kwpeterson
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Aug 13, 2007, 11:19 AM
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1987 Yamaha Venture Royal Engine Bogging
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I just bought a 1987 Yamaha Venture Royal with 28,000 miles. I drove it 150 miles home and started checking it out...replacing fluids, brakes etc.
I discovered the battery was overfilled and the drain not attached so acid had leaked over the top front valve cover etc. Basically, removed all the parts effected, removed and polished the valve cover up and cleaned up the wiring and contacts and put the bike together.
Now, on giving it throttle...the engine bogs down...won't take throttle. Ok, heres what I have done since the problem started.
-cleaned the carbs with industrial cleaner, soaked the jets overnight in the $50 gallon cleaner. I passages blown out with 120 lbs pressure
-carb float levels and needles ok
-checked the vacuum & slider devices per the shop manual- when inverted into an umbrella the don't leak gas ...per the manual...so they must be
good ..right?
-checked all electrical connections and cleaned with tuner cleaner. All CDI box connections cleaned and checked.
-checked out barometic sensor that is connected to intake on left rear cylinder. Voltage is 2 volts per spec. It controls spark advance..
-new spark plugs.
-spraying start fluid into carb openings does not speed up engine. Has adequate fuel
-fuel filter replaced..fuel flow off carb connection great.
-Carb linkages adjustments were not changed so sync should not be a problem...once I get it running I will re syc for fine tuning.
PLEASE HELP I am usually good at trouble shooting but I am stumped! I have spoken to three yamaha mechanics and done everything they have suggested with no change...engine still bogs.
Thanks for reading my post!
kwpeterson@aol.com or 320 260 0972
Ok, I finally figured it out. If the engine was new it would probably pull more vacuum and run without the velocity stack air box and the upper venturi and air cleaner. Without these items installed the engine would not "pull" the slides with the vacuum present. I read the theory of operation on this carb style and figured it out myself. Some tuners apparently lengthen the slider spring to get more performance from this type of carb but I did not mess with that. Anyone have a good source for reliable but relatively cheap carburator sync tools? Please email me at kwpeterson@aol.com
Thanks
(This post was edited by kwpeterson on Aug 13, 2007, 3:20 PM)
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