Post by CrankingWithCG on Jul 17, 2020 4:20:19 GMT -5
Well, no. Generally you'll want a matched head to the big bore kit you choose. If you go with a 61mm kt, you'll want a head made for a 61mm kit. The added benefit here is if you get a good one, the ports will typically be much, much larger which has an added power benefit.
If you went with this cylinder:
You'd want this head:
(You'll have to bear with my examples. I'm out of stock on all of this stuff at the moment. It's been a crazy spring with COVID related supply chain issues and all... ¯\_(ツ)_/¯ )
However, to back up to what was said previously: if you want to get up over 80 reliably, A GY6 isn't the best option unless you just want to throw money at it. A reliable 80+mph build isn't cheap, and a cheap 80+mph build won't be reliable.
A well built 61mm GY6 is for the most part a reliable 65mph-ish bike, with a bit of headway above that when you need it. When you see people posting about a 190cc bike topping 90, that's full tuck, short sprint, WFO. They aren't maintaining that speed for any notable distance.
Personally (and keep in mind I have easy access to pretty much anything you could want to throw at a GY6), If I needed a bike to do an easy 80, I'd be looking at something a 250cc+, and probably closer to 500. Some 250's don't crack 80 without room to run.
Yeah, im kinda learning that now 😂. I threw a 155 kit on, 28mm roundslide, intake, modded exhaust, ported the head, and i went from a consistent 59mph, maybe 60 on a good day to 63 on the first top end run. They really creep up to the top. Even my 250 creeps past 60. I have a bone stock cvt, so maybe i could get 65?
A 171 could easily pull 70+, but even the big boys (GY6 nick, and others) arent getting out of the 80s range with 228s. The GY6 is more a torquey, fun around town motor. Wheelies, racing people on big bikes, its fun. But yeah, you could do a big bore and upgear, but itd creep up to the top, and you'd lose all the low end grunt. I wanted 70, but with how fun and useable the bike is, im happy with where its at. Definitely get a 250. They sell cheap. My Helix is supposed to do 70-75, got good grunt, and im kind of a heavy rider, and its a pig of a scooter. Lighter 250 could easily pull 80, and theyre 10 times more comfy. 63 on the 150 makes me feel like it's gonna fall apart and im gonna die. 63 on the Helix is nothing. Haha just my 2 cents for the thread tho