More VC625 carb voodoo/experimentation

[oldphart]

Originally Posted by HBR

oldphart - I opened up the pilot on my 24mm carb and it was exactly what was needed. With the stock pilot, the idle screw was basically ineffective. I basically couldn't turn it out far enough to make a noticeable difference. But with it opened up and about 1 turn out, the screw controls the mixture in a reasonable range now.

What did you open your pilot up to?

Jim

[HBR]

Jim - I wish I could give you a helpful answer on that. I bought some micro drill bits (cheap chinese made stuff) on Amazon a while back. I found the one that would just pass through and then used the next size up.

I am sure everything I just said makes a machinest like Shepard cringe!

[Shepard]

Originally Posted by HBR

Jim - I wish I could give you a helpful answer on that. I bought some micro drill bits (cheap chinese made stuff) on Amazon a while back. I found the one that would just pass through and then used the next size up.

I am sure everything I just said makes a machinest like Shepard cringe!

Don't worry H - I do the same only I use torch tip cleaners.

[slonomo]

Sometimes you just have to go for it and drill it out. If it makes a positive improvement then you are going in the right direction. If I'm jetting with drill bits I order three or four stock jets to have on hand, then keep them organized with the exact bits you use to open them up. You can invest in an inexpensive micrometer that can help you keep track of sizing. For drilling I use a pin vise drill bit set.

[oldphart]

I....am officially confused. I built a second carb (this one complete with idle speed and mixture adjustments outta' 5/16 tubing w/roll pins through them so I don't have to try to adjust a moving target with a screwdriver) so I can switch back and forth trying to dial this in 100%. For the second time, I installed the adjustable main jet kit from EC, and in now two carbs.....even screwed shut, the minute the throttle is opened enough that it starts using the main circuits, it's absolutely DROWNING in fuel.....won't even pick up rpm beyond 1500 or so because it's so 'fat'. The main jet that came with it is about .080....but after measuring, the needle doesn't bottom in the jet when shut....it's bottomed on the end of the threads on the needle. Do you suppose I got a improperly machined needle in this kit? Makes NO sense....

Any input would be greatly welcomed.......Thanks!

Jim

[HBR]

Jim - do you have a stock clone carb? If so, does the EC adj jet bottom properly in the stock carb?

[oldphart]

It's a Huayi 24mm stocker from VC for the 625. The jet obviously 'bottoms' because the emulsion tube is held fast when it's tightened, but the adjusting needle runs out of threads before it actually seats in the main jet. Do I cut more threads on it, or buy another from a different supplier? I'm sorely tempted to just screw a VM style Mikuni on it....but that's a whole 'nother process of expreimentation to get it dialed in.....and I'd rather not go there.

I was never a fan of Chinese stuff.....and my attitude ain't getting better.

Thanks!
Jim

[HBR]

Sorry, I wasn't clear about the stock carb question. Since I have a 390, in my mind the stock carb is the smaller one that comes on all the clone engines. But if you have the 625 then the stock carb is the 24mm unit.

The adjustable main jet I bought on eBay a couple of years ago works on the smaller carbs and the 24mm carb. I thought if you had one of the smaller carbs and it seats properly on that, then there must be a difference in the bowl depths between the two carbs.

[oldphart]

Thanks! I'll go back to being cranky and baffled.

Shop reefer is full of Bud. That helps....

Jim

[raydhd]

I have both the 460 and 625 carbs here with adjustable main jets. One from EC and one from the cheap E bay seller. I too am a little baffled why your's isn't working right.