LiftdT4R Posted August 11, 2009 Report Share Posted August 11, 2009 Hey, what's up? Ive always wondered, and never asked, on almost any set of carbs I take apart, dirtbike, quad, almost anything, I always come across a plastic umbrella type piece that sits in the main and pilot jet. Its on stock Banshee carbs. Ive never thought anything of it, and always put it back in after taking apart carbs. But, I got into a heated argument with a buddy of mine over what it does and how nessiscary it is. I didn't really have an answer other then Yamaha put it in there so I keep on using it. (not a great answer). I was wondering if anyone knew what the purpose of this piece is. It's part # 18 on the microfiche below. Quote Link to comment Share on other sites More sharing options...
zach45 Posted August 11, 2009 Report Share Posted August 11, 2009 i think that they are splash guards... i dont have em in my bike. Quote Link to comment Share on other sites More sharing options...
tundish2800 Posted August 11, 2009 Report Share Posted August 11, 2009 they are splash guard i thought everyone took them out? Quote Link to comment Share on other sites More sharing options...
slopoke Posted August 11, 2009 Report Share Posted August 11, 2009 yep thats what it is. It works a a baffle Quote Link to comment Share on other sites More sharing options...
LiftdT4R Posted August 11, 2009 Author Report Share Posted August 11, 2009 Good to know, I guess I wont put them in on the next time around. What exactly does it do though? Prevent fuel in the bowls from splashing into the main/pilot? My YZ80, and 250s have them too, and so do most bike Ive seen. Quote Link to comment Share on other sites More sharing options...
FireHead Posted August 11, 2009 Report Share Posted August 11, 2009 Good to know, I guess I wont put them in on the next time around. What exactly does it do though? Prevent fuel in the bowls from splashing into the main/pilot? My YZ80, and 250s have them too, and so do most bike Ive seen. They are stop aeration and cavitavation around the jet sump. They also sort of complete the jet sump..... ..........and, as said before, they need to be installed. :geek: Quote Link to comment Share on other sites More sharing options...
LiftdT4R Posted August 11, 2009 Author Report Share Posted August 11, 2009 They are stop aeration and cavitavation around the jet sump. They also sort of complete the jet sump..... ..........and, as said before, they need to be installed. :geek: Ohhhh, makes sense, but every post before yours said don't run them. I'm trying to remember back to my days in school as to what factors cause cavitation, the only one that comes to mind is when the velocity of the liquid is to high. Does this actually occur in the stock carbs? I cant imagine the fuel flowing through there fast enough to cause cavitiation, but I really wouldnt know. Also, when you say aearation, what is that? I would think you would want the fuel to be better aerated. (mixed better?) Quote Link to comment Share on other sites More sharing options...
LiftdT4R Posted August 15, 2009 Author Report Share Posted August 15, 2009 Firehead where are you???? Quote Link to comment Share on other sites More sharing options...
bansheesandrider Posted August 15, 2009 Report Share Posted August 15, 2009 I don't think they do anything to prevent cavitatioin, but they do prevent aeration. You don't want aeration in your float bowl, you want it in your venturi and intake tract. Your jets are supposed to meter fuel, not air. If you have air bubbles in your fuel, how is yourjet going to do a good job of controlling your mixture. It is probably OK to remove them on a drag bike, but I would leave them in on any bike that is ridden on something other than a smooth track. Quote Link to comment Share on other sites More sharing options...
LiftdT4R Posted August 15, 2009 Author Report Share Posted August 15, 2009 I don't think they do anything to prevent cavitatioin, but they do prevent aeration. You don't want aeration in your float bowl, you want it in your venturi and intake tract. Your jets are supposed to meter fuel, not air. If you have air bubbles in your fuel, how is yourjet going to do a good job of controlling your mixture. It is probably OK to remove them on a drag bike, but I would leave them in on any bike that is ridden on something other than a smooth track. Ohhh, I see what your talking about on the aeration part, makes sense, I personally always leave them in, just wondering what they were always for. Quote Link to comment Share on other sites More sharing options...
AKheathen Posted August 16, 2009 Report Share Posted August 16, 2009 the vibration of the engine mixed with bouncing around the trails, and up/down/sidehilling would make it suck bubbles without them. the vibration alone, while the jet is sucking could create a cavitation effect, if the fuel wasn't dampened by that little chamber. Quote Link to comment Share on other sites More sharing options...
FireHead Posted August 16, 2009 Report Share Posted August 16, 2009 Ohhhh, makes sense, but every post before yours said don't run them. I'm trying to remember back to my days in school as to what factors cause cavitation, the only one that comes to mind is when the velocity of the liquid is to high. Does this actually occur in the stock carbs? I cant imagine the fuel flowing through there fast enough to cause cavitiation, but I really wouldnt know. Also, when you say aearation, what is that? I would think you would want the fuel to be better aerated. (mixed better?) Aeration is cavitation. I just figured that no one would know what I was talking about if I said cavitation. An engine probably runs fine without them, but there is a reason (previously stated) that is there and it makes sense. It may not make a difference in the short term, but in the long term there will be less jet errosion and a better fuel pickup (not sure if you could see a difference on dyno or not. I suspect people are saying not to run them, because they took them off and it didn't seem to matter. If someone has any other reason, I would be happy to hear it. Sorry for the lat reply..... I am not on here much at the moment due to the truck business not being very good and my company taking away my Blackberry for cost saving. Quote Link to comment Share on other sites More sharing options...
tundish2800 Posted August 16, 2009 Report Share Posted August 16, 2009 I took them out they take up space in the bowl. Less plastic more fuel Quote Link to comment Share on other sites More sharing options...
FireHead Posted August 16, 2009 Report Share Posted August 16, 2009 I took them out they take up space in the bowl. Less plastic more fuel Plastic vs. fuel volume difference is probably not worth talking about...... :geek: Quote Link to comment Share on other sites More sharing options...
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