Bogging at rise in altidude - Honda Shadow Forums : Shadow Motorcycle Forum

shadow_94 · 08-03-2012, 07:47 PM

Bogging at altitude

I have a Shadow VT1100 1994. After the winter I took my bike in when it would not start. The dealer got it running, flushed the fuel system and cleaned the carburetors. The bike runs ok in town but had a slight hesitation when applying throttle. If I ride at an increased elevation the bike will what I think is "fouling" and has almost completely quit on me at very high elevation. At a constant speed,60-70 mph, giving a little throttle will cause hesitation/bog and then will accelerate. This is increased as elevation increases.

Each time I take it back they say they found something minor and say all is well: spark plugs, spark plug connector, fuel screw adjustment. I don't think they are test driving it and that my explanation is not getting through to them. A test drive at elevation would surely let the mechanic diagnose the issue but that is a long drive for them and I don't think they are or have done this. I didn't have any issues before they worked on it.
Did they adjust the carburetor for too low of an altitude?

Air/Fuel mix is off?
Fouling?

Can anyone help me understand the possible issue so I can direct the dealer to the issue so they can address it?

cl65ame · 08-03-2012, 08:01 PM

there is an adjustment in the manual for operation at hight altitude (above 6000ft ASL). The bike is geting too rich Turn the pilots IN 1/2 turn and see what happens be sure to fix it when back at a lower elevation

93gc40 · 08-03-2012, 08:27 PM

How much daily altitude change we talking here, from what to what? Is exhaust and intake stock? I would start by getting a manual and quit PAYING for gueses, you can do that for free. Sounds to me like you are running rich. Could be over jetted, or a sticky or miss adjusted float or chokes or sticky slide. Could also be weak charging system or ignition.

cl65ame · 08-04-2012, 03:53 PM

Small aircraft suffer this same issue only they can adjust their fuel mixture on the fly. Increase altitude decrease fuel and vice versa.
The manual tells you how to make this adjustment specifically for operating at altitude.

08-03-2012, 07:47 PM	#1 (permalink)
shadow_94 Junior Member Join Date: Aug 2012 Posts: 4	Bogging at rise in altidude Bogging at altitude I have a Shadow VT1100 1994. After the winter I took my bike in when it would not start. The dealer got it running, flushed the fuel system and cleaned the carburetors. The bike runs ok in town but had a slight hesitation when applying throttle. If I ride at an increased elevation the bike will what I think is "fouling" and has almost completely quit on me at very high elevation. At a constant speed,60-70 mph, giving a little throttle will cause hesitation/bog and then will accelerate. This is increased as elevation increases. Each time I take it back they say they found something minor and say all is well: spark plugs, spark plug connector, fuel screw adjustment. I don't think they are test driving it and that my explanation is not getting through to them. A test drive at elevation would surely let the mechanic diagnose the issue but that is a long drive for them and I don't think they are or have done this. I didn't have any issues before they worked on it. Did they adjust the carburetor for too low of an altitude? Air/Fuel mix is off? Fouling? Can anyone help me understand the possible issue so I can direct the dealer to the issue so they can address it?

08-03-2012, 08:27 PM	#3 (permalink)
93gc40 Senior Member Join Date: Nov 2008 Location: Visalia, CA Posts: 4,331	How much daily altitude change we talking here, from what to what? Is exhaust and intake stock? I would start by getting a manual and quit PAYING for gueses, you can do that for free. Sounds to me like you are running rich. Could be over jetted, or a sticky or miss adjusted float or chokes or sticky slide. Could also be weak charging system or ignition. __________________ 93 VT1100C Harley Killer (1150cc), VH Exhaust, 2mm sleeved and bored, Modified Heads and Valves, Adjustable Timing, Touring Seat, Baby Apes, Metzlers

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