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Discussion Starter · #1 ·
Hey whats up PBP!!
well im not new to pocket bikes ( well i am kinda lol i had a couple when i was younger but had no mechanical knowledge or anything of the sort )
anyway the had got wrecked and blown up. so my brother and i found a real good deal on a pair of MTA-1 i believe picked them both up for $150 bucks both in good running condition. one was $100 and the other was $50 !! couldn't beat it
the one for 100 was perfect condition the other the guy couldn't figure out why the chain kept popping off ( it need bolts to mount the motor to the frame so the motor was moving around so he had no idea what he was doing ..) and that one came with extra parts

NOW FOR MY QUESTIONS
im not sure whether my pair are the 47cc or the 49cc but im pretty sure buying parts for them are the same ??
anyway one of them is gonna need a clutch soon so i figured since the parts are so cheap id get a performance clutch setup for both
what clutch setup do i need to go with ? i need something heavy duty .. my brother is slightly bigger than i am and it struggles a little bit pullin him up hills i can literally pass him and wait at the top but hes honestly not that much heavier tahn i am .. but anyways i need to do something heavy duty and performance ...
we will get that question squared away but im sure ill have plenty to come lol ..
Thanks in advance for any help or insite .. i love my pocket bikes im 22 years old and a father to 3 boys and never thought i could have this much fun on something so small and simple ... i think i just found my new favorite forum:)
Thanks guys and gals
 

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Welcome to the site..............Theres two engines they put in them alright except one is 40mm 43cc and the other is 44mm 49cc.........the 39cc and 47cc are mythical sizes iused to fool the epa.......Both engines use the same parts...........

Best thing to do is buy a cheap stock aluminum clutch and hp clutch springs then mod and lighten the clutch to be a hp clutch..........The hp clutches they sell arent exactly plug and play,,,,they need rework and fitting aswell as proper adjusting afterwards.........
 

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French Fries N Cheese
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dumb question can the stock clutch be adjusted at all? or tinkered with period ?
Yes it can. The springs can be modified, and the clutch can be lightened. after you have done this, you can sand down your pads to make the slimmer. All this will make the lock up point about 1200-1500 Revs higher, giving you more torque.

Here is a lightened clutch with HP springs compared to a stock clutch.
 

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Discussion Starter · #5 ·
^^ good answer lol .. thats what i need a little more torque to pull my brothers big *** up some of the hills in my neighborhood lol ... can your find the springs at a local harware store or do you need to special order them ? this is just gonna be a temporary fix until i order the new ones ... i was thinking of gettin the 2000rpm performance one or would that be to much for a stock motor ? thanks alot guys
 

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Remember that if you sand half the shoe to get that clearance, you will be replacing the clutches alot.
 

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French Fries N Cheese
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Remember that if you sand half the shoe to get that clearance, you will be replacing the clutches alot.
Yup, thats why I have 2-3 new clutches on hand. The grey material ones arent that bad though. get a good 10-12 hrs of riding before they get glazed and worn.
 

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dumb question can the stock clutch be adjusted at all? or tinkered with period ?
My clutches last longer than 10-12hrs before thery glaze up...The key is stabbing the throttle hard and not lifting unless needed.......being gentler and letting the clutches slip in will generate heat fast and glaze the shoes and drum even faster...........

just note when you mod the clutches to deliver performance youre gonna need to be aggressive on the throttle even more the more its lightened......If not your clutch will literally start slipping from heat and glaze within an hour..............

I have plenty of info on the subject in my thread...........there arent any members that i know of that has gone in depth with the mechanics and mods pertaining to the stock cag clutch


this is how you dont want your clutch to look like.....This clutch is a basket case and very problematic



This is how blueprinted,,polished and modded clutch arms look like.......



The clutch on the left has had its diameter decreased by 1.5mm's,,arms lightened and pad mount holes thinned out and polished...




Hope this answered your question................
 

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^^ good answer lol .. thats what i need a little more torque to pull my brothers big *** up some of the hills in my neighborhood lol ... can your find the springs at a local harware store or do you need to special order them ? this is just gonna be a temporary fix until i order the new ones ... i was thinking of gettin the 2000rpm performance one or would that be to much for a stock motor ? thanks alot guys
Sounds like you have a 43cc and in need of more power captain...........

The stock 43cc engine can be modded to deliver 3x the power and the revs will outrev a 49cc engine aswell................

Do a compression test to see cylinder condition....If atleast 80 or above move onto next steps...................

remove engine from frame..............

remove cylinder head

remove piston from rod,,,

polish pin,pin bearing and rod journal,,

clean up piston ,,deburr piston of sharp edges on piston skirt

add 4 small windows in the piston facing the transfer ports and chamfer holes slightly...If adding a 3rd power port window piston in appropriate area



polish piston

take a dremel and add a 3rd port to the cylinder opposite the exhaust port..The 3rd power port should go as high as the transfers and be about 8-12mm's wide and be atleast 1/8" deep but going deeper is better aslong as you dont go too deep........LOL

take the dremel and widen the exhaust port at the cylinder side 1/8" wider on each side

raise the exhaust port 1/16" in the center and slope it down gradually towards the widened sides

taper the exhaust port outwards and open it up for flow

widen the transfer ports at the cylinder base and the engine case

mod the cylinder skirt on the powerport side to slipstream the velocity and mix into the transfer ports with a powerful entrance to make power...



pull the flywheel and clutch off then split the cases,,,then take a dremel and perf port the case for uninterupted velocity and flow





yamabond the head direct to the base and give 24 hours to dry
 

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lighten the flywheel...I like to use a 12 fin design,,,others like a 9,,,,,some even a 6 fin...............


add a rocket key to advance the timing 10 degrees to make power.

mod the clutches by lightening then,,polishing the mount holes and thinning the shoe material so the pads throw out smoothly then add a set of hp clutch springs\



mod the stock coil by replacing the crappy stock copper strand sparkplug wire with a high voltage wire from an automotive set



take the stock exhaust pipe,,cut the expansion chamber in half if theres a catalystic converter comb in there remove it then add 6" to the belly and shorten the stinger 4"

 

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mod the reedstopper,,reedplate and add a composite set of reeds




take the stock carb and do the petcock mod and drill open the fuel inlet on the carb so the fuel doesnt dribble in anymore............

Taper port the stock carb to deliver sick velocity without not having to rejet..........the extra velocity will pull a higher flow of fuel through the same jet with the increased velocity therefore it may balance out with the mods....Taper port the inlet open to 15mm's and at the carb mount open it op to 14mm's and blend in both sides to the 12.5mm venturi...dont widen the venturi......everyone else says they get good results drilling 14mm's straight through but ive tried it against my taperport design and theres no comparison.......my design owned the straight through mod not to mention I had to open up the mainjet pretty large to get it dialed-in.....My design I had to put the clip on the 5th notch and add a couple washers to raise it up a tad bit more.........

But anyway that stock floater carb is crap and I truley recommend you buying the walbro rep retrofit pumper carb kit

After all them mods youll be the envy of your counterpart with the same bike.....................The difference is like nite and day....:eek:
 

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There you go, Pocket 101 like in college,lol. I got my clutch bell so hot it burnt the gold plate off it, plus that heat carries over the the engine & bearings and heats them up. How about a water cooled clutch bell,lol.
 

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Discussion Starter · #13 ·
All i can say is dam !! I love my cars and toys with motors so im on all sorts of forums and you guys have absoulutey without a doubt been the nicest best helping forum .. i like it here thanks alot guys ... Once i get to my computer ill explain what i was working on today its way to much to type from my phone lol
 

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Discussion Starter · #14 ·
ok. so. today i tore apart the clutch and she was pretty glazed, ruffed er up with some 80 grit good to go.. well while im takin a smoke break my brother decides the stretch the spring a very tiny bit. Ah good thinkin bro! or wait was it ? lol .. got it all back together and clutch holds good .. to good .. when you start off it doesnt have that two stroke ping sound anymore until u get higher in the rpms .. i did some thinking couldnt figure out why it sounded dif .... o gee dumb*** because the clutch isnt slipping at all anymore its just grabbed and its bogging down until it reaches higher rpms DUH!

so now my problem ... it really wont get up hills not even my driveway which mayb a 20 degree angle if that .. which is fine cuz it doesnt slip but its just so slow at hills now cuz its not slipping and giving it that extra push its just puttin the whole load on it now ...

now heres my thought if i tighten the springs a SMIDGE more than stock .. just my thoughts here ... while sitting u slowly give it throttle not moving more boom it engages is that what itd be like because its taking more work to expand the feet ( clutch platforms that needed sanded ... or is it just gonna slip like crazy ? im kind stumped lol thanks for any help
im going to buy new clutches and heres the links ... which ones better ?



im still gonna modify my stock one so i can still play until it gets here hahahahaha feel like a kid a christmas ..

also my other bike had a flat and came with extra tire .. so i switched them out but i dont have a huge compressor ( to give a huge burst of air to get tire to seat ) at home like at work so i just did the tie down trick ( get tire on put tie down around middle of tire to push the beads towards rim walls then put some air in realease the tie down tire is against rim now put some more air in .. done ) but every time i do it it put it back on the bike and i cant even make it to the bottom of the driveway and it pops off from the rim and looses all air imediatly ( did this 4 times before i got mad and left it sit for the night until tmoro ) any ideas or tricks to getting this to stay on?

sorry for the million questions
thanks for all the help guys
 

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ok. so. today i tore apart the clutch and she was pretty glazed, ruffed er up with some 80 grit good to go.. well while im takin a smoke break my brother decides the stretch the spring a very tiny bit. Ah good thinkin bro! or wait was it ? lol .. got it all back together and clutch holds good .. to good .. when you start off it doesnt have that two stroke ping sound anymore until u get higher in the rpms .. i did some thinking couldnt figure out why it sounded dif .... o gee dumb*** because the clutch isnt slipping at all anymore its just grabbed and its bogging down until it reaches higher rpms DUH!

so now my problem ... it really wont get up hills not even my driveway which mayb a 20 degree angle if that .. which is fine cuz it doesnt slip but its just so slow at hills now cuz its not slipping and giving it that extra push its just puttin the whole load on it now ...

now heres my thought if i tighten the springs a SMIDGE more than stock .. just my thoughts here ... while sitting u slowly give it throttle not moving more boom it engages is that what itd be like because its taking more work to expand the feet ( clutch platforms that needed sanded ... or is it just gonna slip like crazy ? im kind stumped lol thanks for any help
im going to buy new clutches and heres the links ... which ones better ?



im still gonna modify my stock one so i can still play until it gets here hahahahaha feel like a kid a christmas ..

also my other bike had a flat and came with extra tire .. so i switched them out but i dont have a huge compressor ( to give a huge burst of air to get tire to seat ) at home like at work so i just did the tie down trick ( get tire on put tie down around middle of tire to push the beads towards rim walls then put some air in realease the tie down tire is against rim now put some more air in .. done ) but every time i do it it put it back on the bike and i cant even make it to the bottom of the driveway and it pops off from the rim and looses all air imediatly ( did this 4 times before i got mad and left it sit for the night until tmoro ) any ideas or tricks to getting this to stay on?

sorry for the million questions
thanks for all the help guys
You need to make the engine more powerful.............They sound powerful at idle but theyre gutless lawnmower equipment engines in need of some tweaking to deliver the power rideables need to be enjoyable...

A heavier wieght clutch springs will help a lil but it sounds like you need to tune it aswell...Id crossdrill the clutchpads to get more rpms before lock-up.....get a new NGK sparkplug #bM6A gapped to .030"
Make sure the flywheel isnt rusted up at the magnets and pickup coil...if they are remove the coil and clean both up and regap to .020"...
 

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Discussion Starter · #17 ·
Thanks alot ... Any ideas on which clutch to order and that tire .... Im gonn start workin on most of the things u told me tpday
 

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Discussion Starter · #19 ·
Thanks for all the help cam2 i really appreciate it! ... is it really a good idea to stick with the stock clutch ?

did a compression test both bikes check out great .. running to get new plugs here in a few mins .. and im taking carbs off both bikes to give them a good cleaning might resize the jet. and gonna clean out the reeds cuz the prior owner was running way to much oil in the mixture.

also how do you get the whole clutch off in one assembly ? i took off the 10mm bolt in the center and tried to pull and got no where with it so i just just each foot and spinng off indivdually lol
 

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Do like Cam2 does, run three long bolts into the center clutch piece, thread them in alittle each, till it pops off. I round off the end of the bolt so they dont dig to far into the cases behind. On tapered shaft when you lock it down it sticks on and can be hard to get it off, and sometimes they glue the clutches on.
 
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