Pocket Bike Carbs

[pedhead7]

Phew Just got Home From Work about 20 Min ago, gotta Love Overtime. :D

My Boss, today went and Picked up a a ton of ish from you guys today (speedway Scooters) But he picked up some Gsr40 Hp carbs, and I slapped one onto our Shop bike and Was Pretty disapointed. We have the head decked, 1 Thousandeth off, and a Custom expansion Chamber (our Proto)
and We where running a 167 Carb on it and It just straight Up Hauled Ballz.

Now with the GsrHp Carb, its not nearly as fast. I didnt really tune it Much, as I was running out of day light. With the carb tuned do You think itll get much better Topend? What carb do You think is the Best for these 49cc Motors?
Im digging the way the 167 carb Runs, but its a pain in the *** to Mod the manis, as compared to the simple bollt on GsrHp carbs.
:)

[Robert]

The 15mm HP Walboro carb is a Japanese replacement to the Chinese carb that comes on the 49cc bikes.

As we explained when the carbs were purchased, we have not yet tested the carbs on the bikes ourselves. We have been told by our customers that have used the carb on 49cc bikes that they have seen a performance gain of at least 5 mph. But the motors had no other modifications than the carb and air filter.

Try tuning the carb more and see if you can get better results.

[pedhead7]

The Weird thing about the carb is that the Body of the Carb is identical to the Stock Chinease carb, except where there should be numbers, it looks like someone Grinded them off.

Robert? Is Your last name Stewart?

[pedhead7]

OOOOk I put another One of the Gsr/tanka Hp carbs on a Bike Today and It DEFINATLY had Grind Marks where There are Serials One china Carbs. Also, The hardware Was the Same among a few other things. I couldnt Find any WALBRO or any Walbro Numbers on the Carb ether.
:confused:

[Robert]

The Walboro logo is on the side of the carb directly above were the part number is ground off. The part number is ground off before the carbs are sold, because that part number is proprietary to us.

[Alan_One]

and I've been looking for the upgrades to get a little more out of it. Lots of different ways to blow the money I saved on the original purchase price. Carbs are a pretty mod but I can't say I'm so convinced it's worth the $. Especially when I hear stuff like

"OOOOk I put another One of the Gsr/tanka Hp carbs on a Bike Today and It DEFINATLY had Grind Marks where There are Serials One china Carbs. Also, The hardware Was the Same among a few other things. I couldnt Find any WALBRO or any Walbro Numbers on the Carb ether."

Not like can put these little pieces of isht on a dyno or anything.

Anyone w/ any tangible results out of a 49cc after installing a carb?

Also, can anyone here explain how thos "Juice Box" things work? Looks like a billet box that gets sandwiched between the carb and the engine but I can't figure out how it "pressurizes" the intake.

[pedhead7]

I could Make Your x1 Haul Ballz. You Can Ether Put a Bolt On gsr Hp carb on it, Or With a Little Work You can Put on a 603,167,Or a Wt 257. We also Got Pipes in on Friday For the x1 and mini Ninja!
A Juice Box is Just a Form Of a Boost Bottle. All they do Is Help With Bottom end and Increase Throttle Response. To Put simply, it catches all the Blow Back and Gets it ready for the next Cycle (not Exhaust). Blow Back is Caused when the Piston Goes up past the Intake Port, and "pushes" all the fuel back into the carb, that Didnt Make it into The Crank Case.

[Alan_One]

So it's some kind of one way valve? I guess I don't understand why it's the shape it is and how it does what it does.

I bought a resonated exhaust for the bike. Now I'm looking at one of those spark amp kits

"HP Ignition Set
Amplify your spark more than 1000 times
Complete with a high performance, STAINLESS, Accel U-Groove Spark Plug"

Any comments on this?

link (http://www.sdminimotorsports.com/site/707069/product/SDS80)

[pedhead7]

For $40 Its worth a Try. Im not too shure about the U-shape Plug, Typically Regualar shaped Plugs run the Best in two Strokes. The Boost bottle Basically Catches Extra gas and Gets it Ready for the Next Cycle (not exhaust). Where did You get the exhaust? A reed is a One way Valve.

[Alan_One]

Got the Exhaust from an ebay (MDMOTOcom) retailer that's out here in L.A. ($130) I should add that to my sig.

Anyway, After I put that pipe on I'm gonna wait a little bit before I add anything else. The carb thing is still a big Q for me. not sure if it's worth it overall. Seems like I could just buy a stack and filter and be fine.

So I hate to beat a dead horse and I really appreciate and understand what you've explained to me (pedhead) thus far but what I really want to know is how that little box actually does it's thing. Is it just a box? does it have moving internals? Is the shape or size volumetrically calculated for a particular carb? I'm not trying to bug (believe me) but I'm into knowing what I'm buying and how things work. They look Pimp and I've seen both the "Juice Box" and another made by PBU. They look like about the same but I'm still just looking at a pretty polished piece of Aluminum.

Does this Chinese Mitsu engine have a reed valve?

[pedhead7]

Nope No Moving Internals. Shape Dosent Really Matter. Size Should Be equally to engine CC, if Not a little larger. Nope, the 49 CC motors do not have a Reed, the 47CC pocket Rockets do however.

[Alan_One]

Thanks.

So, seriously, is there a noticable diff when you put in a carb?

I'm planning on the following:

Ignition
Exhaust
replace the spring in the C Clutch
put in one of those shim things
V Stack
cone filter
choke

Do you have any expert Advice?

[pedhead7]

What Exhaust are You going to Put on? Dont you already have a Pipe?
What Shim Thing?
What carb do You Plan on running? Ill be on vacation for the next 2 weeks, and I wont have access to a Computer, so Itll be a While............

[Alan_One]

Yeah, I already have to pipe/exhaust coming.

This is the shim thing link (http://www.pocketbikesunlimited.com/ROCKETKEY.html)

I'm looking for carb suggestions based on your experience of results.

Have fun on your vacation.

[pedhead7]

OOk Im leaving wendsday. Shure, a rocket key would help out, It Just advances timing. How Much work do You care to do on it? Did You buy the Bike at Pepboys?

[Alan_One]

nah, bought the bike from a private party that imports em. As for how much work I'm gonna do I guess you mean the actual labor and if that's the case then I'm doing all of it. I don't have a lot of experience with 2 stroke engines but I have plenty with 4 strokes (both air and water cooled). I plan on running this motor till it pops and then doing a solid rebuild or replace on it. So any new parts will be intended to carry over.

I was bummed when I figured out I couldn't use forced induction on a 2 stroke.

[pedhead7]

So for shure you have a 49 CC Motor? Pep Boys,checker,ETC all have 43 CC motors in them. Look at Your engine, Is the manifold Black Plastic, or Is it Aluminum?

[Alan_One]

This is what I have

http://images.andale.com/f2/111/110/11930431/1087808363403_609.jpg

But Black. I'll check the manifold tomorrow when I get back from San Diego. All the Adverts Say 49cc but I just checked the manual that came with the bike and it says "Displacement 43Ml"

here's the page
http://www.theblankspace.com/alan/x1_spec.jpg

[ADAmike]

Yes that is the X1 bike that is sold as a 49cc but is actually 43cc!

[Alan_One]

That's shady. Would a 50 fit under there?

[Mini Moto 7]

So is there a difference in a x-1 and x-2? And if the manifold is black its a 43cc? :confused:

[Alan_One]

the only diff is the gearbox.

X's are all 43cc

[Mini Moto 7]

That does suck, mine has the CVT I do know that for sure and that our manual discriptions are the same.

[Alan_One]

yeah, but is it an X1 or X2? they all have "CVT's" but that's also false advertising... they have either (X)1 or (X)2 gears depending on the model. A CVT or Constantly Variable Transmission is a very complicated and high tech product. Both bikes top out at about 35mph (stock) on a good day. A CVT would not technically top out untill the engine did. These little bikes don't have CVT's they're just using it as a fake selling point.

[Mini Moto 7]

Good point, I had a Honda Civic HX that had A CVT, so I kinda know what your saying. Is there anyway to figure out what darn Bike I have or engine? Tricked X-1 said they have some motors at WWW.SDMINIMOTORSPORTS.COM's shop that are 47cc(with orange plastics), not all but some. Since some claim the plastics determine the CC's on some bikes. So I really don't know what to think, Did you get my Private messege about that 6.5hp engine at P.B.U its bad. :D

[peakhp]

What is the difference between the WYK Carb Kit and the WT Carb Kit for the 47cc motor? I'd like to know what the tradeoffs between the two are.

[d-a-n]

a little at a time ....yes i did

[mega]

hmm.. most (or maybe all) chinese bikes that say there 47cc are really 39cc. if you want to do the math let me know and i'll send you the calculations how to do it. same for the 49cc bikes, there really ~43cc.

but hey, they still have a good punch, and there fun to tune and ride!

[d-a-n]

i bought my bike at pep boys and its the same as the x-1 . ive been told all the 49 cc parts will fit ... i guess ill find out . dose any one know how the x-1 upgrade pipe sounds in refrence to the stock pipe.....louder or not

[JBonnardel]

Now I'm looking at one of those spark amp kits

"HP Ignition Set
Amplify your spark more than 1000 times
Complete with a high performance, STAINLESS, Accel U-Groove Spark Plug"

Any comments on this?

link (http://www.sdminimotorsports.com/site/707069/product/SDS80)

Those Ignitions are awesome (as long as you properly gap the plug). Mid range power and top end improvements are what you get. It really brings the spark into a range where you can burn that gas! I have found that the U Groove plugs work very well, and resist fouling great.
Heres a pic on my pocketbike. With the X1-X2 you dont even need to extend the plug wire. Its a direct, hassle free bolt on.
http://home.earthlink.net/~sdmms2/images/motor.jpg

[blingslowped]

a rocket key for 12 bucks? RIP OFF MAKE SHURE THE OFFSET IS POINTIN TO THE RITE WEN U LOOKIN AT IT and it takes off top speed bout as much as acceleration and u dont need a plyweel puller iHATE it wen basterders :mad: tyr to rip me off

[JBonnardel]

yeah, but is it an X1 or X2? they all have "CVT's" but that's also false advertising... they have either (X)1 or (X)2 gears depending on the model. A CVT or Constantly Variable Transmission is a very complicated and high tech product. Both bikes top out at about 35mph (stock) on a good day. A CVT would not technically top out untill the engine did. These little bikes don't have CVT's they're just using it as a fake selling point.


Alan, you are incorrect on that one. The X-1's and 2's DO have CVT transmissions. I know. I sell them, and have taken one apart to inspect it to see if we could re-spring it. Its not nearly as complicated as you make it sound. It is a pair of variable pulleys, one gets smaller with speed as the other gets larger, using a belt drive.

Using a CVT allows the engine to get to top RPM right away, (as in low gearing) then as the vehicle picks up speed it gradually changes the gearing to a higher range, which is where the speed comes from. So.... again a little incorrect. CVT equipped bikes will top out in RPM long before the bike is done accelerating.

[datalorr]

just a quick question why have got a "juicebox" and a boost bottle? apart from looking cool( the bottle that is ) the boost bottle idea comes from yamahas energy indution system, a small chamber the size of the crankcase/cc volume to remove the pulse created by the reeds/disk valve and keep the air flow through the carb as consant as possible,
so why both?

for alan one

you could use forced induction on two stroke if you`ve got a carb with a float chamber and the float chamber must be open to the same force as the air intake or the mixture will go lean as the presure increases(ram air suzuki triple 1976 had it awesom)

[JBonnardel]

Yeah, I already have to pipe/exhaust coming.

This is the shim thing link (http://www.pocketbikesunlimited.com/ROCKETKEY.html)


Did you know that key IS the ADA key? Yup... it is.

[JBonnardel]

Yeah, I already have to pipe/exhaust coming.

This is the shim thing link (http://www.pocketbikesunlimited.com/ROCKETKEY.html)


Did you know that is the ADA timing key? Yup, it is!

just a quick question why have got a "juicebox" and a boost bottle? apart from looking cool( the bottle that is ) the boost bottle idea comes from yamahas energy indution system, a small chamber the size of the crankcase/cc volume to remove the pulse created by the reeds/disk valve and keep the air flow through the carb as consant as possible,
so why both?


Its a funny story, I'll try to make it short. A regular customer comes into the shop that has a real Mitsubishi TL43 with a Juicebox. The intake manifold (stock plastic) is cracked and he needs a new one. We did not have any in stock except one that I had drilled out and installed a boost bottle onto for another motor. I told him it wouldnt work, and that I didnt want to open the package, and sell it to him only to know it would be wrong. Well, he insisted and I did it. I installed a boost bottle on a Mitsubishi motor that already had a juicebox.

Heres the important part....

That motor out accelerated EVERYTHING else I had in the shop, including a S2 ported 50cc Active & a S2 Ported Bluebird 57. Its top speed was only marganally improved, but the acceleration was flat out amazing. Yes, I have seen the formulas about boost bottles, and I know the volume of the Juicebox. Sure, for a 43 the Juicebox it is a little small, but after It was proven to me that some larger volume formulas are worthy I started doing it on a few more motors. I know it goes against conventional wisdom as well as my own understanding, but what the heck... I'll say It worked for me.

My only personal expierence with Juiceboxes and tuning is contrary to the printed instructions with the Juicebox. ADA says to lean it out for better performance. I say richen it up. Every motor I have installed one on needed to be more rich (open) in adjustment than its previous setting ( and that does not necessarily mean that those were correct settings, just where the carbs were at before install).

[datalorr]

is the boost bottle an empty can or does it have diapham/ volume compensator in the end, the juicebox should be more effective due to being right on the manifold, yamaha`s answer to getting more "boost" was to use a plastic container that swelled or pulsed with each charge, as the presure wave reach the bottle it swelled and the contraction of the bootle help push the fresh charge on its way,
another thought perhaps the distants between your two chambers would allow each to work at a separate RPM range improving an accelarating engines speed,
a bit like a diffuser works best at a given RPM and in an ideal world if their was a way to alter the expansion chambers length/diameter their would be no power band just raw power

[pingpong]

hey JBonnardel do you think you could post some pics of how you installed both the boost tube and the juicebox? i'm having trouble with mine. it doesn't match up maybe you could PM me thanks

[JBonnardel]

hey JBonnardel do you think you could post some pics of how you installed both the boost tube and the juicebox? i'm having trouble with mine. it doesn't match up maybe you could PM me thanks

Here ya go... sorry but I dont think it will help much as it was taken when it was all installed with the farings.

http://home.earthlink.net/~sdmms1/images/HP%20Carb.jpg

The yellow line behind the Box is the line to the Bottle
http://home.earthlink.net/~sdmms1/images/Tuned%20Pipe.jpg

[Leek1985]

has anyone got a better picture of where the boost bottle goes please i am equiping it to my mini moto,will it fit all standard mini motos