Fine Tuned the carb on the Crossfire

Posts: 74

I received the 130 main jet yesterday from Blade, so I went to work immediately.

After installing the UNI filter, redneck intake mod, along with the DG exhaust, the engine didn't idle as smooth as it did stock and it popped out the exhaust on decel (a little lean), and had a slight hesitation off idle. No stalling or anything like that, just not as smooth as I would like. I started with the needle by shimming it with an extra washer the same thickness as the stock washer. This should richen the fuel circuit from about 1/4 - 3/4 throttle. I had one left over from a motorcycle carb kit. Doing this should clean up the mid throttle pop and smooth the power. I then drilled the cap covering the fuel screw. I didn't drill it totally out, just enough to gain access with a very small screwdriver to make adjustments. Leaving the outer ring of the cap in place will prevent the fuel screw from backing out. The best idle was about 2 3/4 turns out, which was almost backed out against what was left of the cap. I then proceeded to install the main jet.

All is well now. The engine purrs like a kitten at idle, no bogs or hesitations when you stomp the throttle open and there is a definite increase in power with the total package.

Next on the chopping block is a set of 10g rollers, or 12g sliders. Razz

.....The mods will probably end there.

Posts: 296

Could you explain the shimming the needle thing? I'm pretty new to motor mechanics, I just perform basic maintenance, remove/ replace, and basic fabrication things. Owning these buggies has taught me a lot in a short period of time. Any pictures would be helpful, also. Thanks

Greg

Posts: 74

Posts: 74

I took it back apart for pictures. I am not sure that ALL GY6 carbs are the same; so if you own a kart other than a Crossfire, your carb could look different.

Two screws and the top of the carb is off. Watch out for the spring.

Carefully pulled the slide out to reveal the needle. Easy, don't tear the rubber diaphragm.

I'm not sure what this is called, but it holds the needle in the slide, and has a small spring to allow a little movement for the needle. I have never seen a needle "holder" like this before. I has 3 cuts that align it when you place it back into the slide, then it snaps in place.

Here is the needle with Two shims/washers. The smaller one is the stock washer, and the wider one is the one I had left over from another carb kit. If you try this, be sure the shim you use will fit all the way down into the slide cavity. Some washers are too wide, and that will really screw up your tuning.

......................

Now for gaining access to the PILOT FUEL SCREW.

The fuel screw is hard to get to without taking the carb off. If you decide to drill the cap for access, you will have to take the carb off. Here are a couple pictures showing you where to fuel screw is located. I have already drilled it out as you can see. I did not take a picture of the cap before drilling it out. It's just an aluminum cap that is flush with the carb.

Here is a view from the top of the carb.

You can see it easier from the drivers side view of the carb.

Hope this helps?

Posts: 566

Great job on the walk through, as well as good pix, I am sure this will help, I know I have learned something. Tim

Posts: 296

Good Stuff!!! Shouldn't this be a sticky, It will help a lot of buggy owners fine tune their carbs. You get an "A+". Thanks.

Greg

Posts: 1832

Posts: 3572

Those are some great pictures. Good job! Nice to hear you are getting closer to buggy nirvana...LOL

Posts: 74

Thanks for the positive comments!

I just ordered 10g rollers this evening, so maybe by the weekend we'll get them installed and see if there is any difference to be had. The stock rollers may be 10g. I'm not sure what comes stock in the Crossfire -R, but for $8 I won't be out too much.

There is a difference you can feel with the mods so far. It gets up and goes quicker than it did when we first purchased it; and the shocks are a major factor in ride quality. The frame settles down much quicker in the rough with 'real' shocks.

Posts: 566

You could do what I did... Take one roller to the local 7/11 / wawa/ Utotem/ pigly wigly..... and have them weight it for you, if it is a 10gr roller it'll weight ..I think it was 3.5 oz,, some one here confirmed my math, so post back, let us know..
Tim