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Discussion Starter #1
I recently did a hollow mod on my bike and installed a cone type air filter. Obviously, I'm now getting a lot more air, and was wondering, do I need to increase gas flow or decrease? The bike runs ok, but seems a little sluggish at low rpm's. Anyone who's done this, approximately what size jet did you install?
 

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What year is your bike? There are two styles of carburetors, depending on the year. 1987-2000 is one style, and newer than that is the other.

I would advise you to buy 2 or three different sizes of jets. If your bike is pre 2001, I believe a 114 jet is stock, and then I would buy a 116, 118, and 120 or so. I don't know much about the newer style carb as I've never owned or seen one. Mess around with the different sizes and see what works best for you. I am running a uni pod filter and am running a size 115 jet on my 98, but I live at 5500 feet, so at sea level I would go much higher.

Welcome to the forum!

Zack
 

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Discussion Starter #3
Zack, it's a 2012, so I guess I need to find out the stock size and then buy up 2 or 3 sizes. Thanks, it's a start.
 

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Zack, it's a 2012, so I guess I need to find out the stock size and then buy up 2 or 3 sizes. Thanks, it's a start.
Stock main jet on the newer CV carb is 126 on the non-Caifornia, and 128 on the Cali carb. A130 main jet seems to work well on a TW in a stock configuration...might be a good starting point.



Generally, more air means you need more fuel.

jb
 

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If you want it to run better with better throttle response at lower RPM's replace the pilot jet with a #54 From an XT. It also starts easier and warms up faster. I did that mod with a completely stock motor and I still get 77-80 MPG.
 

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If you want it to run better with better throttle response at lower RPM's replace the pilot jet with a #54 From an XT. It also starts easier and warms up faster. I did that mod with a completely stock motor and I still get 77-80 MPG.
I forget, what is the stock pilot jet size? Do the two different styles of carbs have different pilot jets? I should know this but a vicious vortex of forgetfulness enveloped my brain just now.

Zack
 

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I forget, what is the stock pilot jet size?

Zack
Stock pilot jet for the CV carb is a #31.

This is a #34 should the OP wish to try it.



jb
 

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I switched my main jet out to a #130 ( yes, I shimmed the needle and turned out the pilot screw) and I'm between 400ish too 1200 ft above sea level and the bike "seems" to run well . I presume if it is running well ,don't mess with it . TW starts fine, so ,me changing out the pilot jet to a larger size could open up pandora's box.....right ?. TIA
 

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....... I presume if it is running well ,don't mess with it......
AMEN!

Hi Frog,

If you need to turn your pilot screw out more than 3 or 4 turns, you may need a larger pilot jet. This should not be necessary on a stock bike, and may indicate there is a problem with the pilot circuit.

The OP is doing a hollow mod, so he will need to experiment with different jets, and go through the tuning procedure with each change, to account for the increased airflow.

jb
 

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Understood jbfla ,thanks . I'll just leave well enough alone ,as stated above the bike run's well , as far as I'm concerned ...... no surges ,burps ,farts of annoying traits : ) .
 

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There seems to be a lot of carb tuning question threads right now in the Tech help section, as there usually are, yet nobody seems to be finding the http://tw200forum.com/forum/technical-write-ups/591-carb-tuning.html sticky. Find it, read it, follow it. Whether doing a hollow mod or just trying to eliminate the stock lean condition, that guide is awesome. It gives jet part #s, procedures, wisdom, and it will save you headaches.

As for this OP and this situation, you will probably need to go with bigger jets. I think you will want to try that #34 pilot and a #132.5 main. Just my guess. Here are the part#s for the range of jets:

2001+ Main Jet#:
288-14343-63-00 = 125 (TW 01-13 STOCK SOME)(LEAN, GOOD FOR HIGH ALT. >6000’)
288-14355-63-00 = 126 (TW 01-13 STOCK SOME)(LEAN, GOOD FOR ALT. 4000-6000’)
288-14355-64-00 = 128 (TW 01-13 OPT, CA MODEL STOCK)(GOOD FOR FUEL ECON)(ALT. <5000’)
288-14343-65-00 = 130 (TW MOST POPULAR OPT.)(NEUT-RICH, ALT. <4000’)(XT 600 STOCK)
288-14355-66-00 = 132.5 (RICH, GOOD FOR VERY HIGH TEMPS, LOW ALT)(STOCK IN AUS & S. AFRICA)
288-14355-67-00 = 134 [AKA 288-14343-67-00]
288-14343-68-00 = 135
288-14343-70-00 = 140 (XT 600 OPTION)

2001+ Pilot Jet#:

5LB-14342-65-00 = 31 (TW 01-13 STOCK)
5LB-14342-17-00 = 34
43F-14342-19-00 = 38
 
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