Topic: My First 76 CB750f Supersport Cafe Build...

[vargas]

Hey everyone. I'm new here on the forum and have recently started a cb750 supersport cafe build. It all started because I had some extra room in the garage and needed to replace fork seals, its funny how things work out. Now it has become quite the project so I thought I would share and ask lots of questions as building bikes is entirely new to me as are piston motors!

As of now the list of things to do are as follows:

wheel bearings
steering bearing
fork seals
polish aluminum bits
re-lace wheels
head gasket
fiberglass cafe seat
rear brake master cylinder rebuild
brakes all around
powder coat frame, swingarm, and rims
fab an oil reservoir
rewire the bike

As of right now I have a few questions some will be very newbish!

1. Does anyone know what equipment is required in the state of colorado? Horn, blinkers, that sort of thing?
2. I didn't measure the front hub offset before unlacing my wheel. I read hondamans thoughts and it seems like it was originally 3mm or 5mm, but he recommends that you align it with the rear wheel. Is that correct?
3. Here is the newb in me! Whats the tool called to remove the "washe/nut" that holds the front wheel bearing in?
4. And again here is a good one! Whats the part of the engine technically called between the cylinder head and the crank case? And can I replace the head gasket without disturbing the seal between the two?

I will post pictures up tonight or tomorrow. I currently have a few aluminum pieces polished and almost have the bike stripped to the frame. the first order of business is getting the frame and rims off to be powder coated.

[KB02]

1. Does anyone know what equipment is required in the state of colorado? Horn, blinkers, that sort of thing?
   Check with an inspection station. They can tell you what you need/what they look for for.

4. And again here is a good one! Whats the part of the engine technically called between the cylinder head and the crank case? And can I replace the head gasket without disturbing the seal between the two?
   Cylinder block. Or Jugs. 

Sorry, I'm not much help on the other two questions.

Got any pics of the bike?

[Little_Horse]

Before sending the frame to the powder coater, take your time to decide what stays and what goes so that if for example you are not keeping your side covers then you can remove your tabs. This way your frame is clean and thought out so you don't have to consider then chopping your nicely PC'd frame later. JMO

[vargas]

thanks guys, here is the most complete picture i could find of the bike. it has a decent profile when there's not a 8' bench for a seat still attached! as of now im removing all helmet brackets, seat lock, oil reservoir brakets, air box brackets, and horn bracket. i think the horn is required and will probably have to make a mount for it later, but im not worried at this point.

can anyone think of any other brackets that are typically removed. my goal is to be able to see through the frame  where the oil reservoir was.

i spent a couple hours last night trying to remove the motor from the frame. one of the thru frame bolts were badly bent, it looks like the bike must have been in an accident at one time. anyone have any motor removal tips?

[vargas]

Here are some pictures of the shinny bits. Polishing takes way too freakin' long. This is as shinny as I will make them.

[Little_Horse]

The polishing looks good, the only advice I have for removing the engine with the bent bolt is to push the motor up with a jack to relieve as much weight as possible off of the bolt, then wiggle an hammer until it is free, if possible.

[rickmoore24]

To remove the motor, strip the bike down; to the frame if that's where your going, loosen the mount bolts. Tilt the frame and motor on its right side. Support the motor with some 2x4's on the right side (points side), then fully removing all the motor mounts and lift the frame from the motor. I've done it with no help and yes, I broke a sweat. I recommend enlisting a friend if possible. Good luck!

[vargas]

yea that's the new plan. i tried lifting it out of the side by myself but that's just crazy. here's a pic of that bolt. ill be needing a new one of those :/ the right side is bent backwards too.. but u cant really tell from the pic.

[vargas]

....and finally got some work done.





rims were powder coated gloss black. i have one reassembled so far.. but not trued. im pretty sure i got the spoke pattern correct, but the perspective from the camera makes it look strange. i bought a new set of spokes from ebay (not the best idea) they were rather cheap but the spokes don't quite fit how they should and are slightly smaller diameter than the oem ones.. we'll have to see how it trues up with them.

triple tree has also been coated and the front fort assembly is about ready for reassembly. I also chopped all the brackets off the frame and sent it out to get coated, should be back in a week or so.

[Little_Horse]

that wheel looks killer

[flaherty500]

Vargas,

I'm in Colorado too, up near Boulder.

I have been riding a bobber that is pretty stripped down no signals, 1 mirror, no fenders and I haven't had any trouble as of yet (that yet may be the key word).

[vargas]

flaherty500, how do you feel about the no fenders thing?  I was thinking about doing the same but dont like the idea of being hit in the chops by road debris. Also did you add a bracket inplace of your front fender spanning the fork tubes? I hear thats kinda important.

[vargas]

and another shinny piece!



So far i have the rims, frame, swing arm, and triple tree powder coated gloss black. The frame was striped of most of the brackets. All the pieces are starting to look super clean.  Next on the list is get the motor cleaned, polished and painted... then true the wheels. Then I'll buy a new steering bearing and will start reassembling. Anyone replace a steering bearing before? Tips would be great.

[traveler]

Nice build!

Welcome to the forum.

~Joe

[vargas]

LET THERE BE SHINNY PARTS!




update.. school is out so im back to working on this old pile of parts.  assembled the fork tubes this evening and started getting the motor prepped for a good cleaning and some paint.  i also started designing a rearsets for the bike. found some cheap anodized aluminum foot rests that i will try to incorporate.

[vargas]

before pics...







After Pics

[Jerry Rxman Griffin aka MuthaF'er]

Looking good Vargas. Fill in your info so we'll know where you are. Too bad that's an engine mount bolt rather than the swingarm bolt. I have 2 NOS swingarm bolts and can only use one. If you should happen to find new engine mount bolts please let me know!

[boulder74]

Vargas,

I'm in Colorado too, up near Boulder.

I have been riding a bobber that is pretty stripped down no signals, 1 mirror, no fenders and I haven't had any trouble as of yet (that yet may be the key word).

Colorado rider as well.  You don't have to have signals as long as you do hand signals..or at least get caught Not doing hand signals.  The cops do have better things to do unless you are in Northglenn :-)  just watch your back on 25 and 70...people drive with blinders on

[vargas]

Fill in your info so we'll know where you are.

Fixed. Yea I will have to source a new engine mount bolt, the old bent one cant be reused. I was barely able to get it out of the bike. Ill post info about it when I find one.

boulder74 your nuts for riding on 25 or 70! hell Im nervous driving my cars on 25!

[vargas]

"Warning: this topic has not been posted in for at least 180 days.
Unless you're sure you want to reply, please consider starting a new topic."

I think the forum is telling me I need to work on this thing a little more often!

Current status: still needs lots of work




In moving I have also managed to loose a couple components that seem pretty important they are the Starter Gear, Plate and Pin. If anyone has a spare I could really use it. Thanks.

[vargas]

Back from the dead.. still working on this thing. Now I have a new engineering degree, a new garage, and more free time to devote to the bike.

Next on the list is rebuilding the braking system. I opened up the rear brake brake reservoir and it was full off what looked like mud. The rebuild kit for the rear master cylinder for a 1976 is rather difficult to find. I ended up purchasing a front master cylinder rebuild kit and it appears to have many of the same components as the rear. If a person was in a pinch, it looks like they could use a front rebuild kit to rebuild a rear. You would have to reuse the old push rod and dust boot though.

It looks like a rebuild kit from a 1979 cb750F has the correct parts for the '76. I'll have to order one to find out.


In the process I found that my rear calipers are frozen solid now. Anyone have a good trick for freeing and removing the pistons from the caliper? They are soaking in some penetrating oil now.


Before Shots:










I'm also debating if I should paint the calipers black, or try to put a polish on them. Might pick up a vibratory bowl and see if I can easily put a nice burnish on them.

[Stev-o]

Congrats on the degree, now you can put some of that knowledge to work on this bike!

Do you have a grease gun? If yes, connect it to your caliper (you need an adaptor) and pump that piston right out.

Nothing better than a polished caliper in my book.  I'll be installing one on my K4 next month....

[vargas]

Thanks, it was a lot of hard work.

That's a pretty clever idea. I don't have a grease gun but I do need to add one to my growing tool collection. In the meantime, I may try some compressed air to see if that will break it loose... hopefully without launching the piston across the garage.

[vargas]

Back at it. I ended up reassembling the brake caliper to use the hydraulics to force the Pistons out. Worked well. Now to blast and powdercoat. Any color recommendations? Also finally got tires and a new tank since the old one was in such bad shape.

I have been thinking about cutting the frame off right behind the seat cross member.. wish I would have done that before powder coating the frame tho :/

[vargas]

Rear brake caliper rebuild: Done.

Before:



After brushing paint off with brake cleaner and tumbling with green resin media for about 6 hours in water and 2 hours dry:

The green media was a bad idea. The residue clogged the small 1/8" hydraulic passage from one piston to the other side and it took about 6 hours to get it unplugged.



After tumbling in stainless steel nuts (1-2 hours) then a tumble in wallnut shells saturated with polishing compound (4-6 hours):

I would have tumbled longer in stainless steel however I didn't have enough nuts. I probably should have used 3000 1/4-20 nuts for the 18lb tumbler from harbor freight. I bought 1000 for about $40 shipped.



Assembled:



If anyone plans on making parts look nice.. the harbor freight 18lb tumbler isn't a bad choice. The hard part is getting the right media to do the job. The stainless steel nuts were doing a great job on aluminum and I'm willing to be that they would also impart some strain hardening of the components too. Overall I had about 2 hours worth of actual work into the rear caliper. That's aside from the 6 hours to unplug the hole. Lesson learned. If I were to do it again, I would place a good piece of cord or wire through the passage before tumbling and then use that to help clean it out afterwards. The resin residue became very hard after it dried and was difficult to clean out.