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

[mkoski]

Yup, I really like it where its at now and I sure use it a lot living in Canada. I'll reference this picture:



If you look just below the bottom-right corner of my side-cover you can see a black dot, that's the location of my choke now. Its all stock, bracket, knob, cable. I just routed it to the left, up, through the middle two carbs and looped it backwards into position. I can actuate it with my right hand by reaching down and under my right knee (took a while to get used to but now its natural).

I just put the engine mount bolt through the choke-mount bracket, engine mount bracket and into the threaded rod (that I installed to replace the stock bolts).

[mkoski]

Brackets cut. The turn-around time gets pretty good when you pay for your third set... 

[calj737]

What's the wattage of the bulb and the rating of the fuse?

[mkoski]

55/60W, fuse is 7.5A.

Factory spec is 40/50 Watt, is this my problem? By my calculation that means at 12V I can be pulling an extra ~0.8 Amps.

(W=A*V so (60-50)=A*12 so A=~0.833)

What do you think?

[dgilling]

You are correct on your math.  the worst case at 60W would draw 5A.  You can measure this if you have a DMM that measures current.  put it inline and check the current draw to the headlight.  I was blowing my fuse and I had a ground issue.  90% of the time it's a ground issue.  check the wiring for the headlight everywhere, look for holes in insulation or where plastic protectors are bulled back and there could be contract with the frame. 

[mkoski]

Yup, time to pull out the dreaded multimeter and play the fun game of where's the problem. 

Did I ever mention that I hate electrical?

[mkoski]

Post-weekend update time. It was a big weekend!

My seat-pan-thing is now done. I spent a ton of time filling, sanding, filling sanding, priming, filling... ect. I put several gloss black coats on yesterday so she should be good today for a 2000 grit sand and polish. No pics for that yet.

The inside of the tank was something I have been reeeealy meaning to tackle, which I finally got to. A small amount of extremely fine sand and rust was making its was into my carbs even with two filters (very very bad) so that needed to get done. I rinsed my tank really well, cleaned the hell out of it and then did some electrolysis. My tank looked perfect inside from what I could see and still this came out... I ran electrolysis 3 times, until no new rust was getting pulled out.





I also put in new plugs, the old ones are in terrible condition. With new plugs she runs really nicely. I havent had a chance to fully test it out yet, though.



Besides those things, I set my tappet clearances (another thing I was scared of that turned out to be cake) and installed my rearsets with the new bracket.

The seating position is a billion times better without having my knees at my ears!

I popped in a new headlight as everything else seems fine. If I blow this one I'll look into it more deeply.

Right now I have my bike absolutely spotless and under a dust cover. I still have to get a seat-pad made but everything else is really easy (install the honda tank badges, wax the tank, seat, covers and install passenger pegs) and thats it! She wont be ridden until after I get a photo-shoot done.

I want a few really great pics of her before I ride her hard so I can always have a good memory of this project. I'm so happy that I did this project, the feeling of seeing that it might actually and finally get all done is great!

[SOHC4 Cafe Racer Fan]

I hope the vodka on the work bench was consumed by you and not the electrolysis!

[mkoski]

Hahhaha. THe vodka bottles were just to see how much crap was coming out with my gas!  I'm no vodka drinker anyhow, beer's my game.

[SOHC4 Cafe Racer Fan]

THe vodka bottles were just to see how much crap was coming out with my gas! 

Sure!!    I thought you were coming up with a new ethanol formula gas!

[mkoski]

THe vodka bottles were just to see how much crap was coming out with my gas! 

Sure!!    I thought you were coming up with a new ethanol formula gas!

Hah! Gotta wring all the hp out of these things you can! Also, I never noticed that you were the guy that did the nine-lives bike! That was a huge inspiration for me to start this project. I also am keeping tabs on your bionic mongrel, thats a heck of a ride as well. Unbelievable build. Great to have you along for your comments and opinions, they mean a lot.



Last night I finished up almost everything that I can do myself, I think!!! I went through my carbs again to clear any remaining crap out just to be sure the idle jets were mint along with the spray nozzles. I moved the needle clips to the second-from-the-top position from the middle (I was getting delayed throttle response in mid-throttle ranges so I assumed I was a bit rich) to improve performance a bit. I mounted up my brand-new-from-china Honda logos (which look killer from 3 ft away!  )

Rearsets are on and connected. They are almost perfect for my legs now.. Just waiting for passenger pegs to come in to be mounted. Seat is mounted up now too. Very happy with it, needs to be adjusted just slightly to the side. A few minor imperfections in the paint but no worse than my usual spray-it-in-a-dusty-garage job.  I managed to put some press-fit inserts into the frame which allow machine screws to secure it in three places. The seat-pad will velcro over the screws and flat section of the seat, covering up most of the poor look of the wooden seat pan. (I only really focused on the rear bump.)

I also re-routed my breather hose to drain onto the road, to the right of my tire. Too much leakage was occurring through the filter and cleaning that spot is near-impossible. I finally added carb-overflow drain hoses too. I was sick of drippage and can deal with the more cluttered look for a better bike.

Today at lunch I am bringing my new CB550 home and meeting a custom upholstery guy to do my seat pad up. He quoted ~225 CAD which I am pretty happy with if it comes out the way I would like!

Questions:
1. My idle is a bit high with my idle stop screw not even in contact with the stop. Any clue what I can do to back off the rpms of idle a bit?
2. The only remaining tuning to do is jet fine-tuning and carb synch. Can someone give me an idea of what/how much a carb synch will improve my ride? I am going to do it I just want to kind of know what to expect!

Here's the almost-final pics:






(You can see the extent of my shop here! Pretty minimal. Hahha 

I'm so stoked on how she turned out. Its unreal to see the end of something that took so long. I kept my budget very low and on-target mostly by doing everything myself only paying to get my tires mounted and powdercoating done. Everything here is due to the help of my friends and the people on this forum!

Better pics to be posted upon passenger peg arrival and finished seat!

[mkoski]

Seat has been commissioned from a local upholstery store now. I was extremely impressed with the guy's ability to listen and ask questions about what I am looking to get done. Even to the smallest details of how the edges of the leather meet the seat, materials, thread type, stitching pattern, ect. I did a sketch of what I was after based on this:

http://i.imgur.com/K6eIcRw.jpg

Black leather, gold stitching with a small bump at the front to meet the line of the gas tank, roughly. Looking forward to getting it back.

[mkoski]

Couple new updates from the weekend.

My stock master cylinder started to leak a little bit out the back and instead of rebuilding it (as my bike is no stocker anymore) I decided to swap it out. I picked up an adjustable nissin master cylinder from a crashed sportbike from recent years and put er on. What a difference!!! I never noticed how little confidence I had in my front brake until now. It grabs really well with less pressure and more firmness. The CB750 master was very soft and I felt like if I squeezed hard enough it would break! Great upgrade for the money!



I also got a little inventive on my carbs. I know one of the most common complaints/rationals for not using pods/pods not working well is the turbulent airflow coming into the carb throats. In school I took a lot of fluid dynamics courses and remembered a simple device to create laminar flow which has the same principle as using many small tubes to align flow:



Laminar/Turbulent flow is measured by Reynolds number, transitioning around ~3000 for laminar to turbulent. Reynolds number is defined as Re = (density*velocity*diameter)/(viscosity) in simple terms, so the basic principle is by decreasing your diameter from the air-filter hole to the diameter of a straw, you decrease the number/turbulence.

By knowing idle rpm, displacement, 4-stroke operation, number of cylinders, air filter diameter, straw diameter, ambient temp (approx) you get Re ~=998 AKA Laminar flow because Re <3000. Success.

So here is my process, in pictures:

Looked at clearance to make sure flow gets into the circuits.

Make straw sausage of diameter thats a press-fit to filter rubbers.

Cut sausage up.

Looks good.

Press-fit install into filters. Done.


Results: significantly improved idle from previous state with simple mod. Still need to balance carbs as I haven't received my vac gauge yet. Will report back after thats completed to really get a picture of performance.

[calj737]

The intersection of science and style! What a terrific idea. Do you suppose the plastic straws will hold up to the heat over time? And ultimately, is there a "preferred" diameter of straw/density of tubes that will yield optimum results?

[mkoski]

Thanks!

I have ridden around 100 km since I put them in and everything has stayed in place. I pulled one of them out to inspect and there is just a bit of damage from gasoline at the outside, taped area, just minor. Heat hasn't affected them at all as the cool air is pulling through constantly and they only touch the rubber boot so no conductance of heat.

By my calcs the air is well within the laminar range so adding more or smaller straws wont have any effect as there really isnt a range of "laminar" flow, it simply is or is not (or is transitional). The initial flow here shows the transition well from laminar to turbulent:



I was going to experiment with smaller straws but my thought is that having more openings/density of plastic will disturb the flow even more. One thing I want to do is attached the straws to each-other a little better so there is no risk at all of them coming apart and going through the engine, as that would be a catastrophe and a half. (Not that I am worried right now, they are very secure!.)

Now I just need to get my engine tune perfect and balanced so I can remove them and get a really clear picture of how much this helps!

[mkoski]

Here's a pic of my bike with the seat "done".



It didn't turn out as well as I would have liked. (I wish I took more pictures up close to show all the little imperfections and loose ends).

I paid a lot of money to get exactly what I was looking for and its causing some issues between the upholstery place and myself. The fundamental issue is that we agreed upon an image as the standard of the final product, alongside a long discussion, notes and sketches, all provided by me. While it certainly has a similarity to what I wanted, it has the quality comparison of a pair of Ray-Ban sunglasses and a pair of Chinese knock-offs. Just isn't a professional, finished product that I can be happy with compared to the cost.

That said, where do you guys typically get your upholstery done? I dont know a lot about it but what I am trying to get done doesnt seem too difficult in itself from my research. My goal for the final product was this:

[calj737]

yours looks "understaffed" and having used too soft a foam; thats whats causing the billowed edges. Its not bad, the sewing looks pretty good. Just maybe more, or firmer/taller filler?

[mkoski]

I wish I had better pics to show you of the seat. You are right about the foam, firmness, ect. The issue is the following...

Promised but not delivered/issues:

• The stitching is done with a really light thread, I requested a heavy thread for better wear
• Stitch pattern was a simple line, I wanted a stronger/cross pattern
• Stitches were not parallel
• Lots of loose ends, untightened corners
• Very large piping around the seat to cover mistakes and gap
• Lots if inconsistencies, imperfections

I think I will request a refund of my money, I discussed with them yesterday and they are more than reasonable. I feel bad because they seem very genuine in their efforts, its just not good enough for me for the amount I paid and the standards I hold myself to.

[SOHC4 Cafe Racer Fan]

I wish I had better pics to show you of the seat. You are right about the foam, firmness, ect. The issue is the following...

Promised but not delivered/issues:

• The stitching is done with a really light thread, I requested a heavy thread for better wear
• Stitch pattern was a simple line, I wanted a stronger/cross pattern
• Stitches were not parallel
• Lots of loose ends, untightened corners
• Very large piping around the seat to cover mistakes and gap
• Lots if inconsistencies, imperfections

I think I will request a refund of my money, I discussed with them yesterday and they are more than reasonable. I feel bad because they seem very genuine in their efforts, its just not good enough for me for the amount I paid and the standards I hold myself to.

If you want high-end upholstery, check out Ginger MCabe at New Church Moto in Portland, OR.  Her work is tip top.

[calj737]

Ah, thats rotten luck. A buddy of mine go ripped off (I'm not including you in that description BTW) by an upholstery shop. They charged him $300 for a small, simple seat pad. The work was terrible, pleats uneven, an absolute hack job, and 3 weeks turnaround. He called me, I took it to my guy, $125, 3 days, and looks flawless. Pays to know who you subcontract to...

I see you're in AB, so its got to be harder to find every resource locally in other parts of the world. I'm lucky, I know great upholstery, paint/powder coat, machine shops, and frame shops. Makes it very easy to trust the work being contracted out.

Good luck, it should be how you want it for a bike that special 

[mkoski]

Ah, thats rotten luck. A buddy of mine go ripped off (I'm not including you in that description BTW) by an upholstery shop. They charged him $300 for a small, simple seat pad. The work was terrible, pleats uneven, an absolute hack job, and 3 weeks turnaround. He called me, I took it to my guy, $125, 3 days, and looks flawless. Pays to know who you subcontract to...

I see you're in AB, so its got to be harder to find every resource locally in other parts of the world. I'm lucky, I know great upholstery, paint/powder coat, machine shops, and frame shops. Makes it very easy to trust the work being contracted out.

Good luck, it should be how you want it for a bike that special 

Thanks for the encouragement. I have built up a pretty decent little contacts list that I trust throughout this project, this upholstery thing is just not my game!

I just talked to the company that is doing it, they want to try again to make a version that I like... So, I'm going in to see them and tell them with exact details of what I am looking for.

Here's my list of points:

1. I am thinking they should be using two different foam densities, one firmer, under the top pad, a softer foam. The previous version was not nearly firm enough.
2. I would like it to be made of multiple pieces of leather stitched together (previous version was simply one piece with aesthetic stitching to make a pattern)
Example (has leather strip going around the body, stitched to the center-piece):

3. Bumped-up pleats, not flat. This is probably due, as you mentioned, to the tightness of the cover.
4. A bumped-up front with a separate piece of leather so it matches up to my tank nicely.

Anything to add that I should note?

[calj737]

yes, its a small detail, but you will notice it on better made seat pads. The side panel, it gets stitched at the front, NOT the rear. In the brown leather seat you pictured, notice the seam between your legs? Some pay not attention and sew that seam at the rear of the seat pad. Its very noticeable there.

Now that you know about it, look around and you'll see what I mean. The better seats you see, you just say, "Thats really nice" to yourself because you dont see the seams. The seats that you go, "Eh, nice but not great" about, they have seams too visible. You ever know why you don't get moved by things, until you start to pick them apart compared to a really nice version.

They say, "the Devil is in the details..." or "Look small, see small". So take lots of examples of things you like, and 1-2 of versions that are poorly executed in your opinion and show them what you want exactly. I bet they make a seat they are proud of, and you are pleased with!

[mkoski]

Calj,

I took your advice and gave the guy even more detail of what I was going for. The result was a seat that both of us were happy with. I have to give him credit, as well, as this was the first motorcycle seat he had ever worked on.

Pics:

[mkoski]

So, with the seat now finished, I'm pretty much finished my CB750 project. Here are a couple pics I took yesterday after cleaning it. (All that remains is passenger pegs.)







I'm very happy with the way it looks, came out almost exactly to what I had in mind when I started this project!

Unfortunately, just before I took those pictures I was waxing my bike and tank when I somehow managed to drop my tank, upside-down, onto my concrete garage floor. I could have shed a tear. It scratched deeply through the powder-coat along the top ridge of the tank. I couldn't even bring myself to take a picture of the damage. That's just the way she goes sometimes.

To fix this I either will get the tank re-coated (which is the easiest solution) or get a new tank and swap that on. I read that the F-style tanks fit well? I need a tank that will match up almost perfectly. Is the F tank going to fit like this?

[SOHC4 Cafe Racer Fan]

Very very nice!!  Passenger pegs?!  Probably not necessary given the seat (or it will be a nut buster against the tank). 

Sorry to hear about your gas tank.  I am sure it can be repaired.  The F tanks look awesome on Ks but (as I recall) will require some adjustment of the seat location.