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Discussion Starter · #1 ·
I did the clear tube mods a couple of times now and it seems I get it perfect at the 3mm mark and when I start her up and run her for a bit. The fuel level goes whack and changes on both carbs. So im beginning to think I am doing something wrong somewhere along the line. So if anyone has some good tips or can help me on what keeps changing the fuel level please chime in and help. I am getting pretty sick of trying to accomplish this mod.
 

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If your having trouble getting the fuel level at the 3mm mark than try changing your needle valve's & seat's.I had trouble at 1st till I rebuilt the carbs..
Good luck.
 

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Yep had the exact problem when I was doing mine. Change out the needle valves and seats. The ring on the bottom of the seats are probably shot and letting fuel pass thru there.
 

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Discussion Starter · #4 ·
If your having trouble getting the fuel level at the 3mm mark than try changing your needle valve's & seat's.I had trouble at 1st till I rebuilt the carbs..
Good luck.

Yep had the exact problem when I was doing mine. Change out the needle valves and seats. The ring on the bottom of the seats are probably shot and letting fuel pass thru there.
Sorry guys I forgot to mention that I just rebuilt them with all new parts. My problem is not getting to the 3mm mark but keeping it there. I set the both carbs to 3mm and put everything on and start her up and what do you know the fuel level changed.
 

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Master of the Electron
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Vibration will cause errors in the apparent level in the tube - the fuel has to travel a long way to reach where you see the level in the clear tube, and the small passage in the brass overflow tube acts as a low pass filter (for those that have an understanding of engineering), so vibration can cause the level in the clear tube to vary randomly...

Bottom line, I wouldn't worry about it as long as it is at the correct level when engine is off and you don't notice fuel starvation when going up steep hills.
 

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Vibration will cause errors in the apparent level in the tube - the fuel has to travel a long way to reach where you see the level in the clear tube, and the small passage in the brass overflow tube acts as a low pass filter (for those that have an understanding of engineering), so vibration can cause the level in the clear tube to vary randomly...

Bottom line, I wouldn't worry about it as long as it is at the correct level when engine is off and you don't notice fuel starvation when going up steep hills.
Absolutely right, as long as it is right when you set them with the engine not running or set on the bench for that matter, which is the way I do them, that is the important part, engine vibration and fuel flow through the carbs will vary the level some..............
 

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Discussion Starter · #7 ·
Absolutely right, as long as it is right when you set them with the engine not running or set on the bench for that matter, which is the way I do them, that is the important part, engine vibration and fuel flow through the carbs will vary the level some..............
Thanks Quadmaniac and Willykiller but you both miss understood me let me explain myself a little more. When I set both carbs at 3mm and put everything back together and start her up and let her idle for some time i shut her up and the fuel level is way off? Willy can you explain it to me how is it that you bench set them both at 3mm. Please explain it to me like if I was 8 step by step so i can possibly get this right and if you have pics to go with it even better.
 

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You just have to take the tank and the carbs completely off. When you do the 3mm, the carbs have to be sitting on bench in the same position as if they were on your Raptor with your tank above it feeding it.
Does the fuel level not come back up at all to 3mm over time after you shut the bike off? Where is the level at shortly after you turn it off?
You know how you have the tube on there and you undo the bleeder screw, the gas shoots out and bounces around a little bit then slowly gets up to 3mm? With the bike running and using the fuel the floats shouldn't be moving around that much, so after you turn it off it might take a minute for that little bit of fuel to get back in there to be at normal level "3mm".

Just my thought on this...
 

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Vibration will raise the level of the fuel in the float bowls, when you shut the engine down, this fuel level will never recede until you either drain the fuel or start the bike again to draw fuel out of the carbs with the clear tubes in place. When there is excess fuel in the float bowls it will either drain from the tubes you are using to check the height or run into the engine..............
 

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Discussion Starter · #10 ·
Vibration will raise the level of the fuel in the float bowls, when you shut the engine down, this fuel level will never recede until you either drain the fuel or start the bike again to draw fuel out of the carbs with the clear tubes in place. When there is excess fuel in the float bowls it will either drain from the tubes you are using to check the height or run into the engine..............
Ok willy I am going to tray to drain the float bowls and reecheck the fuel level. Hopefully it went back into specs
 

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Discussion Starter · #12 · (Edited)
I'm sure you will find that the fuel level once it is set properly will stay where you set it....................
Dem I drained the float bowls and filled them back up and the fuel level is still pretty high on the left side and on the right side is a little low. I dont know why its changing everything is new? Plus Willy it seems that I am having a horrible time trying to get this Rappy to run right I dont know if these Dynojets are crap or what but from what I seen I see mostly every one runs Mikuni I think I should buy me some Mikuni jets? What jets would you recommend I buy with my mods on my sig? If you’re not sure throw in a couple of jet sizes It will help with shipping so I don’t have to keep buying different ones and have to pay for shipping again? I was thinking like 160L/165R or 165L/170R Mikuni jets. Thanks
 

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Master of the Electron
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Your DJ main numbers seem WAY high - for your mods DJ 146L/148R are what I've seen... the numbers you have in sig (stated DJ 160L/165R) would be about the proper Mikuni numbers.
 

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Dem I drained the float bowls and filled them back up and the fuel level is still pretty high on the left side and on the right side is a little low. I dont know why its changing everything is new? Plus Willy it seems that I am having a horrible time trying to get this Rappy to run right I dont know if these Dynojets are crap or what but from what I seen I see mostly every one runs Mikuni I think I should buy me some Mikuni jets? What jets would you recommend I buy with my mods on my sig? If you’re not sure throw in a couple of jet sizes It will help with shipping so I don’t have to keep buying different ones and have to pay for shipping again? I was thinking like 160L/165R or 165L/170R Mikuni jets. Thanks
Do you have the needles all the way up or down, you are saying the 5th notch............
Anyway, #25 pilots, needles half way up and 160 -165 mikuni mains.......
 

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Discussion Starter · #15 ·
Your DJ main numbers seem WAY high - for your mods DJ 146L/148R are what I've seen... the numbers you have in sig (stated DJ 160L/165R) would be about the proper Mikuni numbers.
Do you have the needles all the way up or down, you are saying the 5th notch............
Anyway, #25 pilots, needles half way up and 160 -165 mikuni mains.......
Ok guys thanks I will order some Mikuni mains. Willy at the 5th notch I mean starting from the top all the way down to the 5th notch. I do have #25 pilots in at the moment but my F**king fuel level keeps changing. So I got to get my fuel level right again. Any adias why it would change
 

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If it is changing beyond the norm, then the only answer is that the float valves are not seating correctly - it IS possible to bend the tangs in a way that forces the float needles out of alignment with the center bore of the seat - they need to slide smoothly in and out of the seat for them to work properly.

Take a look and verify that, when moving the floats up and down, that the needle is cenetered on the seat's bore, and that it doesn't hang up or jerk as you slowly move the float through its full travel... if it does bind or jerk, figure out whether moving the tang sideways would clear the bind. Not too common, but I've seen it before after a float level adjustment.

Also, just to be sure, carefully inspect the floats and make sure there's no liquid inside - a small leak can allow fuel into the float and change its bouyancy, which will cause float level to change over time.

Else, if the level is just changing randomly by a millimeter or two, and it isn't getting incrementally higher or lower over time, I wouldn't worry about it.

Everything about your sig setup and your needle description screams too rich, IMO - DJ needles that are much larger than I've seen with similar mods and the needles being in the full up (rich) position... I'd fully expect significant bogging between 1/2 and wide open throttle. Also, the fuel screws are normally set to near equal values - your's are different by 1.5 turns, which is HUGE. I'd bet that transition between idle and coming on throttle would be affected by this (unless you're way too rich on the needles, which I think you are)...

I suspect that getting your jetting in order, needles in the right place and fuel screws more evenly set will get rid of most of the bugaboos that you would be seeing.
 

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Discussion Starter · #17 ·
If it is changing beyond the norm, then the only answer is that the float valves are not seating correctly - it IS possible to bend the tangs in a way that forces the float needles out of alignment with the center bore of the seat - they need to slide smoothly in and out of the seat for them to work properly.

Take a look and verify that, when moving the floats up and down, that the needle is cenetered on the seat's bore, and that it doesn't hang up or jerk as you slowly move the float through its full travel... if it does bind or jerk, figure out whether moving the tang sideways would clear the bind. Not too common, but I've seen it before after a float level adjustment.

Also, just to be sure, carefully inspect the floats and make sure there's no liquid inside - a small leak can allow fuel into the float and change its bouyancy, which will cause float level to change over time.

Else, if the level is just changing randomly by a millimeter or two, and it isn't getting incrementally higher or lower over time, I wouldn't worry about it.
I think you might be right Quadmaniac on the needle binding on the tang. I will take them apart and inspect them. When the fuel level goes out of spec it will sit in the incorrect lever and not change at all so it might be binding. Thanks
 

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I added a bit more while you were responding, so read my previous post again, please...

Also, keep in mind that the level will not go down without running the engine - the float valves are one way only... it's like pouring soda into a glass - once you've poured Coke in, the only way to reduce the level is to suck on the straw - which is what the engine does with the jets.

If the needle binds, the bowl will overfill until the floating force is enough to overcome the binding force, then it will shut off and stay there until the engine sucks some out.

Does your level (when incorrect) always rise above the original set point, or does it randomly stop both above and below the set point?

Oh, BTW, don't spend too much time worrying about a minor binding in the float valves, because vibration, with the engine running, will almost always shake the needle around enough to keep it from binding... so this issue may just be noticeable when the engine is off.
 

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Discussion Starter · #19 ·
I added a bit more while you were responding, so read my previous post again, please...

Also, keep in mind that the level will not go down without running the engine - the float valves are one way only... it's like pouring soda into a glass - once you've poured Coke in, the only way to reduce the level is to suck on the straw - which is what the engine does with the jets.

If the needle binds, the bowl will overfill until the floating force is enough to overcome the binding force, then it will shut off and stay there until the engine sucks some out.

Does your level (when incorrect) always rise above the original set point, or does it randomly stop both above and below the set point?

Oh, BTW, don't spend too much time worrying about a minor binding in the float valves, because vibration, with the engine running, will almost always shake the needle around enough to keep it from binding... so this issue may just be noticeable when the engine is off.
Ok I just read your post over. The fuel levels stayed the same just if i had set them up that way. The left car is pretty high up I got a little fuel leaking at one point. The right carb is low. The carbs haven’t changed at all. As far as the needles, jets and fuel screws I just been messing with them for some time now so yea your right it runs like crap.
 

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Master of the Electron
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Okay, then check for binding, set the levels properly and leave em - close (within a mm or two) is good enough.

Change your jetting, needles and fuel screw as per our suggestions and you should be close to a good running quad again.
 
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