I recently bought a 150, and 155 main jets along with 6 filtered uni vents for the airbox. I tried a bunch uf setups and found no more power. I thought that a 155 main with no airbox lid would give me more power. it didn't. I have a bike speedo(sure it isn't completly accurate) to test and seat of the pants. I could wheelie easier in 4th and 5th stock. also stock, I went up a long up hill run and got 94km(59mph) with 155mj and no airbox lid I got 92km(57.5mph) I repated the procedure 3 times each way and got the same results. the 150mj and 6 pluged vents feels like stock and I got 94km on the same hill(same speed as stock) the plug reads a light brown color stock and with the 155 and no lid. and yes I checked it at full throttle.(burnt my hand the first time checking the plug) I thought that this was a good way to get more power, but I saw none. all is stock except 3 holes in the end of my stock pipe(behind the spark arrestor) I also wonder if the 155 was getting too much air with no lid. also the filtered vents seem restrictive.(hard to blow through) any suggestions to get more power?

Also, will a 40 or 42 pilot help my bottom end?
maybe I should go with a uni filter, maybe a jet kit? Pipes seem to expensive. thanks.

 

Dont expect to get any noticable real power gains from just airbox mods expecially with the stock pipe. Dont believe all the advertisement and hype, although with a aftermarket exhaust you will notice a little gain. Air box mods will give you better throttle response but nothing real noticable, get a exhaust and you'll notice some gains with the added air flow!