hawkeracing Posted January 29, 2009 Share Posted January 29, 2009 I am new on the forum.....and I'm afraid that although I own a ZX10r I dont own a Yamaha of any description....I do however own a set of 3HE carbs from a 600 that I'm fitting to a project car.(believe theyre 1990) What I need to know is what are the fuel pipes coming of the bottom of the float chambers for and where do they go? There is a pipe attached to each of the 2 pairs of carbs......seems odd! Can anyone help? Link to comment Share on other sites More sharing options...
PICTURE_MAN36 Posted January 29, 2009 Share Posted January 29, 2009 Hello. I run a '93 FZR 600 which I believe is the '3HE' model. I will have a look when I get home for the manual, and will try to scan it for you. Cheers Link to comment Share on other sites More sharing options...
wild foamy Posted January 29, 2009 Share Posted January 29, 2009 well, on my DT they are fuel drains, i would think yours would be the same. does it run without them? Link to comment Share on other sites More sharing options...
hawkeracing Posted January 30, 2009 Author Share Posted January 30, 2009 Thanks.....all help is appreciated! When you say fuel drains, where do they go to? I dont know if mine will run without them as I need to sort out a few seals and things that are leaking....hopefully today. Its odd that they come straight out of the float chamber, I cant see why they would be needed, because the floats should cut the fuel at a set level.....so draining some out of the bottom will mean a constant flow of fuel (like an injection system) Link to comment Share on other sites More sharing options...
wild foamy Posted January 30, 2009 Share Posted January 30, 2009 not 100% sure how they work, but the drains basically would have some fuel pipe attached to it which would just direct the fuel away from the engine so it can be dumped somewere safe. Link to comment Share on other sites More sharing options...
hawkeracing Posted January 30, 2009 Author Share Posted January 30, 2009 Hang on....are you saying theres a pump removing fuel from the float chambers through the 2 pipes?? Surely if that was the case there would never be any fuel to run the engine on? Link to comment Share on other sites More sharing options...
PICTURE_MAN36 Posted January 30, 2009 Share Posted January 30, 2009 Hello. I think what Wild Foamy is saying is that they're overflow pipes. I've had it before with other small Yamaha carbs. If the float's in the chamber are not set properly, the level of fuel goes past the overflow point, and it drains out through the hoses you refer to. I haven't found my manual yet, but I'm reasonably sure that these pipes perform this function. If I could get to my bike (its buried behind the lawnmower etc in the garage) I'd have a look. Cheers Link to comment Share on other sites More sharing options...
hawkeracing Posted January 30, 2009 Author Share Posted January 30, 2009 If you could that would be great. The pipes are at the lowest point of the float chambers...below the fuel inlet, so they will be permanently piping out fuel. Link to comment Share on other sites More sharing options...
wild foamy Posted January 30, 2009 Share Posted January 30, 2009 they are at the lowest point externally, but inside they are connected to a brass tube which sticks up from the bottom of the carb bowl so in the event of an overflow the fuel level will have to rise above the height of the brass tube before it can flow down it and out the overflow pipe. Link to comment Share on other sites More sharing options...
PICTURE_MAN36 Posted January 30, 2009 Share Posted January 30, 2009 Correct. The floats work like the float in your toilet cystern. There's a brass tube that runs verticaally up the middle of the bowl. If the fuel rises higher than the top of the tube (Normally if the floats are damaged or they're not set properly) the fuel drains down the tube, and exits on to the pavement!!! In my halcyon teen days, if someone had dodgy floats on their '50' you had to make sure that you switched the fuel tap off when you switched the engine off, which was fun when you set off chasing your mates, as if you'd forgotten to switch the fuel back on you'd get about 30 yards, and the engine would start to die!! Hope this helps.... Cheers Link to comment Share on other sites More sharing options...
hawkeracing Posted January 30, 2009 Author Share Posted January 30, 2009 Unfortunately not so......Ive had the float chambers open and there is no tube.....they are exiting from the lowest point of the chamber. Link to comment Share on other sites More sharing options...
wild foamy Posted January 31, 2009 Share Posted January 31, 2009 hmm, can't be the fuel intake as i dont imagine it would flow directly into the carb bowl as that would defeat the whole purpose of the floats. are you sure it isnt a drain?, perhaps the brass tube had broken off/was removed. im all out of ideas Link to comment Share on other sites More sharing options...
hawkeracing Posted January 31, 2009 Author Share Posted January 31, 2009 Its very odd......Ive had a pair of them opened and there is no tube up into the chamber.......I have no idea what they are there for. There is a fuel feed, and a set of floats....normally thats all you get on a carb. For now i am going to block them off and see what happens! Unless of course someone thinks of a reason not to....or what they really do!! Link to comment Share on other sites More sharing options...
Moderator Airhead Posted January 31, 2009 Moderator Share Posted January 31, 2009 Could they be for an accelerator pump on one of the carbs, to connect this device to the other carbs? This is useful Here Link to comment Share on other sites More sharing options...
hawkeracing Posted January 31, 2009 Author Share Posted January 31, 2009 No, they are connected in pairs and looking at other ones for sale on Ebay there are 2 seperate pipes. There are user manuals for sale on Ebay.....CD roms at very cheap prices. The only problem is they have letter designations like c, l and w and I have no idea what the 3HE model is in terms of the a-z of Yamaha designation for the fzr!!! This one??? http://cgi.ebay.co.uk/Yamaha-FZR600-W-D-Se...A1%7C240%3A1318 Link to comment Share on other sites More sharing options...
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