You need to get a different carb that will feed more fuel. A buller atomizer, a tilly set up for alky are great choices. 1 1/2 times more than gas is required to run alky. then you need to advance the timing as much as possible for the slower burning fuel. You will gain about 10% increase in power output but watch the head temp don't go over about 325-350 or you got meltdown ready to happen.
You can't just drill out holes, you need a dump tube for the main jet which also requires a special needle valve. They use to sell a kit. You also have to increase the compression ratio for maximum benefit.
I have a wb 20 walbro thats got three races on it almost brand new. Its got a lot larger bore than a wb3a and a dump tube in it. Runs real good on alky. . Would take 100$ for it . I have a highly modified kt and want to go to a Buller atomiser to get the full bang out of it. This carb has new diaphrams and neddle, will do all you need unless you go to a full blown open Kt. Mine has head work and runs 11.5-1 compression. Extensive port work and a 55mm piston. A atomiser will give me a little increase over the wb20 thats the only reason i would sell it. If interested pm me and we will discuss it.
I have 2 of the Buller Atomizers and they work just fine, on an otherwise stock engine. Little Yellow book that at 1 time came in the box with new engines says, stock C.R. is 7.9:1, cut 1.2 m.m., and it increases to 10.0:1.
It’s pretty common practice to measure the compression ratio, in a two cycle, above the exhaust port.
I’m pretty sure you could get away with just nine CC’s in the head. The head is probably already cut to get to 11 CC’s so if it was me, I would cut the top of the barrel to lower the head CC’s to 9.
The ideal fuel/air mixture ratio for alky is about twice what you would run with gas. Alky 6 to 1, gas 14 to 1. And you don't want to just drilled the holes twice as big in diameter. You want to increase the area of the hole by two. Do the math. Pi R squared.
Some of the other suggestions would work too, this is just another way.
Comments compliments criticisms and questions always welcome.
Comments, compliments, criticisms and questions always welcome.
If the data does not support the theory, get a new theory.
If the engine has been blueprinted to WKA, IKF rules the head CC and squish have been set already so you won't be able to get to 9 cc's by cutting the top of the block. If your already close to minimum squish and have an 11 cc head you have two choices, one you remachine the squish area deeper to reduce the size of the hemi-chamber and then come back and cut the relief off again to get the squish back to minimum or you weld up the hemi-chamber to reduce volume. The best way is to get a stock head that has not been b/p'd for a stocker, it's stock small chamber will get you a 9cc head once you set minimum squish with it, whether you cut off the top of the block or cut the relief off the head to get there. Jon