Gain greater control and fine tune your bottom end by upgrading the stock idle adjustment screw on your TPI bike. This upgrade gives you the ability to quickly and easily set the idle on your TPI bike. This idle adjustment screw is included in our TPI Injector Relocation block kit.
What we are trying to do here is get rid of the stock throttle plate adjusting screw (above) and replace it with something you can easily adjust.
We are doing this, because the only way to change idle speed at the stock level, is to adjust the air speed screw seen here. Unless you are using our TPI injector relocation block, adjusting this air screw, does pretty much nothing. Even if using the injector relocation block, adjusting the stock screw doesn't control the idle speed as intended.
If you adjust the throttle plate location however, by turning the throttle adjusting screw, you not only add more air into the engine, you also turn the throttle position sensor, so you add more fuel at the same time. This is the right way to change the idle speed.
To do it, you will need a torx wrench, size T10, and a small propane torch.
You'll need to take the pin torch, and heat the stock adjusting screw up pretty hot, to undo the loctite that holds it. Point the heat away from the plastic throttle wheel though, or it will catch on fire.
Start to twist the screw, even though it probably won't come out. It's loose now, so spray some WD 40 on the threads and let it sit for a bit. Between the WD 40 and maybe heating it up again, it will come out. Don't force it. Then it will come out.
Now you can thread our new screw and tension spring in, and turn far enough to where it opens the throttle plate just a bit.
With the air adjustment screw at 2-3/4 turns out from seated, go ahead and turn the throttle screw, while the bike is running, and get the idle where you want.
You can adjust the idle with the throttle screw, and then fine tune the idle with the air screw, as your riding the bike, to kind of get the idle you want. Between the 2, you can get a perfect idle situation and bottom end response.
The air screw can be between 2 and 6 turns out, for fine tuning. Don't turn all the way in or out past 6-1/2