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Corona Road Star Bobber 2020

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  • Corona Road Star Bobber 2020

    Corona Road Star Bobber 2020


    I have had a passion for bobbers for many years and I was dreaming to ride one. When talking aesthetics I prefer American style with a fat front end, fat tires of the same size and softail frame of course. So when I found occasionally a good lot available for sale there was no need to think twice for me. It was the time to make a dream come true!

    So… I got a donor bike to start with – 20 years old/young Yamaha Road Star XV1600 which has about 40K miles winded on the wheels.

    Here is the list of modifications and components used:

    - Sportster-style handlebars 29” width

    - Handlebars risers 2” tall

    - Sportster clutch control lever

    - HD 5/8” front brake master cylinder

    - Sportster switch controls

    - HD mirrors

    - Vintage-style fat rubber grips

    - Sportster clutch cable 48”

    - Sportster throttle cable 36”

    - Sportster-style fuel tank 3 gal

    - Lowbrow Customs fuel tank cap

    - Lowbrow Customs fuel level gauge kit

    - Lowbrow Customs fuel petcock 22mm

    - Lowbrow Customs ribbed front/rear fenders 6” wide

    - Lowbrow Customs fender mounts

    - Lowbrow Customs seat mount

    - HD WLA-style solo seat

    - Barrel springs 4”

    - Danmoto Highwayman 2-1 exhaust

    - Daymaker 7” LED front light + chromed visor

    - LED front blinkers

    - LED rear blinkers (run/brake/turns)

    - PLC module for blinkers control

    - Chromed horn 4”

    - Front/rear Shinko Super Classic 270 5.10-16 tires

    - Rear axle license plate bracket

    - Swingarm leather bag

    - Plastic box as battery cover)))

    The main goal of this project was to make a motorcycle for “everyday use”. This also means it should be good for line splitting. Therefore the motorcycle should have a narrow profile. Considering this requirement I started with Sportster handlebars 32” wide. When fitted with hand controls and grips installed I found its total width is above engine crash bar width and I was not happy with that. The handlebars went back to the shelf and new ones were ordered - same style but just 29” width this time. These handlebars were much better when it comes to width and overall profile but considering the shorter lever and the motorcycle’s weight I was not so sure about handling. As I discovered later it was just a question of time to become comfortable and few rides after all concerns disappeared.

    HD Sportster control switches were fitted on the handlebars. As you may know on HD bikes you use left hand and right hand switches to control left/right side blinkers accordingly. The switches are push type and this differs from Yamaha’s way. In order to adopt a new approach I decided to use PLC (Programmable Logical Controller). Mitsubishi FX1N compatible PLC was selected. This PLC is equipped with 4 discrete inputs and 2 discrete outputs (relays). In accordance with specification PLC voltage range is +10…+28VDC. Connection diagram is pretty much simple – two turn signal push buttons are connected to the inputs and two output relays are connected to the left/right sides signal lamps. Also an alarm signal feature was added. It is activated by pushing both sides’ switches at the same time – just like you do on HD bikes. The PLC fitted inside a plastic case which is located under the right side cover where blinkers relay was previously installed. Obviously the stock electrical harness had to be modified. The harness was re-wrapped using cloth-type insulation tape and its part that is located above the engine has an additional layer of thin foil in the middle to improve thermal insulation. All the light sources are replaced with LEDs – 7” Daymaker in front, LED lamps in front blinkers and LED combo lights in rear. Ignition lock found its sweet spot on the top of the front light bucket along with a couple of LEDs that are used for neutral and turn signals indication. Sportster’s control switches are paired with HD clutch and brake controls. Sportster 48” clutch cable was slightly trimmed at the engine side and connected using a screw barrel. Throttle cable 36” long, also from Sportster originally, had to be grinded a bit to fit the carb’s plate.

    I have to admit that the biggest headache up to this moment was the front brake master cylinder (MC). By trial and error I understood how important it is to select appropriate MC. Its performance must be appropriate for the rest of the braking system components. Road Star is equipped with double disk front brakes paired with 15.8mm MC. I have started my front brakes experiments with Sportster’s 14mm MC which goes in single disk configuration. This MC is easy to get. There was no big surprise when I found that its performance is not enough for double disk – when you pull the lever all you have is just a weak breaking and 1-2 seconds later the lever drops down to the grip. My next experiment was using 15mm Brembo MC which is installed on HD Tourings in double disk configuration. At that moment I was hoping it must help but it didn’t. Brembo MC behavior was similar to Sportster’s MC and the brakes were weak. Then I had to dig for more info and I found 5/8” (15.8mm) MC from HD. Some previous years HD Sportsters (XR1200) were equipped with such MC as well as some recent Softails (FXDR). So I bought one and also had to find a not so popular M12x1.5 banjo bolt and fitting. That fitting was a reason for another delay because that one I bought had literally “5/8” 12mm” in its description. But it appeared to be that 5/8” does not fit a 12mm bolt and I had to find a proper one. Anyway front brakes are perfect now!

    The stock fuel tank is quite good – impressive capacity, equipped with a speedometer cluster, looking nice from the side. But its profile is way too wide for this project and there is not much to do about that. So the tank was sacrificed in the name of the overall style. The new tank has lesser capacity (something about 12L) but it fits perfectly! In order to observe fuel level two fittings were welded in the right side and then a piece of clear plastic tube fitted. I have made some marks there at empty/reserve/+1L levels. It is just 1L of fuel in the reserve BTW. Beautiful tank cap from Lowbrow Customs reminds me of a spinner nut from a retro racing car. This cap is like a cherry on the cake. The tank is mounted to the frame using two bolts. Rubber spacers are used to relieve some stress level created by vibrations.

    The next key element of the bike’s style is HD WLA-style solo seat. I guess it was the very first item I bought for this project because I had no doubts that I wanted it. In order to fit this seat two rear fender support brackets were cut and the pivot mount was bolted next to the fuel tank. A couple of 4” tall barrel springs are used to absorb bumps. Also using thick rubber spacers it was possible to elevate rear of the seat and improve riding position therefore. The battery located under the seat is protected with a plastic cover that was a food container in previous life.

    The stock exhaust had no chances to be used in this project and was mercilessly replaced with the infamous) Danmoto Highwayman 2-1. This is an inexpensive exhaust which has controversial reviews when it comes about quality. But most of the comments agree about nice sound. And I agree with that as well. It definitely sounds better than stock. The problem rose immediately after replacement was significant backfiring when hitting the throttle. This problem was solved by disconnecting AIS from intake (at the moment AIS just disconnected but not removed yet). Also there is still some mild backfiring when at speed and decelerating but it’s not a big deal. I am going to try adjusting the mixture screw later.

    Because of softail frame it was possible to mount the rear fender close to the tire. I believe it is an important part of the style. Two brackets were welded in the swingarm. In this way approximately half of the fender just right above the tire is free and I was not so sure that the whole construction will be rigid enough. Luckily it was and I didn’t have to mess with adding struts on the sides. I also fitted back the plastic cover in order to hide the hole between fender and swingarm. Right after a few first rides it was obvious that having at least minimal front fender would be an advantage. I cut out original front fender mounts and connected them with the new fender using rivets.

    Next part is painting. Personally I like the look of brushed steel. Therefore the painting scheme is simple. Fuel tank and both fenders were touched with sanding paper to give them that texture. I definitely didn’t want much shine which glossy clear coat usually gives so I had to improvise. I bought some glossy and matte clear coat spray and at the beginning my plan was to add 1-2 matte layers on the top. I found later that it is possible to use a glossy clear coat only and then just by varying the distance between spray can and surface you can adjust the level of gloss effect. There is one more thing to mention about – it appeared that I painted the tank, front and rear fenders on the different days. It is easy to spot a difference with a closer look. So it could be better if I have painted all the stuff at once. Not a big deal anyway! Also I had to re-spray rims, top tree clamp, front forks and their protection covers, belt protection cover as well. That swingarm leather bag was red originally (that’s why so cheap) which was definitely not for me. I repainted it using the same black spray for cars that I used for other parts and it is just fine!

    As I have mentioned above personally I better prefer American bobber style. Therefore I decided to use same size tires on both wheels. They had to be old school “saw-tooth” pattern tires for sure. I opted to use Shinko Super Classic 270 5.10-16. Despite its not so impressive profile width (just 130mm) these tires when fitted on the black rims give that “fat” look that I was looking for. Another thing to mention here is related to the tire pattern. Back then I had no experience with such tires. One day I was riding the same route which I rode hundred times before. There was a tunnel ahead and when I entered both wheels started to wobble like crazy. My speed wasn’t high (about 80km/h) so I dropped the throttle and the bike quickly stabilized. It was unexpected and quite scary. I was reading some reviews about this tire pattern later and it looks like such behavior is pretty much common when you are riding on grooved sections of roads (in some tunnels, bridges, highways). I am not surprised that the “saw-tooth” pattern is not popular anymore.

    Well, the bike needed regular maintenance too. First of all I had to replace the left front fork slider as it was having a crack and leaking oil. Front forks were rebuilt at that time using All Balls parts and oil was replaced. First time I decided to try 10W oil but later I found it a little bit stiff so I used 5W which is the recommended oil. I had to replace the rear shock absorber as well because the original one was simply dead. I wanted to try the well known Roadwing but I couldn’t find it at that time and I ended up buying used 12” Progressive Suspension shock. I have to admit I am pretty much satisfied with it. Also I had to replace the front pulley nut and washer that secures it as the original one was in bad shape and lucky me I spotted that just in time! Original voltage regulator and starter relay looked suspiciously and I replaced them as well. Other maintenance is done including oil, filters, new front brake disks, brake pads. Nothing is done to the engine itself yet.

    Another thing that bugged me right from the beginning was the bike's leaning angle when standing stationary on the jiffy stand. I think it was leaning way too much. In order to fix that I dropped front forks in triple tree clamps about 30mm but it didn’t help much. Next I have tried to drop the rear end using “flip and grid” mod. That seriously affected overall suspension geometry and as a result the bike was almost vertical when on a jiffy stand. Then I found another solution – metal block which is mounted as a jiffy stand base. After a simple check I decided to use a 2” block. You can find some 1 or 2” jiffy stand blocks available for buying but their price is not quite reasonable as for me. So I picked some thick rubber block, shaped it with saw and file and bolted it to the jiffy stand.

    This bunch of work was done in April – October of 2020. It is what it is and it happened that corona gave me some additional free time which appeared to be useful. I even have managed to ride the bike a little bit towards the end of the season. I couldn’t recall any significant problem except the front light bracket cracked because of vibration and it was replaced with a more reliable one. In short words, this bike riding gives me a heap of positive emotions. I'm looking forward to the next season which is already soon!

    Last edited by Jinro; 03-22-2021, 09:58 AM. Reason: Fixed photos

  • #2
    Yikes. Nice write up. You could write a book!


    • #3
      Excellent write-up and Fantastic build!


      • Chromepony
        Chromepony commented
        Editing a comment
        Ditto !!

    • #4
      Jinro, I have a bobber project in process and the rear suspension has been an issue. Since the rear end is so much lighter than stock I can't seem to get the softness I need with the stock set up. I was wondering what you mean by 12" Progressive Suspension shock that you used and liked the results. Do you have a part number and source? I am using a sprung seat like yours and I also have another solid mounted seat with a higher back that I use for longer rides. That's the seat that would benefit from a softer ride. Your project shows a lot of originality and craftsmanship. Great job!!!


      • Jinro
        Jinro commented
        Editing a comment
        Progressive Suspension 12" shock absorber
        I bought used one from Facebook group for $335 (including about $80 shipping fee). That one on the right at the photo above. I am quite happy with it. Stock one was just like bare spring.
        I can't imagine how one can do long rides with solid mounted seat. C'mon, stop punishing yourself)))

      • Chooch
        Chooch commented
        Editing a comment
        Thanks for the info. I should have said unsprung seat instead of solid mounted. It still has the benefit of a soft tail suspension.

    • #5
      Added EVO-style air cleaner. It's slightly modified HD Twin Cam air cleaner + bracket from some spike air cleaner for RS + Mikuni CV carb adapter + 7" cover (about $150 total).
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      • Horsehammerr
        Horsehammerr commented
        Editing a comment
        What did you Blackout your wheels with ?

      • Jinro
        Jinro commented
        Editing a comment
        Car spray paint in cans (primer, black, clear)

    • #6
      Watches added -> grinder + beer x 2


      • #7
        Want to sell those hangers it came with? Lol


        • Jinro
          Jinro commented
          Editing a comment
          The story is they cracked in the middle when I was about to make U-turn. Thanks God not at speed! LOL

      • #8
        Love it!


        • #9


          • #10
            That bike looks cool from any angle against any background, but I could definitely see it fitting in nicely in the rundown warehouse or crusty shipping yard setting. Click image for larger version  Name:	BSBfinal7.jpg Views:	13 Size:	816.4 KB ID:	119282


            • #11
              Man you've done an amazing job on the bike.


              • #12
                What did you do for replacing the stick speedometer, I’m looking for ideas for my project. Thanks


                • #13
                  Incredible write up


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