Looking for input with anyone running formula rd on the stock pipes, I'm leaning heavily on running the stock pipes, the bike is fast ...I can't use rear sets and stock carbs ( no boring) how much more will be gained by a set of chambers on a stocker ? I like the drive out of the corners with the OEM pipes and the tracks I will be running are relatively small , ( new Hampshire motor speedway and canann , ) I tried a few different things with it and in the end went back to stock air box w/ kn filter and took the unknown pipes off and stock back on ...it's noticably faster this way , rest of bike has hagon shocks, fresh fork rebuild, tapered steering bearings and swing arm bushings , just looking for input and your thoughts , cheers , Paul ragan , sarycuse ny.
There will be some significant weight saving going with chambers. You can potentially get some power gains over stock pipes but a lot depends on the carb jetting. You will need larger main jets for sure. The chamber manufacturer should be able to provide jetting guidelines but HVC has some good info here: https://hvccycle.net/carburetor-jetting/
Brand new my RDs were dogs with stock pipes compared to when I put pipes on them and jetted them properly for the pipes. I did notice more of a flat spot around 5 to 6k but thats likely because they actually made enough power to have one. Clearance was also much better with most. It was hard to find anything locally other than DGs or Bassanis though.
Find a microfiche for a 1975 yamaha mx175. the jetting is perfect for an rd350. You have to be careful, because some rd350b models had a noise restrictor in the air filter. get an air filter for a 1973 rd350...it's WAAAY more open. Thank me later.