Author Topic: clear tube fuel level test (Read 4652 times)

screemn2 · « **on:** June 11, 2015, 02:39:02 AM »

trying to get my fuel level down in my pd46c to get my 78 550 running right and it seems that even if i adjust the float height up that my fuel level is still higher than it is suppose to be ....any thoughs on what the deal is ?... been leaving the bowl gaskets off to do the check being they swell and ya cant get them back on till they shrink for a couple days ..dont started at the spec off 12.5mm now at 15mm and still to high....what the heck ? and there is brand new k and l float needles in the carbs $:-\$

JeffM · « **Reply #1 on:** June 11, 2015, 05:47:22 AM »

Float isn't stuck on the bowl? Bike is level (not on side stand)? You're adjusting the tang and not the actual floats? How far off is it?

flybox1 · « **Reply #2 on:** June 11, 2015, 06:47:44 AM »

2.5mm higher float measurement surely would be noticeable
Look for a burr on the float tang where the float needle touches (it might catch on it), a rough float pin(smooth out with steel wool), or stuck float.

screemn2 · « **Reply #3 on:** June 11, 2015, 09:28:54 AM »

Thanks guys....one carb responded well the others not so much will be doon more this eve....pretty amazing that the spec for this carb is 12.5 mm and 15mm is appearing to be closer to what i need ....i think im gonna wear all the parts out just taking it apart and putting it back together $:-\$ ...oh well hope to get it right soon...and i will try to turn the idle screw out another turn ...thanks guys

flybox1 · « **Reply #4 on:** June 11, 2015, 09:36:23 AM »

you should be doing all your carb adjustments on the bench...and continue to do them on the bench until they are right.
make some sort of stand and aux fuel tank for them so you can test for fuel level.
only when they are right, do they get to go back on the bike

screemn2 · « **Reply #5 on:** June 11, 2015, 09:51:17 AM »

Thx flybox....im truly hoping that between the float height and idle screw adjustment it will become drivable....as i am quite puzzled about the whole gig $:-\$

flybox1 · « **Reply #6 on:** June 11, 2015, 10:03:55 AM »

I doubt just those adjustments alone will fix your issue, but they are a step in the right direction.
Once it idles and runs easier, youll need to move on to plug chops to get your main jet, pilot jet, and needle clip position correct.

The main reason we need to use the clear tube method to check for fuel level is the K&L float valves you put in are different enough (longer, stiffer internal spring, etc.) from OEM that fuel level is not ideal when they are used.
'by the book' float height is just a starting point when you use aftermarket float valves.

screemn2 · « **Reply #7 on:** June 11, 2015, 01:21:47 PM »

Plug chops? ...what the heck is that?

flybox1 · « **Reply #8 on:** June 11, 2015, 01:32:43 PM »

youre just getting your bike to run, but you will need to 'tune' each fuel delivery system (jet) in your carbs to match your intake and exhaust setup. PITA huh!?

Its why so many go back to stock carbs, airbox, and exhaust. you can set it an d(almost) forget it

a gas analyzer on a dyno is the best way to check air/fuel mixture in any given throttle position.
dyno runs are $$$, so, many of us rely on plug chops.

a plug chop is where you ride at a specific throttle position (jet), allowing combustion deposits to collect on spark plug insulators, The ignition is cut, to get a snapshot of that specific throttle position mixture..... looking at plug deposits, we can make a jetting change to better the mixture if needed

Quote from: flybox1 on June 09, 2015, 08:50:54 PM

when you post pictures of the plugs, we need to see down into the tips. Side view is not enough info.
A plug chop does not mean 'ride around for a bit' and then see what color the pugs are.
This tells you nothing.
Your carbs are comprised of several fuel delivery systems. Each system engages at different throttle positions. The systems also overlap....depending on your throttle position. Your spark plugs collect detonation deposits, and can give you an idea of what might be occurring inside your combustion chambers.
If you just ride around, you are collecting these deposits from many throttle positions, and many jet overlaps.
Your test needs to consist of a new.set of plugs, and 3-5minutes of a specific throttle position while the bike is under load, to collect deposits for that specific fuel delivery part(jet), so you know what change to make.

screemn2 · « **Reply #9 on:** June 11, 2015, 02:17:14 PM »

Whoa.....thats some.prtty deep stuff...i wonder if mine will ever run.... $:-\$

flybox1 · « **Reply #10 on:** June 11, 2015, 02:23:11 PM »

you can embrace it as a learning experience or treat it like a hurdle....

greenjeans · « **Reply #11 on:** June 11, 2015, 04:15:00 PM »

Do yourself a favor and get rid of those gaskets for some "no swell" gaskets.
The ones that swell, will, and in turn keep your floats from moving freely.
It really makes it easier to set things. Clear tube method is really the only
way to know exactly where your fuel level sits. Get rid of those gaskets.

screemn2 · « **Reply #12 on:** June 11, 2015, 05:25:36 PM »

Im embracing it flybox....can always use an education..love learning stuff...look sloke the fliat height is about perfect for all four carbs at 15mm..i hope i am going to get somewhere with this mess ive created...will do the idle screws as well like you had said...thanks for all the help bib i appreciate it

flybox1 · « **Reply #13 on:** June 11, 2015, 05:42:12 PM »

Clear tube method
http://forums.sohc4.net/index.php?topic=144256.0

screemn2 · « **Reply #14 on:** June 12, 2015, 08:33:16 AM »

Thanks flybox...gotcha..im spot on to the diagram that is shown there...built a bench jig just like you recomended...worked great..

flybox1 · « **Reply #15 on:** June 12, 2015, 10:32:48 AM »

Ok, have you done your valve adjustment, timing, and cam chain adjustment?
If yes, it's time to get your bike started and do a vacuum.sync of your carbs....

screemn2 · « **Reply #16 on:** June 12, 2015, 11:14:33 AM »

Timing double checked...valves double checked ...timing chain adjust havnt checked $:-\$ ...i know wete the adjustment is...but havnt touched it...is the a difficult procedure?....but when ready i do have the tool to vacumn sync the carbs

...and i love your cofidence about this thing running...these bikes must be extremly sensitive the changes...exhaust pods and stuff...as im more familiar with the automotive end of things..this is a whole new gig for sure...major education

flybox1 · « **Reply #17 on:** June 12, 2015, 04:20:21 PM »

Once you go thru everything a few times, these tasks get easier and easier, and sometimes you do the just for the hell of it

screemn2 · « **Reply #18 on:** June 13, 2015, 07:23:29 AM »

well flybox ....it appears as if ive gotten no where ...float levels perfect 2.5 turn out idle screw and all is the same thus far ...this thing has got me ...and got me good

....i do not no where to turn now ..and ideas ?...still only runs with choke nearly shut and fluttering a bit ...exactly the same as before.....am i missing somthing else ? the vaccumn line on top of the head is it ok that that is not plugged to anything ?... i am fricking lost with this thing ....ready to cover it up nd forget about it for now ...any thing else to check ?to at lest get it to idle ?...possible that it just wont run without airbox in place?....

calj737 · « **Reply #19 on:** June 13, 2015, 07:36:40 AM »

Did you take pictures of the fuel level? If so, can you post them?

screemn2 · « **Reply #20 on:** June 13, 2015, 07:45:12 AM »

i did not take pics cal but they are perfect as i did them on the bench with a jig i had made that was recommended 3 to 4 mm from gasket surface on all .....starts first kick ..same as before ...nothing has changed ... im so bummed

dusterdude · « **Reply #21 on:** June 13, 2015, 01:12:05 PM »

Have you confirmed the size of your pilot jets with a drill bit or other suitable measuring device,dont ask why i suggest this

screemn2 · « **Reply #22 on:** June 14, 2015, 04:12:50 AM »

I have not done that duster...the main jets are new from k and l 105..the idle jets are the stock42...but no havnt measured nothin

dusterdude · « **Reply #23 on:** June 14, 2015, 06:33:47 AM »

I had what i thought were 38's in mine and the motor kept sootin up the plugs real bad,after spending money on a new ignition system,cals carb guru figured out my jets were hogged out big time

flybox1 · « **Reply #24 on:** June 14, 2015, 06:54:14 AM »

Describe how you bike idles now.
Are you able to complete a vacuum sync?

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Author Topic: clear tube fuel level test (Read 4652 times)