by Old Dude » Tue Mar 22, 2011 6:39 pm
If you are looking to improve the performance of your 150f removing the baffle alone is not enough. It came from Honda jetted way too lean (sucking in too much air and not enough fuel). The air intake system is choked by the airbox design and air filter. They are built this way to meet emissions standards to allow importation. Simply opening the exhaust by removing the baffle amplifies this condition. You need to open the airbox by removing the 'snorkel' and rejet the carb (110 main and 42 pilot I believe is what most recommend and move the clip down (lower) one position on the needle). Keep in mind that removing the baffle on your 150, while improving performance, will most certainly increase the exhaust noise and may be setting yourself up for citation and/or restrict your ability to ride in some areas, (like around my campsite).
When you get the money, buy a free flowing aftermarket air filter. I recommend the Twin Air unit (available from CRFsOnly) AND put on an aftermarket exhaust. I ran the Carmichael Honda Motorsports system on my prior 150F and 230 I have a BBR system on my current project 150F bike (thats what it had on it when I bought it) both are good additions improving performance and keeping exhaust noise within accepted levels.
I guess I really didn't answer your question though did I? Opening the exhaust will worsen an already lean condition on a box stock 150F: not a good condition. It will run hotter: an engine killer.
Do not remove the exhaust baffle without addressing the jetting as indicated above.
O.D.