Removing pcv valve, add crankcrase breather filter advice

[chris_hu_cheng]

OK this is check I understand what is going on, disclaimer I bought a cheap second hand Chinese derived EC3 GN125 clone, runs, runs better after self servicing, adjustments and few replacements etc.

Used for local commutes and going out with my wife on her 125cc scooter and my son on his 125 (going out with 125 on a much bigger bike is painful).

Also use to experiment and learn a bit more about bikes beyond simple servicing.

I bought a cheap as chips mini crankcase filter, added this to the end of the crankcase breather pipe. Dismounted the PCV valve, plugged the airbox breather pipe inlets and inlet manifold. Made plugs and kept all the bit to make make it easy to reverse.

Result is looks cleaner, more space, and moved the horn back on to the previous valve mounting, subjective I know but looks nicer. Louder getting a nice low "phut phut phut" additional sound at lower revs through the breather. Had to adjust the idle slightly. Performance feels a bit more sprightly (marginal), I have a local test loop and I know what sort of speeds I can get (includes steep hill etc.) and where, doesn't go any faster but gets there slightly earlier.

What have I lost if anything? I can't see any benefit to the engine of getting crank case gas coming into the inlet manifold, or to the air box receiving it at higher revs and load. PCV seems to have evolved mostly as an emission thing. Which lead to second question: will this cause any issues with MOT?

Really just trying things out, going to experiment with a cone filter at some point but will have a new carb to adjust and swap out for that, parts are really cheap with these things.

Edit: Yes before it is mentioned, I know the cone filter thing is pointless but I want to play with a carb and see what if any changes I can make

[Sister Sledge]

What have you lost? Money.
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CCM 404 DS

[Easy-X]

Emissions delete? On that sort of bike the performance gains are barely noticeable but I concede the bike might look a little neater. But I hope you understand that many asthmatic kittens will die

If you must enter into the pod filter stupidity then bear in mind it'll make little odds to performance unless you couple it with a free-flowing exhaust and a pathologically stupid amount of time replacing carb jets.... to get what? 10% more power maybe?
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[chris_hu_cheng]

[chris_hu_cheng]

[Easy-X]

Fair enough, you're going into it with eyes open and without unrealistic expectations, best of luck

The basic point of crank case breathers, exhaust recycling and the like is to minimise the amount of hydrocarbons dumped into the atmosphere. This is more pronounced on carb-based engines that take a "middle of the road" approach to fuelling compared to the (hopefully) more precise nature of EFI.

And that's the beauty of motorbikes: at least when you're confronted by an mob of angry vegan tree-huggers you can make a quick getaway!
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[Sister Sledge]

A fairly cheap speed enhancement that many people forget is to spray the bike (not tyres!) with carpet tile adhesive and smooth it over with aluminium foil from the kitchen.
The very look of a shiny aluminium coating will convince you that it's going faster.

Umm with that breather filter/delete. I could argue that you've made the bike go slower. Why? Well those crank fumes complete with hydrocarbons were going through the engine and burning off. They were actually extra fuel for the engine.
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CCM 404 DS

[Easy-X]

[Sister Sledge]