My build

Hello everybody this is my first post and I am a new user. Just thought I'd introduce myself and show my bike. It's a fixie from Walmart the kind with the flip flop hub I put the sprocket on the fixed side and run the freewheel on the crank side. I like this frame because it's very tall and uses 700c rims and had room for axle tensioners. It has a SkyHawk Gt-5 from 2011 that came on a partial build I found on OfferUp along with a dellorto clone carb everything else is stock. It runs okay I can cruise 20-25 and top out about 35 the only issue I'm getting is it running very hot 300 degrees and up on a long ride and I'm not sure what to do about that I've tried a number of jets and fuel ratios the only thing I haven't tried is a different sprocket as mine looks to be a stock 44t or more. My crank seals are not leaking into the case and I'm not getting air leaks it just seems to lean out at full throttle. Thanks for looking
 

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66/80cc? you might save some rpm with a 40T rear sprocket. have you played with the needle position? what about oil ratio your using? 35mph is good performance for a stock 66cc,, also curious why you think it's running too hot
 
Yes 66/80cc gt-5. The dellorto carb doesn't have a needle jet to adjust, it only has an adjuster for idle the main jet controls flow after that I've tried a few different sizes but nothing helped I actually got it running it's best with a jet I sized up with my very fine drill bit set. Id say it's probably close to 68-70 size now. I run it at 30:1 most of the time and use 91 octane maybe richer here and there never leaner because it already gets too hot I say too hot because I literally checked it with my heat gun after a mile ride and had it around 300-320 degrees on top the head, crankcase is about 150 degrees I don't know how hot these things run but I'm an auto mechanic and that temp is scaring me because it will melt the piston like nothing
 
no need to run high octane in these lower compression engines. you'll be fine on 87. hi octane burns slower to help hi comp engines avoid detonation/pre-ignition. drain your tank and try a couple miles on 87 and note if there's any change. I'm not a 2 stroke tuning expert tho, maybe someone else can reply with thoughts. 300 does not seem too hot tho 375 maybe yes bcs then you'll start to smell sparkplug boot...

you can ballpark see if you're rich/lean looking at the plug lean would be ashy grey white deposits or glazed looking. if it's nice tan powdery, it's good. wet, oily looking/black is really too rich.
many tuning threads on here...
 
Thanks for the welcome
I've been looking at an Oko 21mm power jet carb to put on it for more tuning ability and performance. I haven't seen anybody with one on a gas bike I'm not sure why the one I'm talking about is https://www.ebay.com/itm/Oko-21mm-C...Universal-2-4-Stroke-80cc-100cc-/323103082592
I have seen the Cns carbs available but those don't look very good to me. Also thinking about getting a billet head for it just haven't made my mind up which one I want.
 
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