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looking for carb sync kit

Discussion in 'Modifications and Projects' started by oohsam, Dec 1, 2011.

  1. Hey guys,
    Im going to rebuild my carbs tonight and I am chasing a carb sync kit.
    Autobarn and Repco have no idea what they are...great help. Not sure where to find them.
    Peterstevens said they havnt seen them in years ???? what the ?

    If someone has a kit that I may borrow for a day or two (or buy off you) or if you can tell me where to get it that would be great.

    May look like this


    or this
  2. I've called everywhere. I cant find these pricks anywhere...what the hell!
  3. I mail ordered the Morgan Carbtune from the UK. It arrived in about 10 days. Would have been less if Customs hadn't decided the package looked suspicious and decided to open it for a look. Haven't used it yet though.

    Failing getting the commercial kit (I would have thought that any half decent bike accessory shop should have one), it's not too hard to make up your own manometer from winscreen washer tube, plastic tee pieces, aquarium needle valves and coloured water. As long as you get all the joints airtight it will be as accurate as anything you can buy that doesn't contain mercury and almost certainly more accurate than a set of Chinese clock gauges as illustrated in your first pic.

    The only difficulty arises if your carbs don't have convenient little pogs to stick the hoses on. The commercial kits provide screw-in adaptors for when this is the case. Going the DIY route requires some improvisation.

    There have been threads on this on NR so try a search.
  4. Thanks Pat.
    yeah my float bowls have a screw in teh bottom of them. I've seen some ingenious self made ones, but I just dont trust myself to make it accurate enough.
    Might have to buy a morgan carbtune. I do like them mercury ones.
  5. PS. Have called 8 motorbike shops. No one has them!
    The motion pro ones are garbage from what I heard.
  6. My Mercury ones have developed bubbles,its slighty better now that I have sealed a couple of tiny leaks,lots of fun buying Mercury to top them up,MCA used to sell small bottles but now its like Plutonium,bloody hard to get,scary scary.I wasnt considering drinking it.
  7. Google "DIY Manometer"

    Easy. I have vacuum gauges, but I prefer the two spag bol jars & tubing approach.

  8. A screw in the bottom of the float bowl is unlikely to be the balancing port. I'd expect it to be somewhere between the throttle butterfly and the stub on the carb that goes into the intake rubber on the head. Or, depending on the bike, on the intake rubber itself.

    As for accuracy, as long as you get all the joints airtight and gravity is not tilted, a U-tube manometer is physically incapable of being inaccurate. Further, if you use coloured water rather than mercury it will be insanely sensitive. That can make it awkward to use but, by the same token, a carb imbalance that would result in a 1mm difference in the heights of mercury columns will translate to a 13.6mm difference in the heights of the water columns. Water will jiggle about more though, so it probably evens out in the end.

    The dial type jobs are only useful if you calibrate them yourself. It's not particularly hard to do but it's a certain amount of stuffing around.

    The trick is to understand that you are not looking for an absolute figure but you are looking for differences between the carbs/gauges. That means that all the gauges must respond identically to vacuum. This happens automatically with a liquid column and, to a lesser degree of reliability, the steel rods of the Carbtune. However, analogue gauges, particularly analogue gauges made to Chinese tolerances (and they will be Chinese) are not self calibrating.

    The easiest way I can think of to calibrate a set of vacuum gauges would be to connect each gauge in turn to the vacuum port of (say) No1 carb and note the readings at idle. They should all be the same. They won't be. But you now have an indication of how different the reading of each gauge is when subject to an identical level of vacuum. This allows you to apply a correction factor to each gauge reading when you are actually doing the balancing job. It will get you pretty close.

    Another means of balancing carbs which works well on twins and should be doable on fours is to pull (or short) each plug lead in turn and note the rpm drop. Big drop means cylinder is doing more work and carb should be turned down. Small drop means cylinder is doing less work and carb should be turned up. If the rpm drop is equal on all cylinders, the carbs are balanced. Some caution is required though as many modern ignition systems don't like being fired without the HT lead being earthed to give the volts somewhere to go. I've never blown a black box by pulling a plug lead off (had a few :shock: though :D) but that is not to say it can't happen.
  9. I think Repco had them for sale, though I could be wrong, I know a few Honda mechanics who own a set but they generally have them permanently built in to thier bikes.

    I am going to try a POSA manifold and a single carb - just because I can!
  10. if you do it the home method, i found that you can get reticulation fittings from bunnings that have one end that will slide into aquarium tubing and another end that will screw into the hole on the manifold
  11. Make them.

    For a twin you just need a long piece of tube. For a four you need to join pieces of tube with T pieces.

    Fill them with transmission fluid (coloured so easy to sea/read) but you could use any fluid, oil, water, beer.... and mount them on a bit of board so the tube doesn't flop all over the place, I used a bit of white board so the coloured flid stands out.

    Total cost about $5 for a twin and I dunno $10-$20 for a four.

    Going to be as accurate as you need and will never require calibrating.
  12. Where are you in Melbourne?
  13. I had motion pro mercury guage a few years ago, worked fine. no idea where they are now..
    Float bowl screws wont be for balancing carb's.
  14. +1 on the carbtune. Bought it directly from them. Had mine for years now and does a good job. I'd stay away from the mecury versions. Also heard stories of the mercury being sucked into the motor if you rev it too quickly :eek:hno:

    There should be screws in the head just in front of each carb that you remove to attach the spigots.

  15. My old z900 has plugs coming out from the inlet rubbers that u push the hoses onto,when i did them years ago took of the top caps and adjusted from there.The gauges i used to have were pretty cheap so they were adjusted as previously said on 1 carb first.
  16. In Berwick Flylo.

    Not sure bout making my own...wanna try and get these carbs perfect.
  17. Hmmm....I have a set of mercury ones, but I'm in Glenroy.
  18. Would ya mind if I.borrowed them for a day or two. I'm putting my carbs back together tonight and would come in handy! Obviously I will pick em up and drop em off.
  19. I use a vacuum gauge purchased from bursons for around fifty dollars. To stop the needle fluctuating and get a smooth reading I run the gauge through a vacuum tank made from an old mid sized glass jar with two pronged tubes sticking out of the lid. I connect the gauge to the jar and a hose from the jar to which ever carb Im checking. I believe it provides a consistent reading as the same gauge is used.