1975 Honda CB

CB750F1006168

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1975 HONDA CB750F SuperSport. This little Hot Rod Honda pays homage to the legendary #2 ridden to victory by Dick Mann in the 1970 Daytona 200. It also pays homage to the equally legendary #970 built by Vic World of World Motorcycles. Vic states that there were 180 unique parts for the CR750 which were basic Honda part numbers with the prefix of 970. Vic acquired approx. 160 of them for #970 and doesn't feel it could be done today. I have zero parts prefaced with that number. I may have 970 new Honda parts, but none with that number. The major non-Honda parts used are Dyna, Barnett, Buchanan Spoke & Rim, JE, Swarbrick, Dunlop, K&N, DID, Progressive Suspension, Kibblewhite, Tsubaki, Airtech, Maier, Yuasa, Spiegler, Motion Pro. The rearsets are CBR600F2, the master cylinder is GL1200. The finish is VHT Flameproof Flat Silver. The process for getting paint to stick to aluminum is involved requiring acid etch, alodine, prime paint and bake. The frame, swingarm and other red parts were powder coated. Gaskets, seals are Honda with very few exceptions. Hubs are standard with new bearings and seals. The steering head is now tapered roller bearings and the swingarm pivots on brass bushings instead of plastic. Attention to detail is evident. The CB750 has a reputation for solid reliability. I have no reason to expect anything less from this version. I have only ridden the bike three times, less than thirty miles. It handles fine and I felt like the brakes were bedding in better towards the end of the last ride. I made jetting adjustments last week and revised the turn signals. I think it will stop raining someday so I can validate the adjustments. Lenny. 360-897-6377. 23MAR11: I rode the bike today, nice day in Seattle. I rode about thirty miles round trip to the Honda dealer where I know the service manager. Very stable, very smooth and sounds like a pipe organ, just the way it is supposed to. On Apr-25-11 at 18:35:52 PDT, seller added the following information: The paragraph above is the same as last week, the first week on Ebay. It is pretty much cut and paste from the Cycle Trader ad that has generated only two offers to list it on Ebay for $400. But the paragraph covers most of the “major” stuff. After that I will list what a few of you have had to say and then some of my responses. Sorry about being a little slow putting this together. I work tool design on computers all day, not something I enjoy all that much doing when I get home. I will run on a little to give you more information about what some of the challenges were on this project. Compliments: Pleasantly I received no negative comments. I love your bike but it is out of my league right now. What kind of fairing is that? and where did you get it? Very nice build sir. Tell me please what big bore kit or whatnot was used and does this have a one off set of custom pipes? Also, stock carbs or other? Is that a tiny little head lamp under the fairing I see? Would you be willing to store for a couple weeks after purchase date? Thanks much, DXO I'm having a problem with my device, hope you are not getting this email twice. Beautiful work!! I am sorry to waste your time, but just wanted to tell you this is the nicest modified Honda I have ever seen. Phenomenal workmanship. Great concept. It is making me think I need it. Replies: I won’t list anybody’s name. Airtech.com has many fairings for all kinds of bikes. They have a section devoted to the CR750 with some very interesting reading about the original splashes that were taken by a fellow name of "Greasy Dick Kilgore." Thanks for the compliment. The buy it now price is about 75% of the cash investment. I have about three thousand hours invested. It was difficult to figure out how to do things from forty year old black and white pictures scanned into the computer. The exhaust is from England and I thought "straight megaphones" meant no baffles as he offered baffled megas also. Oops, straight means straight cone shaped megaphones. The instructions were brief; "Cut kerfs 95% through 10mm minimum distance apart. Number of kerfs will vary by mega." It took me over a year to lay a blade to those cans. All I could envision was a $1,000 were of scrap! One of the pictures shows the plan and side views I made of the basic frame structure. In the background you can see the jig I built to layout, shape and hold for welding and cooling. I figured out a way to do it with two ten degree cuts in #2 & #3 and three ten degree cuts in the other two. Can you see where I made the rearset mounts also the exhaust supports? Everything is rubber grommeted with a steel bushing inside so that the fastener exerts just the correct amount of crush on the rubber. I was very pleased with how well that came out. Lenny I can answer even the minutest detail having held each and every part in my hand at one time or another. The 836cc pistons are JE, the bore and fitting of the pistons was performed by CycleXchange. The owner, Kenny, personally did these after some discussion as my local machinist sat on the job for three weeks before begging off. I think he needed a piece of equipment for his boring head and didn't want to buy it for no more often than he receives a work request. The exhaust system is Swarbrick from England. The headers are correctly shaped and welded to wrap #1 & #4 immediately around the frame down tubes for fairing clearance. However, this old hot rod thought "straight pipes" meant no baffles since he offered megaphones with baffles. Not so I found when I opened the package, straight means straight and the only instructions are; "Cut kerfs 95% through, minimum of 10mm apart. Number of kerfs will vary by mega." All I could see was how easy it would be to create a $1,000 pile of scrap metal! It took me over a year to finally get serious about it. I actually returned from a month in Ecuador and decided to finally rebuild my workshop bench to sharpen skills up before committing to the exhaust. I think one of my pictures shows drawings on the garage door of plan and side views that I made. I then entered this information into the computer at work on a couple of Saturdays on my own and solid modeld the bike. I figured out how to do it with two ten degree cuts in #2 & #3 and three ten degree cuts in the other two megas. I made a jig that you can see in the background that had the layout projected down to a plane which I then taped to a piece of MDF for layout. I was able to shift the rear support to the correct angle condition to hold them while they were welded and cooled. After powder coating and assembly I found that I needed to cut chain clearance in #2 which necessitated re-coating. The headlight is one of a pair that are sold as "Driving Lights." I had at least six different approaches over time on how to do it, I just couldn't get myself to cut a hole in the nose of the fairing. This light is 50W and should do fine if a fellow found himself out after dark. The running lights are operated via the Hi-Lo switch. The horn and turn signal switch work as does everything on the right grip. The ignition key setup is stock and actually part of the tach mount is stock, just shortened and turned around backwards as there is only room for one instrument. A friend provided the artwork which was sent to Fast Signs for printing the tach face. The electrics are provided by Oregon Motorcycle Parts. The fellow there, Tony, was also kind enough to fix me up with a Care Package of spades, bullets and females along with some plugs so I could cleanly modify the brand new "K" model wiring harness. That bike had the ignition key on the left side under the tank whereas my "F" bike was on the top triple tree. The plug and shroud for the "K" connector are used at the headlight. I am 61 years old and have 35 Mondays until retirement. After High School and the Marine Corps. I apprenticed in Tool & Die in the automotive industry in my native St. Louis, Mo. The oil problem in 1974 found me in Wichita in the aircraft industry where I have pretty much stayed since 1975, 20 years here in Seattle after working nearly every aircraft company in the United States at least once. I have peers in this industry who also happen to be accomplished re-builders. The man I hold in the highest esteem has ridden the bike and he a couple of others who have made special trips from Canada and California to see it based on what my friend Don told them have all given me a thumbs up. Their approval is worth as much to me as your money. Maybe more, ha. What I tell people is that while the task was very frustrating at times, there are no guidelines beyond the handful of forty year old black and whites scanned into the computer, I never took a shortcut. The frame is actually the second one. Some modifications that had been made to the original were becoming more and more unacceptable and finally when it came to the rearsets I decided I needed a fresh frame. As luck would have it I found one the next day on Ebay for $80 with a California title. Cost me $140 in shipping. But with all of the basic elements defined I was able to apply the learning curve and do a very nice job. You should see the rear tube closures up close. These were fabricated from 1 X 1 X 1/8" steel angle. After careful shaping and fitting they were welded in place and then finish "trimmed." With the powder coat they look molded in place. Everything is done with an eye towards repair. The access is frequently laborious, however, it is straight forward and progresses quickly after you have done it a couple of times. Let me know if you need more information. Lenny. P.S. Oh, the bike is titled and licensed in the State of Washington and the tabs are good until March 2012. I ordered the custom "CR750" license plate in anticipation of riding the bike to the Isle of Vashon vintage gathering last year but it didn't work out because it wasn't ready if you know what I mean. It had to be just right. You will note in the pictures that there are different turn signals for example. The original stalk mounts were a pain in the arse for assembly of the rear cowl and tail light apparatus. The new side mounted on the cowl units are MUCH easier to deal with. Stuff like that happened a lot, and many times the product fabricated from cardboard mockups went into the trash and the head scratching started all over. Sometimes the cardboard mockup itself solved problems by showing me what I could do instead before fabricating. If you ever look at CR750 pictures, old or new, tell me how the heck they mounted the exhaust would you? My rearset mounts support the exhaust via brackets to #1 & #4 and then interfacing brackets to support the other two megas. The rearset mounts I whittled out of 2 X 4 X 1/8" wall rectangular box steel tubing. I don't paint or weld but I fabricated everything myself. One of the best investments at the start of the project was a sand blast booth from Harbor Freight. I fell in love with the look of glass bead and worked diligently to bring that finish to life in a maintainable manner. For aluminum that involves quite a process but the finish is everything if you know what I mean. Now of course I do all that myself but that is different than painting bodywork. The exhaust is mounted with rubber grommets with a steel bushing inside which allows the fastener to apply the "correct" amount of crush on the grommets. Too often people tighten grommets down to solid and thereby defeat the purpose of using grommets to begin with. Everything is rubber mounted or isolated. Fiberglass doesn't like to be hard mounted and vibrated. Lenny. Thank you XXXXX for the compliment. Thank you also for the offer of building something together. Alas, I am older too, 61. I have 35 more Mondays until retirement to Ecuador. This motorcycle project took on a life of its own and challenged me every step of the way. As you know, there is no handbook available on how to do this. I stared for hours at those few forty year old black and white photos scanned into the computer trying to figure out how they did things. What I can say about the effort in the end was that I took no short cuts. But I find few things that I would have done differently although there are a few that I would like to have known more about how the factory bikes were setup. Gordon, this motorcycle is not fast, certainly not by today's standards. My daily rider was an SV1000S that I sold just last week with 68,066 miles on the clock. It is fast, fast enough anyway. This one makes beautiful, howling noise. A person would not want to ride a 500 mile day on it, not as a touring bike anyway. It is a hoot to ride, the feeling is similar to that given the viewer in "The World's Fastest Indian." You are laid out over the tank and the windscreen is just below your eye line. The ride is solid and comforting, it feels planted. The engine revs smoothly, pulls away from a stop smoothly and accelerates smoothly, but it doesn't jerk you back. I have peers in tool design who also have established reputations as rebuilders. Their thumbs up approval, two of whom traveled to see the bike on New Year’s Day, sought after. It is heirloom quality. Look great in your living room:) Lenny. P.S. I'm getting ready to load some pictures and eventually this week I'll add some of the kind of information I have related to you here. This would then become the “new” paragraph. You are probably sound asleep now and I know from personal experience with three wives that when I start spinning a yarn people gain the much needed rest their bodies desire. It is good to know that I am asset to mankindJ After disassembling the motorcycle and stashing small parts and fasteners away the first effort was to clean up the frame which was accomplished with paint stripper, simple green and a drill motor mounted wire wheel. Lots of fun digging those splinters out from the apron or sweatshirt as they poke through. A good vacuum close by is helpful but I doubt it gets more than about 10% in truth. Figuring out how to mount the seat was the next must be done item. The tank is custom from England and I guess to be able to form the metal this way requires using 2024-0 aluminum. You don’t want to know how many hours it takes to make that tank shine, but you can shave in it. So the tank mounts to the stock mounts in the front and only required a neoprene pad and a belt to hold it in place. I made the belt out of the same sheet of neoprene, 1/8” thick and 50-60 durometer. But that was later. This 28 liter tank is shorter than the fiberglass tank. I see that with the bikes that use that tank, the rear cowl attaches at the stock horn mounts. That would be about a 3 ½” gap to the tank, not good. So I made cardboard templates to capture where I could fasten the seat cowl and that allowed for locating simple pillow block looking tabs. I also had Rich Miller weld an 1/8” block that was shaped to the pillow block underneath to bolters against the frame tube and provide additional depth of thread. The stock piece behind the battery that runs across the frame and supports the rear of the battery cage provided ample space to define attach points. Those also have the block welded underneath to provide depth of thread. The rear hoop on this frame was left intact (the first frame had been cutoff and I made two attempts at re-attachment and it was okay but nowhere near as nice as this frame. With the cowl so located I set about modifying the horns into mounts. I cut them off at an angle and fabricate some angle iron to cover the ends of the tubes and provide “ears” for mounting the cowl. With that in place I played around with the seat pan and noted that if I just held it in place and pulled it back into contact with the cowl that the front nested very well into the cowl. So I set that all up with grommet mounts, plywood spacers (yeah, but it is good plywoodJ) with bonded neoprene cushion plates that are counterbored to receive the grommets in the seat pan. The pan is attached through the bumstop. Carriage bolts are fitted into square openings and locknutted into place. Grommets are mounted in the cowl through which the carriage bolts protrude and are fastened with flat washers and nylock nuts. These are American Std. fasteners. The only other such fasteners are those attaching the fairing as that is way the upper fairing mount was supplied to me. But they are readily, if confined, accessed for attachment or removal. Removal of the cowl is required to remove the battery but not to charge it as that can be done by removing the new OEM positive battery cable from the new OEM solenoid (the voltage regulator and rectifier are solid state from Oregon Motorcycle Parts). The stock inner fenders are retained. Unaltered on the forward unit, the rear unit is rather “abbreviated.” Maybe I should say it is a bobber. It is long enough to keep the stock mounting locations for both attachment and light fixture. The trunk are fender are long gone. While this piece was attached from above on the stock bike I needed to be able to access it above the rear tire. This is where the taillight and license plate assembly attach via a 2” UHMW angle. The whole mess weighs very little. With the new side blinkers it is very simple bullet connection with covers. I guess I should mention that the wiring harness is OEM, but for a “K” model. There are slight differences but with gobs of excellent color coded wire hiding inside the original cover I could make any arrangement I needed. Tony at the aforementioned Oregon Motorcycle Parts was kind enough to fix me up with many small electrical parts. My years with slot cars and 1/8 scale gas cars has afforded me very good soldering technique. So everything is properly fabricated, protected and installed with dialectric grease. The “K” model ignition key was on the left below the tank, that plug and cover are now used at the headlight connection. I think I mentioned that once before. There are two rubber parts that I know are not new. The rubber plate in the bottom of the battery box and the piece in the sprocket cover. They were both serviceable but I admit I did not pursue their availability. I did successfully use the “network” through Western Hills Honda in Cincy to locate a new wiring box and they sent me to another dealer for the new positive battery cable. The negative was in excellent condition. I guess that is another aspect of a project like this. At one time or another you hold each and every part in your hands. And the first thing you have to do is clean it. On stress parts like gears you look for anything out of the ordinary. There wasn’t anything like that inside the engine, it was in excellent condition and the 27,000 miles were not abusive. A little negligent maybe, but not abusive. The rat bike that donated the right front caliper components I actually rode home. This motorcycle had a jury rigged ignition key right in front of your face. The guy put a cheap little old lawnmower battery in it and I brought gasoline and it started up. It didn’t run very smoothly so I eased the clutch out so as not to kill it. No worry, the clutch would hardly grab enough to move the thing. So I’m riding up the road, maybe a mile I have to cover, and the ignition switch looks like a kids sparkler on the 4th. As I pull into the garage my wife says it is leaking water. Hmmm, air cooled motor, GASOLINE! I shut it off and close the petcock and it stops bleeding but I can’t believe with all my experience, knowledge, wisdom, good looks and money that I actually rode a ticking bomb, into my garage. The point being that the motor ran. When I took it apart to see how that is done the liquid within resembled something like coffee with way too much creamer in it. It didn’t really feel like oil either. And it ran. The rearsets are clearly non-period. They are CBR600RRRF2 or 3, so early nineties vintage. They were deemed appropriate for three primary reasons; 1) The splines on the shifter linkage are the same as the CB750 and clamp on the shaft in the exact same place. 2) The 1975 CB750F SuperSport was the first model to have the rear disc brake so I had to have a master cylinder. 3) I could see the flat silver pieces with a boot mirror on top. They are completely rebuilt of course with new OEM pieces. It is amazing how many new parts you can still get for $.99 each. I used Motogrid in Wisconsin for a lot of parts. The UPS driver is well known. I think I already described how the rearset mounts were fabricated. The center to center distance of fasteners was easy enough to define and transfer to the plate. I used ¾” square CRS for the step-offs that would be threaded. They match within .003 on each side and within .020 to each pair. With a hacksaw, six inch sander and a file. I drilled a 1/8” diameter hole down the center and matching hole in the plate on centerline. I used a roll pin to hold them in place and clocked them with a piece of 3/8” Momax to hold alignment during welding and cooling. On smaller stuff I usually made some kind of jig to hold stuff in place for welding and cooling so it would fit when I was done with it. I stole a bracket off the frame and had it welded to the inside of the battery box to provide an attach point for the tank belt. I made my own new tank mount rubbers, they fit the new tank very well. The tank uses a stock Honda petcock and I didn’t want to re-use the stock one, even though I had purchased a rebuild kit and it cleaned up nice, it didn’t have the top piece that provides some filtration as well as reserve positioning. So it has a new OEM unit. My local dealer parts manager guy directed me to another repair facility locally that buys the Honda fuel line the only way you can, by the spool. I didn’t that much. Ken had the exact stuff in 3.5mm and 5.5mm. Those sizes just aren’t available readily at auto parts or my favorite, McMaster-Carr.com. I use McMaster for many kinds of fasteners, materials, tools and equipment. Very good prices and reasonable shipping. I used OEM carburetor kits for the stock carbs. I can tell you that they have the needles raised to the highest and I have 125 main jets in them. I have a set of ’77 “K” model carburetors that would go with the bike. They are 32mm and those on the bike are 28mm. Inside the engine are all new bearings, seals, chains. Interesting way you determine bearing size isn’t it? Green. Anyway I was somewhat surprised to see there is no thrust bearing used on the engine and there are no funny looking wear patterns either. The cam chain and guides are new. The chain is Tsubaki “heavy duty.” I’m aware these motors had a problem with high rpm chain throw off and that modifications are available to improve the strength in those areas. Those motors are expensive. This isn’t one of those motors. This is essentially a stock engine with bigger pistons that are very pretty. I used Honda gaskets pretty much exclusively. It didn’t start out that way. I marred the finish on two covers and had to remove them to start over with new seals and everything after putting them through the “process” again. Those cheap ass gaskets leave half on each piece. I did get lucky though, an editorial in Cycle World mentioned that lacquer thinner would take Yamabond or Triple Bond right off. If you use a smallish hobby paint brush you can soak the paper and it will come off a little easier. If you use a Honda gasket you can probably re-use it. It is that much better. The valve springs are Kibblewhite. The exhaust valves have new guides and are ground and then hand lapped by me. The intake guides were good but I installed new CycleXchange intake valves and they are hand lapped as well. The camshaft is stock but I used an adjustable timing gear for setting. The cam guides and rollers are new, the tensioner is not. The tensioner will get its paint curing via osmosis because it has a non-replaceable seal that I didn’t want to cook. On Apr-25-11 at 18:57:18 PDT, seller added the following information: The EazyRizer lift and all attachments are included with the motorcycle.