I am putting a foam pod filter on my 49cc, because stock air box is shot , screws stripped and it wants to fall off. The bike ran great with a 75 main jet and stock air box before, seemed just right. But I read you should up your main jet when you do... I am just wondering from those who run a pod filter, how much you changed your main jet up to compensate. What do you think, 80? ? or what.
Last Edit: Jan 31, 2016 20:51:43 GMT -5 by phatboy
not saying my results are typical, but when I installed my pod uni filter, I up jetted and had issues with running rich, but stock jets in and was fine. I'm also running a 150cc, never had a 50cc so don't know how much different it could be
1985 kawasaki 750 bobber
retired (2013 Jonway 150cc scooter 11pole stator, red racing cdi, and red coil, uni filter. 102 main 45 pilot jets. Micheline City Grip 130/70/13 tires.)
Only a pod... I would say try 4 and buy 2 bigger also- try 4 then try 2 and if you don't hear a (waaaaa/hollow) sound up high especially I would do as small as I could. No hp pipe not much needed. Then,try your down low rich/lean buy a warm up,then get to slowish speed stay on throttle a little while steady...then punch and it should be snappy. If boggs you can bump jet needle clip or if non adjustable,get 3mm flat washer and bump the needle thats on top part of carb. 2 screws and worth the small fuss. Also,check out help files on here about pilot jets. You could prob just turn idle A/F ratio screw back(counter clock) if idle is to lean. Oil breaking down quick is a lean running sign.
OK put on the pod. I also bought a set of jets, 75, 80, , , 95
It's got a bog at WOT off the line though, and I went all the way up to 95 in it and still bogging. I listened to rich bog sounds and it sounds more like a lean bog if anything. WOT off the line it moves slow at first then it revs up and more power kicks in. However, I pulled the plug after a 20 min ride with lots of WOT runs and it does not seem lean, but looking somewhat rich, not black but kind of a charcoal gray.
So assuming it is not running lean, what else could make it sluggish off the line, then rev up and go after 10-15 feet. Variator or clutch maybe?
OK, pulled the plug again after ~20 miles with a new setup and it's brown now, a darker shade of brown. I'm thinking rich, but not excessively?
Here is the plug
I still get a bog that gets worse as the bike is hotter. If I have an extended hill climb where I need to go WOT, it will be fine at first but start to lose power after a block or two, and slow down a lot and won't get power back unless I stop and let the bike idle at the side of the road for a minute. However, on flat ground the top speed is good and does not lose power on a long WOT run.
Also, I am not sure where you are listening to lean or rich "bogs". Typically, a rich bog will produce some black smoke, and a lean bog will just make no power and if you hold the throttle, may eventually "catch" and make very little power unless the throttle if turned up slowly.
new pod filter, thin screw clamp (took two small thin ones and threaded them together), carb cleaning, new fuel lines, tank cleaning, new flter and rejet later the bike is running pretty good. More power too, this hill I could only climb at 32 before, it climbed at 35 today. Definitely it was too lean before, as all those bogging problems are pretty much gone.
Weird thing, though, I seem to have lost about 2 mph on the top end, going down this straight road with a slight decline I hit 48 with the old setup but today just 46, despite the bike running better overall. Is it possible that running lean could give more power on the top end, but less at other RPM ranges?