Hi, Deb_denton20 you need to make sure you have no intake leaks by spraying some Brake Kleen, Contact Cleaner, Starting Fluid etc. around the intake manifold and seals, if the RPM's go up or down significantly then you have a leak that needs to be fixed before you can continue with the carburetor adjustment.
The engine should be at operating temperature with the choke off to set the idle between 950-1050 rpm. Turn the idle skrew clockwise to increase the idle speed and counterclockwise to decrease the idle speed. If you have access to your air-fuel mixture skrew you may turn it as well, if not there is a video below on how to gain access, make sure you start with clean or new spark plugs. Gently turn the air-fuel mixture skrew clockwise until it starts to bottom out "STOP" do not over tighten as it will damage the taper on the end, now back the skrew out 1-1/2 full turns to establish a starting point start the engine and check the idle rpm's and turn the idle skrew accordingly for 950-1050 rpm if necessary, turn the air-fuel mixture skrew 1/4 turn at a time and let the engine settle for about 10 seconds, turn the skrew clockwise for a leaner mixture and counterclockwise for a richer mixture, you are seeking the highest rpm your air-fuel mixture skrew can acquire without going past 3 full turns from the bottom then resetting the idle skrew back down to 950-1050 rpm If you can not detect any rpm change and can not stall the engine by turning the air-fuel mixture skrew all the way in then your pilot/low-speed jet is too big and needs to be replaced with the next size smaller. Final adjustment should be made with a clean air filter mounted to the carburetor.
For more information about your issue and valuable "FREE" downloads that you will need for viewing or printing please click on the blue links below. Good luck and have a wonderful day. https://www.motorcycleforums.net/forum/suzuki/51568-yet-another-hard-start-suzuki-marauder-vz800.html https://www.youtube.com/watch?v=T8ttIqjErJ0 Suzuki VZ800 Service Manual https://www.partsfish.com/page/oem-parts-for-suzuki http://mybikemanuals.com/suzuki
Hi, Rod engine "BOG" is mainly caused by a rich air and lean fuel condition but it can also be caused by a lean air and rich fuel condition this situation rarely occurs and is only caused by the misinformed weekend warrior that owns a toolbox. If the bike has been sitting for months or years you will have to completely disassemble the carburetor and submerge the parts (except rubber parts) in "Carburetor Dip" It usually comes in a gallon bucket with a wire mesh basket that can be purchased at any automotive store. If it is not the above scenario then the following explanation will apply.
The more you open your throttle the more vacuum you are creating in your carburetor venturi and your intake manifold. When you are operating at higher RPM any unmetered air that leaks into your system can become more obvious.
Unmetered air is air that is getting into your system after the fuel has been delivered. If you have unmetered air getting into your system between the butterfly/slide of the carburetor and the cylinder head this will create a lean condition.
All of the rubber components of the fuel system like vacuum hoses and intake manifold that you mount the carburetor to are made of rubber. If none of these components have been changed they are more than likely highly degraded and probably cracked in places to allow unwanted-unmetered-contaminated air into the combustion chamber. Check all of your vacuum lines and vacuum plugs for carburetor synchronization. The vacuum plugs are in the head just after the rubber intake manifolds. The petcock has a vacuum line as well as part of the emission system.
1. Check the intake manifold for fissures.
2. Ensure the bands used to tighten the manifolds down on the intake are secure and have not bound up the manifold.
3. Make sure air box fittings are not warped and fit completely over the carburetor.
Your airbox is metering air and is the first step in the process of consuming air and fuel. The system requires the resistance of the air filter in order to get the proper vacuum to "SUCK" the fuel out of the float bowl and create the proper venturi effect.
Improper mounting and sealing of the airbox will create a small lean effect. This might seem like no big deal but you are inviting dust and debris in your engine that is doing slow damage by not having proper fitment. Fix it so you know it's not contributing to your issue. Pick the low-hanging fruit first.
Do not go and start adjusting anything at this point. It ran fine before. There is something wrong with the assembly or a component. Do not adjust your floats. Get it back to where it was. The moment you start tweaking everything is the moment you lose OEM settings which are a must-have for fine-tuning and maximum performance.
Fine-tuning your carburetor and multi carb syncing come at the very end following the proper procedure established by the Carburetor Gods.
For more information about your issue and valuable "FREE" downloads that you will need for viewing or printing please click on the blue links below. Good luck and have a wonderful day. Bike idles perfect but dies when given the slightest amount of throttle 93... https://www.youtube.com/watch?v=0SPx25YdCCc Suzuki VZ800 Service Manual https://www.partsfish.com/page/oem-parts-for-suzuki http://mybikemanuals.com/suzuki
Check the attached links,Manuals and guides, Good luck with your Bike
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