Posted by Justin on June 01, 2000 at 08:08:41:
In Reply to: Re: discoloration removal posted by Alfred on May 31, 2000 at 09:41:25:
well, drilling the holes in the backplate could do this, but the chances are not very good, there are at least a piece of the plate that stops a brisk breeze from entering the head pipe, so, no, that would not(as easily, i mean.)do the damage.
Now the backfiring could be one of 2 things, either, the valve HAS warped or cracked(Backfiring ALLLL the time). but i doubt it, you probably have not run it enough for this to happen, the most likely cause is however that the lack of backpressure has made the bike run even leaner. The engine needs a certain amount of backpressure to get a correct, or near correct fuel/airmixture, without it, it will backfire pretty bad. My bike an 89' sporty has straight pipes, but was jetted to run rich to accomodate the lack of backpressure. if i didnt jet my bike, it would backfire loud enough to wake up my whole neighborhood. backfiring will not harm anything but your ears. I was just posting to make people aware that backpressure is needed to keep the bike alive, unless tuned to handle it, jetting the bike would fix the backfiring, but it will not make the valves any happier. when ya see top fuel dragsters after a race, the put tennis balls over the headers....this is to keep cold air from rapidly cooling the valves....same scenario. but just something to be aware of.
Justin