gas cap vent

[joenurse]

My gas cap didn't seem to be venting...bike began stumbling after about 5 minutes, and improved after manually venting tank. Thursday, I removed and disassembled cap, and soaked it in CLR (it liiked like it was covered with lime scale). It cleaned up nicely, but on inspection, it did't seem to have a provision for venting. The vent holes on the inner cap ended in a small chamber which was completely sealed by gasket to the outer cap. I solved the problem (I think) by drilling a 1/16" hole through the outer cap to vent. Stumble seems to have dissipated (I was also having rev limiter issues...disconnected it at the same time).

Can someone post a pic of a Vision cap? The gasket on my cap doesnt look like the pictures I have seen on this site.

[vadasz1]

Joe, Are you talking about the gasket under the outer cap that has two nibs on it and the gasket sort of resembles a snowflake shape sort of?  If so I don't think it is a replaceable part.  I took mine apart as well because mine was cracked around the key hole.  Ever since then it doesn't seal right and just bleeds fuel out.  There are aftermarket caps with keys at www.wemoto.com/bikes/Yamaha/XZ_550_RJ_RK/82-86/picture/Fuel_Cap_with_Spare_Key/ and shipped to North America will cost about $25-is all in.