muggzy Posted April 21, 2011 Report Share Posted April 21, 2011 (edited) OK here goes, I know there's been some recent posts regarding this issue ( http://bansheehq.com...howtopic=142399 ) and the answer is "change the filter to Uni's" However no one seems to be able to splain why getting my filter wet results in the symptom of the engine behaving like it is lean. I have some speculation that when I thought it through, seemed to make sense but upon further thought is probably off (see the link). So bear with me my while I get this out: 1st; I would expect a wet filter to behave like the engine is being choked (rich) due to the restricted air flow and under load (in my case) it does. 2nd; But, unloading the engine by pulling in the clutch or putting it in neutral causes the engine to race out of control so that even flipping the kill switch wont shut her down. The only way to shut her down that works (for me) is to pull the choke. I just did leak-down test @ 7lbs for 7min+ and there was virtually NO movement on a 20lb full-scale meter so there was plenty of resolution and really, no air leaking. Checked my compression and I'm getting exactly 145psi on both cylinders. Slides have been checked and re-checked and they're perfect, my jetting is a little on the rich side but the pilots and bleeders are so nice that I can idle low and slow all day long once it's warmed up. btw, i've also got the tors completely removed and idle screws installed and well adjusted. So the question is this: Why, with a wet filter would the engine run lean? Edited April 21, 2011 by muggzy Quote Link to comment Share on other sites More sharing options...
He's A Shee Posted April 21, 2011 Report Share Posted April 21, 2011 Isn't the rev problem (which seems like a lean condition) due to the stock carb's? I'm having this same problem, so I have been doing a lot of research on it. My airbox is bone stock, and I ride with the snorkel on when its wet. Even if I just barely spash the motor with water the bike will rev up. The one time it stuck full and wouldn't shut off!!!!! In other threads they were saying that the teflon wears off the carb slides and the moisture causes the carb to expand/contract causing a minor stick. I'm about to buy new carbs because I have water proofed everything with red RTV and it still does it. New throttle cable too. Oh, and I used a scotch brite pad on the slides too. Stil Sticks.... Quote Link to comment Share on other sites More sharing options...
ionroller Posted April 21, 2011 Report Share Posted April 21, 2011 A little input for you. To get fuel out of the carb, there has to be air flowing through it. If there is no air flowing through the carb, fuel is not going to majically get into the engine. The engine will consume all the fuel that was in the crank case and go on a lean revving rampage!! Quote Link to comment Share on other sites More sharing options...
He's A Shee Posted April 21, 2011 Report Share Posted April 21, 2011 Now not to change the subject, but I have another twist to things. I always seem to get some gas back on my air filter (hillclimbing, fuel is always dumping out) Never get water in the box, but could a partially fuel soaked air filter cause these symptoms? Quote Link to comment Share on other sites More sharing options...
J-Madd Posted April 21, 2011 Report Share Posted April 21, 2011 The revving is from the stock carbs sticking open. Quote Link to comment Share on other sites More sharing options...
He's A Shee Posted April 21, 2011 Report Share Posted April 21, 2011 The revving is from the stock carbs sticking open. Thats what I thought. I need some 28PWK's I guess. Quote Link to comment Share on other sites More sharing options...
Coupelx Posted April 21, 2011 Report Share Posted April 21, 2011 The revving is from the stock carbs sticking open. yep. its well documented on here. Quote Link to comment Share on other sites More sharing options...
muggzy Posted April 22, 2011 Author Report Share Posted April 22, 2011 yep. its well documented on here. Sorry, It's not the stock carbs sticking (at least in my case). Removing my wet prefilter (or the airbox cover) and the problem goes away with the wet material. Quote Link to comment Share on other sites More sharing options...
muggzy Posted April 22, 2011 Author Report Share Posted April 22, 2011 Now not to change the subject, but I have another twist to things. I always seem to get some gas back on my air filter (hillclimbing, fuel is always dumping out) Never get water in the box, but could a partially fuel soaked air filter cause these symptoms? Get off my thread. Lmk when you start your own and I have an (at least partial) explanation for you. Quote Link to comment Share on other sites More sharing options...
muggzy Posted April 22, 2011 Author Report Share Posted April 22, 2011 (edited) A little input for you. To get fuel out of the carb, there has to be air flowing through it. If there is no air flowing through the carb, fuel is not going to majically get into the engine. The engine will consume all the fuel that was in the crank case and go on a lean revving rampage!! Air is flowing through the carb, but some is being displaced by water. However, the venturi effect/Bernoulli's principle still works* and fuel is coming through the carb. or simply low air flow as if the choke were on in your lawn mower. This means that the air-fuel ratio is too rich (<14:1) for optimal combustion so we should have a rich condition that we would expect. What's getting into the the cylinder however, is somehow lean. *If you put pure water through the carb, it would still suck fuel up with it - think about a garden sprayer hooked to the end of your garden hose. Water still suckes bug killer/weed killer/fertilizer/whatever from the hose-end container (bowl) using exactly the same principle. Edited April 22, 2011 by muggzy Quote Link to comment Share on other sites More sharing options...
J-Madd Posted April 22, 2011 Report Share Posted April 22, 2011 Sorry, It's not the stock carbs sticking (at least in my case). Removing my wet prefilter (or the airbox cover) and the problem goes away with the wet material. Do you still have stock carbs? (Looks like it by your sig, but I thought I'd ask) How can you tell that they're not sticking? You can have 1 of them hang and the cable/thumb throttle will still have tension on it and you wouldn't necessarily notice. If you take off the box to look at the slides, they would probably unstick by what you're saying about the wet prefilter. Let me know if you've confirmed the carbs are not hanging. If it's not the carbs sticking, I'm lost. The water should actually increase the velocity of air in the carb by displacing space that would normally be occupied with air, leaving air to have to go through a narrower "tunnel" which should draw harder in the jets and pull more fuel and lead to a rich condition. Also (as you mentioned) by displacing air it should lead to a rich condition. Maybe the water on your filter is contaminated with nitromethane Quote Link to comment Share on other sites More sharing options...
KlotzBanshee Posted April 22, 2011 Report Share Posted April 22, 2011 I still feel its water getting through the carbs somehow, not through the filter. I had a very similar issue a few years ago and found that water was getting past the carb caps and/or running down the throttle cables and into the top of the carbs (boots were cracked and dry rotting at the time). I replaced the caps and put new rubber boots on the cables where they meet the sync adjusters and it never happened again. *And as for the guys who say go to Uni's and don't look back...I ran dual stage Uni's for years. And while I think they do a little better job filtering out dirt, when I put on a set of K&N pods it was like I pulled a cork out of my motor. I now use K&N's and don't look back. I just try to avoid the sloppy stuff when ridding. To me it's a worth while trade off for the increased flow of the K&N's. Good luck Muggzy. Hope you get it figured out soon. Keep us updated. Quote Link to comment Share on other sites More sharing options...
muggzy Posted April 23, 2011 Author Report Share Posted April 23, 2011 Do you still have stock carbs? (Looks like it by your sig, but I thought I'd ask) How can you tell that they're not sticking? You can have 1 of them hang and the cable/thumb throttle will still have tension on it and you wouldn't necessarily notice. If you take off the box to look at the slides, they would probably unstick by what you're saying about the wet prefilter. Let me know if you've confirmed the carbs are not hanging. If it's not the carbs sticking, I'm lost. The water should actually increase the velocity of air in the carb by displacing space that would normally be occupied with air, leaving air to have to go through a narrower "tunnel" which should draw harder in the jets and pull more fuel and lead to a rich condition. Also (as you mentioned) by displacing air it should lead to a rich condition. Maybe the water on your filter is contaminated with nitromethane Yep, carbs are stock. It just happened again yesterday after I washed her down. I went straight for the choke this time but that wasn't enough so I flipped off the kill switch and that shut her down. "How can you tell that they're not sticking?" to confirm or reject this idea, without doing anything else, and as gently as possible, I took the wet prefilter off the top of my airbox and removed the K&N filter from the ProFlo adapter. Looking straight down the throats of the carbs with a flashlight, both slides were bottomed out. Started and reran the engine first without the filter for a minute and then with just the K&N remounted - ran fine both ways. Put the wet prefilter back on and revs like crazy again. "Maybe the water on your filter is contaminated with nitromethane " Funny Quote Link to comment Share on other sites More sharing options...
muggzy Posted April 23, 2011 Author Report Share Posted April 23, 2011 (edited) I still feel its water getting through the carbs somehow, not through the filter. I had a very similar issue a few years ago and found that water was getting past the carb caps and/or running down the throttle cables and into the top of the carbs (boots were cracked and dry rotting at the time). I replaced the caps and put new rubber boots on the cables where they meet the sync adjusters and it never happened again. *And as for the guys who say go to Uni's and don't look back...I ran dual stage Uni's for years. And while I think they do a little better job filtering out dirt, when I put on a set of K&N pods it was like I pulled a cork out of my motor. I now use K&N's and don't look back. I just try to avoid the sloppy stuff when ridding. To me it's a worth while trade off for the increased flow of the K&N's. Good luck Muggzy. Hope you get it figured out soon. Keep us updated. Thanks Asswhore, yeah i double checked all of the rubber everywhere that wasn't checked by the leak-down test that I did a couple of days ago; throttle cable boots that pull down over the carb-top nipples, carb-top gaskets, and carb-to-airbox rubber. It's all mint. Nice and plyable with no cracks. I got a local performance guy that want's to take a look at it. I think I'm gonna give him a crack at it one afternoon this week and see what he can find. Edited April 23, 2011 by muggzy Quote Link to comment Share on other sites More sharing options...
ionroller Posted April 24, 2011 Report Share Posted April 24, 2011 Its definitely not a lean condition if the kill switch stopped it. Get rid of them stock carbs Quote Link to comment Share on other sites More sharing options...
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