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2008 VTX 1300T Carburetor Tuning

Posted: Thu Jan 29, 2009 6:38 pm
by Chuck

We started out with a stock VTX 1300 T
Cobra Slip On Slash Cuts #BLV1179SC
K&N Air Filter #HA1330

Now for the tuning customer started with a DynoJet DJ1192 Jet Kit I installed the kit as per the DynoJet Instructions using a 195 main jet. The problem was it fell on its face of 0% throttle and hesitated under load in low and cruise. I bumped up the main to 200 and ΒΌ turn out on A/F screw it was better but still not good enough. With the enricher partly out the bike ran smoother but still had that annoying dead spot as throttle rolled on. So back to the lift and throw out the instructions from Dyno Jet. Based on the symptoms I figured had an initial load up from the accelerator pump when rolling on followed by a lean condition low to mid causing no power, high was just fine so main jet would be ok.

What I ended up doing the DynoJet needle caused a very rich condition due to its size and taper so I decided to go back to the stock needle and used 1 shim but kept the lighter spring that came with the Dyno Jet Kit. I used a 190 main jet and drilled the pilot jet out to .025 wire gauge size 72. 1 1/2 turns out from seated on the A/F Screw. Out for a test ride result excellent. Great throttle response strong from close to full open. I was happy with the results and thought I would share. Keep In mind that this was a January Tune here in PA and it was very cold out I will post again if I have any issues when summer and 90 deg days are back but for now we have an great running VTX.

Main Jet DJ190
Stock Needle with 1 shim
Dyno Jet Slide Spring
Pilot Jet Drilled to .025
A/F 1 1/2 Turns Out