1979 Honda CB750F

With it so cold out, I haven't spent any time finishing up the Yamaha, so I grabbed the carbs out of the Honda I bought in the spring. On the work table I set up in the basement, I began the tear down so I can clean them up and rebuild them for the spring. This will be my first 4 banger motorcycle I've worked on, and the first one I don't plan on selling.

When I bought the bike the seller told me that he had the carbs all set to go with the correct jets. That didn't really mean much to me since most of the bike was apart, so when I opened them up I wasn't all that surprised. He had HUGE jets in the wrong spot, screws missing, gaskets missing, passageways plugged, diaphragms torn, the list goes on. I even found a bent choke plate.

The next step is to clean the bodies. I picked up an ultrasonic cleaner from Harbor Freight, and it sounds like Pine Sol is an excellent cleaner for them. I need to order rebuild kits which will include stock tubes, jets, gaskets, and seals. I'll also end up buying jets that are about 15% larger than stock so that I can run high flow filters and exhaust. This is where having 4 cylinders instead of 2 gets pricey. I have already bought new stainless hardware to replace the rusty and stripped old philips head bolts. This was only about $15.

Back on the road

After I got the peg mounts welded back up, I went for a cruise with some guys at work. The new foot placement is so much more comfortable and the bike handles even better now too with my weight centered more.

Cut up again

Well, yesterday a co-worker setup an after work cruise with some people down to Pittsburgh. So I decided that because of the route we are taking the bike needed the foot pegs moved finally. I've been thinking about doing this for the last couple weeks because hard left turns my toe hits the ground if it is under the shift lever. This will also help take some of my weight off of my hands having my feet in front of me a little more.

With that decision made, I jumped right into it. Got the rear half of the bike disassembled, I estimated the amount I wanted to remove, and cut with a sawzall. Tonight I have to get the grinder down there to clean everything up and weld it all back up.

little update

I'm a little late on this as usual, but here's some pictures. We were on vacation back to CT last week, so just before we left I was able to get the bike on the road. I'm over 100 miles now. Still no blinkers, the license plate mount is done, heat wrap is on, and the handle bar and foot peg locations are a little uncomfortable. I moved the bars above the top tree and that's a little better, but I think I need to move the foot pegs up and forward to take some of my body weight off of my hands.

For now, here's some pics. I'll get more with a more detailed update this weekend. 

Almost there...

Spent Labor Day working on the bike and got a good amount done. The trailtech speedometer/tach is on, the ignition switch has a bracket mounted under the seat, and the front blinkers have brackets. Last night the new muffler came in. It's made from stainless steel by Cone Engineering. It is their 2" "quiet-er" muffler, and it is definitely quiet-er than I expected, but still very very nice.

Things that are left to finish:

license plate mount

rear brake rod (currently en route via USPS)

exhaust paint and heat wrap 

rear blinker tabs 

wire front/rear blinkers

I also need to modify the steering stops because I re-positioned the handle bars to be in a more comfortable riding location but now they hit the tank at full turn.

Seat is Done

Finished up the seat cover this weekend. Super happy with it, especially for my first time sewing. The seat pan is painted with epoxy paint for rust prevention, there's a whole ton of steel rivets with washers, and has the hardware through for mounting to the tail section.

Seat Work

It's been a while and I kinda forgot to update on the wiring harness, but that's done. I'll get some pics later before the bike is together. Anyway, here's where I'm at now. I made the seat cushion pan to match the seat tail pan. The front end of it was also boxed in to go over the tank mount.

Yesterday I did most of the seat cover in marine vinyl. Took a bunch of test runs making sure that I could get the pleats straight and parallel, then I made a small test piece to see what the final product will turn out to.

I was pretty happy with how this turned out for a first try, so I did a ton more practicing for the pleats then went for it. The foam is 2 layers of 1/4" scrim foam (fabric backed so the thread doesn't pull through). The 3 layers are spray glued together to make the whole process easier.

This last picture has the cover just taped to the pan to get a good idea of how its coming along. Still have to finish the front section, it just got too late to do it (and I was getting a little frustrated with it).

Exhaust Finale and Start of the Electrical

Had a nice long 4th weekend and got a lot done on the bike. The exhaust is fully welded and all welds ground smooth on Friday. The only things left are to find band clamps for the slip joints and to weld a hanger bracket to the frame where the 2" section starts.

The tape on the tail pipe is holding on an extra 6" piece of pipe to illustrate how long the muffler will be whenever I get around to ordering one, but its not cheap so I'm putting that off till later. The tape from the swing arm to the wheel is in place of the brake stay bar that I also haven't fab'd up yet, but that will be an easy addition when I get to it.

On Saturday I took the time to wire up the ignition module to a battery I had laying around. After an annoying series of minor oversights (forgot ground wire to the block, open fuel petcock), I was able to get it fired up without even using the choke. This video probably doesn't work too, I need to find out whats going on there...

Sunday I jumped right into starting the wiring. Didn't spend a whole lot of time but still made some progress. I drew up the entire schematic for the bike and how I want to wire it. 

Next I sat with the manual, the left and right controls (headlights, blinkers, ON/OFF, etc), and I re-pinned them into Molex connectors. I was able to remove about 4 wires from the controls by doing it this way because the original equipment harness had extra functionality that I won't be using; like a starter (haha) and a "blinker canceling unit" which doesn't work very well from what I hear. So at this point all of the controls up front and headlight are wired, now I just need to get some cable wrapping to harness the wires together and start on the rear part of the electronics. This includes the capacitor that will be replacing a battery, fuse panel, LED blinker timer, and brake light relay. The regulator/rectifier needs to be terminated and the alternator wires have to be redone as well. 

Exhaust Part 3:

I finally got everything planned out in my head for the next section of exhaust and it came out pretty good. The next section will be a slip fit onto both tubes that come down the front. This will make removing from the bike possible for things like an oil change. Also if I made it one piece, it would literally never come off the way I have it wrapped around the frame (I did a test piece first with the old exhaust). 

So after making the two sections that turn back under the engine, which was pretty intensive to make them even in every direction and length, I worked on the slip fit merge section. From here I have two pieces of pre-fab tubing that was stretched on one end to fit over the 1.5" tubing, cut to length, then  cut a taper that I used CAD to help me determine the length, angle, and depth to cut. This was very important not only for angle, but at the end where the two pieces are merged they have to match up with the circumference of a 2" piece of tubing that will exit out the right side of the bike next to the rear wheel. 

After carefully squishing the 2" tubing in a vice, the ends line up pretty well and after some more massaging they will be welded up. More to come later as I finish the last section.