Pocket Bike Carbs

[pedhead7]

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

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.

[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]

I've got one of those cheap chinese X1's...

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]

Juice Box

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

[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

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?