GRV-2 Jet Bike Project 10/8/09

Posted on October 8, 2009

       OK, what’s next? I had just finished bolting the front frame back together and was headed toward mounting the forks. After cleaning out the neck bearing races I installed the bearings and mounted the triple trees to the front frame. I also installed a custom hydraulic brake line that was made to length for the front forks. It is a much better fit now and won’t interfere with the other handlebar controls.

       I purchased a new 350 CCA lawn and tractor battery to replace my old one (that I have had since the GR-1 project!!! ). The battery is held in place with a heavy duty Velcro strap that works incredibly well :0)

       At this point the bike is in good shape!!!

       The seat and seat back were upholstered with some black canvas duck fabric. A special polyester padding was used to cushion the seat (not shown). The seat was then bolted to the hinges as seen below.

       At this point I wanted to add a headlight to the bike to finish off the chopper look. I’m sure there will be a few of you that are wondering why but I think it will make sense later on in the build. If I plan on adding an afterburner I may want to run the bike in the evening to accentuate the fire “show” if you will. A headlight will be a must in that occasion and help me see where I am going.
       To find the perfect headlight for the Turbochopper took a little work. I finally found a full sized aftermarket chopper headlight assembly on eBay for about $60. It was a little big for the bike but seemed to be the obvious choice when compared to the others available.

       To mount the headlight I would need a bracket. Luckily the upper fender supports are free and will make a great mounting location for the headlight.

       A piece of angle iron was used as a headlight bracket as seen below. Now you can see why I removed the headlight braces from the stock fork tubes earlier ;0)

       Last but not least, I installed this chrome beauty of a headlight to the forks.

       It kind of reminds me of a vintage Norton motorcycle sporting a 1930’s style headlight.... Or maybe not ;0)

       Now with the seat installed on the bike I was able to really get a feel for it from the riders seat. I rolled the bike down the street a few times to see how stable it felt and was pleasantly surprised for the bike being so low to the ground. However I did notice it is important to “hold” the bike inline with your body as to promote better control of the steering. This is probably due to the very low center of gravity that the bike has.
       At this point I am not worried in the slightest that the bike will be unstable at speed. I just have to hope the bike will go faster than 30 MPH to even merit a concern :0P

       I can’t help but get excited at this point. Things are really falling into place!!!

       The next step is to plumb the rear brake caliper to the master cylinder (MC) on the handlebars. Earlier I had converted the “banjo” style fitting threads on the MC and caliper to 1/8” NPT threads. That way I can use regular pipe fittings to plumb the “hybrid” brake line system.

       Normally you would use a reinforced rubber or steel braided brake line to connect the MC to the caliper. In my case I would have to order an expensive custom brake line that would need to be 86” long! $$$ To avoid that calamity I will be using a steel & nylon brake line setup. A 3/16” steel line will be used from the caliper to the front of the engine frame (steel will handle the engine heat better). A 3/16” high pressure nylon tubing will be used from that point to the MC on the handlebars (this is the same brake line used on racing go carts).
       To connect the steel line to the caliper I used a 45* flared tubing fitting which required me to flare the steel tube as seen below. This type of compression fitting is in my opinion the best for fluids.

       Using a tubing bender (not shown) I was able to form the brake line into the engine frame and out to the caliper. I allowed the tubing space to move which will enable the caliper to slide on it’s registration pins.

       Just in front of the engine frame is where I converted to the nylon brake tubing. This will be a good point to disconnect the line when I remove the front end frame later on.

       I installed the brake line to the master cylinder with a 90* compression fitting. A clear vinyl tube was placed over the nylon tube as to help protect it outside of the frame.

       After all of the fittings were checked I filled up the master cylinder with DOT 4 brake fluid. After several fill-ups I was able to get all of the air out of the system and I have to say the brakes work VERY well :0) This thing will definitely stop but will it go??? Hmmmm, the $10,000 question..........

       One of the more important safety features along with the brakes is the kill switch. This switch will enable the emergency stop function of the ECU should there be a malfunction while riding the bike. It is important to have this switch at the handlebars so you don’t have to remove your hand to activate it. This particular switch is also from a Chinese motorcycle line which was purchased on eBay.

       For throttle control I decided to use a twist throttle assembly. This one is a CNC machined throttle control that is made by the “Coolster” line (China). I used a 88” go cart throttle cable in conjunction with the twist throttle to reach the throttle valve assembly on the engine.

       I only had to modify the throttle valve assembly slightly to accommodate the throttle cable. I added a cable adaptor and shortened the side rails a little to streamline the assembly.

       I installed a set of Scott grips to the handlebar with “Shoe Goo” to complete the front end controls.

I am really pleased with the build so far and I can’t help but be excited to see how the bike will handle under power. It really is a matter of days before I can run the bike so stay tuned for the next go-around of the GRV-2 project!!!

       Till then keep the shiny side up and the rubber side down!!!

Don R. Giandomenico


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