Topic: 1977 CB750 K7 /// Rebuild 2.0, Project Anna

[Yoshimoto]

The engine looks great.  Keep up the good work.  Can't wait to see what it looks like when you are done.

[Trad]

The paint on your engine will be fine. In my late teens I would paint blocks and heads on my sketchy-ass motorcycles with regular paint and I never had an issue. As long as you did good prep you should be A-OK.

[mkoski]

Put the engine in the frame this weekend, starting to look like a motorcycle again. Carbs are apart and getting cleaned, gas tank is looking to be the next goal.



Trad, I hope you are right!

I initially researched the engine paint and I read a post from someone who only used regular paint and said it worked great (which is why I went forward with it), I just think now, in retrospect, it wouldn't have been any extra work to use higher temp paint and now have to worry. Either way, its done now.

[mkoski]

Post-weekend update:

Carbs:

Start:



Finish:



Very happy with these. It took me forever to clean these up and reassemble. Toughest part by far was trying to remember how the choke plate rods worked together with the spring! Not too many resources for these carbs!

I have a concern though, maybe someone can help me out:

My idle adjustment screw (pictured below) doesnt seem to have as much travel as it did before. The spring (which keeps tension on the screw, keeping it in place) is fully compressed just after the screw makes contact with the throttle rod linkage. I cant think of any reason why this is happening, as everything else seems to be lined up just like before and it doesnt seem possible that anything is different. If you have any ideas, please let me know!

Pic:



Unrelated to carbs, I have my last order of parts (except exhaust) on its way and tomorrow I will be powder coating my tank, top triple clamp, oil tank and batttery tray/electronics bracket.



After all these parts are in and the coating is done its pretty much just putting everything onto the bike, creating/fiberglassing the custom seat (I'm looking forward to this!), painting the seat and side covers, wiring her up and then getting her onto the road!

[mkoski]

So I am setting up for an ambitious long weekend dedicated to the project:

1. I want to figure out what the heck is going on with my carbs, so tonight I'm going to crack some beers and get back into a full dis-assembly for the 4th time. (Maybe the beers are the problem...)

2. I am going to attempt to fiberglass myself a cafe-style seat over the weekend. I have a full plan but I dont know how I want to mount it to the frame yet. I'm thinking velcro or rubber-grommet-bolt method, which looks to be simple and common, albeit a little bit red-green.

3. I want to connect up my rear brake (easy) and complete the front brake (not easy)

4. Refurbish/clean and bar-mount my handle-bar controls, even if its only temporary (might want to shorten my bar lengths, they are long)

Question: Does anyone know the thread end for the "Front Brake Pipe" (the bit that goes between caliper and the brake line) or have an idea on how to replace it?

Item #12:
http://www.cmsnl.com/cb750k7-four-england_model14390/partslist/F08.html#row45128323020

I want to run a brake line from the master cylinder all the way to the caliper, eliminating the 3-way with the switch. I'm going to use a universal brake switch/banjo bolt at the master cylinder end, just gotta figure out the plumbing for the bottom. Any ideas would be great!

Alongside those items, I'm waiting on powdercoating and my final parts order now.

Also, just thought to ask this, anyone know of anywhere to buy some k7 exhaust? I cant find anything on the internet! I am looking for some 4-1, black, pipes.

Thanks!

[calj737]

www.slingshot-cycles.com for your brake lines. Use discount code SOHC for a member price.

[mkoski]

Here's the weekend's effort:

Start:


Much work:


With Painters Tape:


Waxed & Glassed:


Still waiting for the epoxy resin to fully cure, once thats done I'll bondo it, paint it and figure out how I'm going to mount it up. I see my parts order is now in Canada, should get it tommorow and my powdered parts will be back by Thursday hopefully!

[SOHC4 Cafe Racer Fan]

Nice job shaping the seat.

[mkoski]

End of another weekend on the bike, time for an update.

Powder-coating was recieved. I asked for semi-gloss black, to match the rest of the bike, they did gloss. I was upset until I saw it, now I'm glad its gloss.

Oil Tank:


Battery Tray:
Looks unbelivable compared to how it was before. Rust, corrosion, ect. It was terrible. Now it looks brand new!


Gas Tank:
Extremely impressed with this. The tank looked like crap before. Originally I was going to replace the tank because I thought it was ugly (as most people do with the 77/78 tanks) but I have grown to love it. While it doesn't give a lot of steering room with clip-ons, it gives a pretty serious amount of volume storage and looks mean because of its width.


So, with these parts, the ordered parts in (headlight, sidecovers, rear-sets, speedometer, handlebars, ect...) I started the final assembly! Here's how she sits right now...



With seat:


Now the final to-do list is short:
-Mount rear-sets, attach controls
-Connect throttle/choke/clutch linkages
-Oil lines
-Brake line
-Breather/vent hoses
-Finish seat, mount with side-covers
-Wire entire bike
-Install temporary exhaust
-Few other odds and ends

[SOHC4 Cafe Racer Fan]

The PC came out great, especially the gas and oil tanks.  I like the lower profile look of the front with the clip-ons flowing through the tank.  What type of gauges are you going to run.  If you can keep them more flush to the top triple tree, it will preserve that streamlined look.

[mkoski]

The PC came out great, especially the gas and oil tanks.  I like the lower profile look of the front with the clip-ons flowing through the tank.  What type of gauges are you going to run.  If you can keep them more flush to the top triple tree, it will preserve that streamlined look.

Yeah, the low and mean is something I always wanted for this bike, makes it look super aggressive! I'm going to shove this guy in:


It fits perfectly, protruding just a little bit, not enough to change the look for the line over the bike. No tach, I'll just use feeling to shift. I love the super-minimal look. Going to try and keep it looking as bare-bones as possible.

My next big thing is to install a hall-effect sensor at the front wheel and on the engine and run it through an arduino into my phone via a custom-coded app, mounted to the triple tree. That would give speed and rpm along with navigation and the like. Mounted flat and black it would look unreal I think.

[martin99]

Nice work! Glad to see I'm not the only fan of the K7 tank on this forum

That's got to be some of the nicest PC I've seen posted. Sorry if I missed it, but where did you get the headlamp from?

[mkoski]

Right?! Every build thread with a modified K7/K8 the first order of business is to find a new tank! Even if you google cafe cb750 K7, every one there has had its tank replaced.

I think its great! Huge capacity, perfect to lay down against too, now.

Headlamp is from Dime City, I got the whole unit for like 70/80$ I think, its sold out currently. I really like the huge, open look it has. Gotta get her wired to see what color the bulb is but I want it to be white/faint-blue for the modern look.

And yes, the new company that did the PC'ing really nailed it for me. Great price too.

Question for everyone: I attempted to paint my ABS side-covers gloss black to match the tank. It didnt go well and looks #$%*ty. Anyone have tips for getting a nice, even coat of gloss on those and making it last?

[mkoski]

Here's a minor update, not really much to do anymore...

I drew up some brackets for my rearset foot controls:


Got them cut out and mounted up:
Right:

Left:


I decided to put my initials in the left-side bracket for the hell of it, adding a subtle personal touch on the bike. The threaded rod had to be bent for the shift side to gain clearance but the bend made it feel a bit sloppy, so I think I need to upgrade the metal rod to something better.

Also, the swingarm pivot bolt is too short with my two 1/4" brackets, I am only getting like 4~5 threads on the nut, which I dont like very much. What should I do about this situation?

On top of that I got my side-covers repainted and smoothed out with 2000 grit paper, I'm very happy with this now as they are very smooth.

Mocked up my exhaust:


...and painted...


Its going to be very loud and very illegal but also very badass until I fork out for 4-1 exhaust with a muffler. I just cant justify a ~$400-500 exhaust with the canadian exchange rate right now, so I'll let that slide for a while until summer.

Choke is mounted in a unique spot, right onto the upper back-left engine mount bracket. I like it here, nice and hidden but still easily accessible... good clearance all around it too.


K&N breather filter installed onto the valve cover:


And finally I have to do the wiring. =( Not a fan of electrical and hiding it well looks like its going to be tough.

Much thanks to burmashave who made this beautiful wiring diagram for the K7, its so helpful!


Oil line has been purchased, will be installed tonight also. When I get in my order (today/tomorrow) with front brake line and new coils I think I will have the bike fired up by the weekend!

[calj737]

Not a fan of the bracket install. Using the pivots lot as youre discovering is problematic. I'd suggest your eWorld the brackets to use the engine mounting bolts  as they're much easier to replace with longer bolts.


Id be worried about knocking the choke with my leg in that position.

You can check out Fast from Past for linkage and offset shifter arms to help with the gear linkage.

[mkoski]

Not a fan of the bracket install. Using the pivots lot as youre discovering is problematic. I'd suggest your eWorld the brackets to use the engine mounting bolts  as they're much easier to replace with longer bolts.


Id be worried about knocking the choke with my leg in that position.

You can check out Fast from Past for linkage and offset shifter arms to help with the gear linkage.

I agree with the bracket install, I will probably have to figure out a new design with different mount point, as you suggested. The choke knob is fine there, I checked it out and hitting it with my foot wouldnt be easy. I looked at that site, lots of great stuff, I'll see what I can come up with.

[seanbarney41]

I think what guys have done before is used a swingarm pivot bolt from an F2/3, as it is longer to accommodate the f2/3 aluminum footpeg brackets.  Looks to me like your peg position is too far back with those brackets though...in general, I have no idea how long your arms and legs are.

[calj737]

I think the peg location is good, it's quite similar to where I have my 550 pegs, and they're quite comfortable with clip ons. Just gotta resolve the bracket attachment.

[mkoski]

I moved the choke location from the frame side of the bracket to the engine side of the bracket, so its now recessed and in a better location, more hidden as well.

The peg position is great for me, I'm 6'3" and the position allows me to fit my limbs on the bike fairly well, about as good as it gets anyways! I'll think about how I want to fix this bracket situation.

Got started at the wiring yesterday, front brake line is done with a switch banjo bolt, oil lines are installed and a couple other small things.

Joker Machine Tach plug:

Nice and clean look.

Just need to finish wiring, pour some oil in and fire it up!

[mkoski]

Spent the last couple days doing small stuff like wiring, re-cleaning idle jet passages, testing the ignition system ect. I was on leak patrol for a couple days too: exhaust, brake line, oil, gas ect. but now everything seems to be good to go and no more puddles below my bike! Always nice...

Note: One leak was from my petcock, the internal seal was munched up really badly. Fortunately for me I work at a company that keeps all sorts of o-rings in stock. I'm an idiot though and forgot to being in the old seal to match it up so if anyone knows off the top of their head the outer diameter of the seal bit please let me know so I can grab the right size! Thanks!

I fired her up over the weekend too, strong idle, can start it with one hand on the kick-start first try, very happy with that. I took it for a little ride and it just wouldn't rev over ~3000 rpm (no tach, just guessing). I mulled over it and checked that I was firing all cylinders. Boom, problem solved. With new coils I know it was either the plug or the boot. Pulled the boot off and checked the resistance... no continuity! That will do it I figure, so I ordered new boots for all my cylinders (5kOhm resisitance) which will be in tomorrow.

I really think this will solve my power output problem, so I'll report back tomorrow night. Thursday I get in my tail/blinker/plate holder making my bike legal for the road!

I have come to the point where I loathe my custom seat. Its crappy, heavy, crooked, ill-fitting and awful. Im going to re-try it and make a new one in the near future.

Layer 154 of bondo:


Sanded smooth:


Another question: will other (69/76) exhausts fit my bike? I'm really looking for a black, 4-1, right-side outlet with a cone-shaped muffler and none exist for the 77/78 and I think I read somewhere the pre-76 will still fit... Any ideas?

Thanks!

[SOHC4 Cafe Racer Fan]

Yes, 69-76 will fit.

[koendd]

older exhaust does fit but you'll probably need the older style clamps on the cylinder head to

[mkoski]

So its been a damn long while since I updated. Since my last post I have:

- Ordered and installed exhaust from MotoGPWerks
- Pulled and completely rebuilt my carbs again
- Thrown away my custom seat
- Finished all electrical except speedometer
- Almost done restoring all badges
- Removed rearsets as they conflicted with my exhaust

A few notes: the exhaust from MGPW looks great and I heard great things about it so I'm excited about that. I rebuilt my carbs because I opted the first time to save $100 and not replace the seals. They leaked terribly so now I am doing it right!

My seat was ugly and the lines didn’t flow. I am called the first version a trial and doing a new one up this weekend.

Here are some pictures:







I have also opted to park my bike, even though the weather is nice, until it is 100% done. I'm doing this because I know I won't finish it unless I park it and commit!

[koendd]

lookin' good!

interested in how you altered the routing for the choke though.
don't want another cable on my clip-ons so I'm looking for a cleaner solution as well.

any pics how you changed it?

[mkoski]

lookin' good!

interested in how you altered the routing for the choke though.
don't want another cable on my clip-ons so I'm looking for a cleaner solution as well.

any pics how you changed it?

Yeahhhh man. I caught some #$%* about the location because people thought it would get in the way. I havent had any issues with that though. Personally, I love the new spot!



So in that pic, you can see its mounted on its own little bracket onto the engine mount bracket. That is the old spot. Its now mounted on the part of the mounting bolt attached to the engine (not the frame). Does that make sense? It is kinda recessed now, much better spot. (In the picture, its right where that ground wire is going over the nut.)