You can buy rubber caps at the auto store in various sizes for just a few bucks a package. I think 7/32" is the size for the intake manifold ports, carb ports may be the same. Measure yours.
wgcarbs.com has quit using rubber vacuum plugs sold at autoparts store because the tend to harden and crack quickly... a month or two at best. We buy vinyl plugs of the same size as Kent mentioned and these last indefinitely. If you can't find vinyl, use the big vacuum port plugs meant to be used on vacuum fittings on carb holders for the VM series carbs. Z1Enterprises.com sells those and they won't crack.
wiredgeorge Motorcycle Carburetors
Mico TX
www.wgcarbs.com
Too many bikes to list!
Go to Lowes and in the hardware drawers you will find WHITE caps that are the correct size and fit snug. five caps for a buck, mine has been on for 2 years with no problems
