I have a '95 Fatboy with a K&N filter installed and I am wondering if the stock air cleaner cover is adequate for this filter or should i look to get a less restrictive Air Cleaner Cover? Modify existing backplate to allow for better airflow?

Looking for suggestions on brands to fit the K&N filter already installed.

 

Might check out some of the sites, j&p has a few options.

 

I looked on Ebay and bought an NOS Screaming Eagle kit for my FXR with the CV carb. It was reasonably priced and still in the plastic wrapping. From there you can pick any cover you like.

J & P, V-Twin Mfg, and Custom Chrome have sites to look at.

From there, may need to re-jet your carb...lots to find here...search function is pretty good, but not perfect...

 

Most high flow air cleaner kits are actually intended to be used with the stock chrome cover. They normally came with a simple metal backplate. If you still have the plastic air filter housing backplate you could modify it so it allows more air into the space around the filter element. As long as air can get to the filter around the cover, it is not going to restrict air flow. Don't allow air straight into the carb, otherwise the filter is not able to do its job!

 

When I first converted to the CV, I had an original plastic back housing. I did drill some holes in the front and back of it to afford more air flow...worked okay

 

That is probably all that is needed. The stock air filter can shift more air than the motor needs unless highly modified, it just needs a little extra help from the air box like that.

 

Thanks for all of the comments and I was actually thinking of modifying the air box to allow for more air in pretty much the way described by Frontiercat but I didnt want to ruin the airflow and be stuck with horrible performance. Then I would have to repair it until I could replace it.
Frontiercat - you said it worked okay. did you notice much of a difference than without the holes drilled?

What kind of improvement woud be expected if I moved up to a new say 42 or 44mm carb with a stock engine?

 

Well, I changed to the CV from the butterfly along with V&H short shots and the modified air cleaner. I did re-ject the CV as per recommendations found here. Now I have the SE backing plate and short shots.

My feelings are that with all my changes, the bike runs much better and I am still getting around 45 mpg with a 50/50 mix of riding highway and in town.

I think drilling some holes in the backing plate (I did 4; 2 in front and 2 in back) with stock exhaust and stock jets you should be fine.

To me, the CV is an awesome carb for the 80" engine. It responds very well and still maintains decent mileage. I do have an Ultima 113" with a Mikuni HSR45 and it gets around 30 mpg on a 400 lb. rigid bike. Therefore I can't compare; apples and oranges those two bikes are...

There are lots of previous posts in this section regarding most of your questions, but I can't recall all of them. There are a couple of more experienced guys on here than me, too.

Good luck and enjoy tinkering on the EVO...

 

I wouldn't bother trying to modify the EPA backplate. It's not that expensive to go to a backplate that is engineered to flow properly.
I agree that the modified CV carb is fine for many levels of engine mods for an Evo.

 

I just switched out my Screamin' Eagle backing plate for a chrome teardrop air filter. I haven't even changed my sig pic yet. I'd be happy to sell you mine. It comes with the filter as well and you reuse your factory air cleaner cover. You of course have to buy your own breather system, but they are all of 20 bucks on ebay to as much as $60 if you buy the better ones with the steel braided lines such as the the Sifton. Let me know if you want it. Make me an offer.