savagecommander

if a wally 663 will support a 23cc single, would it support a 45cc twin? i am trying to avoid tuning issues with two carbs, or am i blowing it out of proportion?.....

Ram Jet

If you can avoid two carbs do it. Then you won't have to synchronize two carbs. Ask any owner of a British motorcycle.

Bill

savagecommander

thats my point, but will i have to go bigger on the carb if i dont double up is my question.

skip1320

Yea,just get a WT 201, 13.!@#$MM venturi,its a DA 50 carb,a proper 25cc carb wont work on 45 correctly,you can run it though,just loose to end, as a matter of fact i happen to have used excellent wt 201 i can sell you.

pe reivers

You do not say exactly what you want to do. Fit two smaller carbs on a single 45 crankcase, or fit two carbs, one on each cylinder of the 45, or what?

Two carbs side by side on the crankcase may be a very good idea, if the second carb is set up to open above 3/4 throttle. This will provide much better mixture control at half throttle, and better throttle linearity. (not tuning for best power here are we?)
First tune the low throttle carb all by itself with only the low carb active, then the high throttle carb all by itself with only the high carb active. Finally, adjust the high throttle carb H-needle for best power, with both carbs active.

savagecommander

id like to keep it to one carb if possible, but all my math points to two. the motor would be split case (and unfortunatly heavy) two coils, two carbs, two cases. i was hoping to just plumb the carb to both intake ports. i dont think the 201 would help much, as the 663 is 12.7mm

soarrich

My Feedback: (98)

Everyone here is assuming this is a 2 stroke motor, is that what you have? Do the pistons come to TDC at the same time?

savagecommander

this is what the crank will look like. split case, two stroke.

the Wasp

My Feedback: (1)

""Ask any owner of a British motorcycle""

sorry for changing the subject,, but there is a big difference between a 4st Jett & Slide Needle carb and a Walbro carb,,

actually if you have lived and rode threw the 60s 70s and 80s a Jett & Slide Needle carb is not at all hard to tune, even twins..

Jim

soarrich

My Feedback: (98)

OK. If it's a flat twin, treat it as a single cylinder, IE you need a bigger carb. If it's a vertical twin you can use the same carb.

savagecommander

ok. now if the pistons were moving in unison, the motor would be "larger" to the carb, right? now, do you think a 12.7mm carb would hold against a 45cc twin? they perform well with 30.5cc but thats about as big as ive seen

soarrich

My Feedback: (98)

Using the small carb might give you better throttle response, but it would probably cut down on your top end rpm & power. If you're using this engine in a car or truck that might be OK, but I'm assuming you are putting this in a aircraft, in which case top in power is probably more important to you. I have a Ryobi which is 31cc and uses a carb that's about 9mm, so I would think a 12.7mm carb would work OK on 45cc.

savagecommander

9mm? wow. my .32 used a 9mm carb... im HOPING to fit the motor into a car, and i'll consider myself lucky if i can get 15k out of the motor( i cant imagine id need much more than that) then again, if i got creative with some fiberglass and made up a plane id be set for a motor. thnx for the help guys