walbro stage 3 carb

[Firestorm102389]

There is a stage 3 walbro carb that uses a crankcase vent to pump fuel in, it's off jnmotorsbikes.com. I was wondering if this would even be worth the money? I'd be putting it on a mountain bike with a 36 t sprocket and voodoo expansion exhaust. The kit originally comes with a speed carb, and the reviews on that walbro one seem to hold up well and great performance. I just want to hear anyone else's experience with it. I don't want to spend the money if the carb isn't any better. May use the bike for some off road use, lightly.

Thanks in advance!

 

[Fabian]

It is all explained below, but give the web page time to load the photos:

http://motorizedbikeforum.the-talk.net/t341-walbro-style-carburettor-for-rock-solid-engines-reed-valve-intake

 

[Firestorm102389]

I've already seen that site, thanks, I was just wondering if the performance was worth the $200

 

[Fabian]

The Walbro style diaphragm carburettor will not give you "ANY" extra performance over a correctly jetted stock standard carburettor, because physics dictates how much air can be moved through a given hole size.
A 14mm hole is a 14mm hole, regardless of what kind of carburettor is attached to the end of the hole.

The diaphragm carburettor will give you ease of tuning through it's external mixture screws and it will "not" leak fuel, nor will it allow air leaks - it is a carburetter that simply works; day in and day out, though you will need to order the thermal isolation spacer for it to run with proper efficiency.

 

[Firestorm102389]

What is the thermal isolation spacer you speak of

 

[Firestorm102389]

Unless it keeps it away from the engine to keep it cool is what you mean, I'm getting a reed valve setup invetween with an intake pipe, so it should stay cool and not overheat.

 

[Fabian]

Carefully reread the thread - the installation photos of the thermal isolation spacer are listed in the photo tutorial.

http://motorizedbikeforum.the-talk.net/t341-walbro-style-carburettor-for-rock-solid-engines-reed-valve-intake

 

[Firestorm102389]

Oh, I don't have to worry about that, the kit I'm getting comes with a longer intake to account for that, it puts a decent space between the reed valve on the engine and the carb, so it should affect the fuel going in the intake

 

[Fabian]

I have no idea what the intake extension looks like, but if it's made from aluminium or steel, an excessive amount of heat will be transferred to the diaphragm carburettor; causing fuel to boil in the circuit passageways; making the carburettor not only untunable but completely inoperable, when the engine gets reasonably hot.