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Help Help with a hesitiating/missing Across

Discussion in 'Suzuki 250cc In-line 4's' started by Arch_Althalus, Jan 17, 2019.

  1. Andych

    Andych Well-Known Member Premium Member

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    You have 4 separate inlet tracts and each carby has 2 mixture screws so you would need the 4 gauge unit.
    Have you done a bench synch on them?
    I found when doing mine originally even with a bench synch I got all the hesitation out by adjusting the balance between the 2 carbs.
    Mixture screws at 2.5 turns if I remember correctly.


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  2. Arch_Althalus

    Arch_Althalus Member Premium Member

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    I tried a bench balance but it wasnt successful so I am going to get the proper guages and do it. After getting a quote from a workshop for the balance and the valves I am going to do it all myslef. I can buy the tools and take my time and save hundreds. Ok. I will order a 4 guage system. Thanks.
     
  3. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    Get a Morgan carbtune, gauges suck. IMHO
     
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  4. Arch_Althalus

    Arch_Althalus Member Premium Member

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    Ok, sorry for the delay, but wprk and kids have kept me busy. My gauges arrived and I went to synchronize the carbs but number 1 showed no change when I adjusted the pilot screw. Pulled out again and cleaned again. For curiosity I swapped my emulsion tube between carbys 1 & 2. Refit and bingo, now carby 2 wont tune. I will be ordeing a full set of tubes once my pay clears and I may be on the road to having this problem sorted. Its been a very steep learning curve for a non mechanical person, but I have been loving it. I also fixed an issue where the electronic petrol cap would not open unless the bike was on, just needed a connection replaced. Fingers crossed this gets resolved after the part arrives.
     
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  5. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    Just checking, when you say pilot screw you mean???? The pilot mixture screw is what you adjust when setting your idle mixture and the stop screws or synchro screws are what you adjust when you want to balance the vacuum across the 4.
     
  6. Arch_Althalus

    Arch_Althalus Member Premium Member

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    Ok you have lost me. The 4 pilot screws are the only screws available at the top of the carbys, except for the screw to balance the left pair to the right pair. I have read through my workshop manual again and cant find the ones you are refering to. Any pictures would be appreciated. Thanks.
     
  7. Arch_Althalus

    Arch_Althalus Member Premium Member

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    Ok, i give up. I have had the carbys out 9 times, cleaned or replaced the jets abd needles. Replaced the clips, adjusted the floats, balanced the carbys each time, tested the seals and said many words that are probably not socially acceptable. Apart from the hesitation at low revs it is roadwaorthy and has rego, whats a reasonable price to ask for it?
     
  8. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    My gauges arrived and I went to synchronize the carbs but number 1 showed no change when I adjusted the pilot screw.

    You do not use a manometer or vacuum gauges to adjust idle mixture, so I was confused by your post.
     
  9. Cbuzz

    Cbuzz Well-Known Member Dirty Wheel Club

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    Can you take a pic of your carbs? I thought the Across carbs were 2 into 4?

    I had a very similar issue a few years ago when I went through my Across fetish :lolsign: & thought I posted a thread about it on here but I can't find it lol...
     
  10. Arch_Althalus

    Arch_Althalus Member Premium Member

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    Four carbs in pairs using a single diaphram to operate two slides. I have taken some pictures to list it for sale. Sadly I am done, I dont have much money left and I am out of time before uni starts. Never had anywhere near this many issues with my old zxr250c.
     
  11. Cbuzz

    Cbuzz Well-Known Member Dirty Wheel Club

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    Don't give up so easy man. You think pulling carbs 9 times is a lot ? I recall pulling mine approx 100 at LEAST over the course of a few months :lolsign: Don't bother with mechanics, they are a rip off & will take them 3 years to fix it (if they even can fix it).

    I won't even go into how many times I pulled my Zxr250A & bandit carbs....

    If you get it running you'll have invaluable knowledge & once it's tuned 100% you'll absolutely love them. They are great bikes, but can be a real PITA to get running perfect.
     
  12. Arch_Althalus

    Arch_Althalus Member Premium Member

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    Update. First I want to apologise for loosing my cool. Happens to everyone, but still should have handled it better. After choice words with the person I purchased the bike off, I was supplied the last repair list that states the compression is down on 1,2 &3. (On a side note apparently I need to work on using my compression tester). So I am now going to be stripping the body off and adjust the valves myself. Does anyone know a cheap place for a shim kit as I have looked at the diameter i need and am hesitant at the $150 price tag for the kits I have found? Again thanks to everyone who has been helping, I am learning heaps about the bike, myself and my vocabulary..
     
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  13. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

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    Measure your clearances and record the shim size (with a micrometer), from there you can calculate what size shims you need and how many. I use an excel spreadsheet to do mine.

    I get my shims from precisionshims.com.au
     
  14. Arch_Althalus

    Arch_Althalus Member Premium Member

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    Awesome.. thanks for the advice and the link.
     
  15. GreyImport

    GreyImport Administrator Staff Member The Big Cheese Contributing Member

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  16. Arch_Althalus

    Arch_Althalus Member Premium Member

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    So my shims arrived, I have replaced the ones that are out of spec, I have re fitted the cams and made sure they were 100% spot on the both position and the pins between the arrows. Everything is refitted and re working and this bike still has the hesitation/misfire at the same spot. WTF. Any other ideas would be greatly appreciated. The exhaust are all equally hot, so they are all firing and the carbys are fitted properly as they dont surge when hit with wd40. So not valves, not carbs, not spark, not air. Anything else? Please?
     
  17. Cbuzz

    Cbuzz Well-Known Member Dirty Wheel Club

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    Out of curiosity, where did you get the shims from ?

    when you install the airbox, do you take the filter out & put your hand in to ensure the lip is fully secure around the carb ?

    I noticed that with my airbox off or not seated properly mine runs like a pile of crap.
     
  18. Arch_Althalus

    Arch_Althalus Member Premium Member

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    I ended up getting a set of pro x shims covering all sizes I needed. It worked out much better value than buying just what I needed. I then measured each one before fitting to ensure the size was right.
     
  19. Cbuzz

    Cbuzz Well-Known Member Dirty Wheel Club

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    Double check your airbox where it connects to the carb on the underside of the lip. They tend to be very weak on the underside. I've seen a dozen across airbox's & most of them are buggered & need to be repaired.

    Got a link to the shims ? May need some shortly lol...
     
  20. Arch_Althalus

    Arch_Althalus Member Premium Member

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    I went through xtreme powersports. If they dont have stock they tend to get it overnight. Great to deal with.
     

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