I have been working on this 1975 CB750K5 for four months now, Is started around April of 2012. I got it more or less stock and proceeded to give the bike a serious diet and shed some unneeded parts. I stripped the bike down to the frame, removed all the paint, and de-tabbed. I cut the rear section off to make room for a U-bend metal loop from dime city cycles. I am going to make a fiber glass seat and then wrap it in carbon fiber. My friend is going to make me a custom leather seat with matching knee pads for the tank and a leather chest pad . As well as custom made leather hand grips. I am getting a slim line LED taillight with integrated turn signals , which will be flush mounted to the rear of the seat. I polished, clear coated, and cleaned up a lot of welds with a flap wheel on my grinder. I replaced the Swing arm bushings and reassembled it to the frame and greased it up. The shocks are still stock, but I will eventually switch to new progressives or possibly Ohlins. The tank has also been stripped of all paint and polished / clear coated the raw steal. I also took a leap of faith and hand hammered out the knee indents. Word of advice to not grind the edge of the gas tanks smooth where the pinch weld is. During the hammering I broke the weld ,which I have to braze to seal it back up. No big deal, just that it could have been avoided had I not been so OCD about the edges looking clean. For the tires I went with a Dunlop elite II for the front and a Coker white wall knobby for the rear ( BTW it looks tits). I cleaned and rebuilt the rear brakes and painted the wheels and hubs, using black caliper paint. I rebuilt the Front brakes, new master cylinder, steel brake lines, and rebuilt and painted the front caliper. I went with black drag bars though I may switch to a raw steel bar instead. New clutch lever and perch, new clutch cables. New push/pull throttle cables. All the carbs have been meticulously cleaned and rebuilt with new parts. Pod filters for now, but I really like the look of velocity stacks. Though im wondering if there going to effect engine performance. I got a headlight from a 1967 Puch 250 , which has a built in speedometer and ignition key. Pretty cool, I stripped it of all paint and polished and clear coated the raw steel. The headlight brackets are from Dime City Cycles, they are high quality forged polished aluminum. New sprockets front and rear. New O-ring chain. Front forks rebuilt using tubes from 1981 cb750. new fork seals, and dust covers. Polished the aluminum on the forks to a nice shine. New all-balls conical steering bearings. I stripped and polished the triple trees and reassembled. I bought a custom oil tank from Curt at anythinggoes74.com. It is stainless steel, pill shaped, with sight gauge on side. I went with the brass cap and fittings. New Braided stainless steel lines for the oil flow and return. New Braided stainless steel fuel lines.
Engine top-end rebuild. Replaced stock studs with Heavy duty, new tsubaki cam chain and new tensioner. New gasket set from Cycle X, New piston rings, Valves lapped and cleaned, new Pamco ignition and coils from cb750supply.com. New plugs and wires. Powered by a ballistic evo8 battery. All new oil seals. Cylinders Honed. Soda blasted the whole engine and covers. BTW make sure you have at least 175 PSI and get a cheap line dryer to keep the moisture out ( Harbor Freight) Its really annoying when it clogs from water. Cases will be painted using Black VHT low gloss for the cases, black VHT wrinkle paint for the side covers, and VHT black high gloss for all chrome covers, also using an adhesion promoter. Exhaust is 4- 2 with baffles drastically reduced and wrapped in black fiber tape.
So far I have enjoyed every minute of this re-build, My advice is to get the manuals ( clymer, hanes, factory,and a parts fiche) and always use proper tools ( I prefer snap on and rigid) and safety equipment ( Glasses, dust mask, gloves). Getting hurt will def slow down the build. Cross reference all parts and make sure you order the correct ones, and buy good quality parts. Cheap stuff only breaks sooner and often times does not fit properly, IE gaskets and o-rings. When dissembling parts always label everything and take lots of pictures ( something I have not done enough of). I recommend getting several of those organizing trays and drawers from home depot, and a marker to label the drawers with part names. For engine bolts and screws I used pieces of cardboard with holes punched out and then I roughly drew the shape of the engine covers and stuck the bolts in the holes and labeled the cardboard. its nice to do this because the bolts are not the same sizes and they need to go into the proper corresponding holes and this method insure that you have them in the correct order. You can never be to organized, it will only help the reassembly process. Especially if there are longs periods where you do not work on the bike. Always stay positive, yes this is very time consuming and tedious work. Often times you will get discouraged because something will not come apart or wont go back together right. Just take a step back some times re evaluate and re check the manuals and this forum for advice. There is always a better way and a proper way. Most important have fun cause in the end all your trying to do is build a sweet ride and go cruising.
