Rejetting highrpm issue

[jonkingphish]

So I’ve got a 2019 ruckus, which I rejetted , as well as delete tbt airbox and add a yoshi exhaust. The thing that’s boggling my mind is if I run a 38 slow jet the damn thing spikes up to 4000rpm
and idles there. It’s constant. I’ve adjusted the throttle cable and relaplaced it. I’ve replaced the whole carb as well. Iv reset the ECU. I’ve tried different length hoses for the intake. Smaller jets will make it stop, but then it runs like crap. I’ve also checked the valves and played with the air fuel and adjusted the choke. I’ve also checked for air leaks. I’m stumped here.

[Baizy]

Hey I think This will help you out. Also, if you want to sell your OEM carb from the 2019 PM me.

If you're suffering from a chronic high idle you might need to lay off the speed. All jokes aside you would have only disturbed 4 systems to swap the jets.
1. Cooling
2. Air
3. Fuel
4. Throttle position sensor

1. Cooling isn't likely the culprit, just something to be aware of.

2. The air system that you removed may now have an air leak causing your ruckus that's jetted a bit rich to run lean making it spool out of control as you've described. You seem to have an unrestricted intake so this isn't really ideal either.

3.1 You may have misadjusted your throttle cable making it too tight to fully close when you get off the gas.

3.2 you lost the float needle when you pulled the bowl off and are overfueling

3.3 the vacuum diaphragm is siezed open

4 you have not reset the tps via the red cable in the battery box, a quick google will tell you how to do so

An addition is have you been able to adjust the air/fuel screw? They're capped off on the newer Rucks making it a bit more of an initial pain to adjust.

This list should get you back on the road if you're not fixed up already. Cheers!