Topic: UNI FOAM AIR FILTER???

[scooter1]

I have installed a uni foam air filter on my 1972 cb500.  It has stock jets, just wondering what would be the best setting for the air/fuel mixture screws or should i start from the stock setting??

[scooter1]

17 views and no input!!!

[Gordon]

Whatever works for your particular bike in your particular situation.  There is no chart for this kind of thing. 

[luckydevil]

I put the uni filter on my 78, and it ran a little lean.  Since my carbs had just been professionally rebuilt and synced, I did not want to mess with anything, so I put the stock one back in.  

I know, not any help, put I have had them on other bikes in the past and just used my air mixture screws setting to fix the lean problem.

[TwoTired]

Prior to the 77/78 PD carbs on the K models, the 500/550 ran pretty much on the rich side with the stock exhaust.

I haven't needed any re-jetting using the Uni Nu-4055 Foam air filter.

Check the spark plug deposits, compare with the chart in the this link:
http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html

Cheers,

[scooter1]

thank you sir!!!

[754]

Luckydev

if you put it on and it ran lean, why not rejet. or tune.
 Shows it works.. If it didnt change the mixture its not gonna give an increase.

[TwoTired]

Luckydev

if you put it on and it ran lean, why not rejet. or tune.

The 77 and 78 K 550 had a more restricted exhaust (smaller outlets, no balance tube), which allowed the carbs to be adjusted lean even with the stock air filter.  Simply changing the exhaust with less restriction, required a jet change/retune. Changing the air filter as well made retuning the carbs pretty much mandatory. 

Shows it works.. If it didnt change the mixture its not gonna give an increase.

Can't agree with that logic, I'm afraid.  An air filter with less restriction changes the carb throat vacuum, which is what pulls fuel through the jets.  Less vacuum = less fuel.  Putting bigger jets in to compensate for the vacuum loss does not prove the engine makes more power.  It can make a difference at top RPM, of course, if it indeed did provide a bigger gulp of oxygen.  But, flow characteristics through the Uni foam at high speeds has not been proven.

I chose the Uni mainly for it's economy.  I don't wind these old engines beyond red line anymore.

Cheers,