Got 'er up to 28 mph today on GPS
- Thread starter atvaholic
- Start date
Are you still in break-in period? Thats is about normal but it might get a little better and once it breaks in a little it is possible it can smooth out and gain a few more MPH.
My bike used to hit 30-31 but I have lost so much compression I am only hitting 23 now.
My bike used to hit 30-31 but I have lost so much compression I am only hitting 23 now.
Usually these motors are broken in after a couple two or three tanks. Yes it will start to perform better as it is breaking in and there will have been a noticeable increase in performance when it is fully broken in.
just hit 27.4 on a stock starfrire gen 2 motor. 
(accroding to a handheld garmin etrex legend gps unit and NOT going downhill) trying to get it up to 30, i guess i still have some tweaking to do on the air/fuel mix? at the moment i have great hill climbing power. but just want those 2 and a half extra mph
(accroding to a handheld garmin etrex legend gps unit and NOT going downhill) trying to get it up to 30, i guess i still have some tweaking to do on the air/fuel mix? at the moment i have great hill climbing power. but just want those 2 and a half extra mph
Last edited:
The elusive 2mph... These stock 66/80 pull a 36T no problem, most of the time. Should get you above 30mph easy and cheaply. I have a 32T, and it cruises half throttle 35mph easy, tops at 44mph on a good day if i'm lucky, and gets to 41 mph regularly. Also required a SBP pipe, slant head, C.E. Intake, CNS carb, plug boot/wire/sparkplug upgrade, taller exhaust port, and port matching. TomTom verified mph. With real and professional porting, where data and actual math is used, These things will fly. Check pirate cycles vids out.
30mph with a stock 26" / 44t setup is nearly 7,000 RPM.
Unless everything is perfect you risk breaking something or at least high wear rates running 7,000 constantly
The 50cc seems happier at these revs though.
But they are all different, some engines will pull over 8,000 others struggle to get to 6,000.
Be safer to get a 36t after break-in then try again.
Then you will be turning around 5,700 at 30mph
Unless everything is perfect you risk breaking something or at least high wear rates running 7,000 constantly
The 50cc seems happier at these revs though.
But they are all different, some engines will pull over 8,000 others struggle to get to 6,000.
Be safer to get a 36t after break-in then try again.
Then you will be turning around 5,700 at 30mph
I had my 48cc Startfire gt-2 grubee engine(all stock) since march 2009 around 1 year and 1,000 miles.
I have a 26" bike with stock 44t sprocket and run WOT @ 28-30mph, i get around 180mpg.
I don't know what rpms its doing but my engine loves it, other engines may not.
I do mostly 1 mile runs to the store and 1 mile back at WOT.
Im just started on my second quart bottle of cheap 2-stroke oil too.
I might get a 36t sprocket,im not sure.
O and if you want extra mph your aircleaner and muffler need to breath, If you have a plastic aircleaner make a couple extra holes. If you have a black muffler take off cap,you see the 3 holes? Drill the 2 smaller holes a little larger,put cap back on muffler. That should give you a couple extra mph for free. And you can still get a sprocket thats smaller than a 44t.
I have a 26" bike with stock 44t sprocket and run WOT @ 28-30mph, i get around 180mpg.
I don't know what rpms its doing but my engine loves it, other engines may not.
I do mostly 1 mile runs to the store and 1 mile back at WOT.
Im just started on my second quart bottle of cheap 2-stroke oil too.
I might get a 36t sprocket,im not sure.
O and if you want extra mph your aircleaner and muffler need to breath, If you have a plastic aircleaner make a couple extra holes. If you have a black muffler take off cap,you see the 3 holes? Drill the 2 smaller holes a little larger,put cap back on muffler. That should give you a couple extra mph for free. And you can still get a sprocket thats smaller than a 44t.
Last edited:
wow, im going 38-40 max and havent changed oil yet. 3rd tank of gas, with 44t sprocket. 80cc starfire gt4
Im not talking about 38-40kph or riding downhill or using wrongly programed speedometers. Im talking about a honest 28-30mph(45-48kph).
i used a police speedometer and passed by it full throttle, flat land outside my house. 38mph. i weigh 110, bike weighs 35
got it to 30.8 today in the snow on a very icy road, all one long flat stretch. took a minute or two at WOT to get it there, the a snow plow guy stopped me and we chatted for about a half hour about my bike oh i just counted the teeth on my sprocket and its a 50t! guess i need to shop around for a smaller one so i can go faster without using WOT all the time, which i assume is not that good for the engine? what size/sources y'all suggest for a sprocket? im not trying to break the land speed record or anything, nor do i need a whole lotta tourqe (all flat roads mostly around here) im leaning to getting a 44 or 41t sprocket. suggestions please heres a pic of my handheld gps http://i881.photobucket.com/albums/ac15/aspireonescs/bike/Photo_00005.jpg (too lazy at the moment to resize it lol)
oh i just counted the teeth on my sprocket and its a 50t! guess i need to shop around for a smaller one so i can go faster without using WOT all the time, which i assume is not that good for the engine? what size/sources y'all suggest for a sprocket? im not trying to break the land speed record or anything, nor do i need a whole lotta tourqe (all flat roads mostly around here) im leaning to getting a 44 or 41t sprocket. suggestions please heres a pic of my handheld gps http://i881.photobucket.com/albums/ac15/aspireonescs/bike/Photo_00005.jpg (too lazy at the moment to resize it lol)
Last edited:
I often go by the "your speed is" radar sign at 34-36 mph...I have a stock grubee 66cc w/slant compression head ...44 tooth on a bike w/700c/29er tires....the tall tires essentialy give me a smaller sprocket than it would be on a 26"....I could go a bit faster but I dont want to realy ring out the motor....it feels like it will keep reving till it blows....this motor is realy smooth at high rpm.....best one yet.......J
