I installed my new diaphragm in my 39mm FCR mx. The new one was slightly different than the old. The old one had a larger button portion; about 1/8". The new one was just about flat. I installed it with the part number facing out. The smaller button on the inside and spring on the outside. My throttle response is really suffering. Just to note, I did remove my spark arrestor. I plan to put this back in to see if it is the spark arrestor removal changing the throttle response. The bike no longer wants to wheelie!!!! I also put my smaller sprocket on the front, the bike should be flipping me off! Did I do something wrong when I put the diaphragm on? I re-lockwired the linkage as well. The only three changes are: new accelerator pump diaphragm spark arrestor removal one tooth smaller gear in front I do not want to go for a test ride right now, severe wobble from somewhere. Fix that, then install spark arrestor, and see what happens.