Carb/Engine Not sure where to go.

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Hillbilly
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Carb/Engine Not sure where to go.

Post by Hillbilly »

I could really use some help on thos one. I finally got the Voyager back together and "running "... sort of. I have been trying to sync the carbs for a while now and I'm ripping my hair out. If your sitting on the bike the numbers go:
12 ,52, 5,1 cmHg. The highest number on cylinder 2 does not change no matter what I do. If I turn the pilot jet all the way in or not. I am being very careful to barely seat them and back them out. Right now there at 2 turns out.and it seems no matter how much adjustment I make they will not match across all carbs.The other thing of concern is again,sitting on the bike, on the left exhaust there is a skip/ light pop that can be heard along with blue smoke that smells like oil/ fuel richness. I will try to load a video later, I had trouble the last time I tried. Let me know what you think.
Thank you
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Nails
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Re: Carb/Engine Not sure where to go.

Post by Nails »

I'm no expert ... and I don't know the history behind this ... but I suggest fussing with the carbs only after a good-faith effort to rule out other problems. I'm talking about the other three of the Big Four (mechanical/compression, spark, and timing), before jumping to fueling.

With the readings you're getting (assuming no problems with the gages or how they're hooked up), I suspect some running issues that you started with might've been falsely blamed on the carbs.

If it really is a fueling problem, you seem to have carburetor issues beyond just balance.
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Hillbilly (Mon Jul 24, 2023 9:17 pm)
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triton28
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Re: Carb/Engine Not sure where to go.

Post by triton28 »

Using pages 2-8 and 2-9 of Section 2: Fuel System in the Motorcycle Service Manual I suspect that you may be using the wrong adjustment for synchronizing the throttle plates to achieve smooth RPMs.
If you are using the air screws located behind the float chambers on the bottom/back of the carbs then you will never achieve synchronization, only proper air/fuel mixture for idle RPM.
The only way to synchronize the throttle plates is by using the 3 spring assisted phillips/(JIS) headed small screws located between the carb upper bodies. But first ensure that each gauge is reading the same vacuum while using a known vacuum source such as a hand operated vacuum puller set to the same vacuum reading for each gauge in turn. Each gauge should read the same for the known vacuum before trying synchronization.
Then adjust #1 and #2 to each other; then 3 and 4 to each other and finally using the center screw adjust 1&2 to 3&4.
Down at the bottom of the Forum list there is a link to the Tech Center should you need a service manual.
The popping sound may disappear when the readings get closer to each other. If it doesn't look for an air leak between the carbs and the cylinder head and/or readjust the air screw in small increments until the popping disappears.
Blue smoke is never good to see. If it does not clear up with proper synchronizing then there may be internal problems such as a scarred cylinder or a stuck ring.
Black smoke is much easier to solve as it is usually a blockage in the inlet tract, (plugged filter), or a misalignment/incorrect adjustment of a carb internal part/jet/float level.
If the blue smoke persists i would recommend doing a compression check.
Good luck,
Dave
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Nails (Mon Jul 24, 2023 6:45 pm) • Hillbilly (Mon Jul 24, 2023 9:17 pm) • cushman eagle (Tue Jul 25, 2023 12:36 am) • GrandpaDenny (Tue Jul 25, 2023 1:07 pm)
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Chris Cochran
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Re: Carb/Engine Not sure where to go.

Post by Chris Cochran »

First off, is your gauge synchronized TO ITSELF, first? My gauges require a hose setup different from the final trying-to-sync-the-actual-carbs configuration. There are screws on the gauges themselves to use to sync them to each other. Once they are sync'd to themselves first in this fashion, THEN you'd configure the hoses for the actual CARB synchronization. I imagine each gauge manufacturer has its own procedures written to accomplish this.

Otherwise all sorts of weird readings happen. Also, the only adjustment screws on the bike to use for synchronization are up top between the carbs and visible when you're standing up over them. There are three of them. Use the far-left screw to sync up carbs one and two. Don't concern yourself with whatever carbs three and four are bouncing around at, just yet. Get that done and then move to the far-right screw to sync carbs three and four to each other, again without concerning yourself about wherever one and two are at. After those are done, then you use the center screw to sync up the two halves to each other.
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cushman eagle (Thu Aug 10, 2023 12:23 am)
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ekap1200
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Re: Carb/Engine Not sure where to go.

Post by ekap1200 »

Hello from NJ. well adjusting the PILOT FUEL SCREWS , will do nothing for balancing the vacuum readings. put the pilots BACK where they were. It is the throttle plates that control vacuum syc. Perhaps you may need to call a friend. Not knowing what you did with these carbs I would not know where to begin with helping you. Do you own a book , or downloaded a free version online ?
"Its not bad if you don't know something, but when you don't know you don't know; That's when your in trouble". Joe Place 1912-2008 (my grandfather)
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