49cc Cat Eye not running properly

Welcome to the forum...........

Cateyes do indeed have clutches........Yours will look close to this...



You dont need the e-starter/generator combo or wiring to run the bike...you take the wires coming from the throttle housing and the two wires coming from the fancase cover on the engine and put them together to make as killswitch......

After that alls you do is set the choke,,,pump the primer 8 times,,and pull til it starts.......

Before you start do a compression test on your engine...You should have atleast 65psi to continue............If you have atleast 65psi...continue onward..............

Pull the gastank,,wash it outy with hot soapy water and clean the intank fuel clunker,,also replace the fuellines...

Remove the carb and rebuild it witrh a walbro wyk series rebuild kit

Get a velocity stack w/built-in choke and hp airfilter

Get two new intake manfold gaskets for the engine and the carb and install them

NGK sparkplug # BPMR7A gapped to .030 will do better

Remove the coil and the flywheel ,,Clean both up,,clip the fins down 3/8 to reduce drag,,add a rocket timinmg advance key and coil up and regap the coil and flywheel to .020"

Remove the e-starter to lighten the bike and increase revs aswell as ease the tension on the pullstarting............ http://www.pocketbikeplanet.com/showthread.php?t=58861

Remove the clutch,,,mod it and lighten it for performance

make a homemade boost bottle setup...I like to use used c02 cartridges

Set the lowspeed needle to 1 3/4 turns out and adjust the highspeed needle to 1 1/4 turns out..........

Get rid of the stock exhaust and get either a rev pipe or fatty pipe.....

gas = 93 octane...............oil..2 stroke synthetic w/fuel stabilizer built in mixed to 40:1 for safety - 42:1 for a lil pep & 50:1 for performance.............

After going over and redoing those things your bike should bring better overall enjoyability and fun........Good Luck

If you have a drill,,files,,hacksaw and a dremel you can do most of the mods youll end up doing anyway because you have to almost disassemble the whole thing to shake it down and when you want more speed will end up doing everything all over again....

No matter though,,,Your call,,,do all the basics and disregard the DIY perf mods to just get it running....After an hour riding youll be begging for more power and speed

The clutch is centrifugal and is simply a twist n go model bike...........

The choke is a flap that closed off the air to aid cold starting..Its located in the stock airbox..............Theres two diff types of velocity stacks,,,with or without chokeflaps......





Got any pics of this ignition system your brother added?

fabian7777 said:

Um no pics but i believe the only mods are a larger cylinder, light weight flywheel and timing system. so i started to take the engine apart and i realize that i have to manually set the choke, but when im going to start the bike do i set the choke so it is fully open so air can come in? and i realized that the engine wasnt burning the gas and it coated the exhaust manifold/pipe in black grease/gas. why is it not burning, too much oil? also what should i clean the engine with once it is taken apart? and my final question is you said to set the needles, are those the various screws on the carb? if not then what are those various screws for and how do i set them up?

Click to expand...

I know your problem................You have a hp pumper carburetor and you dont have the carb spacer adapter and Im betting you or your brother didnt mod the intake either which is a common mistake next to mounting the carb wrong................The teardrop shape of the purgeport on the intake has to be jb welded and drilled straight through so the hp carb seals correctly against the stock intake without a purgeport air leak.............





If you look at the carb body youll see a L and an H casted into the body...The larger screw is your idle adjust screw...

Set the lowspeed needle to 1 1/4 and the highspeed needle to the same then set the carb throttle disc to 1mm of airgap...............After its running and idling raise the reartire,,crack the throttle wide open,,take a small screwdriver and turn the hsn needle either out or in til you get max wheel revs then fatten the hsn up by 1/8 turn for safety.......

Another thing id do is unbind that throttle cable trunion on the carb rotator before it frays and ultimately breaks the cable..you need to open up the hole a tad bit so it rotates freely and get a longer pusher safety spring;-yours isnt long enough to be effective.............Good Luck

sky21 said:

i also have a cateye and when i pull start it with choke on it idles but shuts off like 10 seconds later . but during those 10 seconds if i turn the choke off the bike shuts off.
i think it may need a carb tune. i never knew how to do that.
i need the simplest way to learn how to do that. can anyone help me please on what to do to solve this?

Click to expand...

The best way to know how to retune your bike lies in the sparkplug insulator color..

Clean out the fueltank and intank fuel filter/clunker inside the fueltank

Change your sparkplug...NGK BPMR7A plug gapped to .030"

In the center of the brass slotted screw on the carb rotator top theres a tiny slotted screw that may need to be turned counterclockwise 1/4 turn to richen the fuel mix....

On the side of the carb theres a highspeed needle...set it to 1 1/2 turns out

mix 93 octane fuel with synthetic 2 stroke mix at 40:1 ratio.......

start bike and set idle screw....

prop bike up safely and securely with reartire off ground...

twist throttle fully,,turn the hsn screw on the carb side in or out in slow small incriments til you get the rear tire spinning maz rpms then richen the screw up 1/8 turn for safety......