modify breather?

have heard the more air for breather help with engine performance? drill hole in breather? go to K&N (costly)

appreciate any info

thanx doc

Everyone I know that has drilled holes in the air box has seen performance degrade significantly and lots of pops and backfiring as it leans the engine out.

brian

I drilled two 5/8" holes in air box on my stock 83 setup.

It adversely affected mid range performance significantly.

I have used the same air cover a little this spring in the limited running on the re-born bike and it does not seem to have the same adverse affect with the Vmax heads.

I really don't feel much change with them open or closed. I took bike out with tank cover off and duct tape over holes so I could open them up as I was riding.

Gary

Won't help any on a second gen. You not changing the size of the plumbing the air breathers attach to and its smaller than the opening of the air breather. Also the air breathers attach to a T so your basically pulling thru both breathers at any time as it is.

Search the forum for K&N, but a quick summary is use them if you are only drag racing your bike.

If you are riding it on the roads, you will wear you engine out earlier due to more dirt getting through and your wallet will be thinner for buying the K&N filters and associated parts.

The K&N filters help by flowing more air at Wide Open Throttle, but you probably only run at WOT 1% or less of your riding time, unless you are drag racing only....

If you are looking for quicker accelertaton you should probally start by putting in a final drive from a V-Max due to its lower gear ratio.

Search the forum for K&N, but a quick summary is use them if you are only drag racing your bike.

 

If you are riding it on the roads, you will wear you engine out earlier due to more dirt getting through and your wallet will be thinner for buying the K&N filters and associated parts.

 

Rebuttal.

K&N or any high flow filter will allow more air flow all the time, it will be most noticeable at WOT.

The size of the holes in a K&N are larger that is why they flow more air, and that in theory will allow more small dust and dirt particles into the engine. BUT!!!! the K&N is also an oiled filter and the oil traps most small dust and dirt particles. Why do you think virtually every dirtbike and off road racing truck and dune buggy uses oiled filters. And in very dusty conditions use an oiled pre-filter in front of an oiled filter. Of course on off road vehicles they come from the factory with oiled foam filters so no one changes to K&N.

The theory behind the K&N oiled filter is as it starts to collect dust and dirt it builds a static charge and then collects more dust and dirt, and that is why they tell you not to clean them too often. Not sure if that theory is true or not but I have changed to K&N filters on every vehicle I have had that started with a factory paper filter for many, many years and never had an issue or wore an engine out early. I have not changed on my 07 RSV yet, mainly because I got sick last spring and have not ridden much in the last year, but will as soon as I get a round tuit.

As far as being expensive, buying K&N and cleaning every 20k to 40k is cheaper than buying new paper filters every 8k, isn't it?

I am running K&N filters on my 07 Venture with the air boxes opened up, after I opened the air boxes I needed to reshim the diaphram needles to eliminate a dead spot in the throttle. I would recomend going to the K&Ns, I had them on my 98 Royal for more than 90,000 miles with no problems and the bike is still running with no engine problems.

If I had to do it over again on my Venture , I would use the K&Ns but not open the air boxes.

I am not sure if you can put K&Ns into the air boxes with the stock covers or not, but I do know that you Yamaha says to use the K&N filters if you switch from stock covers to chrome covers.

I am not sure if you can put K&Ns into the air boxes with the stock covers or not, but I do know that you Yamaha says to use the K&N filters if you switch from stock covers to chrome covers.

They fit into the stock covers just fine. Running them on my 06 with no problem.