Sniffer Vs trained human ear

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firefly

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Two weeks ago I decided to try a yamaha dealer closer to were I live, they have a sniffer, the dealer I bought the bike from is the one who did the service since I bought the bike new, I always insisted on one mechanic to do my bike to the point that if he is not in I would wait and go another time, why do I insist on only one mechanic to service my bike?
CLEANLINESS, that guy is meticulous!
Any way, That other dealer had a mechanic that looked experienced so I let him sync the carbs and adjust A/F mixture using the sniffer, Well the tuning feels disappointing though the bike is ~ smooth, the engine sound and vibration level is not so rhythmic as I was expecting from tuning with a sniffer.

Now two weeks later I developed more appreciation to Al the mechanic at the first dealer, though they don't have a sniffer the bike always felt perfect, with the engine Rhythm like a song!
What a difference an experienced mechanic has tuning by ear:ryb: vs the machine numbers say its tuned!
I'll go back to my first mechanic and get him a nice gift next time.
 
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mikemax04

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What works for me Ibrahim is a set of vac. gages and a volt/ohm/rpm meter with three adjustable levels. First I sinc all four carbs with the vac. gages so they draw equally. Then I use the rpm meter set to the 1k range where just a bit of increase or decrease is readily evident when adjusting the idle mixture screws. Then check the vacuum again. When done, crack the throttle and test for responsiveness. If there is a smal lag, turn the idle screws out 1/4 turn each 'till it responds readily. Been doing it this way for 36 years and never needed a dealership. With 4 cylinders, you need some instrumentation to tell you which one does what. The Max is easy, earlier 4 cylinders had dual points and timing adjustments for two cylinders each and it all had to be just right besides the 4 carbs.
 
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firefly

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shawn kloker said:
Ibrahim,Do you still have the welding rods in your velocity stacks?
Yes I do but I had them in from before the sniffer tuning and the bike was fine and crisp, I maintain the bike probably more than I should since I depend on it daily for work, which is street riding short trips in heavy traffic. the sniffer tune is fine and would be considered as great but the by ear guy has his magic touch, I'll leave the tuning to someone who knows what he is doing rather than messing things up and learning from my mistakes and end up paying more.
these welding rods are actually making the bike more responsive and smooth, I'll keep them in,contrary to the argument of not creating turbulence in the stacks ( which will cause hesitation) the bike runs crisp
which makes me think that turbulence in the stacks is not bad at all, I'll try to use a thicker rod and see what happens. now all I need to do is get rid of the 180/55 tire!
 
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1FK00

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I don't beleive it has anything to do with turbulence. Anything you put into the stacks is a restriction to airflow. This will richen up the normally lean idle and off idle jetting, making it run crisper and smoother. Unfortunately it will also richen up full throttle even more so since the airflow is greater. If I use my 85 Max as a judge, they are already plenty rich at full throttle.
 

firefly

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1FK00 said:
I don't beleive it has anything to do with turbulence. Anything you put into the stacks is a restriction to airflow. This will richen up the normally lean idle and off idle jetting, making it run crisper and smoother. Unfortunately it will also richen up full throttle even more so since the airflow is greater. If I use my 85 Max as a judge, they are already plenty rich at full throttle.
I checked the spark plugs after 1000K and they look great with no hint of soot that would result from a rich mixture, all I can say is make 4 of them using a 1/4 th inch welding rods and try them for yourself.
 
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