Author Topic: 1970 CB750 build (Read 9103 times)

Cruzader · « **on:** January 22, 2013, 11:23:38 am »

Hey all,

Recently picked up this 1970 CB750. Ordered a new gasket kit, brake caliper rebuild kit, carb rebuild kit, etc and tools from partsnmore. I will be doing all of the work that I can do inside of my apt (conveniently located on the second floor

).

First item on the agenda is to build a work bench and clear space out in my extra room.

Best,
Alex

At the shop where the guy from craigslist left it at

Next to my daily in my apt complex with the windscreen and saddlebags removed

Cruzader · « **Reply #1 on:** January 24, 2013, 10:57:40 am »

From bare wall to workbench. The calm before the storm of parts that will cover just about everything as I go on.

Viktor.J · « **Reply #2 on:** January 25, 2013, 03:18:32 am »

Interesting ! Looks like a nice bike you've got there !
Is she leaking oil or are you planing on doing any work in the motor ?
Is she going to be a stocker or any modifications ?

ekpent · « **Reply #3 on:** January 25, 2013, 03:50:33 am »

Can you post the frame and engine numbers so we can learn a little more about it.

Johnie · « **Reply #4 on:** January 25, 2013, 05:14:28 am »

Looks like an early K1 built in fall 1970 and titled as a 1970. Same thing happened to my K1.

Cruzader · « **Reply #5 on:** January 26, 2013, 09:12:06 am »

Quote from: Viktor.J on January 25, 2013, 03:18:32 am

Interesting ! Looks like a nice bike you've got there !
Is she leaking oil or are you planing on doing any work in the motor ?
Is she going to be a stocker or any modifications ?

Thanks, looks can be deceiving.
Leaking oil pretty bad through the base and/or head gasket. No extra motor work will be done other than getting her back in running condition (budget grad student lifestyle).
I will be doing a few cosmetic mods here and there. I have already begun on the fenders and handlebars

I will post my engine and chassis numbers when I get a chance to write them down, but I think you guys are right. I think the chassis is 106---, making it a K1

I started disassembly yesterday and saw that whoever had it before, never replaced the frame rails after removing them!!

Also, the right bracket on the top triple tree was cracked and you can see it if you look closely (It came off with the bolt)

So, here is how she sits, waiting for more money and parts to be thrown at her

Any suggestions for the frame rails? I'm thinking about the gordon kit i've read about
I am also looking for a top triple tree (I am indifferent to whether it has a mount for gauges or not, I like the aluminum one at dimecitycycles without the Honda logo)

HonderCB · « **Reply #6 on:** January 26, 2013, 09:51:04 am »

http://www.cb750cafe.com/products-page/body-parts-and-accessories/frame-adapter-kit/

Carpy has a frame kit that will work for your bike. the price is pretty reasonable, but the shipping is really high, so it ended up costing my around $120 i believe. but that was back in like august, so who knows what the price is now. I havent put mine on yet, i'm planning on pulling the head at some time this winter, and didnt want to remove the engine so that is why i bought it. I know at least one person on this forum has used this kit before, but i dont remember who. use the search function to find them.

the Gordon Kit is good too. everyone who uses it has nothing but good things to say about it, it just takes a little more tools and skill to install.

Good luck with your bike, it looks nice.

Old Scrambler · « **Reply #7 on:** January 28, 2013, 06:09:04 pm »

Hope you have an elevator...........I did my first rebuild in 1968-69.......2nd floor apartment in the dining area made for the cleanest custom black bomber in Milwaukee

Cruzader · « **Reply #8 on:** February 10, 2013, 08:18:28 pm »

haha, thanks. no elevator. Me and one of my buddies carried the motor upstairs and on the work bench last week. It was heavier than expected. We used the flip the bike on its right side method for engine removal.

Here she is. I have a bike cover coming in from dimecity. I've found a lot of good things there and there shop is in state so I expect to get it tuesday or wednesday.

Pulled the valve cover off to see that the journal over cylinder #1 is cracked. The screw on the cam tower was loose when I opened it and I suspect this had something to do with it. The cam, journals and cam tower are ruined

Looked over to cylinder #4 and everything seemed fine until I realized how dry everything was. The cam was pretty badly scarred on this side as well.

Cam tower removed. There were a ton of metal shavings here and inside the case when I opened it up. I cleaned some of it before this pic and think most of it come from the cam.

The pistons and lower end especially looked to be in better shape.

The bike was shifting hard when it was running and would need a harder push to get into gear sometimes. I was hoping to find out what it was here in the shifter assembly, but everything was tight and looked okay. The shifting fork does not look to worn and the dogs on the gear aren't worn so I hope that it was just the horrible oil and metal shavings in it that made shifting difficult.

Looks like the factory had a little mix up when numbering my case halves. ha

Split the cases. Everything looks good, enough

I need to replace the counter shaft bearing screws that I had to strip to remove it. It look like I'll be ordering them from the dealership. The rebuild is moving along slower than expected and now I am running into issues with getting the registration for is because FL requires proof of chain of ownership, which means that I need the registration of the last owner, or to prove that the last registered owner sold it to whoever sold it to... the person I bought it from and is on my bill of sale. I may try getting a court order to lift that requirement or by buying a frame with title on ebay and building it back on that and paying less tax overall. If anyone has experience with Florida's registration laws feel free to advise me.

Tews19 · « **Reply #9 on:** February 10, 2013, 08:33:25 pm »

Looks good!

Subscribed!

Cruzader · « **Reply #10 on:** February 11, 2013, 07:55:50 pm »

While I'm waiting from my parts to come in, here are some pics of my last/first bike.

Tews19 · « **Reply #11 on:** February 11, 2013, 08:41:13 pm »

Hey cruzader, I have a frame that has the neck cut off. I'm removing the bottom sidestand mount. If you want I can cut the upper rails off and send them your way. Just cover the shipping. If interested pm me. The frame is a K1. A member here got the neck a while ago for a title concern.

Cruzader · « **Reply #12 on:** February 12, 2013, 08:51:33 am »

Thanks for your offer, but I am also having title problems. I will be going to the court house in the next few weeks to try to get a court order to allowed me to register my bike, but if they turn me down or that becomes too costly, then I'll be picking up another frame to register

Tews19 · « **Reply #13 on:** February 12, 2013, 11:56:12 am »

Search registering it in Vermont or New Hampshire. You do not need a title or be a resident. Do a search on here. Title issues happen a lot with these old bikes.

Cruzader · « **Reply #14 on:** February 12, 2013, 05:31:23 pm »

Interesting, I'll have to take a lot into that. The problem is that I am in Florida, which is a title state. They require that I prove chain of ownership from the last registered owner, if I can't, then I may be able to get a court order allowing me to register the bike.

So whichever method saves me the most money will be done, and I expect the tax I pay on a frame will be much less than the tax I would have paid on the purchase of my bike. It seems inefficient for the state to lose on tax dollars this way since all I really want to do is pay my taxes and register my bike

Cruzader · « **Reply #15 on:** February 28, 2013, 10:46:25 pm »

I've decided to upgrade to HD head studs to avoid future oil leaks (hopefully) and progressive fork springs so she won't feel so spongy in the front when I'm really getting on it. I've been waiting on parts and returning parts and pretty much a lot of waiting to get ready for the engine to be back in the frame.

I need this stud that holds the journal/ cam holder to the cylinder head. It's Part 14 on this diagram, but I can't find anyone that stocks it. If someone see this please let me know if you see it anywhere. Its honda part number: 90055300000

Here are the carbs just before cleaning and rebuilding, I moved from 120 main jets to 110's

A small teaser of what the engine like when the it is back together

Stev-o · « **Reply #16 on:** March 01, 2013, 05:30:58 am »

Hey Cruz, nice project and quite ambitious rebuilding a motor in your apt!
Guessing your a 'nole, my nephew is and lived there on High St.

Cruzader · « **Reply #17 on:** March 01, 2013, 09:07:48 am »

Quote from: Stev-o on March 01, 2013, 05:30:58 am

Hey Cruz, nice project and quite ambitious rebuilding a motor in your apt!
Guessing your a 'nole, my nephew is and lived there on High St.

Thank you. High street isn't very far from me. I've lived in my parents apt next to the stadium since I started undergrad here in '07, I am now in my second year in law school and still at FSU.

Go Noles!

I dont think my mom will be too happy once she sees how many holes are in the wall from workbench, but my girlfriend made the biggest modification to the room that led me to turning it into my shop

(I have since patched that with an iron shaped section from the closet)

Dream750 · « **Reply #18 on:** March 01, 2013, 10:11:16 am »

Quote from: Cruzader on February 28, 2013, 10:46:25 pm

I need this stud that holds the journal/ cam holder to the cylinder head. It's Part 14 on this diagram, but I can't find anyone that stocks it. If someone see this please let me know if you see it anywhere. Its honda part number: 90055300000

DSS (USA) shows the stud (90055-300-000) in stock:

http://www.davidsilverspares.com/parts/by-part-number/partnumber_1565/

But I wouldn't wait too long ...

Cruzader · « **Reply #19 on:** March 02, 2013, 01:26:49 pm »

Quote from: Dream750 on March 01, 2013, 10:11:16 am

DSS (USA) shows the stud (90055-300-000) in stock:

http://www.davidsilverspares.com/parts/by-part-number/partnumber_1565/

But I wouldn't wait too long ...

Thanks for the tip. The problem is that, like cmsnl.com, they want $17 for shipping. A forum member has generously offered to ship me one for free, so it looks like my build may continue.

Dream750 · « **Reply #20 on:** March 02, 2013, 05:21:17 pm »

Glad you found the stud and for free too.

Wow, the $17 shipping charge from DSS (USA) is outrageous, I wonder how they justify that figure.

I can’t ever remember paying that much in shipping from DSS (UK) for small or lightweight parts.

Cruzader · « **Reply #21 on:** March 15, 2013, 05:53:02 pm »

The motor is coming back together smoothly. I have decided to replace the stretched out oem head studs with HD studs to try avoid oil leaks in the future. I also picked up some awesome cam towers from a member and a new cam. I think that the oil starvation from my initial ride came from the 80 highway miles I put on the bike with the oil from the previous owner (dumb idea). I will be checking the oil passages in the head with compressed air next week, just in case.

I took some permanent marker to the tach gauge face and needle to save some monies, and will be deleting the speedometer.

I can't decide if I be rattle canning the fenders and gas tank white silver or flat black. I sprayed them white already but I'm leaning towards flat black. I will be leaving the oil tank cover off and spraying the fuse box cover flat black.

Old Scrambler · « **Reply #22 on:** March 17, 2013, 05:29:20 pm »

The stock crankcase studs should be fine until you build more than 11-1 compression..........the cam-tower bolts are usually good forever........its the soft aluminum threads in the head that are prone to strip from use and over-torquing. The fix is heli-coil or time-certs. Since you had debris in the motor, its likely that an oil journal was plugged which starved the 1-2 cam bearings..........please tell us you cleaned the trap (journal) in the crankshaft before reassembly. Suggestion, hunt around on hear for specific topics for some great advice often accompanied by very good pics.

Garystratos201 · « **Reply #23 on:** March 17, 2013, 07:32:11 pm »

I hope the the cam towers work out for you.......Gary

Cruzader · « **Reply #24 on:** March 19, 2013, 08:56:48 am »

Quote from: Old Scrambler on March 17, 2013, 05:29:20 pm

The stock crankcase studs should be fine until you build more than 11-1 compression..........the cam-tower bolts are usually good forever........its the soft aluminum threads in the head that are prone to strip from use and over-torquing. The fix is heli-coil or time-certs. Since you had debris in the motor, its likely that an oil journal was plugged which starved the 1-2 cam bearings..........please tell us you cleaned the trap (journal) in the crankshaft before reassembly. Suggestion, hunt around on hear for specific topics for some great advice often accompanied by very good pics.

Well my old studs were stretched and had weak points in them, so leaving them in was not an option, because I am not doing this rebuild to come back to a motor dumping oil. You're right, the cam tower studs are strong, but I damaged one removing it so I needed a replacement (got it). I cleaned the entire engine when it was apart. The journals in the crank have nothing to do with oiling the cam, though.

Quote from: Garystratos201 on March 17, 2013, 07:32:11 pm

I hope the the cam towers work out for you.......Gary

Thank you! They look great, I am sure that they will!

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Author Topic: 1970 CB750 build (Read 9103 times)