XR 100 and XR 200 jetting

[Fred T]

Today I'm picking up a used 2002 XR 100 and my son already has a 2002 XR 200. I want to do some work on the bikes and richen up the jetting if required. I know the 200 can use it especially if we open up the air box for him. Now on the 100 what is required to make it so it runs good and starts well? Not looking for HP just good running habits with cold weather coming upon us.

1. What jet sizes should I put in XR 200?
2. What jet sizes should I put in XR 100?

Is it good to add an aftermarket twin air or uni filter? Why?

Thanks you thumper heads, I appreciate it coming from my ring-a-ding world.
FT

 

[Lorin]

The aftermarket air filter is money well spent. For $25, I got a filter with a replacement cage that flows much better. I then removed the exhaust baffle and richened the main jet by 2 sizes. A very noticeable improvement for $30ish dollars. The stock air filter cage is very restrictive.

 

[MxKid512]

Ditto on that. Buying a filter, yanking the snorkel, and removing the baffle or purchasing a new pipe make the bike feel much different. Much more alive.

 

[BigBore]

On my dad's 200, I removed the airbox snorkel, and installed a Uni Filter, which came with a hi-flow cage. I then went to a 112 main jet (still using the stock pilot). The bike starts easy, and rips pretty good for a 200.

Sorry, can't help with the 100 jetting.