Sprockets build: Drag scooter

Cool build!

Spent some time over the weekend reassembling the scooter and doing some more teardown on the Elite 250.

Quick test fit with the bodywork on:

Had to tear down the Elite 250 more, in order to get to the wiring harness. Merging the two harnesses will be a decent-sized job in the future. Not sure if I should try to keep the scooter's harness and integrate the critical parts from the 250, or if I should just try to adapt the 250's harness to the bike.

Also, I have to figure out how all of this stuff will fit under the bodywork:

I also need to fit an air filter and a gas tank under there. In case there's not enough room, I ordered a smaller radiator and overflow tank used off ebay. I've got a gas tank from a weedeater on the way, too. Still need to figure out the air filter situation.

Figured out where the radiator is going to be. Its getting a top mount on the bottom of the new engine mount, and the bottom mount will be extended from the pivot point for the center stand. This will require me to delete the center stand, but since it was no longer at the bikes balance point, it doesn't matter. If the weather behaves, I'll get the radiator mount built this coming weekend.

I've also gotten a new, longer rear brake cable, intake manifold, 90 degree intake boot, air filter, and a few other parts recently. Coolant and tach gauges should be arriving shortly.

With any luck, more progress this weekend.

I'm loving this project! I've heard a story or two about scooter drag racing, but thanks to your build thread I now have a lot more context for this particular grassroots sport.

In reply to ae86andkp61:

Thanks! My build is a little atypical, but then scooter racing is still in its infancy in the US. In places where its bigger, it seems like its overbored 49cc two strokes, but they are slowly being obsoleted by GY6-based four stroke scooters. Some of the stuff coming out of Puerto Rico is amazing - lightweight custom tube frame bikes, with stock(ish) bodywork, and GY6 engines punched out to over 200cc's. I think some of those guys are in the 6s range in the 1/8 mile.

There's no definitive "American style" drag scooter yet, but maybe I'll start that trend with way oversized engines in small scooters

I've got ideas for a future drag bike, and its way more extreme than this one, but I need to finish this guy first.

Speaking of which, spent some time working on the kickstand mounting and the radiator mount of the weekend, took way too long, so I didn't get around to firing up the welder. With any luck though, next time I get the chance, I should have those bits done, and the bike can come down off the work table if I need the space.

We had an above freezing evening here!

Got the upper radiator mount welded to the engine mount, and fabbed up and welded the lower radiator mount. Also, welded together the kickstand assembly. The bike will need this, since the center stand is gone, and I don't feel like building a portable stand for it yet.

Also, I took a frame tube from an old yard sale bicycle, and cut and ground it to fit as a frame brace. By the time I had it fitted, it was getting late, so I'll clean it and the frame up tomorrow, and weld it in place.

I really hope this is it for welding, as other projects are stacking up that need the garage bay. If I'm satisfied with the state of the bike tomorrow, I'll try to paint all the bare metal, then reassemble the bike so it can be rolled around the garage.

love the updates on this thing. fantastic

In reply to CarKid1989:

Thanks! I just can't wait to get this thing running. I think if the weather had been more accomodating over this winter, I'd be pretty much done by now, and just making final adjustments. After this week, I should be down to cooling, fuel, and electrical system work.

Which reminds me, anyone know where I can get 17-18mm heater hose and 90 degree fittings? Seems like 5/8" may be too small, but 3/4" may be too big. I've checked the auto parts places, and McMaster, but no luck so far. I figure I can get one of those size to work in a pinch, but if I can get more appropriately sized cooling hose, I'd prefer that.

this seems like a terrible idea....i love it! when you say its a direct drive the drive pulleys dont change ratio like a snowmobile clutch? i had a 50cc vino and the topspeed limit was set by a spacer on the drive pulley removed the outer cone and spacer and reinstalled the outer cone to get more reduction and a higher top speed. but if your cones are fixed then this wont work for you. watching anxiously.

In reply to peemittens:

Yeah, the Elite E's original drivetrain didn't have a variator, so it only had one gear ratio. Thankfully the 250 has one.

Welded up the frame brace, and although it was probably colder than it should be for it, I hit the various bare metal parts with primer. If the weather is warm enough tomorrow, I'll throw a quick top coat on. Don't really care about the color, just want something to protect the metal. Hopefully, I've got something in the basement that's a decent color.

In unrelated news, I think the battery in the neon is toast. Too many cold days, and the fact that it's a lawn tractor battery appear to have done it in.

Reassembly has begun! Had to throw the scooter together to clear up a garage bay, so I can fix the brakes on the minivan. But, at least the scoot got to see the light of day before that happened:

Once the garage is clear again, I'll be pushing hard to get this up and running. Cosmetics may have to wait until sometime this summer, though. Still not sure what color I want to paint it.

Edit: Also weighed it really quickly. Around 140-150 lbs as is. I'm guessing it'll come in around 165-170 with everything on it. Wheelbase is about 54", and overall length is about 70".

Nice!

Cool build. I've got 3 GY6 based scoots here. All three have been used for road racing at a nearby kart track. Was tons of fun, but racing against motarded CRF150s got a little frustrating. If Twist-n-Gone was closer to me, I'd definitely build one of them into a drag scoot.

Definitely keep the updates coming!

Started tearing into the wiring harnesses. 29 year old electrical tape glue is very sticky.

Got the critical connections labeled at this point, so next job is going to be figuring out which circuits will be retained from which harness. The instrument panel and lighting wiring will stay from the small bike, and the engine wiring from the 250. Just got to merge them properly.

I like it. My wife has an Elite and this is making me question it's future!

novec64 wrote: I like it. My wife has an Elite and this is making me question it's future!

Hehe, awesome. Which model Elite does she have? If its a 94-01 50cc model, you are already most of the way to a drag bike...

Finally seem to have figured out the wiring. I've hacked up both harnesses, now it's just time to join them together. Been acquiring other bits, too, so hopefully all the other systems should fall into place after the wiring harness is finished. I'm starting to run short on time here.

i am sooooo subscribed to this thread. LMAO i love it. I need to learn to weld and do crazy stuff like this

In reply to HaveBlue83:

To me, the welding is the easy part. This wiring stuff freaks me out, which is probably why it is taking so long.

I have a few more parts showing up in the mail this week, and I need to pick up a large computer case fan as a radiator fan, and after that, I think the only shopping left will be for cosmetics. I'm thinking of trying out plastidip spray, maybe get a wheel kit, and hope the 4 cans will be enough to do all the bodywork. I like the idea of something I can spray onto the bodywork, sticker bomb, then remove easily if I don't like it.

Wiring is the easy part? My wiring looks like art and weld looks like crap!

In reply to N Sperlo:

For some reason I have never been able to get the hang of soldering. I'm giving in and using butt connectors with built in heat shrink material for most of this project, and soldering the connectors on the ends of the battery cables I'm making. Larger stuff is about all I've ever been able to do, since it seems a soldering gun is way easier to use than a soldering iron...

As for welding, it tends to come down to prep work, and making sure the settigns are right on the welder, and when it gets messed up, I can usually figure out why.

Started merging the wiring last night, and removing a few more unneeded circuits. I think I got all the required wires at the front forks taken care of. Still need to reattach connectors, extend a few ground wires, make some new ground wires, and make new battery cables. After that, I'll attempt to wrap the wires up enough for them to be out of the way, but won't put them in convoluted tubing until everything has been tested.

Did run into one problem which had me concerned for a bit. Honda uses solid green wire for grounds. They used green/black wire for the temp sensor. The temp sensor and and autobystarter wiring are bundled together, and somehow, the autobystarter's ground was green/black. This led me to think the temp sensor was somehow in it's control loop, which is bad, since I'm replacing it with an aftermarket one. Unbundled everything, and found out they were not connected. Guess someone grabbed the wrong-colored wire back in 1985...

Thankfully, it looks like the connectors, their heat shrink, and some electrical tape are doing the trick. I think the heat shrink material will do a good job to keep wires from coming apart if pulled on a little too hard.

My tethered kill switch should be in soon, so I can be class legal, and maybe even run this at test-n-tunes at some other drag strips.

With a little luck, wiring will be done in the next day or two, and I can spend the weekend working on the van, and getting the scooter's other systems put together. Planning on pulling the vacuum petcock from one of the old bike's gas tanks, and JB Welding it to the new gas tank for now. Maybe I'll replace it with a manual one eventually, but I figure I've got the part, might was well use it.

Got the wiring pretty much done over the last few days. Still need to hook up the kill switch, and possibly a circuit for a radiator fan. I may skip the fan for now, and see how the bike does at its first couple of events, since it won't be running constantly. Would be nice to come up with a way to heat the oil ahead of time, while the coolant is still cold, but there's no time for that right now.

I also did some work on routing the coolant hoses, but only laying it out. I still need to cut a hole in the storage bin to run a hose up to the cap. Tonight, I'll try to do that, and also cut a hole for the fuel line.

Rejetted the carb, in anticipation of need to run a bit richer since I'm switching over to a UNI filter and a short intake pipe. May also grind out some of the welds on the exhaust pipe at the flange to give it a bit more room to breathe.

Also on the schedule for this evening is cutting the floorboard into two pieces. It works as a floor and an inner front legshield. Since I put a brace bar in, I need to cut a hole. I was originally thinking of just slotting it, but I think I'm going to cut a horizontal line either right at the top or right at the bottom of where the brace meets the front fork, and just have two separate parts, possibly with a couple small holes drilled in each to run zip ties through to help align them better once reinstalled. I just need to get to get any cutting up of the plastics right the first time. The Elite E was only sold for a couple years in the US, and didn't sell well, so finding cheap replacement bodywork may not be so easy.

If I really get far, I'll fill the cooling system with water, and see if there are any leaks at room temperature/pressure. After that, its pretty much a matter of getting the fuel system sorted, and it'll be ready to test fire.

Couple of questions:

Does anyone know if you should run a ground strap from a plastic gas tank? I don't know if it'll help or not, but static electricity and gas fumes are a little scary.

At what temps is carb icing a problem? The carb has coolant hose connections, and I'm trying to decide if I can just plug them off, or if I should go ahead and keep running coolant to it.

Hacked up the floorboard, and afterwards figured a better way I could have done it. Oh well. Also finished mocking up the coolant lines, along with the pressure cap, the reservoir, and the fuel tank:

I'll fab up some brackets to rivet to the storage bin in order to keep everything from rattling around. I'm also thinking of wrapping the coolant hoses in electrical tape or something else where they pass through areas that might rub.

And for a quick final thing to do for the evening, I went ahead and sanded and painted the chassis brace. Its not perfect, but it'll do the job:

Next up, still have to deal with the kill switch, seal up the cooling system, and get the fuel system set up.