V4 carb sync

Using thicker oil will help, but using a buffer like they did in my example, will also help. The fluid wil not be drawn up and dawn so quickeley.

How to Adjust Carbs on an Outboard Motor

Putting some kind of restriction in the lines, with only a tiny hole trough it may also be helpfull. You can make adjustments while the engine is off. So you are going to want to make adjustments on those two carbs while the engine is off to get them to a point where it's not going to suck the oil in. Just beware that on start some lines will jump up but then settle down a bit. Then you can leave the engine running and continue the sync. The only reason you need the engine running is because you need live feedback on how your adjustments affect the sync.

As the man in orthopedic shoes said, I stand corrected. I was really referring to fine tuning here, not getting it in the ballpark to begin with. But I can appreciate what you are saying. And in reality, it only took me about 15 minutes to put the whole contraption together, so if it does work correctly, it's definitely worth it.

The only reason it wouldn't work is if there is an air leak in the bottom of the thing by the connectors. Not a difficult issue to fix. Pretty much that. It doesn't take long to get it. AND, since you're using oil instead of mercury, you end up with a much more sensitive device. The longest part when putting mine together was waiting for the oil to level out enough between the four lines when I first filled them. Makes sense and seems like a fun project.

I just wanted to understand the logic there I'm more of a Morgan Carbtune fan as it works like a charm and is very reasonably priced, but it is fun to see this type of Rube Goldberg set-up. On this note, engine running to synchronize the Factory synch tool makes this a whole lot easier.

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v4 carb sync

Start new topic. Prev 1 2 Next Page 2 of 2. Recommended Posts. Posted March 20, Share this post Link to post Share on other sites. How much should I adjust them with the engine off? Posted March 21, Interesting Yankee ingenuity here.

Go To Topic Listing. Sign In Sign Up. Important Information By using this site, you agree to our Privacy Policy.Discussion in ' Mechanics Garage ' started by IvanJul 23, Log in or Sign up.

What are the symptoms of a bad carburator sync? Petersburg, Russia. Well, my question is pretty much all in the topic. IvanJul 23, This ad does not show to logged in members. Click here to register for free. Bad sync results in rough running and really bad throttle response.

How to Sync an Outboard Carb

When it is spot on the throttle feels light and crisp. Performance is also better of course. Doing the job right takes a lot of time and generally starts with a full teardown on the carbs for a good cleaning.

RVFRJul 24, Thanks for the replies! The thing is that I'm getting verry slight vibrations around rpm when riding. I was just thinking is it normal for this bike, or should I be looking into it? IvanJul 24, Same problem here I hope someone knowledgeable answers your question re vibration at about 6K rpm.

I have the same problem, and was about to try a throttle body sync pay to have it done as a last resort - '99 VFR. I have a carb syncer i have used a bunch. And u still have the syncer to do ur buddies bikes for beer. You just need them to match between the respective two to get a perfect balance, rather than an absolute number.Welcome to V4MuscleBike.

Whether you're looking for parts, technical advice or just want to hang out and chat, you've come to the right place.

We have a very friendly and knowledgeable group here. So please take a moment to register and introduce yourself. Member I helped a guy sync the carbs on his '96 today and tried a goofy experiment. After hooking up the manometer he started the bike and had to stop it right away to keep from pulling bubbles into the ATF.

The carbs were way off. My manometer has aquarium valves so I closed the valves for 2 and 4, opened the valves for 3 and 1 and synced 3 to 1, the base carb. Then I closed the valve on 3, opened the valve for 2 and synced 2 to 1. Then closed the valve on 2, opened the valve on 4 and synced 4 to 1. Then I opened all the valves and started the bike.

They were all within an inch of ATF. He did a test ride and said the bike ran great. We did the idle drop but didn't need to change more that a quarter of a turn from the original settings.

I got the idea to do the carbs one at a time because I read an article about bikes with four carbs and the author said that each carb should be treated as if it were attached to a separate engine. He wrote that syncing all four engines allowed them to operate without "fighting each other. It was a fun project but I'm guessing it's been done lots of times.

My buddy's bike up in the air. When I first hoisted it up he was very nervous. Said if I dropped his bike I had to give him mine.

Being able to sit in a chair and look up at the adjusting screws was pretty sweet.To create this article, volunteer authors worked to edit and improve it over time. This article has been viewed 18, times. Learn more So you want to synchronize the carbs on your multi-carbed motorcycle? There are a couple of methods you can use: the vacuum gauge method generally how it's done in a motorcycle shop and the ball-bearing method.

If you have vacuum gauges, try that approach, and if you don't, opt for the ball-bearing method. Please help us continue to provide you with our trusted how-to guides and videos for free by whitelisting wikiHow on your ad blocker. Log in Facebook.

Synchronize Carburetors - GS550 Cafe Racer Build (Part 102)

No account yet? Create an account. Edit this Article. We use cookies to make wikiHow great. By using our site, you agree to our cookie policy. Learn why people trust wikiHow. Explore this Article methods. Tips and Warnings. Related Articles. Co-authored by 7 contributors Community of editors, researchers, and specialists November 18, Method 1 of Make sure your carbs are clean and in perfect working order. Clean the bowls, the jets and passages, the rubber diaphragms under the top lid have no holes, and your carb needles, as well as the floats are hung in the right positions, as indicated by the workshop manual for your machine.

Check the rubber manifolds for leaks, and make sure your idle mixture screws are adjusted to the indicated number of turns. Your bike should now idle somewhat peacefully. Twist the idle mixture screw on each carb - you will notice that the engine idles faster or slower. The spot where it idles fastest is the right one, find that on all the carbs, all the while re-adjusting your main idle to the revs indicated in your manual, usually a bit less than rpm on a 4-cylinder.

Congratulations, you have adjusted and synchronized the idle speed! Pull off the little rubber covers, or screws, that hold the vacuum passage shut on each carb. Attach the hoses from the vacuum gauges, and start the engine. Preferably, it is already warmed up. Open and close the throttle a few times, then let her idle. You will have noticed the indicating needles on the gauges going up when you open the throttle, and fluttering like mad when idling.

First, let's take care of the fluttering. Every clock has a little screw, where the tube gets in or nearby.

Twist that until the fluttering calms, but does not stop completely. Gun the engine in between adjusting, until all the needles on the clocks are fluttering somewhat calmly at idle.

Open her up, and see those needles rise Your next step will be to make them rise in unison. Loosen the countering nuts on the butterfly valve adjusting screw of each carb. Depending on your bike, you might have one carb that cannot be adjusted: that is the one to which the others have to be adjusted to.

Loosen or tighten those screws, bit by bit, opening up the throttle in between, until all the needles on the gauges rise and fall simultaneously, in perfect harmony.Outboard carburetors are designed and function similar to automobile carburetors. Both meter fuel in precise amounts to the engine for optimum internal combustion.

v4 carb sync

Outboard carburetors have a power circuit, metering jets, float bowl and low speed and idle circuit. Adjusting outboard carburetors requires a knowledge of the position of the mixture and idle speed screws on the carburetor. Submerge the lower end unit into a larger rubber container filled with water. Cover the water intake ports, but allow the exhaust port to sit above the water level. You can also perform this procedure in the water by tying up securely to a dock with fore and aft lines.

Check your owner's manual to see if your carburetor adjustment can be made in the water with a neutral transmission setting. Many models require that the engine be in forward gear, with the prop producing resistance in the water. Unclasp the top engine cowl. Remove the spark arrestor, or air cleaner system, with a socket if it impedes access to the carburetor. Start the engine and let it warm up to normal operating temperature. Deactivate the manual choke, or wait for the electric solenoid choke to open fully, if you have this model.

Turn the engine off. Locate the idler mixtures screws for your carburetor. Refer to your owner's manual under "Air-fuel mixture setting. Place a small engine tachometer clip lead around the number one cylinder spark plug. Connect the other tachometer lead to a ground source. If you have a dashboard tachometer gauge, have an assistant monitor it for rpm readings.

Turn each idle-mixture screws in clockwise until they gently seat. For a multi-cylinder engine with dual carburetors, adjust each idle mixture screw with this procedure.

Start the engine and place the shift selector in forward gear. Turn the idle mixture screw in clockwise until the engine sputters. Turn it out counterclockwise until the engine begins to miss. Turn it back in until you achieve the highest rpm on your tachometer, which will be a midpoint between the two stumbling screw positions.

Adjust each mixture screw in this fashion, achieving the highest rpm on the tachometer gauge.The notes in [brackets] are mine. Back to BikeCliff's website. On this page:. Steve Woodin. To bench sync the carbs, you do need to have the rack assembled, but not on the bike. Open the master idle speed adjuster until carb 3 has a gap in the throttle plate that is large enough to put something in. That 'something' needs to be small, like a paper clip. Adjust the idle speed adjuster so there is just a light drag on the paper clip, much like you do when checking the valves.

How to Set the Timing in a Johnson Outboard Motor

You will see adjuster mechanisms between the carbs, so loosen the locknut, adjust the screw so you have the same amount of drag on carb 2, then carb 1. After doing those two in that orderdo carb 4. Now adjust the master idle screw out to close the throttles back down. I like to close them completely, then back in about a turn or two. When you start the bike, be ready to hit the kill switch if the idle speed is still set too high and the engine races when it starts.

Back the idle speed screw out some more and start the engine again. When you have the engine warmed up and are ready to do the vacuum sync, use the same order of adjustment. Notes from other members:. From Mr. Assemble carbs [in the rack like they are] ready to go on the bike. Determine master carb [ 3]. The one that the throttle cable connects to right? Put a small drill bit 1. Adjust the main idle screw until the butterfly just touches the drill bit. Adjust the sync screws until all of the butterflys are the same.

Check the master carb again. Reset the idle screw. Additional comments from :. Steve: Start at 2 full turns out and use a smaller gauge. I have had a couple sets of carbs that would not open to 1.Skip to content. Quick links. Reasons for this are in the FAQ. Disclaimer: I am not responsible for any harm or damage caused to you or your motorcycle or anyone else when you use this guide.

Use this guide at your own risk, if you mess your bike up, injure yourself or anyone else it is NOT my fault. Allen key set. Long number 2 phillips head screwdriver. Stubby number 2 phillips head screwdriver. Pliers, snipe nose or bull nose will do. Right angle screwdriver OR 7mm socket. Piece of 2x4 wood to lever carbs up or similar. Pair of rubber gloves. You probably will need these I advise that you sync your carbs AFTER you re-jet, adjust float heights, change needle washers and check valve clearances or you may have to do it again.

Firstly remove your tail unit, inspection panels and lowers. Lowers not necessary but helps with space Next remove tank, airbox, carbs, and to make things much easier, carb rubbers. Next you need to remove the blanking screws and the vacuum hose take-off for the fuel tap. The blanking screw for cylinder 4 is accessed next to the thermostat housing here: Then screw in the adapters from your carb balancing kit and attach the hoses.

Connect up the hoses to the vacuum gauges making sure you do it so cylinders go from left to right on the gauges. Cylinder config: Front 2 4 1 3 Rear After this stick back on your carbs and airbox. Then put back on your tank or connect up your auxiliary fuel tank. If using your standard tank you'll need to apply a vacuum to the tap if the tap is not modified. If you cannot sustain a vacuum on the tap then apply a vacuum and seal the hose somehow Now here comes the tricky, fiddly and potentially painful bit.

Depending on how you adjust the carb sync screws. Start the bike and adjust the idle a little higher than standard, say rpm - rpm and let the bike warm slightly. You should see something like this: If you are using a right angle screwdriver then simply insert the driver into the vee from the left side of the bike and use to turn the adjusters in or out depending on which way you need the level in the gauge to go.

If you don't have a fancy right angle screwdriver or can't get on with it then you'll be using a 7mm socket and a pair of rubber gloves. With the rubber gloves on and socket in hand put your hand into the vee and locate the sync screws with the socket and adjust as appropriate. Be very careful as the longer the engine runs the hotter it will get and could burn your hand even with the gloves on.

Again I take no responsibility for injury, that is your own fault Don't press on the screws or it will act like the throttle and increase or decrease the revs and you will get a false reading.

When synchronising the carbs first sync no. Carb no. Adjust carb no.

v4 carb sync

Then sync no. Again adjust as close as possible to each other. Finally sync the rear carbs 1 and 3 using the screw that is next to carb no. Adjust as close as possible to carbs no. Yes I have done what you think I have there


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