Carby weedeater carbs

[bikerdude0269]

So I've built my first mb. And am on the fourth tank of fuel at break in mixture. after I switch to reg mixture after break in. hopefully i can fine tune it to work right and not 4 stroke.

But what im wondering is ive been on here lurking and reading and searching if anybody has ever made weedeater carb work on ones of theses builds? or is that not enough carb to supply what these bikes need.

 

[blue 48]

Paper Weight!!!

 

[HeadSmess]

if only the studs were 1.25mm closer together, they would screw straight on

they have a pump that needs a pulse from the case...though from what i experienced fiddling with putting one on a 4stroke... piped to the inlet manifold is good enough.

all ya gotta do is pop em open and drill a wee lil hole.

they seemed to work without any pulse if the tank was "gravity feed"...

um. chainsaw is a better option as you need a fairly large throat. 16mm or so. most brushcutters are 10mm...

currently making a manifold for one the mills taking a cut as i type

 

[bikerdude0269]

if only the studs were 1.25mm closer together, they would screw straight on

they have a pump that needs a pulse from the case...though from what i experienced fiddling with putting one on a 4stroke... piped to the inlet manifold is good enough.

all ya gotta do is pop em open and drill a wee lil hole.

they seemed to work without any pulse if the tank was "gravity feed"...

um. chainsaw is a better option as you need a fairly large throat. 16mm or so. most brushcutters are 10mm...

currently making a manifold for one the mills taking a cut as i type

hmmm interesting so snowblower or chainsaw has bigger carbs? let me know how ur mill intake works.

 

[HeadSmess]

well, so far, so good.

first carb was off an old "talon" 42cc chainsaw.

problem being i pulled it off the engine 5 yrs ago...and have used parts of it on other carbs and so had to try and get it back together and then found an extra line that confused me, swear it wasnt there before....so... it just happens to have an external feed pulse, with a hose to a fitting on the crankcase.

i went for a ride anyways

it was a bit um...lousy. nice, but lousy.

so! whilst riding i realised i had a stihl 010 that i found on the rubbish heap. still in the car where i left it.

out with the crewdriver, fingers crossed and...ye gods! just the carby i wanted!

one line only excellent! fuel goes in.... thats it.

drill and tap a fitting for the pulse line, as i didnt want to try drilling into my manifold again, as it already had a fitting from trying the 1st carb, and id have to have blocked that off... and the existing pulse hole on the carb gets sealed off by the manifold.

if you know walbro/zama you should know what the $#%!#@im babbling about...

oh yeah. had to swap the throttle shafts over because i found some slight interference with my manifold. grrrr.

um. ok.

ridies!

starting will make you cry... i have to change air cleaner so i can have a choke. carb has no primer so it requires full choke to start, no matter what. typical stihl. im sick of poking my finger over the inlet and having no filter...

runs bewdiful once it has primed tuning with those screws is a breeze, and can even be adjusted "on the fly"

changing the air cleaner also requires changing the throttle cable mount as the filter manifold thing i have now IS the cable stop... plus some trimming to clear the frame...

so.

the results are worthwhile but the work involved will drive you insane

but then again, i cooooould mass produce these things now, and with a decent aircleaner...

finding the exact right carb can be a fight

a primer would be nice but then it either sprays fuel everywhere or requires a return line to the tank... (or a secondary lil surge tank)

wheres the bleeding thing for my camera?


founded!





i suppose people wanna see the pushy i do 80 on...


see the rear brakes? neither do i!

 

[blue 48]

ok your getting me to lean towards them now. hows it run compared to the old nt carb?
do the studs go through to the head or are they seperate? i will retract my PAPER WEIGHT comment if i get it to work too

 

[HeadSmess]

starting is nasty if you dont have the technique. we were rolling round on the ground when one of the guys tried taking it for a spin today...took him 5 mins to get going! pop a finger over the inlet for a second and off it goes... otherwise, be prepared to pedal for a while...

once running, it hauls. not as brutal on the top end as the mikuni was getting, but that was mainly due to the 18mm throat... which killed my low end eats the stock carb for brekkie plus did i mention being able to adjust the mixture while riding?

if you got the knowhow and a lump of ali... could make one with a bench drill i guess seperate studs... counterbored in about 30mm... 15` angle i think...

still debating whether to tap into the case for the pulse feed... it may be all thats wrong with the other carb which has a convenient choke built in... it ran but would die occasionally... like it was starving. ie, not pumping. maybe all thats wrong with this one too! starting... not priming quick enough?

(methinks a fourbanger carb that is tapped to the inlet actually has a spring behind the diaphgram... it can only suck, so needs a push...)

 

[HeadSmess]

update;

walbro wt123(463? has both numbers stamped on it...) is a 16(? i think)mm bore carb, with EXTERNAL pulse feed, and a choke. no primer, or at least mine didnt (it has now though its not connected...i just needed the spacer plate to put it back together...)

this carb works perfectly when the pulse feed is taken from the CRANKCASE

meaning i can have an airfilter, no finger needed for choking!

the other carb, from a stihl 010 is a walbro WA-99-(A)

also a 16mm bore, though the venturi is only about 12mm...smaller than the wt123 has.
this carb has no choke bulilt in...meaning youll need one on the airfilter... also no primer, and, while i was using it the last week, after feeding the pulse from the case, i discovered it needs a rebuild kit put through it...it leaks hence the hard starting... um. and the pulse feed is the standard brushcutter style, a hole in the manifold that eventually makes its way to the crankcase. this needs modifying somehow (r/c nitro fuel line nipples, a drill, and a tap...)

walbro makes too many carbs!

feeding the pulse from the inlet manifold doesnt work. vacuum only needs the spring fo'sho! or crankcase feed...

all in all, im very happy tomorrow i go get a lil r/c fuel tank so that the "overflow" from the primer/pump will make its way back to the engine eventually, not end up dribbling on the ground....

the stihls carb is good in that respect...no overflow at all just the leak caused it to go back on the shelf...