 30 years.

Nice! Where did you have those made or did you do that? I bought some washers to try and get an idea and then I am going to have some made.

[reedrunner23]

Also that M-Unit is sweet. I found a place that sells them for $310 plus free shipping but still havent pulled the trigger. Def want to hear about it when you get it wired all up.

https://www.moto-madness.com/motogadget-munit-digital-control-center-v2-p-1285.html

[SOHC4 Cafe Racer Fan]

Also that M-Unit is sweet. I found a place that sells them for $310 plus free shipping but still havent pulled the trigger. Def want to hear about it when you get it wired all up.

https://www.moto-madness.com/motogadget-munit-digital-control-center-v2-p-1285.html

That's the best price I found for the M-Unit.  Moto-Madness does not have the full line of Motogadget products, but they have the best price on that one.  Revival seems to carry most of the Motogadget line.  They have a sweet Black Friday sale on the weekend following Thanksgiving, too.

[GNGSXR]

Turn signal and brake/running light tabs welded on.



Tabs for the aluminum plate that the license plate will be mounted too.

[GNGSXR]

Tank that came with the bike.


The CB500T tank that was modified to fit on here.


Soooooo much work just so I could get a tiny bit thinner tank. The  tank was shortened by about an inch from the back and the "saddles" on the front were relocated. We also had to modify this area to allow the carburetors to do their job.


Getting set to pressure test it. It only needed a couple spots re-tigged to make sure I don't catch on fire.


I think all the welding and fabrication work is complete. The only little things I can think of left to do are relocating the horn and figuring out how to mount the magnet/pickup for the acewell speedo.

[GNGSXR]

I plan on riding this bike a lot. More so up in the mountains along with around town. I have seen a lot of regulators/rectifiers burn up when they are not positioned in a place to get proper airflow. The cowl area would get zero airflow so I decided to mount the regulator, rectifier, and starter solenoid here. I was originally going to mount the solenoid closer to its original location anyways cause extending that stock wire is not possible in a way that I am comfortable with. If you take a look at it's connection to the stator then you will know what I mean. It was a toss up between let the electrical devices bake in an almost sealed off box or put them here as shown. Yes there is residual heat from the oil tank and motor but I hope this is better considering it will get airflow.


It will almost not be noticeable with the bracket powder coated black, maybe spray the regulator black, put black rubber boots on the starter solenoid. I have some weather pack connectors to install as well on these devices.

[SKTP]

WOWZERS! This thing looks amazing

[SOHC4 Cafe Racer Fan]

Tank that came with the bike.


The CB500T tank that was modified to fit on here.


Soooooo much work just so I could get a tiny bit thinner tank. The  tank was shortened by about an inch from the back and the "saddles" on the front were relocated. We also had to modify this area to allow the carburetors to do their job.


Getting set to pressure test it. It only needed a couple spots re-tigged to make sure I don't catch on fire.


I think all the welding and fabrication work is complete. The only little things I can think of left to do are relocating the horn and figuring out how to mount the magnet/pickup for the acewell speedo.

That "little" bit of custom will make you smile when someone spots it.

[GNGSXR]

I didn't realize there was a hole under the cowl/seat area. Well I did but I just assumed the vertical part of the cowl covered this hole. I was wrong. The back of the bike is to the left in the picture. I think I will get enough airflow up into the cowl area especially with how the license plate bracket will be mounted. Time to relocate stuff again. The starter solenoid will most likely go above the K&N filters.

[Zax]

Great project, Any chance of getting details and maybe some pics on the CB550 swing arm mods to allow for the 170mm tire?

Zach

[Badluckhonda]

Hey man quick question when you used the 550 swingarm did you notice that one side of the pivot point was offset more then thee other ? I ask because I wanna do the swap and I'm afraid my stock 750 wheel won't line up anymore

[calj737]

The stock left side of the 550 arm is more offset to allow space for the sprocket.

[Badluckhonda]

Do you think the offset will allow 750 sprockets to align, using the 750 wheel and spacers ?

[calj737]

Should not be a problem to get the 750 wheel to fit. You might need to adjust your spacers slightly depending upon year of wheel etc.

[CognitoMoto]

Should not be a problem to get the 750 wheel to fit. You might need to adjust your spacers slightly depending upon year of wheel etc.

I did this on my cb750. I had to play with the spacers on the back to get wheel centered again.

[7aliveatlast7]

Holy cow, what a nice build! That 500 tank was a lot of work, but details like that are what set bikes apart from others. Late to the party, but tuned in!

[spiffy587]

I have a 77 750k and am trying to run a 550 swing arm the gap between the two where the axle slots are is 1". Not sure if that is too much to widen the 550 swingarm.

[GNGSXR]

Hey man quick question when you used the 550 swingarm did you notice that one side of the pivot point was offset more then thee other ? I ask because I wanna do the swap and I'm afraid my stock 750 wheel won't line up anymore

It should be fine. Just play around with the spacers a bit.