Top Speed

FNTPuck

Well-Known Member
Joined
Jul 2, 2018
Messages
866
My goal is 45 from a stock parts kit/no aftermarket performance parts. That means no jackshaft as well, which would make it easy!

Did 41 on a stock DIY triple40 on a Hyper with just some upped compression, a trimmed base gasket to unblock transfer ports, drilled exhaust baffle, vented clutch cover, and an NGK plug(only part not from the kit is the NGK plug, which I swap to after the first start).

Working on one that will be the same but a fully ported jug, a few other tricks, and more mods to the exhaust. I basically am just curious on how fast you can go on an all stock kit with no aftermarket parts but with any mods allowed. The limiting factor IMO is the stock muffler...with no scavenging effect the top end is really neutered so its hard to rev em enough to go fast.

FWIW my generic motors rarely did over 32mph stock on the same exact route. Most were 28-30 (although that was with 44t vs 36t rear sprocket.)
 


junglepig

Active Member
Joined
Oct 30, 2018
Messages
218
I'm running a totally stock 69cc (47mm X 40mm) generic china girl from an eBay seller, mounted on an old Murray Monterrey cruiser. 10T/44T, 26"x2.125" tires, stock kit exhaust. (EDIT: I believe this is A-80, Long Rod, "B" piston configuration - not confirmed yet.)
I was verifying my speedometer today with GPS and on the flats it will run to 38 mph, at which point the vibration becomes unnerving, and I slow down.
That's just over 8K rpm. At 30 mph (6.5K) it's pretty smooth.
 
Last edited:

HumanPerson

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Joined
Oct 12, 2019
Messages
1,674
I'm running a totally stock 69cc (47mm X 40mm) generic china girl from an eBay seller, mounted on an old Murray Monterrey cruiser. 10T/44T, 26"x2.125" tires, stock kit exhaust.
I was verifying my speedometer today with GPS and on the flats it will run to 38 mph, at which point the vibration becomes unnerving, and I slow down.
That's just over 8K rpm. At 30 mph (6.5K) it's pretty smooth.
Nice Speed :)
 

Lukesky36

Active Member
Joined
Oct 3, 2018
Messages
464
on my next bike im going to sell im putting a 36 tooth on it i always wanted to try a 36t on the road
 

junglepig

Active Member
Joined
Oct 30, 2018
Messages
218
Nice Speed :)
Thanks. I've had very little to do with it, other than a reasonably careful installation. I'm very happy with how well it manages the hills in my area of north Georgia. And it's more than fast enough for the frame it's built on.
 

Street Ryderz

Well-Known Member
Joined
Oct 14, 2016
Messages
3,443
get that with a 36T 33T i was over 50 . 28T ? waitin for the MSX race top kit maybe a 26 T also also picked up a trail-tec vapor computer, rpm,spd ,cyl temp max spd also have the gps speedo app for my Iphone kit coming fr Italy in first part of dec ill make a run we'll see, get a smaller pilot,, 70's, if its cls ill go for IT have whole new build around the GT LTS-1 and the alloy tank frame full susp race egokiller imag gettin spanked by a AARP member yep,,, ol fart
The MXS cylinder's sport/race are designed for use with a centrifugal clutch and a variator and don't perform well down low,these cylinders don't start to make torque until 6-7k with it's peak power at 9.5-11.5 k.That said they dont work well loaded up and wont be turning a 26t gear,not if you want to make use of it's intended power range.Here a dyno graph showing the 70cc Minarelli/Piaggio engine with the variator removed and a fixed gear,this is actually to show the difference in pipes but is a good indicator of our setup types vs the variator,I'll show you that one aswell!
yasuni-power-graphs.png

mxs-kit-cylindre-70cc-sport-dyno sheet.jpg
 
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