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Discussion Starter #1 (Edited)
Hello all,

I am rather new to the forums and equally new to the vstar world. I picked up my 09 1300T last September and love putting miles on it. I have a question regarding the air box, and the drilling of such.

I am running it stock (as far as I know), except for the pipes, which are the Yamaha competition long drag pipes the previous owner put on it.

When slowing down to a stop and using the engine to slow the bike while gearing down, that I get some popping out of the pipes which everyone tells me is normal for more open pipes. It isn't too bad, but occasional.

After reading quite a few posts here and elsewhere about drilling out the air box to give the motor more air, I read a few things that peaked my interest.

1. Some said that with more air, a less restricted exhaust is needed. Since I have the long drag pipes already, is my bike a better candidate to add more air/power since I am assuming the current exhaust is already more open than the original?

2. I read on a post on another site that people described less "lurching" in the gears on take off. I have noticed that the throttle is very touchy (jerky - head snapping back) when opening it again after coasting. Is that the lurching they are talking about, and does the drilled air box help that?

3. I have been told that the popping when slowing down is a result of the air imbalance because of the drag pipes. Would the extra air help that symptom at all?

4. I've read about people just installing aftermarket air filters. Is that instead of, or in addition to drilling the box?

5. Is there any downside to drilling the air box?

I should add that I am not real keen on drilling holes unless it is going to be helpful or worth it. I don't feel the need to dicker with stuff unless there are some real reasons to do it.

Thanks for any help.
 

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I have been reading old posts about drilling your air box, do a search and you will find many. I have a 250 so have no experience, the 250 seems to run pretty well stock. The foam oil filter in mine seems to be large enough to handle all the air it could need so see no need for aftermarket filter, at least on a 250.
 

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There are a couple of good threads about this on the Yamaha Motorcycle Forums site. In fact, I believe there is a template that you can download there. (might even be on this site.)

I did my 950 and never looked back. It really opened it up. The intake on these bikes is right over the engine and you're sucking hot air which is thinner. By drilling the holes and blocking the original path for the air, you getting cooler more dense air which will have a bit more oxygen in it. You'll notice the change in how it responds.

There is also an O2 mod that someone has designed for the 1300, but I'm not sure where you can find it or purchase it anymore. Again, I believe it is on the YMF site.
 

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It all comes down to that hole right there. You can see it's plenty big enough for all of your low to mid rpm needs. Somewhere in the mid rpms, though, the vacuum becomes restrictive. The holes effectively replace this hole. You can plug it up if you drill enough holes. Look through the hole. See the cylinder fins. Drilling also allows cooler air in.

An advantage of keeping the stock jock strap is under the filter. Crankcase ventilation is routed in there. You can just about count on buying an open air breather to handle crankcase ventilation.

Downside? Well, it's still a jock strap.

I have no idea why this image is sideways.

 

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