GPZ550 Boardtrack Racer Project

Pics of my projects progress. 81 GPZ550 had been sitting 10yrs. All kinds of wiring issues, crusty carbs, etc. Took months to get it sorted out electrically and mechanically, but finally got it running tiptop. Now stripped down for modification. GSXR inverted forks installed. Gsxr calipers front and rear mated to Harley rotors. Twin 21" Harley spoke wheels. About to chop off the frame from engine back and fab a custom rigid rear section with 5" stretch. Neck will be goosenecked and raked. Fuel tank and fenders will be hand fabricated from stainless. Tuned length exhaust system also in the works! Fun project! Hope to be done with it by the end of next month, then on to the next one I've already got sitting here - 79 kz650.

Cool looking air filter setup there... Can you elaborate on that some? Did you have to mess with the jetting because of the filter?

Thanks! The filter is a Honda CB750 vintage ABE breadbox that I hung onto when I sold my old CB. The outer 2 holes lines up perfectly with the carbs, the inner 2 holes had to be elongated inwards slightly (about 1/8" I believe). I made my own rubber boots from the box to the carbs out of radiator hose (notched all the way around on the airbox side with a dremel and cutting wheel so that they "snap" into the sheetmetal backing plate securely. Where the air comes into the rubber hoses inside the box I added 4 velocity stacks. The "velocity stacks" used are actually harley evo exhaust "torque cones" or "anti-reverb tubes". I had them on hand and they happened to work perfect. Running a foam filter inside the box, and I have the filter blocked off on both sides and about 1" inwards from both ends top and bottom. So the filter openings left are about 8" long, centered in the top and bottom. This blocks the carbs from sidedrafts and rain, and emulated the air intake volume of the stock airbox. Carbs have stock jetting... I had to mess with the idle screw settings a little and I have the original needles shimmed up a half step with a tiny washer. I'm also running an open 4 into 1 header, so not sure if the carb tweaking would be necessary with stock/muffled exhaust. Bike runs great and is happy throughout the rpm range.

Few extra pics with shocks removed, setting the stance. This will be the bikes final ride height once the rigid rear frame section is added. 4 into 1 header obviously has to go, I'll be fabbing a custom exhaust to run alongside the bottom frame tube instead of under the bike.

That is quite innovative! Could you by chance snap a few more pictures of that filter setup? I'm really sick and tired of buying new carb boots every year and messing with them everytime I need to take the carbs off. I do have some pods for the bike, but dread dealing with the jetting and the side drafts/rain you mention.

Sure, I'll snap some pics for you tonight when I get home from work, no problem. Yeah I heard that pods were a bitch but thought maybe I could use them since I've got the TK22 carbs and not CV's. I was wrong, bike ran like shit and I could never get it sorted out. Thats when I dug out the old breadbox and started working on getting it on there.

Also... just saw in your signature that you also have a RV125? Those things are so cool! I've got a 78 RV125 that I got from the original owner, an old rancher lady. I don't know the exact name of the trim level but it's the type with fat tires front and rear, lights/signals, and hi range/lo range gear ratio lever on the side of the tranny. Unfortunately it was abused and stored outside... engine locked. I may decide to build/fix that bike next after this one instead of the KZ. The RV has been waiting patiently for years. I plan to swap the motor out and replace it with one I've got from a 2013 Honda CBR250R. I love the RV but don't really dig the sound of their 2 stroke engines. Swapping motors will fix that... I'll be swapping in a modern 4 stroke fuel injected 250cc engine with a close ratio 6 speed (FUN!). Aside from the engine swap, I want it to be a stone-stock looking restoration. Only a purist would notice that it isn't original. I've got the title for it and it can be licensed for the road so its gonna be an awesome little bike for running around town (on and off road).

And you've got a Harley as well, so do I. She's a 1958 FL... panhead with a shovelhead top end. Hmmmm... what are the odds... 2 dudes both with a kawasaki 4banger, suzuki RV125, and a HD? LOL... Nice to see another bike enthusiast who doesn't discriminate.

I'll get you some pics later on, take care man...

I agree. The only bikers I don't like are the ones that dig on other guys rides - and its usually the HD crowd that does it...but they even pick on their own (VROD and Sporty owners).

As for the RV - Yes, mines a 75, red with silver stickers on it. Has the fat tires, luggage rack, onboard tire pump, blinkers/headhlight/tailight and the hi/lo range. I rode that from 3rd grade or so til I got my 550 at 19. We got it from the original owner in the early 90s for $300. Had a top end refresher done on it once. Don't have the original blinkers anymore, but other than some dirt and a few dings it looks new. Usually starts with 3 kicks after sitting for a while. Problem with the bike is it's geared very low. Low range you maybe can go 35 mph with it all wound up. In high range you can squeek out 55, but she's just screaming and the tach/speedo is bouncing all over from vibration and everyone can hear you coming from a mile away. I always wanted to find a different sprocket to make it more road friendly. Definitely a unique looking bike. When dad came home with it I was like "what in the hell is that ugly thing?" but now I appreciate it. My folks still have it and my dad will take it out and ride with my mom on her Honda Metropolitan.

I guess the RV is actually worth quite a bit - but I'm not sure why.

Heres a pic - this isn't mine, but looks EXACTLY like mine. About the same condition as well.

Yep, if you left that one sitting outside for 30 years uncovered it would look just like mine as far as I can tell. Onboard airpump, so THATS what goes in the weird holders at the front of the backbone on the left side. I always thought maybe a coil went there at some time and had been swapped for a different kind or something, wasn't sure. It was a mystery I could never figure out. Now I know!

Cool project.
Got some old parts you're looking to unload?

Well the bike wasn't really "complete" when I got it, but I've got some parts to get rid of, yeah. My friend wanted the wheels so they're gone, but I've got front and rear brake calipers, front end, speedo/tach, ignition switch w/ key, dashboard w/ lights, square headlight, maybe some other odds and ends. What were you looking for?

Possibly the forks (more specifically the fork lowers). The tank is gone?

PanShovelMike wrote: Well the bike wasn't really "complete" when I got it, but I've got some parts to get rid of, yeah. My friend wanted the wheels so they're gone, but I've got front and rear brake calipers, front end, speedo/tach, ignition switch w/ key, dashboard w/ lights, square headlight, maybe some other odds and ends. What were you looking for?

If you'll give me your email address I can send pics of the lower legs this evening when I get home. I do have the fuel tank, haven't looked at it too close. It's kinda beat up and previous owner said it was real rusty inside. Since I was building a custom it didn't really matter to me. I'll dig it out and send you pics of that as well.
-Mike