do I need this air filter

[Mikey]

on my stock 75 do I need this filter labeled # 21 on the parts diagram
I plan on rebuilding the air filter labeled # 16 with Uni Filter BF1 12" X 16" X 5/8" 65-PPI Green Fine Foam
Thanks Mike

 

[kshansen]

Is that item #21 actually a filter or some kind of silencer for the intake? I've only worked on a 1972 and some 1978 up and they don't have that item!

OKAY did a little searching one line at Yamaha and found this:
21 447-14441-00-00 SILENCER, INTAKE 2

So I'm guessing it should be a reusable part that if dirty you could just wash out with soap and water. Actually look similar to items used on man heavy equipment machine I have worked on!

If you are going to eliminate it you may have to do some carb tuning and it would change the sound of the bike I'm sure, how much don't really know.

 

[YamadudeXS650C]

Yes, I believe Ken is correct. They are a silencer, not a filter.
I found them on my totally stock '75
Pulled them out and found no discernible change in performance or spark plug color.

But the colors on my ride in the fall of 2017 were changing fast.....

 

[Mikey]

the 75 I ride never had them and it seems to run fine
Now that I look at it again with the big holes it really wouldn't be a filter
I guess if the bike never missed them I'm good to go
Thanks guys for the reply
Nice 75

 

[gggGary]

they usually crumble to dust when touched.

 

[kshansen]

they usually crumble to dust when touched.

gggGary,
Are you talking about the item #21 in the parts book or those leaves `dude took pictures of on his ride?