So was working on this Garelli the other day and had some issues. OK. I clean the carb, replace the bottom end fluid, make sure the throttle is properly opening all the way, points are at stock setting, but bike wont rev out. So of course I think its a clogged pipe so I clean the pipe and header, still acts the same way.... Pull the pipe off and look up into the exhaust port to find this carbon build up from years of use. Carbon build up can be caused by a few different things, running too rich and using cheap 2 stroke oil. This will result in a loss of power and more routine maintenance is needed. Also you can get carbon build up under your rings which doesnt allow them to seat properly. The way I see it, It's worth the money to just buy better oil and not have to rebuild your top end when you dont want to. I personally run Amsoil Sabre at 100:1 and havent had any carbon related issues in the last year. It's rad to run a 100:1 capable oil because a quart lasts so much longer. Look at these photos hahaha. I cleaned this up with files and it proved to be a bit harder than I thought.