Roland
05-01-2005, 09:21 PM
I did some tuning on my bike today and got some good results. Its a 490 fdo built play bike, 11:1 compression, hotcam stage 2, clean-up port, crf 450 carb from Servicehonda. It's about 18 months old and has been run hard, most of the time woods and half a dozen trips to the dunes, Winchester and Sand Mountain.
I had a K&N on it with a pre-filter cover over a UM aluminum box, I also left the battery in the stock location. The K&N you get for the 400 is only 4 1/2 inches long, and the box is about 12 inches..I had this set-up for 18 months and never had a problem, so in the quest for more power I ordered K&N #RX2820, it's 9 inches, with filter on the end, ( instead of the chrome cap). The filter has way bigger pleats. You need to get a 3" diam. x 3" long piece of exhaust pipe to connect filter to boot, but its a clean install, then you put the pre-filter on the top of the box. After start up it was running way too lean, so today I worked on the jetting. Left the pilot alone, before 170 with clip #5, now 188 clip #4 screw 2 1/4, sealevel. I could not believe how much better it runs. The filter must allow more airflow, I'm going to get one for the wifes bike now.
I had a K&N on it with a pre-filter cover over a UM aluminum box, I also left the battery in the stock location. The K&N you get for the 400 is only 4 1/2 inches long, and the box is about 12 inches..I had this set-up for 18 months and never had a problem, so in the quest for more power I ordered K&N #RX2820, it's 9 inches, with filter on the end, ( instead of the chrome cap). The filter has way bigger pleats. You need to get a 3" diam. x 3" long piece of exhaust pipe to connect filter to boot, but its a clean install, then you put the pre-filter on the top of the box. After start up it was running way too lean, so today I worked on the jetting. Left the pilot alone, before 170 with clip #5, now 188 clip #4 screw 2 1/4, sealevel. I could not believe how much better it runs. The filter must allow more airflow, I'm going to get one for the wifes bike now.