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Help Adjusting mixture and multiple bike starts.

Discussion in 'Maintenance' started by DieDemon, Aug 1, 2020.

  1. DieDemon

    DieDemon Member Premium Member

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    So a quick one, I'm sure there is a simple stupid answer.

    The short question: How do you guys get around draining your battery when trying to get a bike started after its been sitting for a long long time?

    The long question: I'm adjusting my mixture on my bike as I've just cleaned out the carbs and replaced the fuel line and filter after it having a rusty fuel from sitting around. The problem is the bike is taking a lot of guts to start so its draining the battery. At most I can get 5 starts out of my bikes battery, a jump pack and a car battery. How does everyone get around this because after I've drained everything I'm forced to call it a day?
     
  2. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    Do a compression test please.
     
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  3. ShaneP

    ShaneP Well-Known Member Premium Member

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    You're draining a car battery in 5 start attempts? Is your starter melted? If your jump leads are not good enough, you may be only drawing a few amps out of the car battery and relying on the bike battery for most of the current. Less than 12.4V is a flat battery, make sure your battery is charged up properly and that you car battery is working properly.
     
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  4. DannoXYZ

    DannoXYZ Active Member

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    Stop cranking it so much! If it doesn't start in 5-10 seconds, something is WRONG with bike. Continually cranking it will not remove corrosion from wire, will not fix worn-out crank-sensors, will not replace plugs or plug-wires for you, will not clean dried petrol plugs from carbs, will not scrub carb-passages clean, not not ultrasonically soak your carbs, will not replace worn rubber carb manifolds or plug rips and holes in them, etc.

    So, after 2-3 attempts, max, STOP the INSANITY!!! Doing same things over and over again expecting different results. Instead, pull out multimeter and test all electronics, all switches, measure resistance of each and every single wire end-to-end. Pull out vacuum-gauges and measure manifold pressure. Something is WRONG with bike, fix that problem and symptoms of difficult starting and dead batteries will go away!

    To prevent destroying batteries, keep it on smart-charger full-time 24/7. When cranking, use jump from extra battery or car battery (car off). Charged car battery should let you crank bike for 5-minutes straight. You'll fry and burn out starter in that time and bike still won't start because problem is not battery or starter. Find actual problem and fix it. Then bike wil start easily.
     
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  5. DannoXYZ

    DannoXYZ Active Member

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    BTW - "cleaning" carbs is more than just spraying "carb-cleaner" through jets. Really needs complete disassembly down to every single component and scrubbing everything until it's factory-fresh clean. Use nylon brushes to scrub out all hidden fuel-circuits between jets and carb-venturi. Use PEA-based fuel-system cleaner mixed with acetone to brush out passages. Replace all rubber O-rings and seals (pilot adjustment O-rings), fuel-rail O-rings, float-valves, float-bowl seals. Soak in ultrasonic cleaner for 4-6 hours. Scrub with brushes again. Poke soft copper-wire of matching diameter through all bleed-holes. Finally, micro soda-blast to clear out all circuits of flake crud you've dislodged with scrubbing.

    Bike ran perfectly fine off showroom floor with carbs in factory-fresh clean condition. Fact that it doesn't run that way now, means carbs aren't factory-fresh clean. Many, many people have had to pull their carbs 4-5x for ever deeper cleaning and bike finally ran like new. I suggest not doing that and going with full restoration on next attempt.
     
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  6. DannoXYZ

    DannoXYZ Active Member

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    Yeah, and do compression-test and post numbers you got here.
     
  7. DieDemon

    DieDemon Member Premium Member

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    Ok I'm taking advice. First bike I've seriously worked on so I'm learning. Originally I read through a member Linkin project bike post on this forum which is the same model as mine.
    https://2fiftycc.com/index.php?threads/linkins-gsf250v-bandit.10448/page-2
    He said "Went through the service data and found the mixture screw standard settings - 1.5 turns out. Straight away I knew they were going to be at waaay more than that out... and they were... 3.5 turns :headbang:

    Set to 1.5 out and ran it, lazy throttle response and hanging idle. Another 1/4 turn out was better, good throttle response and good, smooth feeling on the road. Revs cleanly and returns to idle nicely."
    So thats where I got that idea from. Anyway

    I've cleaned my spark plugs, all the wiring looks good barely any rust or wear. I cant really do much more apart from a full compression test and running over the wiring with the multimeter as I'm waiting on a carb rebuild kit (as shown in the pic). Will get back to you with compression numbers as I ****** it up have to get the end of my compression nozzle out of the spark plug hole.

    Will get back to you with how it all goes.
    Thanks for the advice.
    [​IMG]
     
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  8. DannoXYZ

    DannoXYZ Active Member

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    At stock 1.5-turns out on pilots, it should run like brand-new. Hanging idle is sure sign of lean-mixtures. Cause is dirty carbs. Previous owners tried to make up for dirty carbs by unscrewing pilots more to compensate. But it only works somewhat. Similar to desperate measure of installing larger-jets by many people to make up for clogged carb passages. But it's not really fixing really problem.

    Be sure to get variety of nylon scrub brushes and solvents to scrub out fuel-circuits beyond jets. Each and every one of jets has passage behind it that leads to carb-venturi. You'll want to scrub path of petrol entire way. I posted some pictures of types of fuel-circuits involved that needs to be scrubbed here: https://2fiftycc.com/index.php?posts/135362/
     
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  9. ShaneP

    ShaneP Well-Known Member Premium Member

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    Don't clean spark plugs, just replace them. Too easy to have a short up the core when under compression - you'll get a spark when the plugs are out, but not when in the bike.
     
  10. DieDemon

    DieDemon Member Premium Member

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    Hey for those guys asking finally did a compression test. Cyl 1: 75 psi Cyl 2: 75 psi Cyl 3: 70 psi Cyl 4: 80psi.

    Also this probably isn't so good on the end of my compression tester.(see pic)

    IMG_20200804_155445155.jpg
     
  11. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    We've just had someone else with incredibly low compression numbers, although consistent - turns out the issue wasn't compression at all, BUT the location of the schrader valve at the gauge meant that the volume of the hose lowered the numbers in the results
    His bike wasn't firing on 1 cylinder for another reason besides compression.

    Read here
    https://www.2fiftycc.com/index.php?threads/fzr250-project.10828/page-9

    Don't know if your compression tester is the same, but you've got consistent numbers with low readings on all 4

    If you do the numbers, you've got ~5 atmospheres pressure
    5:1 compression
    Swept cylinder volume is 62.5cc, compression ratio 12.5:1
    Cylinder head volume is 5cc
    If that tube has a volume of ~7.5cc before the schrader valve you'll get damn close to the compression numbers you have and there aren't any problems with the rings
     
  12. Andych

    Andych Senior Member Premium Member

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    Realistically, if you do the test properly the hose will have little to no relevance unless is is super cheap hose that bulges with each compression pulse.
    You will find that on a cold engine.. the numbers will be down.
    You need to
    A Make sure you have the carbie off or you are able to hold the throttle wide open with slides up.
    B Keep spinning the engine (with all plugs out) until the needle stops moving on the gauge.
    C Check it dry.. then again with a squirt of oil to check the difference in readings.
    D Dont bother with a Compression test... do a Leak Down test... it gives you a much better read on what is going on..
     
  13. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    Yes, a leakdown test would be nice. Gee, we're never satisfied are we? :)
    At least your numbers are consistent.
    Cold engine start is no throttle and choke fully on.
    Hot engine start is no choke.
    Mixture screw on those carbs is a fuel screw. 'n' turns out is just a guide. If you can't do it by ear https://litetek.co/Guide_FuelScrews.html then set them all the same and keep experimenting until you are happy. If the idle hangs with a hot engine then it is too lean.
     
  14. Andych

    Andych Senior Member Premium Member

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    Nothing wrong with a Compression test if done correctly with good quality equipment... where a cheap Leak down tester will give you all the info you need rather than relying on a squirt of oil..
    As for the Carbies, their overhaul and settings... I defer to @maelstrom every time... and his gear (litetek) is the best on the market... bar none.
     
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  15. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    Well thanks Andy but there is always someone that knows more than yourself. @kiffsta is very quick to get these oldies up and on their feet in no time. Most of our problem comes from trying to help each other online. Not like being there.
     
  16. DieDemon

    DieDemon Member Premium Member

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    Yeah my first thought was at least I'm getting the same numbers across everything. Taking the head off to do valves and rings seems to be its own pig.

    I found a pic online of my compression tester the schrader valve is on the end of the hose itself not on the gauge. I borrowed it from a guy who works on 50s cars so I assumed there wasn't anything up with it.

    As for an ultra sonic cleaner for the carbs I'll have to buy one.

    For the test itself I probably did it wrong I had the carbs on with no throttle or choke. Ill do it again today with the carbs off and ill post those numbers, hoping for a good outcome.
    1259586505.jpg
     
  17. DannoXYZ

    DannoXYZ Active Member

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    no, the bleed-valve is that right-angle thing sticking out just below gauge. What this does is include volume of hose into combustion chamber and gives artificially low numbers.

    I used similar gauge to test my turbo Porsche 951 with 8:1 compression and it reads 150 psi.
    Use exact same tester on my Ninja 250R with 12.4:1 compression gives me 140psi, WTF?@!!! Manual says 195psi!!!

    Well, since volume of hose is fixed, it contributes to larger errors on smaller combustion chambers. Small 250cc 2-cyl engines have smaller combustion chambers, it throws those reading off more. And even smaller 250 4-cyl would have smallest chamber and largest error.

    yeah, repeat with carbs off and let's new numbers. Engine's most likely fine since it's even across board.
     
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  18. Andych

    Andych Senior Member Premium Member

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    Dont get hung up on the actual numbers you get from the compression test... dont bother to try and compare your numbers with those from the manual either... it just isnt relevant. What you want to compare is each cylinder to the other.. they should be very close to each other.
    The reason to take the carbs off is to allow air into each cylinder. With the carbies on the bike and the throttle closed you severely limit the amount of air that can enter the cylinder.
    When cranking the engine for each test.. make sure you keep cranking (with a booster on the battery) until the gauge stops climbing.. with all your plugs out it should only take 10 to 15 seconds each cylinder... and write down the readings.
    Then do it all again after a quick squirt of oil... tis will help seal up the rings if there is any blow-by.
    As I said before.. if you think there is a problem with either a head gasket, valves or worn pistons.. see if you can borrow a Leak-down tester.. it will tell you all you need to know. All the compression test will do is you if all the cylinders are doing the same thing or not.

    As for an Ultrasonic cleaner... unless you are going to keep on doing carbies dont bother. Better to spend you hard earned $$ on spares for the bike than on tools you might never use again.
    You can get a great result by being meticulous without using an Ultrasonic cleaner.. a few cans of Threebond (should be able to get it in NZ) and either an Air compressor or a few cans of compressed air and some patience and you will get there.
     
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