I badly wanted this part to help increase fuel for my go kart. I have a 6.5hp Honda clone and am trying to increase responsiveness and speed.

I tried to install a number 98 main jet, however it was always VERY difficult to start. In fact it was practically impossible to start. I had to go back to a number 88 when i was using the original GX200 emulsion tube.

Now that I've installed my GX140 emulsion tube it allowed me to try the 98 main jet again. Now the engine starts so much better and it's become heaps more responsive. I don't think it's helped with the top end, but I'm going to do more straight line testing to gather more date... It's worth noting that I've also upgrade both my exhaust and air intake. I've installed a custom (home made) stage 1 high flow exhaust and used the FAUKC1 Air filter upgrade kit fpr the air intake.

I absolutely recommend this combination with a 98 main jet and GX140 emulsion tube fpr optume performance.