90Bansheedude Posted August 28, 2015 Report Share Posted August 28, 2015 Ok, i am familiar with how to set float height and check the fuel level with a clear tube while the quad is running, done it on other quads. I set the float height when putting the shee together, but think 1 or both might be slightly off as i am trying to fine tune my jetting, and it tends to spill a little out of the overflow if it sits awhile, so i am trying to check the fuel level with the clear tube method. Here is a link to a smaller pdf of the carb stuff, the fuel level measurement is on page 9. http://bansheequad.chez.com/manuel_yzf350t_chapitre5.pdf Yamahas nice clear pictures and specs they give dont make sense to me. How i read it is.... the fuel level should be 3-4mm ABOVE the carb bowl to carb seam at the center of the carb, as the say "3-4mm Above the Carburetor Body edge". That seams way too high to me, isn't it? Or what are they considering the Carb Body Edge?? Right now, my left carb is about 2mm below and the right is pretty much on the seam or slightly above. According to how i read the specs, they both need to be raised, but then it will likely spill over even more, unless that is just sticky needle. I think the right side needs to go down, but i dont know. Anyone else messed with this or able to clear it up for me? Brian If you want to see my entire build, see it here. http://bansheehq.com/forums/index.php?/topic/146660-90-banshee-total-rebuild-project/ Quote Link to comment Share on other sites More sharing options...
90Bansheedude Posted August 28, 2015 Author Report Share Posted August 28, 2015 I set the float height when putting the shee together, but think 1 or both might be slightly off as i am trying to fine tune my jetting, and it tends to spill a little out of the overflow if it sits awhile, so i am trying to check the fuel level with the clear tube method I appreciate the response, but i already know that and mentioned that i already set the float height to the spec listed in the service manual. I want to verify the fuel level is correct by the clear tube method, but I cant seem to find much searching for it to verify were I think Yamaha wants it to be. Quote Link to comment Share on other sites More sharing options...
JTmachining Posted August 28, 2015 Report Share Posted August 28, 2015 Stk carbs? Stk intakes? Details help. If the needle/seat etc is good, then u jus need to adjust float height more Quote Link to comment Share on other sites More sharing options...
90Bansheedude Posted August 28, 2015 Author Report Share Posted August 28, 2015 They are Mikuni. I am pretty sure they are stock carbs without the TORS crap, just screw on lids. The overflowing after sitting is probably just ever so slightly leaking needles. I can readjust the floats, but i did them when i put them together. I always like to verify the actual fuel level to make sure it is running were it is supposed to be. Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted August 28, 2015 Report Share Posted August 28, 2015 I appreciate the response, but i already know that and mentioned that i already set the float height to the spec listed in the service manual. I want to verify the fuel level is correct by the clear tube method, but I cant seem to find much searching for it to verify were I think Yamaha wants it to be.If you do indeed have the height set correctly, and it still dribbles you need to look at the Needle and Seat. It may have crud on it or beginning to wear. So when the float goes up and presses the metering needle in to the seat, it may not be sealing properly. Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted August 28, 2015 Report Share Posted August 28, 2015 Also, make sure that the Vent tube is not bent ever so slightly. Quote Link to comment Share on other sites More sharing options...
90Bansheedude Posted August 28, 2015 Author Report Share Posted August 28, 2015 Yes, thanks, i am aware of that. My needle and seat may be old/worn, but probably only letting a couple drops per minute at the most. I still would like to find out if someone is familiar with testing the fuel level height outside of the carbs with a clear tube. Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted August 28, 2015 Report Share Posted August 28, 2015 Yes, thanks, i am aware of that. My needle and seat may be old/worn, but probably only letting a couple drops per minute at the most. I still would like to find out if someone is familiar with testing the fuel level height outside of the carbs with a clear tube.No real point, you need to have a float bowl that let's you put a line on it to see that. Or maybe you can try tipping it till the actual over flow line fills then hold the line up and see what happens... For real though. You keep saying you know this and that, but still have a problem. Just sayin'.... Quote Link to comment Share on other sites More sharing options...
90Bansheedude Posted August 28, 2015 Author Report Share Posted August 28, 2015 It is laid out in the manual on how to do this, but how i understand Yamahas measurements (being 3-4mm above the float bowl seem) doesnt seem right, thats why i am asking if anyone else knows anything about this. The carbs overflow nipple also serves the purpose for checking fuel level with the clear tube (as talked about in the manual), you just have to slightly crack the screws on the bottom that would drain the carb bowls down the overflow tube. Now i have cut smaller chunks of tube to slip on there and make easy to read both at the same time as they mention and am not using the bikes 2 into 1 overflow tube. I am fully aware of how to set float height (not checking the actual fuel level) and have cleaned, rebuilt, jetted many different carbs on different applications. Originally i thought the fuel level was too high causing it to go down the overflow, but now i think it is just after it sits awhile, which would mean that my needles are not seating 100%, which will not affect the performance of the quad if it is only a small amount, as it uses more fuel than it would leak past. This is why Yamahas mentioned fuel level seems to high to me, it is much higher than any other one i have done. Most or atleast alot of them are at or below the float bowl seam, not above 3-4mm like it reads in the manual. Does that make sense now what i am asking? I did this on my Raptor 660, and the specs make sense for it. It is actually a better method to fine tune your TRUE fuel level than just setting the float height, as the raptor has some performance gains by fine tuning it with this method. Not trying to raise a stink, just trying to get some clarification. Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted August 29, 2015 Report Share Posted August 29, 2015 I suppose. None the less, it's dribbling. If the needle and seat are good for sure, then move the tab on the float 1mm at a time till it ceases. These machines can be pretty simple to work on and they should be. It makes it easier to enjoy them. Try not to make things harder then they need to be as it can just create frustration. Quote Link to comment Share on other sites More sharing options...
90Bansheedude Posted August 31, 2015 Author Report Share Posted August 31, 2015 Ok, i just pulled them back off and rechecked the float height. They are both sitting at 21mm which is between their 20-22mm spec, although the left carbs actual fuel level when the bike is running is atleast 2mm lower than the left. This is why i prefer to check the actual fuel level, not just the float height. So Yamahas specs must be off on fuel level (not float height), as with my floats set at recommended setting, the actual fuel level is no were near the 3-4mm above the bowl to carb seam as it suggests. The left carb runs at about 2mm below and the right runs almost dead on the seam. I can cheat the left carb to 20mm float and right to 22mm float so that they will be the same actual fuel level height (which is what really matters), but I would still like to know were it is supposed to be. If for nothing else, peace of mind. So i will continue looking or waiting to see if anyone actually knows this. Quote Link to comment Share on other sites More sharing options...
hoppedupandcutdown Posted August 31, 2015 Report Share Posted August 31, 2015 what page of the service manual? I would like to check this out. Quote Link to comment Share on other sites More sharing options...
90Bansheedude Posted August 31, 2015 Author Report Share Posted August 31, 2015 Page 7 through 9 in this PDF http://bansheequad.chez.com/manuel_yzf350t_chapitre5.pdf OR chapter 5 page 6 (pg177) through chapter 5 page 8 in the full pdf or manual. Yes, that would be great to get a second opinion. Quote Link to comment Share on other sites More sharing options...
90Bansheedude Posted August 31, 2015 Author Report Share Posted August 31, 2015 Also, if some of you that are pretty sure your float height is correct want to check your fuel level via the clear tube method, i would be curious is to if any of yours meets yamahas 3-4mm above the seam spec. All you have to do is take your drain/overflow tube from the carb bowl and stick it up along the side of the carb in the center while it is running and loosen the drain screw just enough to get the fuel coming into the tube. Then make sure you dont have any air bubbles in it to mess with your reading. Quote Link to comment Share on other sites More sharing options...
hoppedupandcutdown Posted August 31, 2015 Report Share Posted August 31, 2015 I've also used this method on other engines and like it. I see where you found those specs. But also on page 5-1 same exact picture and says .5 to 1.5mm fuel level. I also see no need for it to be running for this test either. I read ALOT of manuals and instructions on many other things that just make you pull your hair out. Quote Link to comment Share on other sites More sharing options...
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