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  1. L

    No air filter - too lean?

    Hey Everyone, I am constantly tinkering with my first build - I can't seem to get it to run quite right. I am running a YD100 engine with an NT carb mounted to a Mongoose dirt bike. I've recently done some modifications but now my bike runs TERRIBLY. Can't even crack 5 mph on flat ground and...
  2. C

    No power in engine

    I recently completed my first build, and I thought I put everything together correctly. After filling the tank with 1:16 oil gas mix, I attempted to start it like everyone does by pedaling with the clutch pedal squeezed, and then slowly letting the clutch engage as I hold down the throttle. When...
  3. Degoragon

    Clutch (help!) SkyHawk GT5 Stubborn clutch removal

    I have a Grubee Skyhawk GT5 2 stroke engine on my bike. Recently, I had a rear wheel bearing let loose on my motorized bike, sending the wheel into the frame. Afterwards, I noticed that the clutch will jam in a particular spot, so I suspect it is bent. I ordered a new clutch, and now, I am...
  4. Vendedda

    A few questions from a new Builder...

    So I purchased an older used 2 stroke bike from a guy. First time ever riding one of these things, and sooo much fun 👍😁 Worked pretty good for a while, but now its having some issues. So I decided to try to build one on my own for the first time brand new. Ordered an 80cc PK80 off Amazon. A...
  5. G

    Clutch/bucking bar too short.

    I have a Zeda firestorm. I decided to write it this year through a Vermont winter which is been an experience. You have to ride the clutch pretty hard to ride in the ice and snow, and I've gone to a lot of clutch arm / camshafts. I've had to also cut longer and longer bucking bars, as stock ones...
  6. xspade17x

    Clutch Grinding sound after engaged clutch

    While riding I hear a grinding sound when engaging the clutch. I always disengage the clutch when slowing down and reengage the clutch when accelerating again. Upon reengaging the clutch I hear a grinding sound. I just put a spring tensioner on, a new carburetor and a new spark plug the ngk...
  7. T

    Quick Question!

    when I pull in my clutch lever, this screw doesn't extend far enough to lift the clutch cover off of the pads. is it too long? solutions?
  8. E

    clutch case cover won't fit back on bc pin is sticking out

    So I am building a new bike and after putting the new chain on I went to put the clutch case cover back on (goes over the little gear on the engine) but the pin in the center of the gear is sticking out too far and I can't push it back in, so the cover won't fit back on. Could someone please help ??
  9. RB55

    Important clutch adjustment required for maximum grip.

    After 300 miles, my clutch pads started to wear down to the point where the bike became difficult to start because the clutch kept slipping and wouldn't crank the engine properly. I got new clutch pads and followed the flower nut tightening procedure, which helped a little but the bike was soon...
  10. oliverw123

    another clutch mod

    In addition to my previous clutch mod, thought I'd go one further and improve the clutch arm cable connection. I used a hose clamp for this one, straightened out the metal and cut, drilled and bent into shape. This prevents cable flex as the arm moves in and out and potentially reducing...
  11. C

    Clutch Clutch bevel wheel rattle

    Hi everyone, I recently bought and installed a 80/66cc 2 stroke engine with clutch lever. After a few uses there seems to be a rattling noise coming from the clutch bevel wheel. I've tried to tighten the central nut keeping it in place but it already seems tight. Has anyone else experienced a...
  12. Waxxumus

    Looking to buy replacement Clutch

    Do any of you know of a good website that sells the clutch assembly (gear, bevel, bearings etc pressed together ready to go)? Not looking for the spring or the shaft just the main clutch gear with everything in it. So far I have only found websites that offer it but are out of stock. If you know...
  13. Y

    Friction Drive with Predator 79cc Or Other motor? Need help form the pros =)

    Hello there, I am new to gasoline powered bikes, Years ago i built a Lithium brushless, but got out of it. I just want to cruse on a motorized bike, simply and not get too involved. Speed doesn't matter just a little engine roar, ill be pedaling the whole time as well with it. System must be 4...
  14. herbilious

    Bike accelerating without using throttle

    Hi, I've got a relatively new (3rd tank of break-in) 66c motor that has a weird issue. I just installed a new expansion chamber banana exhaust because I broke the stock one, and something I've noticed is that once I start the motor and let out the clutch, the bike accelerates relatively fast...
  15. H

    Clutch arm issue

    In sure this is somewhere if someone could point me in the right direction. After messing around with the clutch from both sides. The pin that the lever actuates seems to be sticking out too far. Forcing my lever to be in the wrong position. Tried to make it move anyway but it's not budging/I...
  16. D

    I think I have a clutch issue

    So I’m fairly new to motorized bikes and I’m building my first one. I already took part the clutch box and experimented with it and I realized the plate was too tight. So I loosened the flower nut and the clutch plate and reinstalled the camshaft and clutch lever when I realized I might have a...
  17. G

    Disengaging clutch while in motion?

    So I was riding my motorized bike the other day. I'm going about 15 or 20 mph and I decided to squeeze my clutch lever to disengage the engine. I was trying to stop but something weird happened. It happened really fast so I'm not really sure what it was. It made an odd noise and my bike tilted...
  18. G

    Clutch and Throttle (problems?)

    I just built my brand new 49cc 2 stroke bicycle last week, and tried to ride it about half a mile. I'm really pretty sure it should be operating differently than this? what happens is the clutch DOes disengage and the bike rolls freely, until I let go of the clutch, and the engine starts just...
  19. G

    clutch revs instead of letting me coast??

    Hello, can anyone tell me what I'm doing wrong here...? I've heard from my experienced friend that: while my engine is running, I can squeeze the clutch lever to just coast and hit the brakes at the same time if i want. Yet, when i squeeze my clutch, it just revvs way up, way too much...
  20. MotorBikeFab

    Primary reduction and clutch question

    I am looking for a primary drive reduction for the 79cc Predator. I am finding some that have a plate that bolts to the engine around the 5/8" output shaft but do not know which ones are more reliable. Is the Max-Torque clutch the one to get? I am seeing several others, some that are tuneable...