New member in Denver, CO 1979 CB750K

[V10Pilot]

Hello everyone. This is my first post and I’ll just give a quick introduction about myself and the build.

I just moved to Broomfield, CO which is between Denver and Boulder. We are originally from Lafayette, LA but came up here for work and a massive change of scenery. I’m a corporate pilot and have worked on my 2000 Viper and a few other projects but this will be my first attempt at building an old bike. I am by no means a mechanic but love to wrench in my spare time and hope to learn a lot from you guys and gals.

I picked up a 1979 Honda CB750 K/L. I’m still trying to figure out if it’s a K or L and if there is really much, if any structural difference. I’m starting out completely cold on this project and only learn about the bike as problems present themselves to me. I still don’t know exactly which direction I want to go with this build but I think I’ll let the bike tell me what it wants as I move along. Brat/Cafe/Tracker etc...

I picked it up two weeks ago for $500 and it is 100% stock from what I can tell. I got it home and the biggest problem I’ve run into so far if the stock fuel tank looks to be pretty much trash. I was really hoping to save it because I think it would be nice to rebuild the entire bike as new but keep the tank with all it’s history and character. It’s a 79 CB750 10th Anniversary Edition and at first I thought it was ugly but now the paint is actually starting to grow on me. I saw internal rust when I bought it but after hitting it with a pressure washer it’s got more than a few pin holes of daylight and a few holes about 3mm. Most everyone I’ve talked to says it’s scrap and it’s better spending the money on a newer tank than trying to salvage this one. I’ll start my search soon as to which year and model tanks might fit with little to no modification. I no longer have a shop so my in house fab will be limited.

I also plan of finding wire spoke wheels rather than the stock Com Stars.

Thanks for any input and advice you guys have.

 

[Jimbonaut]

Love seeing these 750's! Welcome mate from Montreal, and check out my thread (http://www.dotheton.com/forum/index.php?topic=72170.0) which essentially turned into a walkthru on how to rebuild this model bike. I had no idea what I was doing when I started and so had to ask a million questions, all of which were answered by members here. You're in the right place.

Dunno man but that tank looks pretty roached - perhaps someone here can let you know whether or not it's salvageable. Rest of the bike looks like it's in great knick, good score!

 

[palepainter]

Welcome. I live right up the road in Lafayette, Erie area. Good ol Boulder County. Find another tank. They are out there. Check with these guys. Down the road from you not far.


TD Motorcycle

2896 W 64th Ave, Denver · (303) 287-0027

Closed now, opens at 9 AM Saturday

 

[V10Pilot]

Thanks guys. It’s a little discouraging that the entire bike cost $500 and a small part like a tank looks like it’s going to cost at least half that. That tank isn’t really showing up anywhere so I’m trying to figure out other options that may fit with little to no modification.

 

[Jimbonaut]

Dude I don't want to sound like a smartass but there aren't really any small parts on these older bikes (unless we're talking nuts and bolts of course) - in my limited experience if you need to replace same with same then you end up paying for it. Tanks are a pretty big deal, especially originals, and yeah man it sucks that you have to shell out large for a replacement. And there will probably be a few more things on the shopping list you'll need to pick up before you're done too. But it's all part of the restoration/custom process involved in getting these older bikes back on the road. Don't be discouraged! This bike'll look great once you've made it yours, and while the learning curve may be steep (trust me, I found out all this stuff - like everyone else - the hard way) the rewards are well worth it.

See if a regular 750K tank (mine is an '81 and looks the same) would fit on your '79. Bet there are some options that would would work great, and still keep the same look.

Good luck!

 

[palepainter]

I paid the same price for my 750ss tank as I did the rest of the bike's original purchase price.

 

[V10Pilot]

Don't worry about sounding like a smart ass. I didn't take it that way. I'm not above paying for parts but have been trying to research my options before I drop the cash. I'm not really finding much when I search for 79-82 CB750K/L tanks and am looking into 900 and 1100 tanks to see if they fit from the same years just to widen the search. I'm also actively searching for wire spoke wheels that will directly swap and it sounds like 79-82 CB750 came with them stock on the K model. I've also determined that mine is an L not a K as previously thought.

 

[adventurco]

Welcome to the madness.

That is a really weird spot to rust out on that tank. Usually its down by the seams. Seems odd that it has a 750K badge on it if its an L. Try calling around to some salvage yards, usually eBay stuff goes for top dollar but there are always deals to be had. Bikeboneyard.com may be a good option as well.

Depending on what your plans are you may want to swap it for a completely different tank in the end so that's another option to explore.

Also, check this out re: comstar conversion
http://motosynthesis.blogspot.com/p/products.html

 

[V10Pilot]

I found two labels that identify it as an L now that I've really looked at them. The chain cover has CB750L and there is a label with Vehicle Emission Control Information - Engine Family Identification - 79QP (C750L). The main search now is for wire spoke wheels. I'm not a fan of these Comstars but I cant find them for sale anywhere.

As for MotoSynthesis, it seems like his website has been dead for a while and he hasn't responded to any posts on his social media accounts. Wonder what happened.

 

[Jimbonaut]

Spoke wheels definitely look cool but there's a lot to be said for Comstars too. For one thing you don't have to worry about buying new spokes (not cheap) if necessary, or restoring them (like I did), and you don't have to true the wheels either. You can add some paint details to the Comstars that I think looks wicked cool. If you're looking to save a few bucks then holding onto them might not be so bad.

Run what you brung and all that.

You get any further with the teardown? Photos man, photos!

 

[coyote13]

Prerty sure you can also run tubeless or tube tires on the comstars, as opposed to just tube tires on the spokes. Nice perk if you're into that

 

[V10Pilot]

I haven't made much progress last few weeks with the teardown. I'm a corporate pilot and I've been on the road a lot recently. I did manage to tear down the carb and rig up a Figi water bottle fuel tank and got her running. I didn't try to ride it yet because it feels like the old ass oil has glued the clutch plates together. When I try to push it by hand in gear with the clutch pulled in, its nearly impossible to get it rolling unless I pop it in 4th or 5th to give me more mechanical leverage. I plan on doing a complete teardown and refresh. Ill be home Wednesday and should have time to get more pics and a video if it running.

 

[V10Pilot]

Coyote13 this bike is not going to be a daily or longhaul bike. I have a sport touring bike for that. This ones all about style and all the pains in the ass that come with it. Thanks for the input though. That's what I'm here for; input, critiques, guidance, tips and trick. I'll be the first to admit I don't know what I don't know. Old bikes are new to me.

 

[V10Pilot]

Maybe I didn’t put the original post in the right spot. I’m getting views but no replies. Maybe one of you guys had some input. Here is copy of the original post.

“Quick question. I bought a 79 CB750L and it all appears stock however I think the previous owner may have replaced a few soft parts on the carbs (keihin vb42a)

I can’t find any really good pictures of the accelerator pump rod in an idle position on line to compare. When the throttle is completely closed, the actuating plate that is part of the throttle linkage assembly is about 4mm from the end of the pump rod. This is my first time messing with these style carbs but I’d imagine they are supposed to always be touching each other so any time the throttle is applied, the rod is immediately pressed down actuating the pump.

The way is sits now no matter how far I open the throttle, it never touches the rod and I don’t see any adjustment to bring the actuator plate closer. I’m guessing that maybe the previous owner bought the wrong pump and the rod is too short.”

 

[V10Pilot]

Well it’s glaringly obvious now that I’ve figured it out. The previous owner replaced the pump with a new one and he installed the dust protecting bellows on the shaft inside the housing. It was so compressed that I just figured it was a bumper. It finally hit me looking at kits online that all the pictures had a bare metal disc with no such bumper. Duh!!!

 

[V10Pilot]

Decided to start an actual build thread.

1979 CB750L. My first cafe/brat project. Denver Area
http://www.dotheton.com/forum/index.php?topic=75285


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[V10Pilot]

Finally getting shit done


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