Honda Spree and Elite 50 Forums

I've gotten myself into an interesting situation. I FINIALLY got a chance to build a SpreeDio and I am left with a GK8 (spree) engine and I am going to school as a machinist. I need a capstone project to finish out the year with and I'm trying to figure out what I should do. I have a chance to attempt to build the fastest spree engine ever. What parts do I have to keep to have it still be a "Spree"?

Does one of a kind variator rule me out? Second cylinder? Custom Frame? Basically I can build what in the real world would be a many thousand dollar scooter and I can get most of the raw material for free, and can put on my resume and get a grade for.

No method of fabrication is off limits, we have the ability to do lost PLA castings, welding, custom electrics, EDM, pretty much anything.

And obviously there will be a build thread.

Follow the guide in my signature, port the block as well. Variator not possible, good luck. Second cylinder would be sweet too. Would love to see one machined.

EDIT: Would HIGHLY RECOMMEND pitobread's sweet build: viewtopic.php?f=16&t=34045

Reference how he gone an dun it!!

Otherwise, yes, you can have a Spree block ported, but you're looking at a 19mm carb at best, nothing bigger. But if you are talking fabricating a Spree engine by like maybe sticking 2 together and some type of variator system, then yeah, it can for sure be done. That thing would frikken rip and I'd like to see it.

But from a conventional standpoint, the block is one sad mess. Dual pistons might bump up the torque, sure, but the CVT (or lack there of), is the real limiter. Doesn't matter if you can get it into the 15,000 rpm range.

I guess if I was gonna try making it fast with zero CVT, I'd do high gear along side belt pulley mods and different belts, I bet you get over 60mph out of it easy.

Wanna impress ME personally.. do it, and keep the plastic intact.. Now THAT I wanna see! (Along with a custom CVT system that would fit the engine without changing the crank). Good luck with the grade, but if you pulled that off, I'd give you an A++.

Ask yourself "what would Allen Millyard do"?

Spree needs to be 1 speed, and so you need to keep the single pulley. Everything else to me is fair game.

If you have access to a full machine shop, I'd find the biggest, meanest bore that will fit the case and swap that on... 80cc+, then stroke out the crank, and see what you can get from that.

So if I can fit it under stock plastics and no variator I'm golden? Does Flintstone power count to get it started off the line?

Also as far as Alan Milyard I don't think he thinks in the right units, this is a 49cc engine not a 49 gallon one

Flintstone takeoff is 100% expected on a single gear Spree for highest top speed.

I'm guessing you can probably find a way of modding the clutch as well. A different contra will do no good since you have no rollers/variator to work with, though the strength of the spring might affect the overall "wobbling" that occurs in a CVT and might prove helpful, but best focus would be on shoes and springs, and drive face properties. If you bump up the torque, you'll wanna bump the rpm's that the springs engage as high up as you can. This will ease the burden of the Flintstones takeoff to an extent, and yeah.. TORQUE BABY, TORQUE.

Then there is always getting an assist at launch if the gearing and belt mods bring you out super high by having someone push/tug you off.

I've only calculated using stock belt/pulley with 15:81 gears for 12,000 rpm, and there your talking, what 57mph@12,000?

With pulley and belt mods and tweaking, this speed could be much higher and merely 9,000 rpm. For sure you'd be doing over 60 as long as you have the torque that will fight the rider weight and wind resistance.

The "CVT" tuning, as it were, is the same as tuning for top speed on a more modern CVT driven scooter, it's just you'd be modding it specifically for a high top speed. They'd be worthless for everyday use, but you said "FASTEST SPREE". Which I am assuming you mean top speed, not launch.

Here's an idea that might prove simple.. design drive gear that let's you use an aftermarket (machined) clutch that is made simply.. just for higher rpm springs that wouldn't normally fit a Spree. You'd fix the flintstone takeoff, and hey, you might have found a side company to start.

Wanna revolutionize...Build a rear belt driven automatic transmission, patent it, become a millionaire, borrow me $20. EVERYBODY machines the d*** block.. that's old. How about.. machine the transmission gears in the rear. *, you could go chain driven from the crank to the back if you could fit all that gearing into the space where you normally mount the gear box cover. Work from there on out. It's tiny, so you'd have to miniaturize I'm sure.