See Tuning for Speed, "Improved Cylinder Filling", by PEI.
Haven't read that for some time, I'll have to dust off my copy.
H
See Tuning for Speed, "Improved Cylinder Filling", by PEI.
Yes you can tune them with plates for sound but more important for power! Peter Volkers is using a normal Vincent diameter Supertrapp and he won several horsepowers on a Dyno. With the 500 I rode with an open cone (like on the picture in this thread), but later I discovered that with a closed endplate the riding on the 600 was nicer and more smooth through all revs. I am not an expert in this, but maybe the same reason that megaphones are not a good solution for Comets?
if you are worried about the noisetest, there are two easy things to try out. But only do this temporaryly to pass the test and return to original after !!!
First increase your valve clearance (standard is zero) for the visit to the MOT station. Especially with a hot cam this works wonders, it dramatically reduces the overlap and takes the sharpnes out of the exhaust note (changing the sound from bang bang to almost fluff fluff). I would suggest something like 0.3-0.4 mm, but you can simply try in your yard. WARNING! Do not overdo it, the last thing you want is the pushrod to jump out of the adjuster or cam follower!
secondly put some fine steel wool pads ( ask your wife, she probably has them in the kitchen, but use the ones without soap in them) into the front of your silencer and check they do not fly out the end when reving hard. they are easy to remove afterwards or simply burn away. Drive to the MOT station slowly and it should last the test.
Over here in Germany, once the bike is registered nobody will ever check it again, so this works well.
I did this on my BSA B44 VS which is definately very loud and passed the MOT with ease.