I read a recent post from someone who wanted to make his MX more woods ready. One of the responses was to get a reed spacer. What characteristics does this give a bike and technically, how does it do it?
its a spacer that fits between the engine and your reed cage, it is supposed to give your engine more air flow so you can more low rpm lug. I have one on my 125, it's not a big deal, i just got it so my carb would fit in my air boot better..but mxa said they got more bottom from there test yz125 in 2001.
depending on how the cylinder is , it can do two things lessen primary compression on the two stroke and possibley move the reed block back from blocking the ports of the cylinder.
ive heard fron the local cycle shop owner (whos been racing since he was 15 hes 41 now) that they do nothing at all. Rember im not saying this. some time ill get one and just see if it does, but till then this is what i know.
I have a '01 YZ 125. I tired a Mossbarger (10mm or 12mm - can't remember) reed spacer on it. I couldn't tell much of a difference, so it didn't stay on the bike long. I could tell a lot more of a bottom-mid gain from a V-Force reed cage with the reeds set to low tension (although the cage costs 5 times more than the spacer).
i dont think the reed spacer made more power, i just think it kept it from stalling when being lugged. I guess the extra air kept the motor running longer.
Speaking in general terms moving the carb away from the cylinder increases air flow into the cylinder at low rpms and therefore aids low end torque.Conversely moving the carb closer helps an engine flow more air at higher rpm to aid top end power. Some of the factory MX bikes that are modifed for only top end use special carbs that are milled down so much that the choke circuit is removed from the carb! Just to give that little bit more top end response by moving it closer to the reed cage.