• Announcements

    • WhiteWolf

      Donation Info   11/12/2017

      If we can make it thru to the end of March we will be good till then PayPal thechopperunderground@cox.net Thanks WhiteWolf
Crazy Cats

Another cb750

211 posts in this topic

5/3/10

Got the jugs on. That was a far bigger pain in the ass than I ever imagined it could be. I've rebuilt a fair share of motors, mostly harleys, and while I don't consider myself an engine builder per se, I do work on bikes for a living. I have never had a set of rings give me so much hassle going into the cylinders. It was a bitch. But it's done and the pistons move smoothly so I am assuming that they are in right. lol. I guess if I have no compression when I'm done I'll have a place to start looking. The head is on now also although I forgot to snap another pic. I'll be working on the top end tonight so I'll get some more pics of the progress.

photo2-26.jpg

photo-32.jpg

The engine paint I got is crap. I have a ton of chips that are going to need to be touched up.

Got the head on and torqued down.

photo-35.jpg

On to the cam and rocker goodies

photo5-3.jpg

The cam towers are in place, the cam is almost in, the sprocket is on it, just have to get the chain on there and drop it all in place then bolt the sprocket to the cam. Ran out of time before I could get it finished tonight.

5/07/10

Well I have the valve train all assembled and in place. I didn't take any pics of the process because my hands were all gooped up with assembly lube. All that's left up there is to torque down the caps for the cam towers. I'll try to remember to take some pics the next time.

Share this post


Link to post
Share on other sites

5/08/10

So I go to work, feeling pretty groovy. All that's left is to torque down the caps for the cam journals. Grab the torque wrtench and go to work. I have it set for 8 ft-lb. Click goes the first, click goes the second, click goes the third. The fourth just keeps on going. give it another turn, nope. One more...nope. This is what I get:

photo3-19.jpg

This is what the top of that stud is supposed to look like:

photo4-13.jpg

The %$@!*&%*&@% stud was pulling right up out of the head! I called Terry at TAS and he has another pack of locking inserts coming this week for me. I figure if this one is weak, I might as well do them all while it is apart. The bolt holes were already done. I should have been a stamp collector or something. Oh well, I'm going to throw a cover over the motor and work on the engine covers while I wait.

Share this post


Link to post
Share on other sites

This thing is gonna be sick. RC Engineering was the $h!t back in the day. You got some fairly hard to find parts in there. Can't wait to see how it turns out.

Share this post


Link to post
Share on other sites
This thing is gonna be sick. RC Engineering was the $h!t back in the day. You got some fairly hard to find parts in there. Can't wait to see how it turns out.

I'm really looking forward to this one running. I'm used to dealing with big horepower HDs, but this is a different animal all together. There is a nitrous kit sitting here just waiting for the frame to be ready so I can hang it. The bike will probably not see a lot of commuter time, but spend most of it's road time at rallys and such. I'm not shy about using the throttle though, so we'll be able to see what it can do.

Share this post


Link to post
Share on other sites

Great build on the engine,good detail,and you've made it easy to follow,thanks

Share this post


Link to post
Share on other sites

5/11/10

Here are a few more pics of the covers before and as I started smoothing them.

photo-37.jpg.

photo3-20.jpg

photo2-29.jpg

photo4-14.jpg

The original plan was to polish everything before powdercoating. I was going to use a transluscent red powder over the polished metal. I have several different metals though. There is the cast loonynum of the riginal covers, the billet loonynum of the oil filter adapter and points cover, the chrome plated steel of the starter cover and clutch cover, and whatever alloy the intake manifolds are made of. I decided to just clean and smooth everything then instead of polishing I am going to use a chrome powder under the red. That way everything should have the same shade.

Share this post


Link to post
Share on other sites

5/15/10

My oil filter adapter from Nater came yesterday. It looks awesome. I went out to the autoparts and picked up a filter for it today. I ordered a new switch for the ignition and a plug for the oil pressure switch hole. I found these scotchbrite discs for the 4 1/2" angle grinder. They did wonders for smoothing these parts out. I also switched my blast cabinet over to glass beads today. What a difference. It works very well and doesn't seem to dig into the surface as much. I was covered in dust and dirt and didn't want to leave the camera sitting in the dust so I don't really have progress pics. Here are a couple of shots after things have been cleaned up.

photo2-31.jpg

photo-39.jpg

photo3-21.jpg

photo2-30.jpg

photo-38.jpg

I still have to get them all masked and degreased to be ready for powder. Had to order the chrome powder. I could have sworn that I had some, but I guess not. It should be here midweek.

Share this post


Link to post
Share on other sites

5/17/10

Got a surprise when I came home from work today. Copperhedz machined me a new ignition cover and it was tucked in the side door. Just what I was looking for. He made it extra deep for me to help balance the sides of the motor.

photo-48.jpg

photo3-25.jpg

photo-43.jpg

5/18/10

Got home from work late today, so no real work got done. There were a couple of boxes waiting for me though. My inserts came in from TAS. I also got a box from mcmaster car. that one had my ignition switch and a couple of boxes of bolts for my head. One other little goodie was tucked in there though. It was a plug to plug the oil pressure sensor hole. It's a nickel plated brass pipe plug. The thread is 1/8 BSP, and it comes with a nifty little o-ring already in place. The part number for any one interested is 4860K125 and they run $3.22 each. I bought a couple. This is what they look like before and after installation.

photo3-28.jpg

photo4-16.jpg

photo2-40.jpg

photo-49.jpg

Share this post


Link to post
Share on other sites

7/02/10

Finally got back to work. Started doing the repair work to the head. As a refresher, this is the problem:

photo-58.jpg

You can see where the stud is pulling up out of the head. I started taking the top end apart. Cam caps and rockers off:

photo2-47.jpg

I have the cam towers and cam out of it too, but forgot to take pics. lol I'm going to pull all four of the studs and reinforce all of the holes as a preventative measure instead of doing just the bad one. I'll be out there working on it today, so more to come.

Share this post


Link to post
Share on other sites

7/04/10

It took me a couple of days, but I got back to work today. I had finished taking the cam goodies off last time. I pulled the oil jets and o-rings. Then out came the studs. I have a relatively inexpensive stud puttler from autozone and it works awesome. Hasn't failed me yet. Pulled a set of used spark plugs out of another head sitting on the shelf and put them in to plug the holes. The bottom the the stud holes is drilled all the way through into the chamber where the spark plugs go so I didn't want anything dropping into the cylinders.

photo2-49.jpg

I have these silicone plugs that I used to plug the oil jets as well as the return drain holes next to the valves.

photo3-37.jpg

Since it is on an engine stand, I am going to turn it on it's side so anything that gets past the nozzle of the shop vac will hopefully fall to the floor. I'm going to grease the drill bit and tap too to keep the loose chips to a minimum. More after lunch.

Share this post


Link to post
Share on other sites

7/06/10

Well I never made it back to work on the 4th. I got distracted by BBQ. Spent the afternoon doing family stuff. Did some work this morning though. The cam cap bolt holes opposite the studs were helicoiled to 1/4 20 thread. I'm not a big helicoil fan to start with, but I didn't like the idea of mixing bolt sizes either. You can see the remains of the hleicoil in the left hole here.

photo3-38.jpg

This is what they look like after they come out.

photo-63.jpg

Coils pulled and holes drilled for new inserts. Still have to do the stud holes. The holes for the studs are drilled too.. This is what the inserts look like.

photo2-53.jpg

The holes are drilled out to 5/16" then a standard 3/8" - 16 tap is used.

photo2-52.jpg

I have this handy dandy countersink tool. It is made for wood, but I use it to deburr loonynum holes.

photo3-39.jpg

All tapped and ready to go.

photo-64.jpg

Inserts are in. The bolt hole side is recessed enough for the dowel pins on the underside of the cam towers. The dowels fit very nicely inside the threads.

photo3-40.jpg

After doing the four holes on one side, I flipped the motor in tha stand and did the four holes in the other side. I plan on getting it put back together this afternoon. We'll see.

Share this post


Link to post
Share on other sites

7/06/10

I got her put back together. I took a few pics but for some reason they are not loading to photobucket. Nothing really earthshattering there though. The top end is together and I just need to install the cam chain tensioner then set the valve lash.

9/06/10

Well I finally had a few minutes to devote to this project again. I didn't make much progress, lol, but something is better than nothing. I wanted to get my starter cavity cover drilled for my switches and stuff before I powdercoated it.

elec.jpg

You can see the coil pack in the background. It is not mounted yet, but that is where it is going.

Share this post


Link to post
Share on other sites

Well that's it as far as past updates. This brings us up to today. Work is starting to ease up and it looks like I'll actually have time to ride this summer, so I figured that I better start getting the chops in order.

Did you ever have that feeling that something just isn't right? For instance, when you are leaving for the weekend and when you are about 5 miles away from the house you get that nagging feeling that you forgot to shut off the coffee pot? Well I was having something like that last fall about this motor. I just went about my business and tried to let it slip away. It was persistent though. I finally broke down and pulled the top end back off of the motor last October. Two of the cylinder studs were barely hand tight. So I reset them all. Finally put the top end back on it today. The valves are adjusted and it turns over smooth. Next step is to get back to the covers then I think that I'm going to swap it out for the motor in the Denvers just to break it in while I finish the rest of the bike.

Share this post


Link to post
Share on other sites

Thanks Kev, I can't tell you how helpful this thread is for me. Well done sir.

Can't wait to either pay you a visit or have you up here, maybe both if I'm lucky. Let's have a start up video.

I want to hear this bad boy run. :thumbsup:

I did get a good clean start up on my punched out motor in the fall so I will not be taking it apart again, if all goes well.

My goal is to test run it in the Lowlife here in April before cleaning it up one last time for the Voodoo Chop.

I'm still planning that "extra" goodie to bolt on to the motor as well when the time comes! :wink:

Share this post


Link to post
Share on other sites

Thanks Joe. I am ready whenever you want. Here or there. I'm really looking forward to getting this thing running. I want to get enough break-in miles on it before the BBB that I don't have to baby it. It'll probably still be in the Denvers. I'm hoping to have the rest of the bike done for Stugis this year. We are building a bike for the AMD show and I refuse to show up riding even a remotely stock bike. lol.

Share this post


Link to post
Share on other sites

oh noes, joe are you going to run your punched out bike on the dyno?.

and crazy cat, that engine is insane.

Share this post


Link to post
Share on other sites

Schooter, I haven't given that any thought as of yet.

Kev, didn't know you were going to Sturgis this year. Have you got a group from work going?

Share this post


Link to post
Share on other sites

Joe, that's the plan right now. We definitely have a group going, but the actual lineup can change depending on who is needed to stay at home and work. I don't have any vacation time though so the only way I can make it is as a working trip. I'll know more when it gets closer.

Share this post


Link to post
Share on other sites

Joe I sure will.

Well I need to expand this thread and add a bike to it. I want to put the motor in this bike for break in:

photo-66.jpg

This bike is actually the next project, more of a restoration than a build. It will serve my purposes nicely att his time though. I need to do several things to make this happen though.

1. A spray bomb paint job is in order just because the engine going in will have red covers on it so the blue on the bike needs to go.

2. One of the springrods is bent. I have it removed right now and new ones need to be made.

3. The needle bearings in the rockers need to be replaced.

4. One of the petcocks leaks and needs to be replaced.

5. I have the original full length 4 into 4 pipes that came with it. They need to be repaired since they are no longer available. One of these days I will have them recreated, but I don't want to spend the $$ right now.

6. The rear sprocket carrier needs to be changed to match the offset of the motor.

Share this post


Link to post
Share on other sites

I had a couple students start tearing a few things down. They pulled the exhaust, the carbs, and a good chunk of the electrics.

photo1-17.jpg

photo2-74.jpg

Share this post


Link to post
Share on other sites

wherever this bike is reminds me of PSI (power sport institute)

lovin the build!

Edited by Piglet

Share this post


Link to post
Share on other sites
wherever this bike is reminds me of PSI (power sport institute)

lovin the build!

lol...that's exactly where it is

Share this post


Link to post
Share on other sites

Had a couple guys pull the tank to get rid of the blue spots. The tank is covered with runs so they will be redoing that on monday. I'm not looking for fancy, lol, but there has to be a line somewhere.

photo3-58.jpg

photo2-75.jpg

photo1-18.jpg

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now