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Discussion Starter · #1 ·
I have a 49cc cateye with a non clutch transmission. i dont know what kind of tranny its considered. some background of this bike is that i received it from my brother and he did some upgrade to the engine and put some type of timing system in it also. he did this 5 years ago and ever since it has sat in a garage/outside in the rain/heat to rust and build up dirt/grease. i have replaced the gas tank, pull start, spark plug (bm6a is what i currently have in it). i also fixed up the broken fuse/ charger port wires. my problem is now that it starts but wont accelerate or dies quickly. i opened up the tranny to see if the drive sprocket was running and it runs fine. it just seems as if the engine isnt burning the gas properly/ efficiently so the bike dies or wont go faster than 3-5 mph. also when the tranny/chains are on, the chains wont move even though i can spin the tires and the chains run smooth. in the tank i put 91 octane gas when i just tried to run it to see if it would run and then i put racing gas w/ oil at 1 gal of gas to 2oz of oil (at first the spark plug i tried became covered in thick gas and the exhaust had the same thick black gas around the manifold area. im really not sure what to do at this point to get it running properly.
 

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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



 

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Discussion Starter · #3 ·
Thanks for all the great advice. i still have a few questions. At this point in time im not looking to put performance parts on it because it requires a lot of money. right now im just trying to get it running. my questions are:
If a cat eye has a clutch, but no clutch lever then is it a auto transmission?
What exactly is a choke? how do i set it and what do i use it for/when do i use it?
What exactly do i have to do to fix the problem i have and make the bike run like stock?
 

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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?
 

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Discussion Starter · #5 ·
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?
 

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That's not the stock carb, it came with a 15mm Walbro SHA copy carb, that is a 16mm WT-603 pumper carb. Can't see the manifold, is it plastic or alum?
Might be the carb is not pumping fuel. Try putting alittle gas down the carb., then close the choke plate and try to start it. You need a V-stack and good tapered air filter.
 

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Discussion Starter · #7 ·
So i think i found the problem, but let me know if im wrong. Could the engine not be burning gas properly and the chains struggling to move when the engine is on because a combo of bad gas/oil ratio, mediocre spark plug, bad clutch, and choke being closed while the bike is on causing the engine to not receive and oxygen for proper ignition?
 

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lol.... :eek: Yup! All of the above... Time to trouble shoot! How is that spark??

Its a centrifugal automatic clutch! YAY
 

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These engines are very tempermental, everything has to be just right, if you want to haul to mail,lol. The height of the exh & int. ports is your timing. My advice is to get a Boosted306 Ported & Timed 49cc Zenoah/Mitsu Cylinder and it comes w/ a new set of rings, if your pistons good, $60. I put that and a Walbro WT-813 pumper carb and Jet Pro exhaust on my 49cc scooter ith seat, it pops wheelies, and moves out.
 

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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?
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
 

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Yeah, if you put a WT carb on that manifold without modding on sealing off the bottom part of the pluse channel it will leak at the bottom, and may not want to pump gas. It would definately cause running and starting problems.
 

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Discussion Starter · #12 · (Edited)
Ok so i finally got the bike running but it still has a few kinks.
1. the bike wont idle but dies when i let go of the throttle and dies if i give it too much gas right away.
2. the bike wouldnt start when i removed the electric starter ignition coil but as soon as i put it back on it started even though im pull starting it.
3. the engine gives off some steam when it turns off, is that normal?
 

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Steam, what do you mean, off the head or out the exhaust?
 

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Ok so i finally got the bike running but it still has a few kinks.
1. the bike wont idle but dies when i let go of the throttle and dies if i give it too much gas right away.
2. the bike wouldnt start when i removed the electric starter ignition coil but as soon as i put it back on it started even though im pull starting it.
3. the engine gives off some steam when it turns off, is that normal?
You need to tune your bike in a lil richer.........The steam is from thick humid air literally steaming off your cylinder head because your head temps are abnormally high from running too lean.....................Thats not good....

Theres a lowspeed needle aswell as a highspeed adjustment screw.............You need a small jewelers screwdriver asswell as a small flatblade screwdriver to adjust it better......Also try readjusting your pluggap a lil wider to .035"
 

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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?:confused:
 

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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?:confused:
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......
 

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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......
Thanks for your help !!!! really helps!
 

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Discussion Starter · #18 ·
what is meant by saying the bike is running to lean and needs to be a lil richer and how do i fix that problem?
 

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Lean means your too deficient on proper air to fuel atomization which is pretty dangerous for both 2 and 4 stroke engines..........
 
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