single filters

[joe smith]

I have been thinking about going to individual air filters and was wondering what the general concensus is concerning them. I know I will have to probably rejet. will they increase performance or is it a waste of time and money???
Thanks
Joe

[JP]

No but they'll make your teeth whiter.

Seriously, I haven't heard of ANYONE who did any dyno testing with before and after numbers to make any definitive claims. I suspect that there's a bit of a placebo effect by making that sort of change.

Put on Kerker pipes and that throaty sporty sound makes you sure you're quicker, more responsive, yadda, yadda. You get more sound feedback from individual filters and I suspect a similar result.

Until I see something conclusive in the way of documentation I'll be a bit cynical.

[Mike Hart]

I have dyno proof, but not on an XS!

Here's the deal - you increase airflow in and out, you jet up to accomodate it, you get the same gas mileage, but more power, providing you jet properly. (Same gas mileage, because with more power, less throttle opening for a given speed in a given gear)

It's common practice on lots of bikes. BUT... here's the rub... the XS had decent flow to start with, so a 4-into-1 plus individual filters only buys you a coupla few jet sizes, and a merely nominal increase in power. Believe it, it is there, it just isn't very impressive (5% possibly? maybe less?)

On the Bandit, I went from 102.5 mains to 150 mains, almost 50%, when I increased air flow a lot. I got roughly 15% more hp and torque. Well worth it. So rough that to a 3/1 jetsize/powergain ratio. If you can get enough flow on an XS to get you up 4 jet sizes, say 110's to 120's, that's about 9% jet size, 3% power gain. It's a gain. It's not big. 3-4hp? But it's there.

While your desire for proof is reasonable, it is also reasonable to assert that some power gain is realized, based on long-established techniques. This is not crop circles, it's balancing jet size with air flow.

Point well taken, the cool sounds make that 3-4hp seem like 10 or more!

[Mike Hart]

btw, Joe, see Denny's Jetting Recommendations article.

A 4-into-1 maximizes the effect of the individual filters and rejetting.

I just put individual filters on my XJ, see my follow-up post in that thread.

One reason to do it is ease of r and r carbs! Sounds really cool too.

[Bob]

individual filters

I put indiviual filters on my 79 XSF solely because I like the looks of them on the bike. Performance enhancement? I couldn't tell you. There were so many things wrong with the fuel/air delivery system on my bike that I did most of the work at one time. The ones I got (second time around) were the oval ones found at www.partsnmore.com. They price at $8.00 each, but when I put them in my cart, they came up at $10.00 each, which at $40, is still cheaper than anywhere else I've found them. I got foam filters the first time, but where I live, they deteriorate too fast IMHO. BTW, some of my Harley friends think they look really neat on my Yamaha My .01 worth.