73 Honda CB750 Custom Build Part 37 - Front brakes

hey we need to get a front brake on this thing welcome to hack a week the cb750 k3 as in 1973 came with a single disk on the front it is possible to put two disks on the front and that's what we're going to do today all right got the front wheel up here on the bench I'm going to pull the speedo drive off taking the axle nut off on the other side so get that out of the way so let's get the disks on the first thing we want to do is drop these on with the there's a flat side here that's machined away that goes in board drop that on line it up with the six holes that are in here it's going to go on a little bit tight I think on that adapter for the speedo that's an aftermarket adapter that goes on there it makes things a little bit tight we've got these flanges that just go on they drop on there like so so six bolts I've got bolts that will run all the way through let's just run those in there for now drop it in like that okay all six bolts are punched on through there boy there's just enough sticking out to do the job put the little lock tabs on we'll get some nuts threaded on there we'll run them all down here quick and I'm going to tighten all these to 15 foot-pounds now we can bend the tabs over whoops take a look at that it's it's crooked doesn't drop all the way on you know why because this side was not meant to have a rotor on it and it just double checked on my drawing here and the speedo drive side is the one that has that but the disc went over on this side the rotor so hmm be kind of nice to keep that dust seal there but it looks like it will work but some of this metal is going to go away let's check that out I think we got it now we can put the axle back in shove it all the way through get the axle nut tighten back up doesn't have to be real types just got to squeeze into the spacer that's in the middle of the hub that's between the bearings now we can put it back on the bike but we've got to put the pieces on the bike the calipers as such once again referring to the drawing this is everything that's got to go on the forks but it's got to go on both sides so I've got all the pieces collected together and we're going to start putting this all together the very first thing that's going to have to go on would be the mount for the caliper so let's just get it all out here on the bench first these caliper arms are powder coated this is why I frickin hate powder coat anywhere that it gets inside of something that's critical tolerance you've got to deal with that afterwards and whoever powder-coated these they let the o-rings inside they didn't even pop the o-rings out so I had to pop those out of there there's an o-ring goes on each end of this pivot shaft and I can't put it in all the way so I got to clean all that out the closest drill bit I could find is like a 20 5/64 freaking English system anyways it's closed but it's still a little it's going to take some work here's the old ones you know some other ones I had to the guy gave me two sets this was just the aluminum no powder coat it's all dirty and cruddy look at that goes right in like crazy yet you know I might just clean these up and use them now what's wrong with that cleaned up aluminum lovely I think it might have some gray paint on it but it looks fine and look at that bolt I think it goes in there just fine all right we're going to use this so we're going to mount the caliper arm on here and it's got let's see we got the caliper arm we got the mount up top we got the pin that goes in I've got some grease on the pin here a little bit up inside there I already pushed it in there one time just to get a little grease going so we'll put that in there like that we're going to put an o-ring up on the top side too and we'll slide the upper portion in place and then we can put it up here against the fork we've got two six millimeter bolts that go in there six by 25 and there's an 8 millimeter bolt goes down here you might have to squish that oring just a little bit to get that bolt to get started let's run these up and we're going to torque the six millimeter bolts to nine foot-pounds and then we'll fork the 8 millimeter bolt to about 15 foot-pounds should be just fine this should move freely and indeed it does so this dual front disc set up on a 73 CB 750 is just as new to me as it is to well maybe most of you something I'm already noticing these two arms they're not mirror image of each other they're exactly the same so the offset on one versus the other is a little bit different so you can you can see it here if I get the camera just right where we're looking down this plane being flush just take a look at where everything is here go over to this side and you can see that it's it's mounted inboard just a little bit a few millimeters difference so I don't know I guess the caliper will just maybe compensate for that I guess we'll find out because I'm just going to keep assembling here and see what happens I'm going to go ahead and put some calipers on here without any of the Pistons in place just for test purposes only here it's all temporary so I'm not really torquing anything yet this inboard pad gets a cotter pin in it but this particular pad has the hole for the cotter pin offset in such a way that I can hardly push it through well I guess okay good enough for now yes so you know I tried putting the wheel on here and this is just totally screwing this makes no sense to me whatsoever one side wants to go and the other doesn't not even get it to you know I just struggled with it for 15 minutes it makes no sense at all because you know it's not it's not mirror imaged you can't just throw one on the other side and have that work I really don't know what the hell the deal is here with this modification but you know what I'm going to go back to just bone stock going to put a brake on the side it was on one breaks enough I'm not going to race the thing I don't need to break from 110 miles an hour one break okay so back to a single break set up got the caliper arm on there the calipers on the floor I've still going to clean that out get the seal in it hone it out and put all that together got the single disc back on the front the left side of the bike speedo drives over there glad I had that spare dust cover that's not ground down maybe someday I will figure out what the the mod is and how this all works out but for right now I'm just not even wanting to mess with it I just want to get front brakes on this thing so I can drive it okay let's move right along so we got a caliper we got to clean out a little bit here I'll get some light on this get it up close and personal there's a bunch of corrosion in there I got to sand out and way down in there in that can you see it I don't know if you can actually see it but there's a there's a groove down in there that's a little gross it's got some stuff in it I got to clean that out probably a wire brush would be the call there because that's where the caliper seal goes the piston seal I mean goes in that little groove and then the piston brand new one here rides inside that so get that cleaned out so a small flat blade screwdriver down in there on the groove part anyway does a trick I need to hone out the cylinder here so I'm going to put a little bit of Marvel Mystery Oil in there for Lube got my brake cylinder hone here tuck that down in there it's a lot like the cylinder hone for the Pistons on the motorcycle except this time I'm not going to move it in and out I'm just going to let it rotate over the tiny bit and that's good all I was after there is to clean it up get rid of any burrs any pitting any strange stuff going on down in that cylinder and I'll clean it out now a little bit of brake clean parts cleaner and there we go got a nice clean bore in there now okay a little silicone grease again on this seal just to help it get into that groove a little easier just smear it with a tiny bit and we're going to put it down inside there and get it in that groove just going to get one side started and work your way around there goes pop right in okay let's get the piston in there now the side that's open stays out and the flat side goes in going to put just a little bit of silicone lube on there tiny bit down inside there on the seal and just give it a little push there we go and it goes ok the piston is in place now we need to put this little guy on this backup pad that goes into the piston just kind of drops in there I've got another one right here you can see how it's shaped with a convex shape to it then we can put the pad in but before we do that there's a little screw that goes in the end here didn't come with the pad I did a little research and found some pictures on the Google image search it always helps with solving problems so I made this little screw out of a six millimeter screw and I ground it down a bit to that size so that it will fit into that little recess right there and it keeps the pad from rotating as it where'd a little silicone grease around the outside of the pad just on the metal part not on the pad itself just a little bit to help it move a little easier in the caliper keep it from seizing up we'll put just a tiny bit inside there and then we'll drop the pad into place and a little screw I made sits in there just right now on the other side of the caliper I put a little grease around that one put the pad in put the cotter pin on the back and bent it over now we can assemble this to the arm here we are with the arm again with the pin through there the o-rings on each end and them out up top and let's see this is going to be the inboard side so we'll put the caliper here this caliper here and let's get a bolt started just start it by hand get the next one in there also started just by hand we'll run those in until they bottomed out and I'm going to torque those to 25 foot-pounds there we go let's get it on the fork we've got the fork tube rotating it around where you can see it here this is going to sit like this okay so well actually like that and then we need to put the guard on for the rotor disc I call it a rotor as I'm used to working on car rotors now we can get the we're going to leave these loose for now actually I'll just put one bolt in there to hold it for me while I'm working on this next part put the adjuster bolt in we're going to put the spring in and and we'll get it started in here screw it in screw it in till it just takes up the slack there with the spring leave it just like that for now we have a washer that goes here and a nut and that nut is going to be what locks us in place once we get it adjusted now I've got a few bits and pieces here a fender that I'm going to replace like there's some grommets that I need to replace here but I can do that later but for right now I'm going to go ahead and mount this up there's a side with two small holes that goes right here on this upper caliper arm mount so let's see if we can shimmy this in here hmm how about if we swing that around here and then see if we can swing the arm back around there we go got you on the other side here so you can get a better view what I'm doing next now I've got to get the fender down in there get that lined up with that bolt hole we're going to get a bolt started in there wait cooperates and gets started fairly easily a little tricky to get these to line up just right here we go let's get the next one back all right back to the other fork I'm gonna move these into position got a couple of 22 millimeter long m6 bolts go in there now we can go ahead and tighten all these up and we'll tighten all the six mil bolts to nine foot pounds and finally we'll tighten this 8 millimeter bolt 8 by 35 to 15 foot-pounds all right then I got 4 more attachment points to take care of for the fender two on each side hit those on let's get a front tire in let's swing the caliper out of the way a little bit get the tire in here a little bit of an angle you see I've got the front end supported by a jack stand they're doing this on the oil filter housing which is probably yeah you know maybe not the best idea but there it is okay and let's get over here and take a look at this to try to get a nice tight shot of what's going on here with the pads make sure that they're separated and then slide the the disc has to go right in there between the pads now we can go ahead and raise it up into place now the way I do these is I just raise them up into place once so wedge my knee under it and throw the cap on there and then I put one nut on with no washers just to keep it in place I'm going to do the same thing on the other side just put a nut on to keep it in place then I'll come back over to this side with the nut and the Watchers I've got a flat washer and a lock washer there and I can take this one back off also put a flat washer and a lock washer and just repeat the same thing on the other side back over on this side you want to make sure that the speedo drives got just a little bit of a downward angle to it now I'll draw these up with a ratchet till they just bottomed out on both sides and then I'll torque them to 15 foot-pounds now as far as the adjustment here goes right now there's just a tiny little bit of play in it brand-new pads so there's still a little bit of a gap if we come over to this side you'll see on that adjuster screw there's a bit of a gap between the caliper arm and the screw and I'm going to go ahead and turn that in until that just touches the caliper arm right there still got a little bit of play that way we're sure that when you back off on the brakes its freewheeling now out here tighten down the lock nut there's a slot in the end of that bolt so that you can get a screwdriver in it let's put the Reg on the nut hold the bolt and just give it a good snug not too much check it again got just a little play in it all right okay back to fully stock one disc I might go with two later for right now I just want to get the thing together get something working right and I might go with two I might not after doing some research putting two on is a little sketchy because what you're doing is you're putting on an arm that was meant to go on this side of the bike and you're trying to put it over here and then you have to compensate with some shims and it gets a little crazy over here with clearance for the brake line is whatnot and I'm sure it does indeed help the braking performance immensely but I don't know I'm kind of thinking I'll probably just leave this alone because the other thing to consider is you're having to apply pressure to two calipers but I've still got the stock master cylinder over here on the bench that's designed to just push one caliper because it's displacing fluid inside here and I imagine it would work okay but anyway for now single caliper so let's move on now to the lines and the master cylinder I've got this brake line assembly with the splitter here that's got the brake light switch on it and it's got a line that runs it upside down runs up to the master cylinder then we get a line that runs down to the caliper and needs to bolt on right here so let's run this line up through here we're going to put this through the forks now there's a little locator that goes on here what this does is just keeps the banjo bolts in the proper place when you tighten it up gives you something to tighten against and as always tighten them to nine foot-pounds and lastly tighten up the banjo bolt just a good snug feel where you're crushing the two crush washers that are on there the bikes back down on the ground now we'll push this little grommet into the holder and last but not least to get the brake line connected the hard line here now my general rule of thumb when you're putting these in you should always be able to start them with your fingers if you can't thread it with your fingers something's wrong don't get a wrench on there and start cranking on it thinking it's just tight you will end up screwing up the threads in the caliper I learned this the hard way working on cars for thirty years right now this is bumping into the bracket so do a little bending and tweaking here alright that's a little better okay now let's see if I can get this started look at it from this angle look at it from this angle make sure it's perpendicular wiggle the line a little as you turn it make sure you can get at least a half a turn down there now I'll get a wrench on it and it should turn easy if it isn't turn an easy stop double check to make sure you don't have a cross threaded there we go half is that let's take a look at what we got here the brake line comes up it doesn't touch anything it clears the fork it clears the fender and there it is located in its little grommet now that we've got everything installed there on the bottom tree we can go ahead and connect up the brake light switch wires they're right here they come out right behind the fuel tank so we'll go ahead and put those on well here's the master cylinder and here is the rebuild kit for it let's open this up we have some seals that need to go on here and then all that assembly is going to go down inside here but inside there it's a little you take a look it's a little corroded looking see if I can give you a look inside there not sure if you can see it but there's some corrosion and yuck down inside that cylinder need to clean that out and earlier in the video you saw me use a cylinder hone to do that job but I don't have one that's that tiny what I do have is some 320 grit wet Oh dry sandpaper okay we're going to make a cylinder home I'm going to roll up this piece of WeDo dry 320 paper and get some oil on it and a little on there already shove it down into the cylinder and then I'm going to put a hose clamp hair this way take a 3/8 drill bit shove it down inside the sandpaper we're going to tighten up the hose clamp onto the drill bit thus locking the sandpaper into place and hopefully this will spin with the drill and we have a little cylinder honed gotta get it a little tighter lovely there we go Ichiban would be proud of this one let's get a little more oil in there oil helps it cut a little better well that looks better what do you think not bad I might go over it again with maybe some 600 and there it is after some 600 that looks good there we go we got a single disc mounted up front got a caliper on cut the brake line on I'm going to save the master cylinder until next week I've got to order the proper rebuild kit the one I've got doesn't have the check valve it's missing a couple parts I don't know what the hell this kit was but it's missing two critical parts really strange but anyway I'm going to order another one next weekend we'll put the master cylinder on I'll show you how to put that together and bleed the brakes will have brakes then all the way around after that it's the seat the rear fender a few nuts and bolts and I think maybe we're about ready to take it for a safety inspection and get it licensed haha I'm stoked I can't wait to get riding this thing so there you go that's it for this week thanks for watching thanks for all the donations and support and until next time um I've got to pull the speedo drive off no that's not the drive for my bathing suit for all you people who grow up in the 70s

Channel: HackaweekTV

Views: 65,529

Rating: 4.8707781 out of 5

Keywords: electronics, diy, hardware hacking, hackaweek, motorcycles, circuit, automobile, mechanical, brakes, front brakesm disc brakes, honda cb750k3, cb7850, cafe racer, custom motorcycle, brake lines, speedometer drive

Id: GPXLyqhUleg

Length: 31min 3sec (1863 seconds)

Published: Fri Apr 15 2016