1. B

    Mod List?

    Hey I'm new to motorized bikes (my first engine is still shipping), and I was wondering, what are some good performance mods to do on a cheaper budget, and in what order? I was thinking to do: -Exhaust -CDI -High compression head -36 tooth rear sprocket -?
  2. Will'smotobikes19

    Best carb for 74cc stroker engine?

    Hey guys just wanted to ask what carb setup you guys recommend for a 48mm bore x 41mm stroke engine I'm building. The ports are 40mm. Would a 19mm delorto clone with a #90 jet be good? it is a iron lined cylinder.
  3. B

    Performance loss .... HELP !!!

    So it all started when a screw for my exhaust broke inside the cylinder I tried to remove it every way possible, sadly it didn't work. I then got a replacement one online, when installing it I tightened it to much to the point that the cylinder head cracked. Unaware I tried to ride it and ended...
  4. 6

    What else can be done to maximize shitty Chinese engines

    So far I’ve replaced every shitty, self stripping nut and bolt I can. I live in the US so finding metric bolts is sometimes a challenge. I reinforced the engine mounts and chain guide and placed make shift rubber shocks between the frame and the engine to stop it from shaking so hard the chain...
  5. J

    Performance parts before break in

    I ordered a new bullet train 80cc motors and I was wondering is it safe to use performance parts on it like a sbp expansion chamber and other things like reed valves and a speed carb.
  6. A

    Honda GX35 Power Increase

    Hi all, Sorry if this has been covered before but I am new to this site and have not been able to find the exact information I have been looking for. I am currently in my last year of a Mechanical & Manufacturing Engineering degree and my final project is titled as follows; "To improve the...
  7. Matt Barrack

    Chainsaw VS Kit Engine

    So I got an old chainsaw that works very good. I also have a motoried bike with an engine from one of the kits you can buy. Would the chainsaw engine work better than the one from the kit? I know I made a thread like this earlier but this is more specific to my build. The current engine is a...
  8. M

    Engine Trouble Low power after remounting engine to new bicycle

    Quick story Old bike frame broke while riding. The frame had snapped right above the rear mount due to a small crack that got worse after a month of engine vibration. (Vibration isn't bad, I used the frame with knowledge of the crack) During my ride the back wheel seized and I slid to a stop...
  9. N

    Exhaust My Murphy McMonkeyPatcher diy exhaust replacement - effective, ghetto AF, expansion chamber exhaust

    originally I had the voodoo brand I think of banana tube expansion chamber that came w/ the kit I ordered (IIRC i talked the guy into throwing it in cuz I got a aluminium gt frame kit plus a relatively premium engine kit at the same time) but I had problems w/ it not quite fitting, then when i...
  10. Arty

    New Pipe

    I recently completed modifications on what was called a "Fatty Performance Pipe", replacing the "banana style" pipe I had, and am I ever pleased. The header pipe is a nice piece from CR Machine. I had to extend the header and add bends etc. to get it to fit where I wanted it, and modify the...
  11. Eddiesilverbullet

    Gas octane?

    Does anyone know if it really makes a difference what kind of gas you use to enhance performance?