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I have a USA 2020 Super 8 50x, it was getting right at 25mph flat when I got it. I pulled the CDI pink wire and it started getting up to 33/34 mph flat & downhill. I just changed out the variator boss from the shouldered to the unrestricted (they were both the same length 38mm), and afterward I am still getting the same max speed, only now it seems like it's taking longer to get to 33/34. It has the stock variator with the factory 6.5g rollers and I am about 6ft, 230lb.  What could be causing this limitation that would make removing the variator boss restriction have no effect?

This happened to me when I first derestricted my variator with a grinder lol. Are you now at a lower rpm than you were at that speed before? Like before you used to top out your gearing around 25 then Rev out to redline. Now your gearing doesn't top out til like 37, you're not reaching peak hp. Pull out that intake washer, get a jet kit and do whatever to derestrict the exhaust

Unlikely relationship.  However, retrace in your mind everything else you did about the time of the exhaust installation that might have involved wiring - even inadvertent things.  Did you pinch or damage a wire accidently?

Second that. There's a short somewhere. A positive wire is pinched/exposed/melting, the wire is contacting metal, which grounds it

If you did the exhaust, see if there's a wire hanging on it. Did you smell burning rubber?

It's just getting broken in.  Wait for it!  When BBKs blow up, they make a grinding, crunching sound and then they stop gracefully.  Then you get to do it all over again!

I broke it in for about 100 miles and it's been just fine. If it blows up that's an excuse to go up to a 57mm spacing case lol

Roy,  What year is your Super 8?

2015 bought and bored in 2016

Would it be cheaper to find a used 125 engine on ebay you could bolt in?  Or is it the quest to find out what the limits?

The only ones I can find use a different engine mount location. I'd love to throw in a $250 150cc turnkey gy6 but then I gotta get back to welding. I already had to redo the extended engine mount I have now twice to get it right how I want it. The only big difference will be case shape and cylinder bolt spacing really


Once I blow it up, because I will never stop making it faster, when that case or crank is no longer usable, might as well do a proper swap so I can get even bigger cc's with the 57mm spacing block

There are 63mm cylinders for 54mm bolt spacing. Also found a 4v head that even uses possibly the same cam (y shaped rocker) so if I'm lucky I'll run my a9. The head fits on a 63mm bore with 54mm spacing. I do love an over-square motor, gimme all them rpms. It looks like it uses the same size gy6 valves just twice as many.

The bore is like 50 bucks for the jug, pison, rings, gaskets. The head is over 400 for the complete head and valve cover. So bore first, running the big valve head that came with my current 72cc setup

I am fully aware the crank is eventually gonna pop. Offerings to the gods of speed. Gotta look into something that can handle stupid rpms, like aiming for 12k. The kymco crank is high quality but I'm really pushing it with that giant piston. If I do upgrade I'd like to keep it at the same stroke, maybe go up to 200cc but idk.

Has anyone done this? Aside from boring/rotary grinding the case, what should I expect to deal with?

There will be a steel pan under the seat to protect myself from catastrophic engine failure shrapnel

Gonna make a new engine cover/cooling duct for the cylinder and probably get a fan with curved blades instead of the cheesy factory ones. Maybe a leaf blower impeller lol

I'll step up the carb too, running 22mm now, gotta figure out what size I want n get the jet kit

I have a 2015 4T

Here is what I did to get 70-75km/h (roughly 40mph) depending on the wind

Installed the smooth boss and upgrade the variator to a Polini Hi-Speed (6.9 gram rollers)
Installed 1000rpm springs (Torque and Clutch)
Installed Big Bore Kit (72cc)
Up jetted the carborator to 92 (comes with 80 installed)
removed the restriction ring in the pipe between the carb and motor
Installed Silent Pro exhaust (looking to upgrade more for looks)
cut the purple/red wire on the CDI (look this up on youtube even it is there.) to take away the rev limiter
Installed new gears (15/52 to 14/53 I think. It was one tooth difference)  Didn't get the extra top end above 70km/h till after I did this.

Hope this helps and shows you what kind of work goes into it.  The only thing I didn't install was the BBK  I let a mechanic do that.

This is all a great way to go.

A lot of my setup matches this one
I ground the collar off the variator boss on a bench grinder, made sure it slid smooth, slapped it in and it's been great since
I ran a 22mm carb, aluminum intake elbow.i  have the carb, elbow, and intake runner all port matched. I can fit a quarter all the way through. I have a 72cc big bore with the big valve no emission head, a9 cam, straight pipe.

Cutting the purple wire will give you power and more top speed, however it's still rpm limited with the stock cdi. I wired in an adjustable derestricted 6 pin gy6 cdi it's easy to do.

Big bore was like 60 bucks, cam was 12, don't remember carb price. Jet kit was a great purchase. Keep sizing up til you find the most power. Cdi is 16 bucks. Get the red spring for the Trans and maybe lighter weights in variator

Cdi and carb are gonna get you the most results

Simple enough, whatever you did to it, short a whole engine swap, let's hear some results. Verification would be cool too however you can manage.

Got it folks. Pretty standard, I bought a 6 pin harness n just cross referenced, a little poking with a test light, and boom. I have a running GY6 deristricted 6 pin cdi conversion in my super 8 50 r with adjustable timing. Recommend this if you're looking for power