Seriously, take it from me, I did these a few weeks ago. Spent hours faffing around on the bench trying to set the float heights and its so much easier to just do it with the carbs on the bike, plus it has the benefit of having the carbs at the correct angle and putting the float needles under fuel pump pressure so there are no variables. Put the bike on a paddock stand so its level, pull off the tank and airbox and if possible hook up an auxillery tank. Then pull off the float bowl and mark the 9.2mm on it, then just check the levels with some tubing and adjust as you go, its simple enough but time consuming and the screws for the no4 carb bowls is a bastard to get at with the frame in the way.
Yeah that's how i've done it previously on this bike but you cant see how exact it is With the bike on a paddock stand that raises the rear wheel 45mm off the ground, so the bike is no longer level, i had to put some wood under the front wheel at the same time as the rear on a stand to get the bike back to level again
i get what you mean, you cant get eye level with it. the main problem i found with setting the floats rather than the fuel level was when you hold the carb at the correct angle, the float needle comes out of its seat, so its hard to measure exactly when the tip compressess. its hard to explain what i mean so i recorded it on my phone, link below. https://drive.google.com/file/d/0B-6LVdXzRTTGcTNmQVNnZmN0b1U/view?usp=sharing
Excuse my laziness at not re-reading the entire thread, but have you installed new needles/emulsion tubes? Your woes sound remarkably familiar - I know many years ago I eyeballed my emulsion tubes with a drill also and incorrectly diagnosed them as good, then others found new carb kits, fitted new emulsion tubes and problems solved. Consider a virtually imperceptible amount of wear with the needle occupying the emulsion tube hole at idle, any wear of the tube will significantly change the fuelling at idle, changes at higher RPM will be imperceptible
It's a lot easier to set the float level's with the float assembly in your hand, compared to doing it on the carby/bike Yeah the carb's have had a thorough clean out and i used new full Keyster kit's in them, so it's got all new fuel jet's, air jet's, needle's, emulsion tube's, needle and seat, o ring's and gasket's etc etc, the 4x diaphram's look like they've been replaced, top o'ring's are new, plastic diaphram cover's have been faced, slide's are all good, intake manifold's are all good eg no crack's / no leak's after testing with engine running and spraying them all over with carby cleaner Tried numerous mixture screw setting's and changing idle speed to check the throttle plate's were as close to closed as possible
OK just to put the cat amongst the pigeons - someone else remarked that the keyster needle/seat valve wasn't much chop they found some difference in the spring strength, so there's a possibility that your float height is perfect, and the needle may not be shutting the fuel flow correctly checking the fuel height with the carbs fitted and fuel pump providing you the actual pressure will give you the best information at this point
Yep, so carby's need to come off the bike, be set up at correct angle on the bench with pump connected and then i can check fuel level's
cool, keep us posted, and put up some pics of your rig. Im only a couple of steps behind you at the moment so its nice to know the pitfalls in advance. unlike this poor zeal owner i came across a few weeks back: http://www.bow-miaow.0j0.jp/garage/zeal-yumen/ someone needs to tell him
Check this post for the pic of how I used to check fuel height https://2fiftycc.com/index.php?threads/my-fizzer.872/page-32#post-15537 It's really simple to do with just the tank removed I got so used to bad behaviour that I just left four of those attached and then I could check with just a screwdriver and a flashlight. It did help me once with a blocked fuel filter. However as it wasn't fuel height causing idling issues it was a classic case of not seeing the wood for the trees
I fixed my cracked windscreen today. I went down to the wrecker's the other day and had a look through their old screen's, i found one off an old ZXR750 that was about the same size as the FZR, it's made by Panlite and has DOT approved on it, the condition wasn't that good, scratched, scuffed and faded but it was only $20 so i bought it. Today i rubbed it back and polished it, came up well, next thing was to take the old screen off and sit the ZXR screen up against the fairing and mark it up to cut. It only needed about 25mm to be trimmed off the bottom edge, and the hole's to be redrilled. That took a hour or so and i've got it bolted back on ready to go now, hopefully it last's a bit longer than the cheap china screen's that are only 2mm thick, the ZXR750 screen is 3mm thick and has a 6mm thick bead running across the back.
I changed the float levels to 15mm this afternoon and just took it for a quick ride. It seems to be a bit better again, depending on how it goes when i take it for a longer ride tonight i might have to raise the floats to 14mm. The fuel levels are roughly 9mm-9.5mm now but i cant tell exactly as i left the carbys on the bike. Mixture screws are at 2.75 turns out.
Check me on this - was there a change in fuel height from 3LN1 -> 3LN3 & 5 and the zeal also? Reason I mention it is because somewhere in there is a Yam 250 where the fuel is 10.5mm so that would make the float height 14.7mm for that bike, based upon what I found that with a float height @ 16mm the fuel level was 9.2mm for the 3LN1 So you may be headed in the right direction...
Yep they might be different, i can't remember seeing a fuel height listed for the 3LN3 5 or 6 in the 3LN supplement. That Zeal thread beano linked above has the fuel height at 10.5mm Although his pic's show it being 10.5mm below the line ? I read on another Zeal blog that the service manual had it wrong and it should be 10.5mm.
Took the bike out for a longer ride, it's definately going better again I think the fuel level still need's to come up a little though I might have another go at it over the weekend
i didn't get around to adjusting the float level's over the weekend But i did take the top tripple clamp off and cleaned it up, i filed back all the casting burr's to give it a smooth finish and then bead blasted it, gave it a coat of black etch primer and then 3 coat's of gloss black I'm not sure if i'll keep black now, it does seem to make the bike look longer though ? @Joker do you remember what your float height's are set at or your fuel level's are set at on your 3LN3 ?
Not off the top of my head. I'm starting to put the engine back together now. I've never actually bothered checking the float heights (I have the philosophy if I don't want it broke I should not touch it lol)
I've been doing a bit more research on the 3LN3 float/fuel level's. I found some post's on a Zeal blog saying the float's should be set at 13.7mm, and the mixture screw's at 1.75 turn's out Also i've been trying to find a decent wiring diagram for the 3LN3, to see if running the COP coil's off an extra relay will help at all. It look's like the coil's run directly off the fuse box, powered when the ignition switch is turned on. I found this wiring diagram for the FZX250 Zeal, and i guess the FZR250 would be very close
Here's an english diagram for the zeal, if it helps https://2fiftycc.com/index.php?resources/yamaha-fzx250-zeal-wiring-diagram-english.223/ What would the relay do in regards to the coils? Fire only one plug at a time instead of two? I'm about to start the coil on plug conversion on my ZXR
No, from what i have read it seem's there is a voltage and current drop to the COP coil's when using the standard wiring from the TCI This can cause the COP's to run at 85%, but apparently they still put out more power than the original coil's. My FZR has a .3v drop between the battery and coil's, i'm trying to work out if a relay and new wire's to the positive side of the coil's will solve this