I searched the 900 forum, and, still have questions about de-baffling the stock exhaust? I know that many members have done this 'mod' while waiting to gather the cash for a full exhaust system- so, there must be a ton of people who know the answers!
* What is the largest drill bit (1/2"?) that will fit between the inside wall and the the center baffle? Someone mentioned using a 15/32" bit, but, he didn't say it was a tight fit...
* What is the I.D. of the center counted baffle? I would like to use the largest possible bit to smooth the flow through the baffle. People had mentioned that there is a 'plug', or, a plate in the baffle, which should be punched out to increase flow...
* Has anyone used a variety of bit sizes to vary the hole sizes in the inside plate? I was considering putting 5 1/2" drill holes-evenly spaced- and then adding holes to increase flow by using progressively smaller bits each time. If anyone has already done that- how well did it work?
* Will a 3 1/4" hole saw be the MAX size that will fit the I.D. of the stock exhaust pipe? Apparently, for some reason, a 3" hole saw is not effective, but, 2 3/4" works, as well as 2 1/4"- but, so does a 3 1/4" hole saw. I'm sure why this is the case- but, if I can buy a hole saw that 'fits' the I.D. perfectly, I will buy that one.
My intent is to: deepen the sound of the stock exhaust, while increasing flow and reducing some of the back pressure. But, I also plan on modifying the stock airbox very soon- so, I will need to determine air/fuel controller works best with the 903cc engines fuel injection. ("Search" is my friend, but, also feel free to add input- looking for 'idiot proof', as I'm not strong with complex programming systems!)
At this point, Stage 1- cover plate removed, baffle cut back & 4 holes drilled in plate seems to be what everyone who has done it- wishes they stayed with. But, like everyone else, I will probably end up going Stage 2, with at least 8 holes- if not more. Which means I will have to marble it to reduce popping & whistling (varying the hole size may reduce it? Hopefully?)
At the end of the day, I would like to get the MOST: horsepower & torque available from this motor without tearing it down at all. So, intake & exhaust is where I will start, and, stock is what will cost the least. Besides, I love the look of the stock exhaust... Intake- I have no problem installing whatever aftermarket product produces the most (tuned) power- it's less of a concern.
Hate to create another de-baffle thread, but- experienced people will save me from cutting twice- which is expensive on chromed stainless steel!
Thanx in advance!
Dave
* What is the largest drill bit (1/2"?) that will fit between the inside wall and the the center baffle? Someone mentioned using a 15/32" bit, but, he didn't say it was a tight fit...
* What is the I.D. of the center counted baffle? I would like to use the largest possible bit to smooth the flow through the baffle. People had mentioned that there is a 'plug', or, a plate in the baffle, which should be punched out to increase flow...
* Has anyone used a variety of bit sizes to vary the hole sizes in the inside plate? I was considering putting 5 1/2" drill holes-evenly spaced- and then adding holes to increase flow by using progressively smaller bits each time. If anyone has already done that- how well did it work?
* Will a 3 1/4" hole saw be the MAX size that will fit the I.D. of the stock exhaust pipe? Apparently, for some reason, a 3" hole saw is not effective, but, 2 3/4" works, as well as 2 1/4"- but, so does a 3 1/4" hole saw. I'm sure why this is the case- but, if I can buy a hole saw that 'fits' the I.D. perfectly, I will buy that one.
My intent is to: deepen the sound of the stock exhaust, while increasing flow and reducing some of the back pressure. But, I also plan on modifying the stock airbox very soon- so, I will need to determine air/fuel controller works best with the 903cc engines fuel injection. ("Search" is my friend, but, also feel free to add input- looking for 'idiot proof', as I'm not strong with complex programming systems!)
At this point, Stage 1- cover plate removed, baffle cut back & 4 holes drilled in plate seems to be what everyone who has done it- wishes they stayed with. But, like everyone else, I will probably end up going Stage 2, with at least 8 holes- if not more. Which means I will have to marble it to reduce popping & whistling (varying the hole size may reduce it? Hopefully?)
At the end of the day, I would like to get the MOST: horsepower & torque available from this motor without tearing it down at all. So, intake & exhaust is where I will start, and, stock is what will cost the least. Besides, I love the look of the stock exhaust... Intake- I have no problem installing whatever aftermarket product produces the most (tuned) power- it's less of a concern.
Hate to create another de-baffle thread, but- experienced people will save me from cutting twice- which is expensive on chromed stainless steel!
Thanx in advance!
Dave