Fuelie factory carb tuning

[d.rosenhoover]

I got my xb used and I was wondering what the factory carb settings are, and how do I tune this thing I'm used to nitros. Any help will be appreciated

 

[Guest]

The base settings are:

1 1/4 out (low needle)

1 1/2 out (high needle)

To get to these settings turn the needles all the way in just till they stop. Don't tighten or you will damage the needle. Then back out the needles the desired number of rotations.

Every carb will be slightly different.

You will want to do high speed runs leaning to increase performance.

Small 1/8 or less turns at a time.

After every adjustment do a high speed run and check the color of the spark plug. You want a nice brown paper bag color. Any white or ash color and you are way too lean. Black you are too rich. Here is a plug color chart. http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html

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[d.rosenhoover]

Ok thanks Alot

 

[d.rosenhoover]

What needle do I turn after fact. Settings while I'm tuning it In

 

[d.rosenhoover]

In what order

 

[Guest]

Start with the low lean it just a bit. The rpms will increase. You can lower the idle stop screw. If you can't get the idle to drop you are too lean.

After you get the low set where you like it you can move onto the high needle. Remember to check your plug after you start leaning the high needle.

 

[d.rosenhoover]

Ok got it. Is there supposed to be any kinda of a smoke trail

 

[Guest]

Not a trail but you should see it when you hammer the throttle. When you see a lot of smoke you are on the rich side. The base settings are on the rich side. They are "safe" settings. Not really for performance. You use those for break in and a starting point when you begin to tune. If you have trouble getting it to start, it is always best to go back to the base settings to get her running. Tuning takes a bit of practice. Once you get it tuned you can leave it alone. You will need to be a little richer in cooler weather as the air is more dense.

A side note if you run synthetic two stroke oil you will have less smoke. Its better for the engine and makes driving more enjoyable.

 

[Deluge]

When you do the plug test, do a high speed run and kill the engine immediately. Otherwise you won't get an accurate reading.

 

[Deluge]

Also, get rid of the stock carb. More trouble than it's worth. The Walbro 990 is a great carb, you should check it out.

Walbro WT-990 High-Performance Carburetor

 

[d.rosenhoover]

Ok guys thinks a lot. Got it running like a champ. I will have to order a 990 when I order a jetpro side pipe once again thinks

 

[Guest]

No prob...

The 990 is a good carb. Tunes nice and holds that tune. No low end bog like he stocker.

 

[d.rosenhoover]

Seems like a winner

 

[Deluge]

It is. The difference in performance is really noticeable.

 

[DMZamora]

No prob...The 990 is a good carb. Tunes nice and holds that tune. No low end bog like he stocker.

Would a 997 be a good choice too?

 

[Deluge]

No. It's basically a 668. Which is pretty much the same as the stock carb. Go with the 990.

 

[DMZamora]

No. It's basically a 668. Which is pretty much the same as the stock carb.

Hmm... but a 990 has no choke valve, doesn't it lead to hard starts?

 

[Deluge]

Not at all. Mine starts up within 2-3 pulls.

 

[BertR]

If your worried about not having a choke you can put your hand over the intake and pull 1 time then one without the hand it will fire up no problem , in a seance your hand is the choke lever

 

[Guest]

Once you have it tuned it does start easy. My XB sat several months with out being ran. Filled it with fuel, primed it. Started on the 3rd pull!