Author Topic: UPDATE: She's Running! 1971 CB750 sat since the 80s. ADVICE needed  (Read 7213 times)

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Offline DesertKyorugi

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  • '87 GS450 '86'87 ZL600 '73 CB500 '70 '71 '71 CB750
My first post here on SOHC forum, not new to restoring bikes but nothing older than 1986 before. Bought this from the original owner who just quit riding and parked it in storage with 20k miles. Front brake was seized, 30+ years old tires still hold air, minimum rust, motor turns(spark plugs out, WD40 squirted in and hand pushed kick starter), gas cap latch broken, front forks leaking and missing some parts(I think).

What are my options for restoring this? Should I keep it as is and just get it running? Or try to do a complete rebuild and restore(not deep pocket so just a reproduction parts resto)?

The carbs are coming off today and they will get sent off for complete rebuild. How do you open the gas cap? Knock out the pin that's holding the broken latch?

Thank you all in advance for your help and advice.


**I know more pics are needed and they are coming. I am just trying to recover from the 300 miles drive, finishing up my coffee
« Last Edit: February 25, 2020, 02:27:50 PM by DesertKyorugi »
US '71 CB750K1 Stored for 39 years, currently running
US '71 CB750K1 Currently running
JDM '71 CB750K1 Stored for 21 years, currently running
US '70 CB750K0 Stored for 28 years, currently in restoration
US '70 CB750K0 Stored for 43 years, currently in restoration
US '70 CB750K0 Currently waiting to be restored
US '73 CB500K2 Stored for 40 years, currently running

Offline jgger

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Welcome to the site.

That bike looks like it will need too much stuff, bring it up to Corona and drop it off in my driveway........I will properly dispose of it for you, no charge.

I can't help too much , but on the gas cap if there is still a nub where the button was you may be able to turn it with some pliers. Push down on the cap when you try to release it, that helps take some tension off of the latch.

Good luck,

P. S. You need like 5 posts to be able to send PM's, so post so.e more then PM me and I will send you my address where you can drop it off. Just trying g to help.😁
"The SOHC4 uses a computer located about 2-3 ft above the seat.  Those sometimes need additional programming." -stolen from  Two Tired

The difference between an ass kisser and brown noser is merely depth perception.  Stolen from RAFster122s

Offline seanbarney41

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Best plan is get it running and safe enough to put 100 or so miles on it.  Then you will be able to determine what you are working with.  Watch out!  Let's of danger with sending carbs out to get fixed.  You need to know exactly what your rebuilder intends to do and replace.  It is unlikely that anything needs replacing, stuff just has to be clean inside.  Lots of hacks claim to know these carbs, but you can end up paying hundreds for butchery.
If it works good, it looks good...

Offline jlh3rd

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depends on what you want it for, and how much you wanna spend.
there's a lot to clean up it seems and how good is all the chrome. Even a restoration with aftermarket parts and ebay can be expensive. Try to get NOS parts and you'll be paying real good money. Pipes, seat, rear wheel just a start.
Not to mention tank, side covers......and hope the engine is sound.
Clean it up and ride a period correct accessorized bike? Some people do that. Gotta love those handle bars, 16 inch fat rear tire, sissy bar and seat.
Not for me though........I like,original, NOS, unrestored bikes......so....
Your money, your call....

Offline Scott S

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 Tell the carb guy to use the stock brass.

 I agree...give it a tune up and hear it run. See if all the gears are there. Brakes are important, too! ;)
'71 CB500 K0
'17 Triumph Street Scrambler
'81 Yamaha XS650

Online HondaMan

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You have picked one of the MOST RESTORABLE vintage bikes around! You can find the help you need here, for sure. I can rebuild the carbs correctly if you don't want to, or even the whole engine: PM me for details. I have 5 of them in my garage at the moment, and one set of carbs, a swingarm....not from my bike, which I ride often instead. That reminds me, needs an oil change...
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

Link to website: www.SOHC4shop.com

Offline DesertKyorugi

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  • '87 GS450 '86'87 ZL600 '73 CB500 '70 '71 '71 CB750
Thank you Everyone. Yes I have a good carb guy and he is excellent. Some of you know him but I am going to keep him my secret so I can get him to keep his 2 to 3 weeks turnaround time  ;D  He's done more than a few of my carbs.

@jgger LOL this bike actually came from your neighborhood

@Hondaman Thank you, will definitely call on you ....

OK, Need a little help with the front forks. What am I missing besides the rubber stanchions(I think that's what they are called)?

I am restoring this and another bike with my son so elbow grease is free and available. Going to go for used parts and eBay repros to keep the cost down.

US '71 CB750K1 Stored for 39 years, currently running
US '71 CB750K1 Currently running
JDM '71 CB750K1 Stored for 21 years, currently running
US '70 CB750K0 Stored for 28 years, currently in restoration
US '70 CB750K0 Stored for 43 years, currently in restoration
US '70 CB750K0 Currently waiting to be restored
US '73 CB500K2 Stored for 40 years, currently running

Offline 69cb750

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Quote
OK, Need a little help with the front forks. What am I missing besides the rubber stanchions(I think that's what they are called)?
Forks are covered by expanding rubber boot, 71 came with painted headlight brackets, chrome brackets are newer.


Offline DesertKyorugi

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The carbs are off the bike. All the fuel hoses were hard and brittle, snapped right off as I was trying to figure out how to lift the gas tank off.

If you guys have extra used parts available that I need on my bike and would like to sell please let me know. I am open to swapping my rusty parts out for better condition parts. Thanks
US '71 CB750K1 Stored for 39 years, currently running
US '71 CB750K1 Currently running
JDM '71 CB750K1 Stored for 21 years, currently running
US '70 CB750K0 Stored for 28 years, currently in restoration
US '70 CB750K0 Stored for 43 years, currently in restoration
US '70 CB750K0 Currently waiting to be restored
US '73 CB500K2 Stored for 40 years, currently running

Offline DesertKyorugi

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  • '87 GS450 '86'87 ZL600 '73 CB500 '70 '71 '71 CB750
Quote
OK, Need a little help with the front forks. What am I missing besides the rubber stanchions(I think that's what they are called)?
Forks are covered by expanding rubber boot, 71 came with painted headlight brackets, chrome brackets are newer.

Thanks. Is there a front fork rebuild kit or one need to source all parts separately?
US '71 CB750K1 Stored for 39 years, currently running
US '71 CB750K1 Currently running
JDM '71 CB750K1 Stored for 21 years, currently running
US '70 CB750K0 Stored for 28 years, currently in restoration
US '70 CB750K0 Stored for 43 years, currently in restoration
US '70 CB750K0 Currently waiting to be restored
US '73 CB500K2 Stored for 40 years, currently running

Offline DesertKyorugi

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  • '87 GS450 '86'87 ZL600 '73 CB500 '70 '71 '71 CB750
depends on what you want it for, and how much you wanna spend.
there's a lot to clean up it seems and how good is all the chrome. Even a restoration with aftermarket parts and ebay can be expensive. Try to get NOS parts and you'll be paying real good money. Pipes, seat, rear wheel just a start.
Not to mention tank, side covers......and hope the engine is sound.
Clean it up and ride a period correct accessorized bike? Some people do that. Gotta love those handle bars, 16 inch fat rear tire, sissy bar and seat.
Not for me though........I like,original, NOS, unrestored bikes......so....
Your money, your call....

Definitely would like to revert it back to original but will have to keep it as is for now to keep the $$$ low. Will try to revert it slowly over time. Period correct accessorized bike may be what I am looking at for now. Lol, not too crazy about the handlebars. It is probably going to go first before I start riding it.
US '71 CB750K1 Stored for 39 years, currently running
US '71 CB750K1 Currently running
JDM '71 CB750K1 Stored for 21 years, currently running
US '70 CB750K0 Stored for 28 years, currently in restoration
US '70 CB750K0 Stored for 43 years, currently in restoration
US '70 CB750K0 Currently waiting to be restored
US '73 CB500K2 Stored for 40 years, currently running

Offline jlh3rd

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Yep. The chrome looks a little worse than what i originally thought. Yet, i have seen honda chrome clean up surprisingly good. You'll only know when elbow grease is applied.
One thing i just thought of, is make sure the frame is straight before money  goes to cosmetics......Like someone said, the fork covers are wrong and even one of them is bent.....so, id make sure it's straight......

Offline seanbarney41

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To me, it looks like a lot of elbow grease, lots of small parts like cables, and a couple big parts and you can have a presentable and fun old bike.  A little chrome polish and some 0000 steel wool goes a long way on a bike like that.  You are gonna get real familiar with the parts for sale and wanted sections here.   Most of the rubber parts are still available new from Honda and are worth it.
If it works good, it looks good...

Online HondaMan

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Wow, Valley Green, too! Chances are, that's an Old Factory K1. When it's all running again, it will idle like a purring kitten. It may also have the brass floats in the carbs: let me know if yours have corroded holes in them.

The forks: I have seals separately from kits (if yours are in bad shape), you just need 2 of them. Those forks are almost impossible to kill, short of a wreck that bends them more than 1cm from middle-to-end. Just pull out the snap ring and the spring, and operate the fork a few times (off the bike) to pop the old seal up. That way you don't have to undo the screw at the bottom to release the inner fork tube, which can be troublesome to reseal afterward. You have a choice for the fork boots (the rubber accordion-like things, aka 'bellows') in that you can use the Honda ones, or else use little dust covers instead The latter isn't OEM and isn't real pretty, but is cheaper. If you get the bellows, DON'T get the aftermarket ones. They will last about 1 year and then fall apart, seen it several times. The Honda ones are worth the extra $$ in this case. My own K2 has the Honda ones on it now 6 years, look fine still.
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

Link to website: www.SOHC4shop.com

Offline MauiK3

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Before get too far into this one, do yourself a favor, buy Hondaman’s book, it is essential to keep you out of trouble.
Also, spend some time getting the parts breakdown pages from one of the sites that has them. That way you will be able to identify what you need.
You have a great one to restore, it will be worth more the “stocker” it is.
Looks like the head gasket is leaking.
Looking forward to following this. It will slowly get you in its grip and you can’t escape.
Check Markb’s thread about his journey with frame 100/ engine 97 he restored to stock. Museum piece, it’s a great read.
🤯
Parts sources:
Yamiya
Davis Silver Spares
CMSNL
There are others too.
1973 CB 750 K3
10/72 build Z1 Kawasaki

Offline DesertKyorugi

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  • '87 GS450 '86'87 ZL600 '73 CB500 '70 '71 '71 CB750
To me, it looks like a lot of elbow grease, lots of small parts like cables, and a couple big parts and you can have a presentable and fun old bike.  A little chrome polish and some 0000 steel wool goes a long way on a bike like that.  You are gonna get real familiar with the parts for sale and wanted sections here.   Most of the rubber parts are still available new from Honda and are worth it.

Yes, there will be a lot of chrome polish and steel wool time in the near future. The main idea is to have a presentable fun bike while preserving the value. Everything is so simple on it we might go ahead and disassemble it to properly fix the surface frame rust.

Wow, Valley Green, too! Chances are, that's an Old Factory K1. When it's all running again, it will idle like a purring kitten. It may also have the brass floats in the carbs: let me know if yours have corroded holes in them.

The forks: I have seals separately from kits (if yours are in bad shape), you just need 2 of them. Those forks are almost impossible to kill, short of a wreck that bends them more than 1cm from middle-to-end. Just pull out the snap ring and the spring, and operate the fork a few times (off the bike) to pop the old seal up. That way you don't have to undo the screw at the bottom to release the inner fork tube, which can be troublesome to reseal afterward. You have a choice for the fork boots (the rubber accordion-like things, aka 'bellows') in that you can use the Honda ones, or else use little dust covers instead The latter isn't OEM and isn't real pretty, but is cheaper. If you get the bellows, DON'T get the aftermarket ones. They will last about 1 year and then fall apart, seen it several times. The Honda ones are worth the extra $$ in this case. My own K2 has the Honda ones on it now 6 years, look fine still.

The PO ordered the seats, handlebars and sissy bars with the bike, paid $1369 at the local Honda dealer in 1971. He said everything else should be original with all work done at the Honda dealer till 1981. Never been down, in an accident or any sort of impact.

Are you from So Cal? Is your book available in digital form? Will get the book but digital copy is easier for this blind old dude to read and see. I am going to make a list and get back to you.

US '71 CB750K1 Stored for 39 years, currently running
US '71 CB750K1 Currently running
JDM '71 CB750K1 Stored for 21 years, currently running
US '70 CB750K0 Stored for 28 years, currently in restoration
US '70 CB750K0 Stored for 43 years, currently in restoration
US '70 CB750K0 Currently waiting to be restored
US '73 CB500K2 Stored for 40 years, currently running

Offline DesertKyorugi

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  • '87 GS450 '86'87 ZL600 '73 CB500 '70 '71 '71 CB750
Before get too far into this one, do yourself a favor, buy Hondaman’s book, it is essential to keep you out of trouble.
Also, spend some time getting the parts breakdown pages from one of the sites that has them. That way you will be able to identify what you need.
You have a great one to restore, it will be worth more the “stocker” it is.
Looks like the head gasket is leaking.
Looking forward to following this. It will slowly get you in its grip and you can’t escape.
Check Markb’s thread about his journey with frame 100/ engine 97 he restored to stock. Museum piece, it’s a great read.
🤯
Parts sources:
Yamiya
Davis Silver Spares
CMSNL
There are others too.

It's not leaking from the head gasket(I hope). Two of the spark plugs were stuck and full of muck, I sprayed PB Blaster/WD40 all over it before I got on the road
US '71 CB750K1 Stored for 39 years, currently running
US '71 CB750K1 Currently running
JDM '71 CB750K1 Stored for 21 years, currently running
US '70 CB750K0 Stored for 28 years, currently in restoration
US '70 CB750K0 Stored for 43 years, currently in restoration
US '70 CB750K0 Currently waiting to be restored
US '73 CB500K2 Stored for 40 years, currently running

Offline DesertKyorugi

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  • '87 GS450 '86'87 ZL600 '73 CB500 '70 '71 '71 CB750
Wow, Valley Green, too! Chances are, that's an Old Factory K1. When it's all running again, it will idle like a purring kitten. It may also have the brass floats in the carbs: let me know if yours have corroded holes in them.

Yes they are brass floats. Looks pretty good for being in storage for 30+ years
US '71 CB750K1 Stored for 39 years, currently running
US '71 CB750K1 Currently running
JDM '71 CB750K1 Stored for 21 years, currently running
US '70 CB750K0 Stored for 28 years, currently in restoration
US '70 CB750K0 Stored for 43 years, currently in restoration
US '70 CB750K0 Currently waiting to be restored
US '73 CB500K2 Stored for 40 years, currently running

Online HondaMan

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    • Getting 'em Back on the Road
One thing to check for on the Old Factory K1 frames is: Honda forgot to drill water-bleed holes in the lower frame, right behind the engine bolsters, when they put those bolsters in the frame. The frame has openings in it back by the middle downtubes (you can see them in the web supports near the footpegs) that allowed water in, and it collects behind those bolsters and can rot the frame there. Some of the holes were forgotten, some were painted over: if yours does not have those holes (one on each side, bottom of frame tube), drill in a 1.8" hole on each side to prevent frame rot in the future. It sounds like this one was garage-kept, so it's probably OK, but high-pressure car washes were born in 1967, just in time to force water into these frames!
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

Link to website: www.SOHC4shop.com

Offline scottly

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The fork lowers don't look like they have K1 style caliper mounts, at least from what I can see. Please post a straight side view.
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....

Offline DesertKyorugi

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  • '87 GS450 '86'87 ZL600 '73 CB500 '70 '71 '71 CB750
One thing to check for on the Old Factory K1 frames is: Honda forgot to drill water-bleed holes in the lower frame, right behind the engine bolsters, when they put those bolsters in the frame. The frame has openings in it back by the middle downtubes (you can see them in the web supports near the footpegs) that allowed water in, and it collects behind those bolsters and can rot the frame there. Some of the holes were forgotten, some were painted over: if yours does not have those holes (one on each side, bottom of frame tube), drill in a 1.8" hole on each side to prevent frame rot in the future. It sounds like this one was garage-kept, so it's probably OK, but high-pressure car washes were born in 1967, just in time to force water into these frames!

Will take a look. Thanks


The fork lowers don't look like they have K1 style caliper mounts, at least from what I can see. Please post a straight side view.

Here you go, please elaborate on what it should have. The master cylinder is shot so if I need to work on this, I would rather get the right parts to start from. Thanks
US '71 CB750K1 Stored for 39 years, currently running
US '71 CB750K1 Currently running
JDM '71 CB750K1 Stored for 21 years, currently running
US '70 CB750K0 Stored for 28 years, currently in restoration
US '70 CB750K0 Stored for 43 years, currently in restoration
US '70 CB750K0 Currently waiting to be restored
US '73 CB500K2 Stored for 40 years, currently running

Offline scottly

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Definitely not K1; up to K3 calipers used a "C" shaped caliper arm to fork bracket, while K3 and up used a "T" shaped bracket. The lower on the left is a K1 "C" style, while the one on the right is the later "T" style:
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....

Offline jlh3rd

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different fork lowers, chrome headlight ears....as stated before.......maybe that's not the original front end.....PO says all original....never wrecked....I dunno........better check that frame....

Offline scottly

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PO's never lie.. ::) ::)
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....

Offline DesertKyorugi

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Thanks guys. Now I know what to look for in the next few days.

I spent an hour pouring through his receipts before I purchased it. He's not the most well-organized guy but all his receipts are in a big box. I didn't see anything that resembled accident repairs. He did mention he replaced the front brakes a few times because they keep seizing up and the mechanic at the dealership did all the work. And I did see there were quite a few receipts for brake work. My thinking is that the high handlebars were the reason he's having front brake issues. I am not an expert in motorcycle frames but I am a retired engineer, I looked at the front and side triangles part of the frame for evidence of being down and didn't see any distressed or abnormal area on the frame 

US '71 CB750K1 Stored for 39 years, currently running
US '71 CB750K1 Currently running
JDM '71 CB750K1 Stored for 21 years, currently running
US '70 CB750K0 Stored for 28 years, currently in restoration
US '70 CB750K0 Stored for 43 years, currently in restoration
US '70 CB750K0 Currently waiting to be restored
US '73 CB500K2 Stored for 40 years, currently running