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Air Fuel Mixture.


Guest VF500FInterceptor

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Guest VF500FInterceptor

Im in the middle of syncing my carbs and it still is not running real great. Wondering if the air fuel mixture is off. What is standard on these bikes?

Sent from my XT907 using Tapatalk 4

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Im in the middle of syncing my carbs and it still is not running real great. Wondering if the air fuel mixture is off. What is standard on these bikes?

Sent from my XT907 using Tapatalk 4

Air fuel mixture and synchronization are entirely different beasts, each with their own set of symptoms that in some ways appear to mimic each other.

Synch pertains to the positions of the individual throttle plates relative to each other. If one is a teensy bit more open than its neighbors it'll throw the vacuum off and result in a tug-of-war. You'll see unstable and slow/hesitant return to idle, revs hanging high between gears, and the idle will tend to rise uncontrollably as the bike warms up.

If the air fuel mix is off you'll still see poor idle characteristic but it'll rev up and drop out *more or less* normally and won't hang high. Unless it's so bad that one or more cylinders are far enough off to the rich or lean that they don't fire properly at all.

Compression is king so the first thing we do is put the gauges on, and if it's not perfect--or more significantly if it's low on one cylinder or more--we want to move forward and have a look at the cams and valve clearances. This ensures that we're on the trail of the actual problem instead of maybe chasing ghosts.

OSC

http://www.oldschoolcarbs.com

http://www.youtube.com/watch?v=H0LfUyQzNCI

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Im in the middle of syncing my carbs and it still is not running real great. Wondering if the air fuel mixture is off. What is standard on these bikes?

Sent from my XT907 using Tapatalk 4

Air fuel mixture and synchronization are entirely different beasts, each with their own set of symptoms that in some ways appear to mimic each other.

Synch pertains to the positions of the individual throttle plates relative to each other. If one is a teensy bit more open than its neighbors it'll throw the vacuum off and result in a tug-of-war. You'll see unstable and slow/hesitant return to idle, revs hanging high between gears, and the idle will tend to rise uncontrollably as the bike warms up.

If the air fuel mix is off you'll still see poor idle characteristic but it'll rev up and drop out *more or less* normally and won't hang high. Unless it's so bad that one or more cylinders are far enough off to the rich or lean that they don't fire properly at all.

Compression is king so the first thing we do is put the gauges on, and if it's not perfect--or more significantly if it's low on one cylinder or more--we want to move forward and have a look at the cams and valve clearances. This ensures that we're on the trail of the actual problem instead of maybe chasing ghosts.

OSC

http://www.oldschoolcarbs.com

http://www.youtube.com/watch?v=H0LfUyQzNCI

The bookmarking OSC, thanks!

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Maybe some of the carb insulators are leaking. I had this once with a poor running bike i was servicing. After valve clearance adjustmet (al 16 valve's to tight) synchronisation was not really succesful, after testing i found air leaks. All insulator clamps not tightened. :wacko: After correcting this and synchronising the carbs, the bike ran so good, that the owner not familiar with a powerfull bike, nearly crashed it with a highsider. :tongue:

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