Bike engine kits require frequent maintenance. It is important to assure engine kits are continually being serviced and looked after properly. No other part of the engine’s life is more important than its break-in. Engines have a long and successful life when broken in properly. Oil/Fuel:
Quick Mix Bottle and Scooter Pro Oil
Because 2-stroke’s are such simple motors, the oil needed to lubricate the gears in your engine needs to be mixed in with the fuel before putting fuel in the gas tank. On most engine kits the ratio for the “break-in” period (the first three tanks of fuel run through your engine) is 40:1, which is 3.2oz of 2-stroke oil. Only 2-stroke scooter oil, such as Maxima scooter oil, should be mixed with 1 gallon of gasoline. The recommended gasoline to run in your engine is 87 Octane, standard unleaded gasoline. This will cut down on sputtering and knocking when running your engine. Once your engine is out of its break-in period you won’t need as much oil in your mixture, so you’ll want to mix your fuel 40:1 (3.2 oz of oil to 1 gal of gas). Carburetor: The majority of carburetors that come with engine kits these days are NT carburetors, which only have three adjustments: the choke, the idle screw, and the jet needle. When starting your engine you’ll want to be sure your engine is warmed up by using the choke.NT carburetor for bicycle engine kit choke guide The choke allows a limited amount of air into your carburetor in order to enrich the fuel mixture enough to warm the engine. While the engine is choked you will hear the idle run higher and higher- this is normal. When the idle starts to run at a high rate, start opening the choke. What that revving is telling you is that the fuel is warming up and needs more air in its mixture. Opening up the choke will lower the idle- again, this is normal. However, be sure to ease the choke down. Though the engine is warm, it might not be warm enough. Move the choke down halfway. If the engine is still idling at a high rate then completely open the choke. If the engine runs at a lower rate than needed to operate the engine, raise the choke back up just a little to regulate the idle. Move the idle down and up slightly, always moving downward, until the idle is running the way you need it to. If you’re not able to get the idle you want no matter how long you choke the carburetor, you more than likely need to adjust it. The screw on the side of the carburetor is the screw to adjust your idle. Turning the screw in increases the idle, turning the screw out lowers the idle. Be careful not to set it too high, as this can cause unnecessary wear on the engine and the parts. Operation: Before you start riding your engine you’ll want to do a few things: First will be the tension on your chain. The slack on your engine chain should be ¼” to ½”. If the chain has less than ¼” of slack you risk the chain snapping; more than ½” of play and you risk the chain of the chain jumping off the sprocket all together. Moreover, check the chain to be sure that it runs in a straight path. A crooked chain can pull the drive sprocket out of place and subsequently bend or damage the shaft. You’ll also want to think about silicon gasket sealer for magneto housing. If you are in a high-humidity area or you’re exposed to a lot of moisture, you’ll want to be sure that you have some sort of sealant or protection against water and moisture that can jump on to your electronic components. Any amount of moisture can short your electrical components, so be sure that they are protected from the elements to make your engine last.
Inside of engine block of chain drive engine
Before and after each ride you will want to take a couple of wrenches and check the bolts on your engine- from the head to the carburetor to the exhaust. Because 2-strokes naturally vibrate when idling, the bolts on your engine will loosen. Failing to tighten the bolts on your engine can lead to parts falling off of your engine while riding, rendering your bike virtually useless until the part is replaced. If you’d like a permanent solution you can put some Loctite on the threads to keep the bolts from coming off. Lastly, never forget safety. Riding a bicycle requires wearing a helmet, and even more so when riding a motorized bike. Make sure you also have a headlight and tail light in case you ride at night, and reflective material to be sure you are seen on the road. Remember: motorized bikes are fun, but a ride to the hospital is not.



Great info thanks

Angel Geranie

thanks for the tips.very important information.


Great information thank you, I needed to know


“Hey Harold,

Great looking out, the engine is still being broken into this is common to have the high RPM during your break in to get the engine going. This just means your engine is good to go and ready for taking off however, we would advise finishing your first 4 takes before going full speed."


Great question, Matt! You’ll want to make sure that your motor doesn’t exceed 450°F while running because anything over that and you start risking a busted head and cylinder damage.


I have a brand new area 80cc I have not even used full tank yet …engine has a high wine with rpms…is this part of the engine being broke in.?

Mark Arrand

“A very informative article.
Every 2 stroke I have ever owned were already broken in or were clapped-out piles of junk when I got them. This article answered my questions and then some on how to properly break in my new 80cc bicycle motor. Maybe an article on mods for these type of motors would be the icing on the cake.”

mark klimczak

This is my second day breaking in my new motorized bike I install the motor the idles too low I will try the chip on turning the screw in thank you you’ve been very helpful

jon bikeheadz

i just put a 70 cc upgrade kit on my 49 cc ssr lazer bike. I just do 2 heat cycles. on idle. let cool down between the two . Change the oil after 50 miles , thats it take it easy on her for a week or 2 .. then open her up to 5 – 6 ooo rpm. change oil monthly// i ride daily .

Mark David

Its always necessary to do auto service time to time, to keep it safe from breaking down. Thanks for sharing.

matt bobinski

I have a temp gage on my 2 stroke bicycle what is a safe running temp

Bob Kling

“Thank you so much for the information your site has been invaluable to me I really appreciate what you done I will purchase the all my upgrade parts from you from now on in the future. I made a mistake and bought an engine that was cheap in price from another company and boy did I pay the price not with money but with a lot of bent broken cheap parts and shipping it was a disaster but as I have heard and read on the internet bike berry very reputable so thank you and I look forward to doing business with you sincerely Bob.
P.S please feel free to put me on your news letter to my email address I would be happy to receive any information from you that you send out thank you again Bob.”

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