[johnrush]

Here, just north of Boston, we are buried in snow and losing our sense of humor. Every other day or so, I go to the garage and hug my 2003 Honda Shadow Spirit VT750DCB3. I was hoping to be riding again in March. Not sure now that is going to happen.

My bike is all stock as far as I can tell, definitely stock exhaust pipes, air filter, and air filter housing. I was thinking about replacing the stock air filter with a K&N hoping it would boost performance, even just slightly, even though I am satisfied with performance, a boost never hurts. But further reading leads me to believe a K&N air filter will not help so much if I don't open up the bike further by modifying exhaust pipes (both more open and louder), air filter housing (remove air snorkel or replace with a hyper charger), and then re-jet the carburetors.

So is there any performance benefits from upgrading a stock air filter to a K&N air filter without all the other modifications? If not, I am happy just replacing the stock filter with another stock filter come March. Or April.

 

[Furball Zen]

B3? What model is that? And no. Do not do a K&N, youll have to tear apart your carbs to rejet immediately. Also hyper chargers dont do anything for you for the cost you have to pay. I ran my 750DC for 8 years with the stock airbox (modded and 'tuned' for my jets) save for a short time i had a custom 4" car filter on it, till it rusted.

Best bet is: pipes/adjust mixture screws, 38T rear sprocket. Later on you can rejet and open up the bean box.

 

[bd*]

welcome aboard John and best of luck with that Shadow. Bob in Lowell.

 

[adlowe]

I was thinking about replacing the stock air filter with a K&N hoping it would boost performance, even just slightly...

Not likely. The only performance increase I've noticed is due to increased money for fuel since I'm no longer dropping $25 - $30 a couple of times a year for new air filters.

Looking at it logically, increasing air flow through an already-lean bike isn't going to do much to enhance performance. Not that the air flow changes much at all.

 

[7xclm]

^^^^^^^^^ +1.

I have run a K&N for a couple of years. Have not changed the jets and have no problems. Just follow the directions for cleaning the filter.

 

[Leathel]

To increase power you need to increase flow.... but if you dont open the exhaust it wont flow much different at all


If you do open the exhaust as well then a bit more fuel is needed to keep the mix right so jets as well

On a std exhaust the bonus with the K&N is as mentioned, buying once... but you do need to clean it do forget that part

 

[johnrush]

Thanks Mighty Furball, I like the order of modifications you recommended. I haven't seriously considered replacing the exhaust pipes because I do not want to the bike to be too loud. I might make the sprocket change when it is time to replace the chain, which is likely this summer. But I ride secondary highways along the northeast coast of MA, into Maine and back, for fun and scenery—two lanes, twisty, through the old town centers—so it is rare for me to get up to 60 mph. It seems with the sprocket change, I would never need fifth gear. Do you agree?

 

[johnrush]

Jealous of your shed, Bob. I'm in Beverly.

 

[johnrush]

Thanks for the advice, adlowe. New filter is going in this Spring, and based on what I'm reading it is likely to be a stock filter.

 

[johnrush]

Leathal, that confirms what I thought: stock pipes + K&N filter is just for convenience of cleaning the filter instead of replacing it, but no better performance until exhaust pipes are opened up. Problem is, I don't want a loud bike so I'm likely to leave the pipes as they are.

 

[Furball Zen]

Thanks Mighty Furball, I like the order of modifications you recommended. I haven't seriously considered replacing the exhaust pipes because I do not want to the bike to be too loud. I might make the sprocket change when it is time to replace the chain, which is likely this summer. But I ride secondary highways along the northeast coast of MA, into Maine and back, for fun and scenery—two lanes, twisty, through the old town centers—so it is rare for me to get up to 60 mph. It seems with the sprocket change, I would never need fifth gear. Do you agree?

No. Even with the 38T i used 5th a lot, but not till around 50-55ish. I also just ran a stock paper filter. In fact i doubt i ever changed the filter over 26k miles more than once. There was no reduction in performance either.

If you dont change anything other than the rear sprocket and chain, i think youll do ok. You could always drill a couple 3/8" holes in the back of each muffler to let a little more noise out without being obnoxious.

 

[johnrush]

Thanks, Furball. I have yet to read a post from someone who made the sprocket change and regretted it. So come new chain time, it is likely that I will change the sprocket to 38T.

 

[jpr1968]

Try a Uni air filter(part number NU-4129). Cost's close to price of an OEM air filter but it's washable and reusable and it works as good as a OEM filter. I put stock pipes on my Sabre shortly after I got it. I prefer peace and quiet. Makes long rides much more pleasant.

 

[johnrush]

Thanks jpr1968. I hadn't heard of that filter before but will look it up. I'm retired, so usually when I'm out riding, it is for 4 or 5 hours.

 

[rs_ss350]

I was about to ask a similar question... mine's got cobra exhaust and has been rejetted, dyno tuned, but with a stock air filter. was wondering if the K&N would require a rejet as well...

 

[Furball Zen]

Yes, because you are letting (potentially) more air in. Ive not seen one person who dynoed their bike (Shadow) before and after installing a K&N so prove it gives you any gains. Doesnt mean there isnt someone who has though.

Now, on an FI bike? In my case, it made a HUGE difference, mainly cause i could actually hear the intake vacuum after installing it. I already had a tune loaded into my PCV so thats why i can say i felt a huge difference, the tune was made with a K&N and i was running a stock filter still at first.

 

[bd*]

Hi John, I bought my bike new 15 years ago and Im still running the Stock Pipes, Just loud enough for me. But I did go to a 38 tooth sprocket and LOVE the difference and I ride mostly back roads.

 

[johnrush]

Okay, bd, thanks for mentioning that, especially since your ride conditions are like mine. When my chain is replaced this Summer—I'm pretty sure it will not last through the summer—the sprockets are going to be replaced and that back one is going to 38T.

 

[7xclm]

I recommend you research a DID O-Ring chain.

 

[Furball Zen]

No need to get an expensive one. But it does have to be an O ring chain. I got mine from the local dealer along with the sprocket put around 10k on it before i sold it, they were cheaper than anyone online. They will also ship out of state, if you want i can hook you up with their number.