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CB650: The Jersey Devil Project

Discussion in 'Motorcycles & Boats' started by walnut, Apr 10, 2013.

  1. walnut

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    #176 walnut, Nov 7, 2015
    Last edited by a moderator: Sep 7, 2017
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  3. walnut

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    #178 walnut, Nov 7, 2015
    Last edited: Nov 7, 2015
    The Bike:
    1975 CB550 K1
    The weather here today isn't being cooperative so I'll roll everything out and document with photos tomorrow.

    Its Background:
    The previous owner races CBs as a hobby and would seem to have a lot of experience working on and maintain bikes similar to this. He purchased it about 2 years ago out of nostalgia; he had one in the '70s and wanted to build a copy of his old bike to ride around. After riding it for a while he decided to tear it down and do some maintenance. I've purchased it near the end of his work but before completion. I had posted on another forum (caferacer.net, where I will be posting a thorough resto-mod thread as I go along) that I was looking for one and he contacted me. It wasn't currently listed for sale and he told me that if I didn't buy it from him he was going to continue to get it back together and keep it. I had a suspicion which was later confirmed that he saw an opportunity to get some money for another race bike and was willing to give up on rebuilding his "old" bike in order to get a build out a higher spec race bike.

    What it doesn't need:
    The carbs have been professionally rebuilt and jetted to stock. Air filter in the OEM airbox is in good shape and the rubber boots that hold the carbs to the block are brand new. The brakes have been serviced, and the top end of the engine has been gone through. A new, up-rated clutch as also been installed which is good because the OEM clutch on these is known to be weak. The valve springs and seals replaced, valve seats lapped, valves cleaned, pistons have new rings, etc. The tires are also very fresh. All-in-all, its in really good shape.

    What it does need:
    There's some finishing work to get it back together but I have almost all of the stock parts so bolting things up won't be a trouble. It does need to have a new wiring loom installed but it came with the brand new one he bought. The other option, more likely options, is that I will wire it up using the Motogadget M-unit as I had done on the CB650 since it really simplifies the whole ordeal. It does need a chain, and a couple of other tid-bits.

    My immediate plan:
    Lets get this thing back together and running. As I complete the assembly I will replace OEM parts with the aftermarket stuff that I have such as rear-seats, clip on bars, the switch gear I had bought which is already set to work with the M-unit, etc. Once its together, I'll get the carbs tuned out and then start on the "fun" stuff.

    Longer term plans:
    I will be upgrading to dual front discs and a single rear disc for the braking. I'm going to upgrade the suspension at both ends but I'm not 100% sure which components I'll go to. Up front I'm going to run a 110/70R18 and in the back a 140/80R18 or something very close to that setup. With all of these changes I am going to need to ensure that the front trail is maintained and that anti-squat, anti-dive, and anti-rise are all covered so I'm actually upgrading the performance instead of making it worse. Eventually the seat will be replaced with a "cafe-style" seat in a 1-up configuration. There will need to be some cross-bracing and gusseting of the frame too. The rear swingarm of the CB550 is world-renowned for being super-flexi and will be replaced with an aluminum box-beam arm based on a late '80s GSXR unit. It is going to take a lot of custom parts and plenty of welding but I'm dead-set on doing things right this time. Obviously there are a LOT of details that will need to be addressed as I go along but if I wrote that all out this post would be massive and no one would read it! After all of the work is done and I'm satisfied with the ride it'll all come back apart of paint, powder-coating, and anodizing but the performance takes precedent.

    Way out on the horizon:
    I will eventually be building another engine based on the CB550 lower, CB650 upper, and potentially over-bored cylinders and pistons from a CB750 along with some Keihein CR carbs with velocity stacks. That's all way down the road though but I will be keeping that in mind to ensure I do not do something in the earlier phases that will need to be undone later.

    Questions for you folks in F-chat land:
    1) I've been debating weather or not I should ditch the electric starter and just run kick-start only or not. This will further simplify the wiring by removing some components, reduce system weight, and let me utilize a smaller battery which will be easier to house what will be limited under seat space. So what do ya'll think, keep it or ditch it?
    2) I've also been debating converting to USD forks (GSXR) or swapping to standard style units that are more sturdy, lighter than stock, but not as rigid as the USDs would be and keeping with the original design. I am inclined to go USD since I will likely be able to get ones with more adjustment options to really dial in the suspension easier. Additionally, my aesthetic goals are more of a retro-modern appearance than trying to stay true to the period. That said, making the front end very rigid will match up better to the box beam swingarm but the combo will make the frame the weak/flexi point meaning that I'll really have to spend a lot of time and effort on the frame bracing to ensure it doesn't cause riding/control problems and doesn't become so stiff that it breaks under loading. Opinions?
     
  4. walnut

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  5. walnut

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    #180 walnut, Dec 1, 2015
    Last edited by a moderator: Sep 7, 2017
    I've been working on getting the new bike wired up. It required a bit more soldering to get the hand controls/switches the way I want them and is a bit different than what I'd done on the CB650C due to the differences in the charging and ignition systems. The hardest part has been finding time to work on it. I wish I was further along than I am, but this month I should definitely have it up and running. From there I'll move on to the frame and bodywork. Last will be the suspension, wheels and brakes as those will be the most expensive parts and will take some time to save up for.

    I've almost been convinced by discussions on the other forum to go with RSD style forks from the last gen of R6 that was so equipped. That would give me dual disc fronts, and I'll find a way to match up a single disc rear with the GSXR swingarm that is going to replace the heavy and flexible stock swingarm. I have some ideas on the the frame mods which aren't going to be cheap so before I jump right into cutting, grinding, and welding, I'm going to do some modeling and FEA to see if they will do what I think they will or if something better comes along.

    I know the picture isn't much to look at (unless you want to make fun of how trashed my garage is at the moment which I couldn't blame for) but it does show the current state of the project, or at least, what of the project isn't on a work bench or desk somewhere inside the house. As of right now, the biggest hold up is getting the underseat electronics tray modified to mount the few pieces it needs to hold. Once that is ready, it should be time to turn the keys and push the buttons.
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  6. walnut

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    Well, the latest update is that I tried to get it running but was having issues with not getting any spark. I believe I've found a solution to that which for the time being will allow me to get it running so I can do a proper inspection on the charging system. I've done all the checks which can be done without it running but have to get it at least idling before I can verify that the output from the alternator is as it should be, that the rec/reg is functioning properly, that the battery is charging, etc. I am hoping to try firing it up again tomorrow and feel fairly good about it. I charged the battery earlier this week and have verified that my alternate wiring for the ignition coil voltage source leads to spark on the 4th cylinder. I'll double check the other three prior to hooking up the fuel tank.

    The new swingarm is beginning its modifications. I've got a coworker who has a nice machine shop at his house and is going to take the bulk of pieces I need to remove, which is mostly the mono-shock suspension brackets, and get it back to me to clean up with my Dremmel. After that I'll be able to figure out how much needs to come off the overall length and get it sized down and the new box bracing in place.

    The front end I purchased (2004 YZF-R6S) is just about ready to go on also. I'm going to get the top triple cleaned up a bit, just removing the gauge cluster mounting points and the bracket for the key/lock. I have to see if the stock front wheel will fit between the brake calipers without being relaced. I've not decided between using wire spoke wheels which will be quite pricey or getting some alloys.

    Short version of the story, its moving forward slowly. I just need to decide what to do about wheels. I would like to try to use the stock ones for the time being instead of spending money on new ones. We will see if that is feasible or not.
     
  7. walnut

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    Its Alive! It officially runs so I'm full steam ahead now on getting the rest of the stuff modified and fitted.

    Wheels from a 1986 GSX-R 750 on the way, bearings, seals, top triple clamp is getting cleaned up, etc. Feeling pretty good about this now.
     
  8. walnut

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    Ok... I know it seems like it's dead, but it isn't. With some changes in job assignments, fun with the kid-o and moving again, there's been no progress. BUT, I've haven't given up.

    Stay tuned.
     
  9. walnut

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    Well, that was fun. In all the time I was away from this project, I never truely stopped thinking about it. Eventually, I came to the realization that this and many other hobbies I enjoy or want to get into require specialized parts to do it the way I want to. That starts to get expensive. Solution? I'm built a workshop at the house and equipped it with a CNC Vertical Milling Machine and plenty of space for other machinery in the future. Now that the workshop / lab is pretty well setup, I'm in the process of moving the CB550 and all of the parts I've collected as the time has gone by. The plan is still pretty much the same in terms of the overall layout and parts selection. Once I get it to the shop, I'll start posting some updates as I get moving along again.
     
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  10. walnut

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    Image Unavailable, Please Login Compared with the previous picture of my “work space”, I think the new one quite a bit nicer! Just waiting for an extra set of hands to and some time to get the bike disassembled and moved (shop is in basement). Cabinets on the right are pretty much filled with parts.
     
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  11. walnut

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    Tonight, I finished up my first milled part; a shock mount bracket for the rear swingarm. There were a few “learning experiences” along the way with the CAM software but I’ve got the hang of the basics and am ready to cut two more (this one’s going on the wall!) for the project.
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  12. walnut

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    I spent some time working with the CAM software and making some practice pieces but now I have both shock mounts ready to weld onto the swingarm. Once I get the brake torque brace mount made, I’ll get them all welded on at the same time.
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  13. walnut

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    Well then, I guess I've really dropped the ball on this project. Time to start correcting that!
     
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  14. walnut

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    In an effort to get moving again, I've planned a few baby-steps for this week and am trying to commit to alternating between this project and another hobby project I have going on as time is available for at least as long as the weather is nice enough to work in the garage.
    1. Pull the old bearings from the frame neck.
    2. Get the new steering stem (and triple) into the freezer.
    3. Get new stem bearing components (press fit onto stem) out of the freezer (put them there by accident)
    4. Replace front wheel bearing spacer and replace bearing that has to be removed to do so
      • I made it 79mm as measured from the stock one but it looks from all I can find and measure it should have been 80mm
    5. Prepare the aluminum stock material for the rear brake arm bracket.
    6. Get the nasty old tires removed from the rims so they can be cleaned up and painted properly.
    This should let me get the new triples into place. Once the rear brake arm mount is fabricated, I can get the swingarm welded up and installed as well. After having gotten the bike running previously, I realized there is a lot of "clean-up" that I could have done with the wiring harness so I'll likely be rerunning a lot of that in the near term as well.
     
  15. walnut

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    I am very close to having the new front end on. Unfortunately, I had a little issue getting the lower bearing onto the stem. Back into the freezer with the stem for another try.
     
  16. walnut

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    Pardon the messy garage in the background, but here’s Hodge sporting a new front fork! I bought a 12-ton Harbor Freight press and it did the trick for the stem bearing!

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    Yes, it is only one step of many but it’s a step in the right direction!
     
  17. walnut

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    The front forks and brake calipers are from a 2006 Yamaha R6S. The front wheel will be from a 1987 Suzuki GSX-R750. I will need to either get customized rotor hats or adjust the caliper mounts to account for the difference in spacing between the two. The rear swing arm is from the same model 1987 GSX-R750 but modifed for length to maintain the same wheelbase as the CB550 and accept the twin rear shocks vs. the single on the GSX-R. The rear wheel will be from the same GSX-R so much easier to mount than the front.

    This allows me to meet my goal of twin front rotors and rear single rotor instead of drum (after mounting the rear master cylinder to a custom made rearset).
     
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  18. walnut

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    Correction, it is from a 1986 GSX-R750, not '87.

    I have discovered some information online on using the stock mechanical speedo drive housing to make a hall effect sensor for a newer style speedo and will be looking more into that. What I'd like to use is the Aceweel MA085-554 or similar series gauge. Its a nice "all-in-one" display, analog tach, digital speedo, and plenty of available sensors to pick up on the important status measurements of the bike.

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  19. walnut

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    This weekend, I pieced together the rear swingarm assembly. The reason for this was to determine where the mounting point for the brake torque arm needs to be located and if the arm needs to be modified for me use. Not surprisingly, it needs to be shortened, flipped the opposite directing, etc. Not a big deal in the long run, just means there's a little more welding that I'll need to have done than I had hoped for. I will get the cutting and fabbing done this weekend and then get it to someone for welding, hopefully next week.

    Another good part of this is that I was able to figure out what is required to get the pivot bearings/bushings of the Gixxer swing arm to fit the CB550's bolt. It looks like, I need to press out the spacers/bushings and bearings (wanted to replace the bearings anyway) and replace the spacers/bushings with new ones that have the desired inner diameter. Easy-peasy.
     
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