factory front springs rubber sleeves

[wr450]

did the pass side lowering spring yesterday and forgot the rubber sleeve that was in the oem springs, i did the driver side a month or so ago and put it in the new spring so is having it in one side gonna be a problem and what function do they serve

 

[Tabres]

Their purpose is to cancel noise. You may have a very, very slight height difference side to side and may get some noise from the passenger side.

They're not required, though. Some people remove them to get the lowest drop possible.