1. D

    Need help with registration numbers!

    My yz250f 2008 blew the engine today while I was riding it. I need to buy a new crate motor but the bike itself and the motor will have 2 different serial numbers. Will I have to take care of 2 ownerships? Someone tell me as much as you can about this topic.
  2. DignifiedRain

    Engine Trouble No spark - Two Engines, CDI, SPARK PLUGS, SAME ISSUE!

    Hey all, Original Issue has been resolved: I needed to tighten the Clutch cable! They really should provide better instructions to how the clutch works! XD Remember 90 degrees is engaged, 45 degrees disengaged! New issue: I am getting no spark. The of the same engines, two CDI's, two spark...
  3. C

    How to set up 4 stroke carburetor - what do these hoses do?/how do I hook up these hoses on my engine

    Hi, I am new to building motorized bicycles, but have been doing fairly well following the instructions and finding information for my first build, but I have been unable to find information regarding the carburetor for my engine. I have added pictures with my questions, I hope they will be...
  4. V

    need help with first build.

    As the title states, I’m looking for some help. Parking at my work is getting horrific, and I live only about 4 miles away. So I wanted to start looking at alternatives, and this looks pretty fun. For the first part, I’m stuck on bike choice. i would prefer a mountain bike as it is not exactly...
  5. 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 ??
  6. wesrb

    Chain Popping Off

    About 2 weeks ago I built my motorized bike and had much fun with it. A week ago I was messing with the air/fuel mixture on the carb and testing it out. I went around the block a couple times, and then on my last lap I full throttled, went over a bump and a couple seconds later the chain fell...
  7. wesrb

    Offset Intake Manifold?

    So I just built my motorized bike, but unfortunately I am having to run it without a carb filter because I cannot get the carb filter to fit onto the carb because it runs into the frame. I was wondering if the Offset manifolds would affect my performance negatively or not. Any suggestions and...
  8. wesrb

    First Time Building

    I'm new to motorized bikes and everything that comes with it. I would like some help on what fork to buy im looking for less than 100 dollars. I plan to buy this frame bbr-tuning-26-motorized-bicycle-frame-w-2-4l-gas-tank On Bike berry I would also like to note that I am a fairly heavy rider...
  9. A

    Wanting to motorize an vintage Schwinn Mohawk trike

    Hello, I found this really old neat trike a couple of years ago at a garage sale. I like it a lot, it looks very unique (and upon further research, seems pretty rare to find). Anyway, I've been thinking it would look even MORE cool if I could motorize it somehow, but I just don't really know...
  10. J

    Twin ignition system

    Is have just bought a twin ignition system from and I have no idea on how to install it can anyone help
  11. Sharif

    New to motorised bikes (Hello! & little help)

    So at the time of purchasing the 2 stroke kit for my bike I really didn't know what I was getting myself into until spending the last 2 weeks putting it together and dealing with one issue after another. I realised there is a lot for me to learn and I should have hopped on to the forums before...
  12. R

    NEED HELP no top end!

    So i tried posting a thread and it disappeared because I didn't have an account, well I'm back and I will use copy and paste until it works. Its a lot to read but if u can help me It'd be great! So I'm having trouble with my 66/80cc China 2 stroke. I recently built a new bike because my frame...
  13. N

    Is my bike motorizable

    I have carraro crp690 and i wonder if it is motorizable. here the link of bike. It has hydraulic disc brake and 26 inch wheeles. Frame size is 18inch.
  14. RIZ


    Hello all, I've made a terrible newbie mistake and purchased a GT frame from Gas pain Bikes. Now I can't figure out what headset and crankset will fit the frame. GB's info sucks so bad that I can't find the info I need to make the correct purchase. Can anyone be kind enough to help me out...
  15. J

    Choke does nothing, can't find vacuum leak...

    So I will preface this question by saying that I have had a lot go wrong with my bike lately and there may be multiple issues at play here... So the problem that I am having is that the motor is idling high and when I start unscrewing the idle adjust screw, once I pass a certain point it goes...
  16. 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...
  17. You need people like me.

    Hello do you think this is a good deal?? Its 65 dollars, but im not sure if itll chooch like i the old one. I already have a pk80 engine kit from seeutek on amazon its been pretty good till i broke it doing amature work on. It now im looking for a new motor. Anyhelp would be greatly appreciated.Thanks
  18. P2skater1

    Leaner vs Richer Setting On Carb

    My spark plug has black residue on it, which means I'm running my carb to rich, correct? And if so, I'm going to adjust it to make it leaner. Is a leaner mixture going to decrease my bikes performance though? Or will it stay the same/increase?.
  19. P2skater1

    Break In Back Wheel is Extremely Hard to Move

    Hey, I just finished building my first motor bike and I have some problems. First off, the Back Wheel doesn't free spin when I engage the clutch. It is extremely hard to pedal and takes all my body weight (140lbs) to push down the pedals while pedaling. Once it starts up, it accelerates to...
  20. L

    Break In Back Wheel Is Extremely Hard To Spin

    Hey, I just built my bike and have some problems. When I engage the clutch, my Back Wheel doesnt free spin, and is incredibly hard to pedal. I have to stand up on the pedals and pedal with all my strength to get the bike moving while holding the clutch down. Then once the bike starts, it gets to...