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Carb Sync Tool: Liquid or Dial?

Discussion in 'XJ Technical Chat' started by ScreamingGigabyte, Mar 14, 2013.

  1. ScreamingGigabyte

    ScreamingGigabyte Member

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    I'm going to need to sync my carbs after I check valves and clean them, but I'm not sure which gauges to get. I've read that the liquid ones are easier and faster to use, but have seen YouTube vidoes that say to use the Dial Gauge tools as they are better.

    I've never done a carb sync before and am leaning towards the liquid due to ease of use, but if I will be better off with a Dial Guage I will get one and learn instead.

    Any input is greatly appreciated.
     
  2. biggyfaction

    biggyfaction Member

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    both work great. the liquids seem to cost more. you can get 4 vacuum gauges from a hardware store pretty cheap. depends on your budget. i have friends that made there own that work great. liquid is cool but i dont like the prices.
     
  3. XJOE550

    XJOE550 Active Member

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    Might also consider mechanical, Morgan Carbtune. Very easy to use and cost about the same as the Motion Pro liquid type. No need to worry about liquid evaporating. I think it was around $95 shipped.
    Morgan Carbtune Demo
     
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  4. ScreamingGigabyte

    ScreamingGigabyte Member

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    One thing I didn't like about the liquid was the evaporating or the fact that if my bike was way off it may suck in some liquid. The Gauge ones look complicated, I don't know what any of those notches mean, though I guess with some reading I could figure it out. As far as making my own, I may have to look that up, as these tools are quite pricey. I'm guessing it can't be too difficult to make.
     
  5. ScreamingGigabyte

    ScreamingGigabyte Member

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    That seems like a good route, gonna look them up when I get home this weekend and have more time to research them. They are a bit pricey, though.
     
  6. ScreamingGigabyte

    ScreamingGigabyte Member

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    Also, will I still need to 'colortune' my bike or will just a carb sync work? I've heard about colortuning and i know it deals with the spark plugs, but will I need to do that too?
     
  7. iwingameover

    iwingameover Active Member

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    You can make the sync tool. I made mine with tube, a yard stick and ATF. If ATF is sucked into the engine the only harm is the smoke out the muffler. Cost about $5.

    Colortune is not necessary but can be helpful if you've never tuned an engine before. It lets you see what's going on in the cylinder when it fires.
     
  8. 750E-II_29Rbloke

    750E-II_29Rbloke Active Member

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    I've heard the opposite re liquid/mechanical, in that the mechanical are easier to use but less accurate than the manometer. This makes sense as the graduations of the manometer are much larger hence easier to get closer than dials, and the manometer's are more fragile & sensitive to how you hang them (whereas you can just dump dials on the top yoke, connect and go) that said I have the 4 dials on a blue plate "standard ebay carburettor balancers" and they work very well for me :)
     
  9. XJOE550

    XJOE550 Active Member

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    As mentioned, you don't need the colortune to set your fuel mixture. You can use the traditional method as explained in your service manual. And I wouldn't say the color tune is for the novice. You can melt it if you are not fast enough. And to do it properly, it requires you do the three separate test on each carburetor. One test is at idle and you check/adjust for correct color. The second test is to slowly increase the rpm and third to blip throttle to 3000 rpm. And these have different correct color at different stages of the rpm. So it does take a bit of practice to. As for making your own, $5.00 is pretty cheap. I would have tried that instead of purchasing the Carbtune. But when researching it, most home made ones I saw were in the $30 range to make. So, I figured I would rather invest that $30 into a professional one. And one point to remember, the home made ones don't give you a scale. Even though the idea is to balance the carbs relative to each other (Some makes have a reference carburetor), the service manuals do give you a an actual cmHg value that the balance should be near.
     
  10. 750E-II_29Rbloke

    750E-II_29Rbloke Active Member

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    Yep they do LOOK complicated, until you realise that all the graduations/red & green areas, late timing areas etc mean nothing to us, all we're looking for is 4 needles showing the same draw when set with a tiny amount of flutter.

    FWIW my 750 showed 120 whatever-is-was's of vacuum on all 4 at 1100rpm, that's good enough for me ;)

    EDIT- Joe550, how did you find the carbtune? Aren't they just awful?! (I'm referring to the crappy overpriced bit of orange plastic intended for twin carbs on cars, surely you didn't sync with one of those?....)
     
  11. iwingameover

    iwingameover Active Member

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    My method is on here several times already but here it is again.

    All you need is a bit of ATF, a yard stick, some tape, and clear tube of the correct diameter to fit your carb nipples.

    I used ATF because it's red and easy to see and if some is sucked into the motor it will burn off with no harm to the engine. Your neighbors may hate the smoke cloud though.

    To build make your tube into a U shape and tape the bottom of the U to the bottom of the yard stick. Then tape the tube up the sides but do not cover all the tube. Add the ATF. I did this by sticking one end of the tube in the bottle and the other end on a vaccum port on my Jeep but the bike would do it as well and run the motor for a few seconds. Let the ATF settle in the middle and then hook each end of the tube to the carbs you want to synch. With the engine running adjust the sync screw until the fluid is level across the yard stick in the two tubes. The measurement is not important.
     
  12. XJOE550

    XJOE550 Active Member

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    Hey 750E-II_29Rbloke, I have the four cylinder model (can be used on twins of course). Nothing on it that has orange plastic. Quality is acceptable as for the construction. Seems pricy for what it is though. But functions perfect. No synchronization required. I have a link in my first post on this thread where I am balancing my KZ. Gives you how an idea how stable it is compared to dials. Even though for all practical purposes, adjusting with the dial type will do the job more than adequately.
    My understanding is that the carbtune and liquid type are more accurate than the dial type, and less prone to jumping around. Of course this assumes you properly installed the restricters. But the advantage of this over the liquid is you don't have to worry about air bubbles that can skew your settings.
     
  13. 750E-II_29Rbloke

    750E-II_29Rbloke Active Member

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    Ah yes, I should read more carefully sorry, I was thinking of Gunson carbtune! (that's all we got called carbtune over here & it's TERRIBLE! costs about £20/$40 as well...)

    As per my first post, I'd say you're right on manometers being more accurate due to larger range/scale over dials. (I find dials are easier to just "sling on the bike and get on with the job" without worrying about them being level etc, guess it's subjective though)
     
  14. TIMEtoRIDE

    TIMEtoRIDE Active Member

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  15. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    The Morgan CarbTune (now Pro) is a UK-made, mechanical 4-stick manometer. http://www.carbtune.com/ I have one and it works VERY well.

    The Gunson ColorTune http://www.gunson.co.uk/tools.aspx?cat=673 is likewise UK-made, and it is very valuable for mixture adjustment. Using "by ear" methods on a 4-cylinder, running bike can be an exercise in frustration.
     
  16. 750E-II_29Rbloke

    750E-II_29Rbloke Active Member

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    I didn't mean Gunson carbtune (or colortune), was getting confused (not hard when I haven't slept for 2 days!)

    Fitz, search for Gunson carbalancer, that's the orange nasty I was meaning! I know the colortune's a good bit of kit ;)
     
  17. MiCarl

    MiCarl Active Member

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    One thing that is nice about gauges is they give you an absolute pressure reading. A well running engine will pull about 10" Hg. If you're synced and they're much below that you have one or more cylinders not doing their job. On the other hand if you sync them and they're a bit above 10" you can be confident you have a tight engine and your mixtures are in the ball park.
     
  18. ScreamingGigabyte

    ScreamingGigabyte Member

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    So after more research I think I'll go with the gauges. What adapters are needed for a 1983 YICS XJ650 Maxim? I find some that say they only have 5mm adapters and that most Yamaha need the 6mm adapters.

    I'm also seeing different ones on ebay. Some are blue and some have an orange case, any difference between these? Will my bike be able to use the brass extensions? I've found a kit that has the 6mm adapters included, but not sure if I need to pay the extra $10 for 6mm adapters.

    EDIT: If the bike had good compression the last time it ran, does this need to be checked again and I'm guessing the carb sync tool won't tell me if there is low compression, will it?
     
  19. MiCarl

    MiCarl Active Member

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    You don't need any adapters for an XJ, the hose just slips on the intake nipples.

    I don't know about the orange one, but the hose that comes with the really popular blue on is junk. It'll split in no time. You can get good vacuum hose at the auto parts store.

    Low compression will show up on a vacuum gauge, but how much depends on a number of things. I just did a 4 cyl bike that was only pulling about 3" Hg at synchronized idle. Turns out it has an exhaust valve leaking. That leak was bad enough it wouldn't move the needle on the compression gauge.

    I repeat my earlier statement: If they're synced and pulling 10" or more you have a tight engine (good compression) and the fuel mixtures are close.
     
  20. 750E-II_29Rbloke

    750E-II_29Rbloke Active Member

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    Good point on the vac hose with those gauges. The hose on my set lasted long enough to sync a 500 twin & a couple of 4 cylinder bikes but you could tell it wasn't fuel proof & I guess the vapours killed it as next time I picked them up it was a sticky mess on the lower 8", As carl says, get some good vac hose from a motor factor & use that instead ;)

    It's good practice to know your compressions are good before starting to sync, even if they were last time for the sake of 5 minutes it's worth being 100% sure
     
  21. ScreamingGigabyte

    ScreamingGigabyte Member

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    Only thing is, I don't have a compression gauge and they aren't cheap either. Running out of money to work on the bike.. :-/ A $600 project has turned into an over $800 project.. I'm guessing this is common, though.
     
  22. iwingameover

    iwingameover Active Member

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    They're about $25 at most parts stores. Some, autozone for one will loan them. You pay for it, take it home and then return it and get your money back.
     
  23. 750E-II_29Rbloke

    750E-II_29Rbloke Active Member

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    Yes, very common for projects to take as a rule of thumb, 2 times your budget & 3 times the hours you originally estimate to do things properly.

    At least you're not saying "I'm running out of money so screw it I won't bother", you have the right attitude ;)

    As iwingameover says, they aren't really expensive & once you have it you'll get more use than you expect from it (they're that quick and easy to use that I consider them an essential diagnostic tool for any running/starting issues) If you really can't afford one then I'm sure somebody, friend or shop will be able to lend you one :)

    EDIT-: One other thing nobody's mentioned yet & I should have said before even talking about good practices or compression tests, is that it's essential your valve clearances are checked & in spec, I don't know if you've done it yet but this is THE most important thing to have right or you won't get synced properly
    If you have to choose between buying a comp. tester or a set of pure metric feeler gauges, get the feelers :)
     
  24. ScreamingGigabyte

    ScreamingGigabyte Member

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    I haven't done the valve clearance check yet. I need to find a place that will take the old gas in the tank before I can drain it and check the valves. I have the small feeler gauges, though I will probably also need a valve cover gasket too, won't I?

    A compression gauge also requires an air compressor, doesn't it? I don't have one of those either. I wish I had the money to get all the tools I need now, but i don't. I also was hoping to finish my bike before April, as I am going to Law Enforcement Academy in April and won't have much time to work on it once I start. :(

    I haven't checked any local auto parts store for the compression gauge, I just saw some online that were about $40-$50.
     
  25. 750E-II_29Rbloke

    750E-II_29Rbloke Active Member

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    You can lift the tank without draining (unless your petcock leaks?) but it's a good idea to drain tank into old jerrycans anyhow as it comes in useful for cleaning stuff IMO

    It's not the size of the feeler gauges per-se, it's the graduation. Imperial ones with metric on aren't good as you don't get a true exact measurement, you need PURE metric (I believe Fitz said autozone have them in a prev. thread but will look)

    No, a basic compression only gauge doesn't need a compressor, more expensive 2 dial ones you probably saw need an air supply to perform a "leak down test" but this isn't needed for our bikes or even particularly relevant for older, air cooled engines IMO.

    Before you even think of getting sync gauges or comp. testers you need to check & set the valve clearances (Dave, member "hogfiddles" runs a shim bank so at least you don't have to shell out for new shims!) as a sync will me meaningless without these being right.

    You'd be well advised to contact XJ4ever and get a valve cover gasket & "pressure washer donuts" also. I know it can seem like a lot of over-cautious excess spending but it saves you doing things twice or more &/or kicking yourself when you have oil leaks later. Hang tough & get the valves checked you *may* even have a pleasant surprise if the P/O kept on top of it ;)

    EDIT-:
    K-D tools #2274 there we go :)
     
  26. 750E-II_29Rbloke

    750E-II_29Rbloke Active Member

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  27. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    Nope. A compression gauge (compression tester) just requires the motor to screw it into. Cranking the engine produces compression which the gauge reads.

    Compression tester at AutoZone, $26: http://www.autozone.com/autozone/access ... 87835_0_0_

    If you don't want to make the investment, use their "tool loaner" program.
     
  28. 750E-II_29Rbloke

    750E-II_29Rbloke Active Member

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    Fitz, what do you reckon to the one I found for $15 and free shipping? seems reasonable yeah?

    Valve clearances first though ;)
     
  29. ScreamingGigabyte

    ScreamingGigabyte Member

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    Will I need to replace gaskets on the carbs once I clean them or can I reuse the ones that are on it? Or I'm guessing it may be a 'depends on the situation' kinda deal? I need to order exhaust gaskets too. I want to order everything together from XJ4Ever.

    This project has become a money sink, but I get so excited watching how-to videos on stuff. Watched a carb cleaning one at work last night.. Doesn't look near as difficult as I thought it would be. And the valve clearance check doesn't seem difficult either, I am just a bit intimidated by the shim thing and figuring out the correct shim to get..
     
  30. quebecois59

    quebecois59 Well-Known Member

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    I suppose you're talking about the float bowl gaskets? Actually, it depends on what they look and feel like. Sometimes, they are all dried out and easily destroyed when you try to remove them form the bowl. SOmetimes they peel off easily and you could reuse them.
     
  31. Ground-Hugger

    Ground-Hugger Member

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    If you have a lawn mower mix it with new gas and run it in the lawn mower.
     

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