After listening to years of buyer complaints about their incapacity to deal with poor Gold Wing efficiency signs and the ruthless exploitation by many restore retailers again within the Eighties, we have been compelled to check the issue. In 1990, an answer was offered in writing that was handed out to my clients with none obligation on the a part of the reader to purchase something. We obtained lots of of thank yous from clients and people who by no means bought components from us however took time to write down. Those that made the substitute based mostly on our answer and tuned up their engines, eradicated a complete sequence of issues, together with the burning out of head gaskets and, through the years, we obtained many declarations of drastically improved fuel mileage and general efficiency.
AIR CUT-OFF VALVE
The Air Minimize-Off Valve is an especially vital a part of the gas / air consumption system that’s regularly missed even by competent mechanics, most of whom will not be even conscious of its existence or the way it features. Over time, air cutoff valves will harden up, perforate and/or disintegrate leaving your motorcycle in a completely lean, low RPM vary (0-2200).
Most early mannequin Honda, Kawasaki, Suzuki and Yamaha bikes use air cut-off valves. Each Honda CB650, CB750, CB900 and GL1000 has one, positioned within the air consumption tube between the air cleaner field and the manifold. The GL1100 has 4, positioned within the high air consumption passage of every carburetor, and each GL1200 has one positioned within the plenum field beneath the air cleaner field much like the GL1000.
These valves are “air blockers”, together with the carburetor o-rings, serving to limit air movement, rising the fuel-air combination ratio when the carb slides are within the decrease RPM vary, as much as closed in order that the machine will begin and idle easily with just about no choking and speed up quickly, with no stumble or hesitation.
When typical beginning requires heavy and extended choking to maintain the bike working, when stalling and hesitation happens even whereas “warmed up” and when backfiring pops whereas the throttle is shut off whereas cruising, most individuals will begin fooling with the air screws to attempt to overcome the issue, solely making it worse together with lowering their fuel mileage.
Working with dysfunctional air cut-off valves could cause extreme engine injury or failure. When the valves are dysfunctional, the engine pulls practically whole air into the low RPM vary via the carbs and on to the combustion chamber. The fuel-air ratio is extraordinarily poor with pre-ignition lengthy earlier than the traditional 38 to 40 diploma…firing level, producing an infinite quantity of warmth, with no energy, which is trapped an extended time frame within the cylinder earlier than the exhaust valve opens.
This warmth goes principally up via the cylinder head, regularly incinerating the top gaskets and permitting engine coolant (antifreeze) to seep into the engine. You may simply spot if you find yourself in bother by a puff of bluish-white or white smoke on first beginning the engine. Do not go away it alone. Change the top gaskets instantly or you might take out your backside finish bearings, ruining the engine.
For these of you putting in new exhaust programs, you’ll discolor your head pipes, both blue (lean state) or gold (wealthy state) if the indicators are ignored. You an destain your pipes utilizing Blueway or Blue-Off however watch out to not rub the chrome, simply dab gently. These destaining compounds are often discovered at a Harley seller or Harley-oriented aftermarket store.
Honda real pipes, like many Yamaha pipes, have a double wall for a portion of the top pipe which masks discoloration – but in addition masks a foul state of tune. Even when your pipes are authentic and nonetheless in good condition, do not assume you are secure in case your motorcycle has any or all the dysfunctional air cut-off valve working and performing traits.
In case your 1975 to 1987 Gold Wing is just not getting 50 to 58 miles per gallon (20-23 kilometers per liter), you’ve one of the vital apparent indicators of bother. It’s seemingly your air screws have been backed out to attempt to overcome the consequences of the poor working, stumbling, beginning, stalling and quitting.
Discuss with your Clymer, Haynes or Honda Workshop guide for location and set up procedures.
Exchange your air cut-off valve/s then resynchronize all 4 carburetors to the #three carburetor vacuum degree utilizing a mercury carb sync software (carb stick) or vacuum gauge synchronizer software. The quantity three carb is the fixed fastened movement carburetor set on the manufacturing unit.
DO NOT try to set by ear or simply by guessing because the outcomes may be anyplace from pathetic to disastrous.
DO NOT deviate from the guide settings of your Honda, Clymer or Haynes guide. Wiser individuals than all of us designed this very efficient and environment friendly consumption and carburetion system.
To additional insure in opposition to any further vacuum loss, exchange your cheap carburetor manifold o-rings. Vacuum loss can happen there and mimic the impact of a foul air cut-off valve. Paste a brand new set in with vaseline and ensure they’re sealed with an ether verify.
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