Author Topic: My 1975 cb 750 Build (Read 17778 times)

PPG9944 · « **Reply #25 on:** January 05, 2015, 05:09:54 AM »

Calj, I already had to ditch the speedo unit from the front axle because the cb wheel wouldn't fit on the vfr forks. Someone suggested running the magnets on the front sprocket and sprocket cover for the speedo which sounds like a real slick and hidden idea.

I havent taken the rear of the bike apart yet so im not sure what im looking for in terms of the swingarm being bad. Am I looking for lateral movements?

Also thanks for the speedhut plug im going to have to check that out, never even heard of them before.

PPG9944 · « **Reply #26 on:** January 07, 2015, 04:19:21 PM »

Oh hell yea. Got some fun bits back from the engine shop. New valve guides. Fresh hone. I'm stoked to figure out how all this goes back together.

PPG9944 · « **Reply #27 on:** January 07, 2015, 07:56:05 PM »

Got a new cam chain in the mail too. Since it's FREAKING -25 degrees here in illinois currently I'll probably wait till the weekend to put this together. Need to read up on this stuff.

Riceman · « **Reply #28 on:** January 07, 2015, 08:05:50 PM »

That's what the kitchen is for,it has a nice work bench AND it has a
fridge ....

WhyNot2 · « **Reply #29 on:** January 08, 2015, 03:40:16 AM »

Quote from: Riceman on January 07, 2015, 08:05:50 PM

That's what the kitchen is for,it has a nice work bench AND it has a
fridge ....

and plenty of light, and solid floors, so when you drop one of those round thingys, it won't get lost in the dirt.

PPG9944 · « **Reply #30 on:** January 08, 2015, 04:15:48 AM »

Haha unfortunately I dont think the kitchen is an option for me. I didnt realize how many little seals go on the cylinder block. It's crazy

PPG9944 · « **Reply #31 on:** January 08, 2015, 07:17:00 PM »

Got the valve spring assembled with new valve guide seals. Holy #$%* was that a pain in the ass. That wrench has been my best friend throughout this build so far. Somehow I always defer to that thing.

PPG9944 · « **Reply #32 on:** January 11, 2015, 07:43:28 AM »

Starting Reassembly!

Scraped off the old base gasket remains

Looked in the oil pan. Determined things looked nice and clean. Cleaned it up and closed it back up.

In replacing the timing chain we went with this method. Grind off the ends of the links off one of the links and pop it out. Then used that removed link to clamp the new timing chain together.

This is how we felt after getting the chain replaced

Went to harbor freight to get a chain breaker, managed to break it within a half hour. Lesson learned haha

PPG9944 · « **Reply #33 on:** January 11, 2015, 07:48:33 PM »

Things were going so well until this happened. Oh well I tried getting away with using the original studs. Lesson learned. APE cylinder studs are on the way as well as a Pamco ignition. I'm stoked to see the thing resemble a motor again.

PPG9944 · « **Reply #34 on:** January 18, 2015, 07:06:35 AM »

Was able to get some stuff done yesterday. Had to sacrifice that base gasket due to the snapped cylinder stud. Called a few places but no one had one, oh well got a new one ordered.

Snapped cylinder stud.

To go about removing, we used the double nut method and some help from some vice grips. The broken stud we put a pair of vice grips on super tight, and tapped on the stud with a hammer while putting lateral force on the stud. After some swearing and a few slips we were able to back the stud out.

Since I couldnt find a base gasket, we installed the new pamco ignition that came in. I'm hoping for a reassembled engine next weekend.

PPG9944 · « **Reply #35 on:** January 22, 2015, 04:39:57 PM »

After a whole bunch of crap, this thing is finally starting to look like a motor once again! Going to retorque the nuts again tomorrow, and the on saturday I'll retorque again and drop the cam towers in and the camshaft. Should be a great time.

I also got my push pull throttle from motion pro. It will clean up my handlebars a little bit and keep things tidy.

So much to do but I'm stoked!

PPG9944 · « **Reply #36 on:** January 24, 2015, 04:57:11 PM »

WOO hit a milestone today! Dropped the camshaft in. I spent a lot of time reading posts regarding the cam tower and I went with Hondaman's technique of not using the 5mm bolts to hold the shafts in place and I drilled out the little oiling holes. I dont plan on racing this bike but hell I'll give it a shot. If it blows up then I'll rebuild it.

Need to learn about tappet clearances, timing and I need to figure out if the stator works or not.

PPG9944 · « **Reply #37 on:** January 26, 2015, 06:59:58 PM »

So I'm planning on running coils from a 2001 Honda Magna With the pamco ignition. Will I have any issues with this setup?

PPG9944 · « **Reply #38 on:** January 27, 2015, 07:18:55 PM »

Started making slugs for the frame and the rear hoop. Need to figure out how im going to bend the rear hoop still with no fancy tools.

And the covers started getting the red scotchbrite treatment. I have to spend a lot more time getting those brushed out.

PPG9944 · « **Reply #39 on:** January 28, 2015, 07:07:23 PM »

Some of you have fancy tools. I have a grinder and a vice. Had to taper that tube which will eventually be cut and used as frame slugs for the rear hoop.

Anyone know how to bend a tube without a tube bender? Does the sand thing work? Or sand and a little bit of heat?

PPG9944 · « **Reply #40 on:** January 29, 2015, 04:23:48 AM »

Ok that makes sense. I think I'm going to build a dye out of some wood to get the shape I want.

PPG9944 · « **Reply #41 on:** February 02, 2015, 06:32:38 PM »

Got some more covers polished up. And Adapted the stock coil mounts to the VF750 coils.

I had to mount the coils underneath rather than on top of the mounts. I think Im going to make a notch in the one bracket to lift the coils just a bit so I have some room.

PPG9944 · « **Reply #42 on:** February 06, 2015, 04:22:44 PM »

This came in the mail today. So pumped. It'll get painted so im not concerned about the state of the chrome at all. Hell yea!

PPG9944 · « **Reply #43 on:** February 06, 2015, 08:57:59 PM »

My buddy let me play with his engraver. This valve cover was already messed up so i wound up sanding the chrome off the top and then did that with a stencil.

PPG9944 · « **Reply #44 on:** February 08, 2015, 08:09:26 PM »

So I got that Breadbox soaking in some Evaporust to clean it up. I'll let it soak for another day and scrub it all good. I put it up to my carbs just to see fit and it seems like the Outer Carbs will line up but one of the inner carbs will be a little off. Can I get some rubber hose or something to make adapters or something.

Also i was thinking i should probably use the stock airbox boots which are a little smaller in diameter than the hole in the plate.

Any input on all this stuff would be excellent because I'm still a bit unsure of how it's all supposed to work.

Also for reference, the boot on the left is what is in the breadbox, the right is the stock CB750 air boot. Could anyone identify what the left one is off of?

PPG9944 · « **Reply #45 on:** February 15, 2015, 11:48:39 AM »

This thing cleaned up pretty good. I'm still doing research on how to make this thing work because the inner 2 holes are offset a hair to the carbs. Im thinking about getting the stock rubber stack intakes in there and then connecting them to the carbs with a radiator hose. Also tossing around the idea of using the stock airbox mounts to hook up up to the top of the box. The chrome is in pretty poor shape but it will get painted so I dont really care too much.

PPG9944 · « **Reply #46 on:** February 18, 2015, 05:37:38 PM »

Did a little cooking with some wintergreen oil. I put all the rubber boots in my pot with some water. Let that warm up then added the wintergreen oil. I only had 1 ounce but I'm hoping that will at least get the boots somewhat pliable.

This stuff starts out smelling not so bad and then turns into a pretty rough smell haha oh well.

PPG9944 · « **Reply #47 on:** March 07, 2015, 04:50:34 PM »

The weather in illinois finally warmed up enough to do things. I rebuilt the oil pump, checked the stator but I'm a bit unsure about it, I got a reading of .8 ohms between the 3 wires. Is that acceptable?

Looks pretty clean under there.

Getting that screen off was a pain but I got the oil pump split, replaced the gasket checked out the internals and replaced some o-rings.

And mounted back up.

Tested the stator and field coil. The field coil had a reading of 7.3 ohms which is cool but the Stator had readings of .8 between the 3 wires. Again, is that a problem? What is acceptable?

I also got the clutch lever and switches mounted from a 2003 honda cbr954rr. The controls will look cool. The speedometer is just a rough idea of what i want to do. Thinking about getting one of the acewell units.

PPG9944 · « **Reply #48 on:** March 10, 2015, 05:01:42 AM »

I'm definitely learning how to weld. The welds look like #$%* but I'll grind the excess off and clean up the spots that i missed. This thing will definitely look mean once I am done with it. I've got a few more ideas on what i want to do to this thing.

Vinhead1957 · « **Reply #49 on:** March 10, 2015, 06:12:32 AM »

A round surface is very difficult to stick weld. Have you tried gas welding? It takes time to master but it can be fun learning. Many welding suppliers have free learn to guides on their websites.

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Author Topic: My 1975 cb 750 Build (Read 17778 times)