I was working on my kids ATV (TRX90) to clean the air filter. I went under the seat and found a plastic cap with a small circular hole in the middle. It fit perfectly on the end of the snorkle outlet from the air box. I put it on and it idled fine, but when we ran it around it was doing miserable. I took the cap off and it worked great. My question is why would Honda make a cap for the snorkle (limiting the air to the carb)? Cold weather or something?

 

It's made to de-tune and de-power the motor so a kid can learn without the bike having much throttle. As you have seen, it's only good if the bike is running on level ground as power is cut down to almost zero. However, if you have an inexperienced kid, it makes for an ideal training tool so that they can get the basic feel of the bike and safely figure out things like turning and braking. I would expect that even the most inexperienced child would grow past the restrictor in just a couple of days.

BTW, there is also a limiter screw on the thumb throttle that will limit the speed yet can be adjusted for more speed than the air intake restrictor.

Jaybee

 

You can also cut the pink wire going to the cdi ( rev limiter ) to let the engine rev higher.