Removing air filter on SHA moby

I have a moby 50v with SHA 15.15 carb. Will removing the air filter help me at all? I see on the tuning spreadsheet some people run stock non-ported with no air filter.

How does it effect performance and jetting? It makes you run leaner, right?


Re: Removing air filter on SHA moby

Nope, it shouldn't help you at all. The filter on those is pretty free flowing and basically keeps out rocks and big stuff. Removing it will make it run slightly leaner. People that remove the filter are probably running too rich or just too lazy to find a filter that fits.

Re: Removing air filter on SHA moby

keep the filter. if you need to lean out, change the jet (its really easy).

Re: Removing air filter on SHA moby

Did you notice how much louder it is (through the carb), compared to the Gurtner? It seems that metal screen and simple black cover are tuned, or, are just open enough to let it flow. On a stock motor, it just can't gulp anymore air then you are feeding it anyway.

Re: Removing air filter on SHA moby

Keep the filter on and port that cylinder so you can make better use of that carb!

Re: Removing air filter on SHA moby

i have a ported to shit moby with 16 sha and no box or filter. you don't need it on a moby its useless. just jet accordingly. i. upjet. similar peugeot racing carbs don't even have a place to put a box or filter. some argue the box provides vacuum but ive never noticed a difference. i have never once ever ever ever heard of a rock getting into a carb. especially when its a back facing carb.

Re: Removing air filter on SHA moby

Thanks for all the tips.

My main problem is the acceleration seems poor and the engine doesn't seem to be making enough power.

I just realized my throttle cable adjuster at the carb end was screwed in too tight, so the throttle wasn't opening all the way, that made a bit of a difference.

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