They have special "Umbrella" patches. As was noted in an above post. It is a rumor that you cant repair a motorcycle tire. A rumor put out there by people who sell motorcycle tires... imagine that!!!
I have seen friends bikes with 5000+ miles on tires with patches in them. One on a 949RR with 2 of the umbrella patches up front and 3 in the back. He regularly did 130 mph plus and did one track day with them. Its perfectly safe to do if you use the appropriate patches and they are applied by someone who knows what they are doing.
Dont go down to an autoparts store and buy the plug kits for auto tires. Thats not a good thing to do. I use them on my car and truck but a motorcycle.. no way.
If you go to a shop that fixes motorcycle tires you can look on the packages and even see they are listed to be used in motorcycle tires ( the umbrella patches that is) I worked at a chevy dealer doing oil changes, tire rotations and mounting balances even a few alignments. If a plug wouldnt work I broke down the tire and used the umbrella patch. It is a patch with a plug that sticks through the hole and has a metal rod on the end to help you pull it through and get it in tight.
As with anything else prep is a big part of success. You have to sand the area flat where the patch will be applied. Then clean it very well once you have a perfect surface. Apply the rubber cement or whatever kind of glue your particular patch calls for. Pull the sticker cover off the underside of the patch and pull the plug part through the hole from the inside to the outside. Using your patch roller tool with the teeth on it work that patch over really well. Making sure to go over the whole surface area of the patch several times. At this point you can smear some rubber cement over the top of the patch for added safety. That part is up to you and isnt really needed. Trim the protuding plug area flush with the rubber or if its in between the treads you can trim it a little below the tread height. The plug is rubber and will wear down with the tire.
These little plugs are wonderful for auto and motorcycle applications. The boxes they came in said they have been tested on Automotive, Light truck, Commercial, Off road and motorcycle applications of all types and speed ratings.
There are several different types of mushroom capped plugs some have a gun type tool to insert them with their own vulcanizing juice already on them.
This isnt 1975 anymore tire repair has come a long way.
www.patchboy.com has many different styles.
Hope some of this was of use to you guys
-vJ-