I need to know if a silencer on the end of a tuned pipe(RCR) should have an inside diameter, the same size as the end of the pipe, larger than the end of the pipe , or smaller than the end of the pipe.The one I have on the end of the pipe now ,is smaller inside than the end of the pipe and I was wondering if this has any negetive effects on performace or the jetting problems I have been having.It is just a cheap universal fit silencer I have on it now.

 

sparkys

I too am in this same boat. I have a silencer that Mike Chero gave me that is meant for the RCR pipe and I have a YZ250 FMF Shorty that I altered to fit on it. The YZ is slightly smaller in diameter than the regular RCR silencer. I think it also looks and sounds better than the regular RCR silencer.

I called and talked to Rick about this. He said that the smaller diameter silencers actually work better in the higher rpms than the regular RCR silencer, to a point. The regular RCR silencer would have a smoother curve from top to bottom. The smaller diameter cores wouldn't have the bottom end but would give you a stronger hit in the mid to upper rpms. As long as the smaller diameter doesn't get so small that it actually reduces the required air flow.

By the way, I changed my jets in mine again yesterday. Now it won't even start. The carb came with a 280main/50pilot. Without the air box attached it would start right up and idle itself for ever. I dropped down to a 230/40 and it seemed to help. I went to put the air box on it yesterday so I dropped to a 220/30. It never even fired. it just kept fouling plugs. I figured with the air box on it, it would richen itself up but I guess I couldn't believe it would be that bad. I got discouraged and left. I'm getting closer to finishing this thing up but I do have ALOT of little things to finish up. It atleast has a set of 489XT's on it the whole way around now and my tie rods are all hooked up along with the polished front calipers. I have new plastic coming for it to anyday now.