Building a 4-stroke bicycle

It’s a great engine. I’m two years in and only really had to adjust valves and keep the oil changed regularly.
That's good to hear.
I'm looking forward to getting it done. Almost there, all the hard stuff is complete, just all the little details left to do.
I've been side tracked with spring clean up, work and a new motor cycle.
Hi guys. Can anyone guide me on the method to move my output sprocket in towards the transmission some.

I have the 4G grubee transmission, and I bought a bigger output sprocket from Staton inc.

It fits, but I need to move it inward on the shaft maybe less than half an inch.

I see the output shaft has these spacers, but I'm not sure the proper way to remove one.

I have another steel spacer which will give me the clearance I need, but I need to remove one of the original ones.
Disregard guy's. I just ended up taking the whole transmission apart.

I cleaned up everything, added new clean Grease, and reassembled.
Guys. I am in need of making my air intake box smaller or perhaps using something different so I can reposition it.

Are their any options like the image below for us 4 stoke engine guys?

Screenshot_20240614-002808_Amazon Shopping.jpg
Yeah. I've rode it plenty of times. I had a output sprocket that was causing the chain to slightly contact the air box.

Plus I like those air filters like the above, but I'm not sure if they would fit the Hausheng engines.