cegan09 Posted May 31, 2011 Share Posted May 31, 2011 So i'm finally getting serious about getting this bike back to good condition. Issue number one was wiring. fixed that by just making a new custom stripped harness. Issue number two was the fact that i'm running pod filters. I've upped the jets and upped the jets, but it was still just not running right, and frankly it was running dangerously lean (i came close to overheating it the other day). from my reading, my theory is that without the restriction and resulting slight vacuum from the stock airbox, the carbs don't pull fuel through like they should. In addition the slides won't respond correctly. The pod filters offer little to no resistance (usually a great thing for performance), and as such the bike won't run right (as many have much experience with) so here is what i've done. Since i have no interest in getting the stock airbox i've been trying to imitate it. My first attempt was to tape off half the filters, but that really didn't do anything. Then i looked at the filters that came on my second bike. They were foam cylinders with large springs inside to keep their shape. I pulled out the springs, cut them down, and fit the trimmed pieces inside the pod filter. This seems to have helped. temps at the top of the engine are a good 40 degrees cooler than the other day when it was close to dangerously overheating. Pops are about eliminated from the exhaust. Biggest problem was the vacuum from the engine starting to pull the foam into the carb opening. This blocks the air slot to the top of the carb, and kills that cylinder. A little superglue should solve that problem. So, anything blatant i've overlooked? Have others already figured this out and i'm just late to the game? Link to comment Share on other sites More sharing options...
kindest Posted June 1, 2011 Share Posted June 1, 2011 i run pods no problem. bike runs great. went up one size on jets... not sure why your bike refuses them Link to comment Share on other sites More sharing options...
Paulwhite Posted June 1, 2011 Share Posted June 1, 2011 i had a similar problem (for my cbr 125 engine) i ended up attaching half a silicone U bend to "imitate" the airbox then a free flow pod filter with a shroud. worked quite well but the idea is to make the intake suck the air from the carb. so by rights it needs some resistance. the foam inside the filter isnt a good idea.... last thing you need is bits of foam entering the engine. have you thought of making a shroud of some sort for the filter? something like a beer can chopped in half then a hole in the bottom to push the rubber boot of the filter through. this should create the resistance needed to sort it out. (need to re-jet to suit) might be worth a play to see if it helps. Link to comment Share on other sites More sharing options...
cegan09 Posted June 1, 2011 Author Share Posted June 1, 2011 i run pods no problem. bike runs great. went up one size on jets... not sure why your bike refuses them what carbs does yours use? My 500 has Mikuni carbs, which if my memory is working correctly (often not the case), are CV carbs. My friend's KZ400 has Keihin carbs, and for whatever reason those accepted pod filters with no problems. Mine was suffering from hanging revs, constantly running lean, insanely hard to start, and an inability to idle. Most of these seem to have been fixed with what i've done. but the idea is to make the intake suck the air from the carb. so by rights it needs some resistance. the foam inside the filter isnt a good idea.... last thing you need is bits of foam entering the engine. I'm not too worried about that. the foam i'm using is from a pair of filters that was nothing but foam. It's flexible, in good health (not dried up), and was meant for this use anyway. I just need to secure it inside the pod filter a little better (not that it could ever cause damage. it can't make it through the carb, it would stop at the slide). Link to comment Share on other sites More sharing options...
kindest Posted June 1, 2011 Share Posted June 1, 2011 what carbs does yours use? My 500 has Mikuni carbs, which if my memory is working correctly (often not the case), are CV carbs. My friend's KZ400 has Keihin carbs, and for whatever reason those accepted pod filters with no problems. Mine was suffering from hanging revs, constantly running lean, insanely hard to start, and an inability to idle. Most of these seem to have been fixed with what i've done. Mikuni BS34 carbs for me. Link to comment Share on other sites More sharing options...
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