Author Topic: 1976 CB750F Condo project (Read 3270 times)

ScoobyRoo · « **on:** June 02, 2011, 09:05:57 PM »

Hello all

I just recently picked this bike up off Craigslist for $600, not really sure if I overpaid though. I recently moved to Minnesota from Florida, in a condo now so there's really no space for any toys with the exception of the gap between my roommate's car and the wall of his parking stall, which is just fine for a motorcycle

I have some experience with bikes but nothing this big before, or personally mine.

(more pictures+damage)
h t t p://imgur.com/a/mzIvb/all
(remove spaces from http, cant post urls)

Is that a factory exhaust? I couldn't find a picture of it online, just similar ones.

I was told that after sitting some time a new battery was put in the bike about 2 years ago and the harness started shorting out. Being too busy with his job the bike sat in storage until now. He said he put stabil in the tank but I'm not sure if it made it into the carbs though. Also would any of you cb gurus happen to know what the wire that burned out goes to? In the pictures it looks to be a teal wire but its just corroded bare copper.

Ultimately I'd like to made it into a bit of a cafe bike but for now I'd love to hear it running.

BeSeeingYou · « **Reply #1 on:** June 02, 2011, 10:12:43 PM »

I could not view the pics but here is a color coded wiring diagram in two parts to help you along. Also a pic of my stock 76 F1 so you can compare. Looks like the stock header but after that I can't tell. Dump all the gas out stabil or not and take a look at how clean the tank is and pull the carb bowls to check if they are gummed up. Welcome to Minnesota.

If your intention is to cafe the bike and you don't want the luggage rack let me know. I have one just like it but it broke in two places so I would mind finding another.

$600 is not a bad price so as long as the bike isn't really messed up you did ok. If you are missing the sidecovers a member here makes nice repros that are popular with members.

ScoobyRoo · « **Reply #2 on:** June 02, 2011, 11:54:44 PM »

thanks for the reply

I do have both sidecovers, the other was laying in the grass at the time. As for the rack I probably will end up removing it, there is a matching leather sissy bar that attaches to it though. It seems it all came from a custom shop around Minnesota somewhere, I haven't gotten a chance to do much looking over the bike since it got dropped off.

BeSeeingYou · « **Reply #3 on:** June 03, 2011, 11:11:57 AM »

I bet the rack says Motorcycle Accessories Isanti Minnesota. It is just like mine which also has the sissy bar. The seat grab rail is a modified part for the rack so if you plan on keeping a grab rail look for a stock one, they show up often and don't go for all that much. The stock one turns in at the rear and not up. Keep me in mind when you get around to removing it.
Jeez, those handle bars are something aren't they? Other than those and that seat it looks to be in decent shape and like I said before it does have the stock header but looks like a Mac slip on muffler. Is the headlight bucket still in there behind the fairing? Sometimes they remove them and due to all the wires there the wiring gets mucked up. Post a pick of the wiring issue if you can.
Looks like you have a K bike rear fender on there too.

Bankerdanny · « **Reply #4 on:** June 03, 2011, 11:21:20 AM »

Interesting choice by some PO to make an F bike into a tourer.

It looks like a great candidate for a cafe type mod since much of the original bike is gone anyway.

ScoobyRoo · « **Reply #5 on:** June 04, 2011, 09:42:30 AM »

Quote from: srust58 on June 03, 2011, 11:11:57 AM

I bet the rack says Motorcycle Accessories Isanti Minnesota. It is just like mine which also has the sissy bar. The seat grab rail is a modified part for the rack so if you plan on keeping a grab rail look for a stock one, they show up often and don't go for all that much. The stock one turns in at the rear and not up. Keep me in mind when you get around to removing it.
Jeez, those handle bars are something aren't they? Other than those and that seat it looks to be in decent shape and like I said before it does have the stock header but looks like a Mac slip on muffler. Is the headlight bucket still in there behind the fairing? Sometimes they remove them and due to all the wires there the wiring gets mucked up. Post a pick of the wiring issue if you can.
Looks like you have a K bike rear fender on there too.

There are a few more pictures in the gallery above, I put spaces in the url since I don't think I can post them yet.

ScoobyRoo · « **Reply #6 on:** June 04, 2011, 01:32:42 PM »

Just got the fairing and seat off today, will take some pictures but the seat seems to be an old Corbin gentry seat?
The flash seems to bring out the worst in the dust and dirt on it, it doesn't look that bad in person.

The bad news is the electrical gremlins seem a bit more extensive than I previously thought

Would a harness from a 75' work? Sadly I don't know if it was a k or f

Retro Rocket · « **Reply #7 on:** June 04, 2011, 03:28:01 PM »

Quote from: Bankerdanny on June 03, 2011, 11:21:20 AM

Interesting choice by some PO to make an F bike into a tourer.

It looks like a great candidate for a cafe type mod since much of the original bike is gone anyway.

What , the rear ducktail and seat..? That bike is more standard than modded, the frame and 90% of it are stock.
Handle bars, seat and tail section and that bike is almost dead stock. That bike has piles of potential. Another bike cut up as a cafe is another one lost forever, no wonder they are sky-rocketing in value......

ScoobyRoo · « **Reply #8 on:** June 04, 2011, 04:04:08 PM »

Quote from: srust58 on June 03, 2011, 11:11:57 AM

I bet the rack says Motorcycle Accessories Isanti Minnesota. It is just like mine which also has the sissy bar. The seat grab rail is a modified part for the rack so if you plan on keeping a grab rail look for a stock one, they show up often and don't go for all that much. The stock one turns in at the rear and not up. Keep me in mind when you get around to removing it.
Jeez, those handle bars are something aren't they? Other than those and that seat it looks to be in decent shape and like I said before it does have the stock header but looks like a Mac slip on muffler. Is the headlight bucket still in there behind the fairing? Sometimes they remove them and due to all the wires there the wiring gets mucked up. Post a pick of the wiring issue if you can.
Looks like you have a K bike rear fender on there too.

Indeed it did

Good eye, I'll snap some pictures of the seat once I clean it up a bit, its got a few rips along the front where it rubs up against the tank but it looks fixable.

BeSeeingYou · « **Reply #9 on:** June 04, 2011, 07:20:23 PM »

The 75 and 76 CB750F bikes are the same. They have many differences from the K bikes though there are many parts that the K and F share the electrical is different. Looks like the headlight bucket is gone so no telling what got mucked up there. It should have a plastic junction box on the frame above the headers, this is specific to the F and hopefully it is there. A new harness may be the way to go if it looks like it has been hacked up too much and shorted out in several places.

ScoobyRoo · « **Reply #10 on:** June 04, 2011, 07:30:43 PM »

Quote from: srust58 on June 04, 2011, 07:20:23 PM

The 75 and 76 CB750F bikes are the same. They have many differences from the K bikes though there are many parts that the K and F share the electrical is different. Looks like the headlight bucket is gone so no telling what got mucked up there. It should have a plastic junction box on the frame above the headers, this is specific to the F and hopefully it is there. A new harness may be the way to go if it looks like it has been hacked up too much and shorted out in several places.

Do you think the rectifier is toast, coils perhaps too? Also would the 75 k harness use the same connectors at least? Perhaps I could just salvage those and mend the harness with new wires.

ScoobyRoo · « **Reply #11 on:** June 05, 2011, 01:18:52 PM »

Went ahead and picked up the 75 harness, it was cheap enough to be worth the gamble. Ive been searching the forum since last night and haven't really turned up much though. I don't want to seem like I'm asking to be spoon fed answers

I'm just a bit unnerved by how much of the harness is actually toast.

immortal · « **Reply #12 on:** June 05, 2011, 02:38:40 PM »

Nice project bike you have there and $600 is a good price, looks like a sold bike. The 750K harness will not work with the 750F in part because the connectors are different. Well that's what I have been told by a lot of people. I was looking to replace my 1976 CB750F harness and after months and months of going back and forth I finally decided to go to Vintage electrical parts and replace connectors etc and rework what I have.
So my 2 cents is compare the harnesses....you may be better of doing what I am than trying to rework that K harness.

Retro Rocket · « **Reply #13 on:** June 05, 2011, 04:08:59 PM »

I see no problems with the "K" harness, i am going t use one on my "F" project, although i will be starting from scratch, i never liked the "F" fuse box set up and will rewire everything to suit the "K" harness....As long as you are semi competent with wiring you should be ok, you may have to buy some vintage connectors to make it all work, they are easy to get.....

ScoobyRoo · « **Reply #14 on:** June 05, 2011, 04:28:21 PM »

Thanks for the reply guys

I think the 75 harness I picked up is indeed from an F, among the other parts being sold of the same year one was the rear toolbox that flips open, as I understand it that was only on the F models? If so I might have lucked out! Any clue as to what else could have burned up with that much damage? Should I wait until the extra harness comes or start working on pulling it off the bike as it is and testing components?

BeSeeingYou · « **Reply #15 on:** June 05, 2011, 11:36:36 PM »

Wait till you have the "new" one in hand, that way you won't have to remember how it was all routed. Reversing the polarity on the battery seems to be the main reason for burning out the rectifier and frying wires. Does it seem that you have melted wires/connectors or are there wires with worn of insulation that shorted out? The wires that run up the handlebars will be separate from the harness and hopefully they are ok. they join the harness in the junction box I mentioned previously.

ScoobyRoo · « **Reply #16 on:** June 05, 2011, 11:43:45 PM »

The wires seem more melted, maybe one was pinched or worn through? a lot of the damage is centered around one wire that burnt the insulation off all the way up under the tank and where I cant see. Two things I did notice right away earlier were that there is no start button in the handlebar and I suspect it was rerouted to a marine/boat looking momentary switch stuck in the fairing, the other was that the fairing had a cigarette lighter in it which was pointing up and filled with rust, not sure if it was unhooked though but perhaps it shorted out?

BeSeeingYou · « **Reply #17 on:** June 05, 2011, 11:55:30 PM »

The starter button is a common "age" failure point on the F so that may be unrelated to the rest of the carnage in the harness. The complete right side control is available for $100 but not just the button itself so many just wired up a makeshift repair like the PO may have done. More and more it sounds like the replacement harness is a good choice.

You can check out the parts diagram on bikebandit.com to see the differences in the K and F wiring harness. The forum search function is also a good resource as many questions you will have as you dig into your bike have been discussed on other threads.

ScoobyRoo · « **Reply #18 on:** June 06, 2011, 12:22:38 AM »

Thanks

I guess all I can do for now until the harness comes is start draining the gas and probably ungunking the carbs.

BeSeeingYou · « **Reply #19 on:** June 07, 2011, 11:32:30 PM »

Saw this on another thread. Might help if you need new connectors.

http://www.oregonmotorcycleparts.com/connectors.html

ScoobyRoo · « **Reply #20 on:** June 08, 2011, 01:41:38 PM »

Quote from: srust58 on June 07, 2011, 11:32:30 PM

Saw this on another thread. Might help if you need new connectors.

http://www.oregonmotorcycleparts.com/connectors.html

Thanks for the link, I got the replacement harness in the mail, every connector I could find and compare matched in shape and wire color so I guess I lucked out there, the downside is the harness connectors though useable to get the bike running for now are all sun rotted so this should help out when I go to rebuild it.

ScoobyRoo · « **Reply #21 on:** June 20, 2011, 11:09:21 AM »

just a quick update, last night I was testing my coils using the guide on here. My gazinta and gazouta wires test spot on for the correct ohm ranges however on both packs only the gazinta have continuity and the gazouta do not. What could be wrong here?

BeSeeingYou · « **Reply #22 on:** June 30, 2011, 11:54:55 PM »

Try clipping off a small amount off the end of the spark plug (gazouta) wires and also have the caps removed for the test.

Accolay · « **Reply #23 on:** July 01, 2011, 09:39:42 AM »

Welcome to Minnesota. If I ever get my stuff out of storage I'd let you borrow some tools if you need them.

ScoobyRoo · « **Reply #24 on:** July 03, 2011, 02:24:16 PM »

thanks for the tip and offer guys

For some reason I didnt get any emails for a reply to the thread, I'll give it a shot today.

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Author Topic: 1976 CB750F Condo project (Read 3270 times)