|
Post by humanshield on Apr 3, 2016 21:53:53 GMT -5
Yup. I've barely even touched the CVT at all and it hit 51 on GPS yesterday. You'd HAVE to be winding better than 8000 rpm to hit 51 on stock gearing.....right? That's really tough on a crank and bearings with that heavy piston I'd think. I ordered the piston so soon I'll try it out. The HP guesses were just that ....WAGs Yeah, maybe 7 hp is more realistic topped out. I'm probably gonna change the final drive ratio a bit tho. 55 @ 7200 sounds sweet I know there are already electric scooters but.... I keep pondering the idea of a 25hp electric motor transplant into one of my 50cc scoots. Has this been done? I don't see why the output shaft couldn't be setup to replace the current crankshaft going into the CVT. Just machine the output shaft to match the Crank at the variator, weld up a suitable cradle, get a varistor for the throttle, add a marine deep cycle battery and Zoom Zoom. With 25HP, it would need the extra weight of the battery and motor to get traction. The Silent but deadly killer "49cc" scooter
|
|
|
Post by cwazywazy on Apr 3, 2016 21:58:54 GMT -5
Yup. I've barely even touched the CVT at all and it hit 51 on GPS yesterday. You'd HAVE to be winding better than 8000 rpm to hit 51 on stock gearing.....right? That's really tough on a crank and bearings with that heavy piston I'd think. I ordered the piston so soon I'll try it out. The HP guesses were just that ....WAGs Yeah, maybe 7 hp is more realistic topped out. I'm probably gonna change the final drive ratio a bit tho. 55 @ 7200 sounds sweet I keep pondering the idea of a 25hp electric motor transplant into one of my 50cc scoots. Has this been done? I don't see why the output shaft couldn't be setup to replace the current crankshaft going into the CVT. Just machine the output shaft to match the Crank at the variator, weld up a suitable cradle, get a varistor for the throttle, add a marine deep cycle battery and Zoom Zoom. With 25HP, it would need the extra weight of the battery and motor to get traction. The Silent but deadly killer "49cc" scooter Yeah, I don't have my tach yet, but new final gears are on the to do list. I have thought that a hybrid would be a neat idea. Have some way to combine the electric motor into the motors output then shove a ton of lithium batteries under the floorboard or in the seat bucket then wire a switch to turn it on and off, then have it go in conjunction with the motor from throttle input. Or something.
|
|
|
Post by dan50 on Apr 4, 2016 3:02:42 GMT -5
With a BBK, gear ratio swap is in order. Going to a lower ratio, like 10:1 or 9.75:1 will increase top speed.
The higher horsepower of a BBK will take the taller gear ratio.
|
|
|
Post by humanshield on Apr 4, 2016 21:16:22 GMT -5
I REALLY hope this new piston from STG does the trick. I've bought probably 6 Big Valve Heads and butchered them trying different things to get them to work.
If the piston clears and the compression is in the 190+ range, it'll make a big increase no doubt. I can feel the current setup losing power as the rpms increase and I'm fairly certain a lot of that is that it can't move the exhaust out and the new charge in fast enough to keep up.
The big valve head makes so much difference in fact that last time I had the big valve head on the compression was around 70psi and it STILL almost made as much power as my best day without it simply because it was moving the charge in and out so much better....but at a much lower pressure
|
|
|
Post by niz76 on Apr 5, 2016 1:08:31 GMT -5
Yup. I've barely even touched the CVT at all and it hit 51 on GPS yesterday. You'd HAVE to be winding better than 8000 rpm to hit 51 on stock gearing.....right? That's really tough on a crank and bearings with that heavy piston I'd think. I ordered the piston so soon I'll try it out. The HP guesses were just that ....WAGs Yeah, maybe 7 hp is more realistic topped out. I'm probably gonna change the final drive ratio a bit tho. 55 @ 7200 sounds sweet I know there are already electric scooters but.... I keep pondering the idea of a 25hp electric motor transplant into one of my 50cc scoots. Has this been done? I don't see why the output shaft couldn't be setup to replace the current crankshaft going into the CVT. Just machine the output shaft to match the Crank at the variator, weld up a suitable cradle, get a varistor for the throttle, add a marine deep cycle battery and Zoom Zoom. With 25HP, it would need the extra weight of the battery and motor to get traction. The Silent but deadly killer "49cc" scooter I was into electric scoots before I came over to the world of exploding dinosaur juices. Electric is awesome! Instant torque- always. Unfortunately it has too many drawbacks for me at the moment- the biggest being cost. For the cost it takes to build a decent battery pack, you can buy a complete gas scoot! 160 hp/120 mph Electric Twist n Go Superbike ($30k):
|
|
|
Post by humanshield on Apr 5, 2016 6:30:32 GMT -5
I was into electric scoots before I came over to the world of exploding dinosaur juices. Electric is awesome! Instant torque- always. Unfortunately it has too many drawbacks for me at the moment- the biggest being cost. For the cost it takes to build a decent battery pack, you can buy a complete gas scoot! I figure $300 for the motor, $150 for a battery, $200 for a controller and another $200 for misc..... so yeah....about the price of a good gas scooter...but FUN COSTS MONEY Besides...where can you get an $800 gas scooter that'll do zero to 60 in 3.4 seconds?....all while not making a sound? I keep thinking about it, then I jump on my Yamaha that'll do 0 - 60 in 3.2 seconds
|
|
|
Post by cwazywazy on Apr 5, 2016 10:46:36 GMT -5
I was into electric scoots before I came over to the world of exploding dinosaur juices. Electric is awesome! Instant torque- always. Unfortunately it has too many drawbacks for me at the moment- the biggest being cost. For the cost it takes to build a decent battery pack, you can buy a complete gas scoot! I figure $300 for the motor, $150 for a battery, $200 for a controller and another $200 for misc..... so yeah....about the price of a good gas scooter...but FUN COSTS MONEY Besides...where can you get an $800 gas scooter that'll do zero to 60 in 3.4 seconds?....all while not making a sound? I keep thinking about it, then I jump on my Yamaha that'll do 0 - 60 in 3.2 seconds Find a crashed Nissan Leaf (Or a Tesla) and use the motor from that..
|
|
|
Post by underbone on Apr 5, 2016 11:45:38 GMT -5
Looks like (quick Google search) this piston is made specifically for kymco stock cam and head sold as a kit as well
|
|
|
Post by Silar on Apr 22, 2016 10:45:38 GMT -5
I REALLY hope this new piston from STG does the trick. I've bought probably 6 Big Valve Heads and butchered them trying different things to get them to work. If the piston clears and the compression is in the 190+ range, it'll make a big increase no doubt. I can feel the current setup losing power as the rpms increase and I'm fairly certain a lot of that is that it can't move the exhaust out and the new charge in fast enough to keep up. The big valve head makes so much difference in fact that last time I had the big valve head on the compression was around 70psi and it STILL almost made as much power as my best day without it simply because it was moving the charge in and out so much better....but at a much lower pressure Humanshield, keep us updated on this. I may end up going the same route. My scooter fly's with the 50mm BBK, big bore head, and A9 cam, but if the piston does help increase compression, I could only imagine what that would be like!
|
|
|
Post by Clank on Apr 22, 2016 13:22:58 GMT -5
If your using a 139QMB you definitely need a thicker base gasket. I've got video of my first install of this piston and it was a horrible racket. It even left a mark on the piston where the exhaust valve was hitting. I cut up a peg board to make a super thick base gasket and dremeled the piston some to get it to clear. Getting the timing chain on was bit©#! Airsal 50mm Standard 50mm
|
|
|
Post by underbone on Apr 22, 2016 14:34:25 GMT -5
No problem for me with airsal jug. Used the thin base gasket in the kit.
139qmb case Airsal Jug and Piston Growsun 50mm small valve head 64mm valves ported to match 24mm intake A9 cam
Bolted up easy peasy...
I'll post compression numbers Sunday -- that's my fun day
Jets arrived from China today so will post top speed as well
|
|
|
Post by humanshield on Apr 23, 2016 18:50:30 GMT -5
I'm thinking that right now I'm making about 4.5hp I'm pretty sure the Big Valve head (with porting work) and domed piston would up that to around 6-7 due to increased rpm range and breathing. But at that point a carb size up grade to 19 or 20 would probably nudge it up to 7.5 - 8hp Custom made free flow pipe....maybe 9. I kinda doubt that, to be honest. It's a ton more powerful than stock, but I doubt it makes more than 5-6hp right now. Probably will make a bit more when it's actually tuned correctly though. Hopefully I'm getting a "parts" Taotao ATM50 or whatever (It actually runs according to the seller) so if I can get that riding I'll do a comparison with the ass dyno. EDIT: According to this, the 50mm tops out at 5HP. 49ccscoot.proboards.com/thread/2953/displacement-torque-tables-gy6-139qmbA plain 50mm BBK I would agree. And I agree 7-8 is probably a bit optimistic. But with a cam, bigger carb, better breathing pipe and big valve head (23mm intake) no doubt could push that higher. Maybe 6 - 6.5
|
|
|
Post by humanshield on Apr 23, 2016 18:59:35 GMT -5
So noone's tried the AirSal piston yet....looks like I'll get to be the GP
|
|
|
Post by underbone on Apr 24, 2016 6:14:11 GMT -5
So noone's tried the AirSal piston yet....looks like I'll get to be the GP Clank ran the piston...IIRC he was over 50mph and the crank let go I'm running the AIRSAL piston and jug...tuning it today
|
|
|
Post by humanshield on Apr 24, 2016 13:13:25 GMT -5
Right now I'm at 8,000 rpm at 41mph
|
|