Diagnose This Bike Fault - Skills Test

[gleno]

OK. Sherlocks.

This is a skills test for you petrol heads who want to test their motorcycle fault diagnosing prowess. :ummm:

This quizz is based on a true story.

I can usually sort out engine problems PDQ but I have just spent two days working on a friend?s Honda CX500 trying to figure out why the bastard wouldn't start.

Problem is now solved and the bike is now running like a gem. :clapping:

Now it?s your turn to put your skills to the test.

Let?s see if you can diagnose the problem. Are you up for it?


Bike: Honda
Model : CX500
Year: 1980
Odometer Reading: 53,000kms on the clock.
Picture: Attached

Recent History : Running fine prior to being parked under an awning for eight months.

Specs:

Engine and Transmission
Displacement : 497.00 ccm (30.33 cubic inches)
Engine type : V2
Stroke : 4
Power : 50.00 HP (36.5 kW)) @ 9000 RPM
Compression : 10.0:1
Bore x stroke : 78.0 x 52.0 mm (3.1 x 2.0 inches)
Valves per cylinder : 4
Fuel control:OHV - Carburetor, Kei Hin CV 35mm Venturi Bore
Cooling system : Liquid
Gearbox : 5-speed
Transmission type
Final drive : Shaft drive (cardan)
Physical measures
Weight incl. oil, gas, etc : 221.0 kg (487.2 pounds)
Chassis and dimensions
Front tyre dimensions : 3.25-19
Rear tyre dimensions : 3.75-18
Front brakes : Dual disc
Rear brakes : Expanding brake
Speed and acceleration
Top speed :176.0 km/h (109.4 mph)
Other specifications
Fuel capacity:17.00 litres (4.49 gallons) 87 Octane

OK ARE YOU READY?

START YOUR ENGINE.

The battery is fully charged.

You crank the starter, the engine turns over and and it splutters to life. It's running very rough and finally splutters and dies after about 10 seconds.

You hit the starter again and it splutters, almost starts and dies again.

Using the choke gets the same result.

You continue to crank the starter trying all the combinations of choke and throttle until the battery gives battery gives up.

While the battery is on the charger you pull the plugs. They are wet and sooty.

You clean and gap the plugs, replace the re-charged battery and check for spark by grounding them plugs to the rocker covers and cranking the starter.

You have a big fat spark at both cylinders.

WHAT DO YOU DO NEXT?

 

[Thevmaxrider]

If it were me I would be looking inside the airbox for the critter that has now made a home there. There are only 3 things an engine needs to run: fuel, spark, and air. With wet plugs (I am assuming that the fuel was properly treated and no water in it) and good spark I start looking at a plugged up airway. Of course as I said that is assuming that no water got into the gas tank during storage. If water intrusion is the case, dump the fuel out of the tank, refill with fresh gas, and try again:biglaugh:

 

[slowpoke]

its a honda, burn it to the ground.... :clapping:

id check the air box and make sure nothign has claimed it as a home and restricted air flow

 

[Thevmaxrider]

To add a bit to this, after looking at the picture again, check and make sure that the exhaust hasn't been plugged somehow by a critter or even worse filled by water during storage:bang head:

 

[slowpoke]

themaxrider beat me to it... i thought air box mainly because of the soot on the plugs tells me its probably not getting enough air to burn right... that and ive had my share of animals claim the air box as a home. it could very well be exhaust too. not lettign the gases escape would cause sooted and fouled plugs as well.

 

[gleno]

Drained old fuel. Refilled with fresh stuff.

Removed air box cover and checked the filter - all clear.

Removed, cleaned and reset the carbs - TWICE:bang head:

And if you nominated a blocked exhaust YOU WIN THE CIGAR :clapping:

I haven't seen a blocked exhaust since I stopped riding two strokes!!!

The little bugger (literally) pictured is a mud dauber wasp. This little dude had bricked up the exhaust outlets with a mud nest that was like concrete.

I didn't tweek to it till I removed the air box to observe the carbs blowing fuel vapour out of the carb inlets.

TWO DAYS for a friggin' insect house :bang head::bang head::bang head::bang head:

I even had one of these set up house in the hollow of my rear axle!!!!

If you are interested here's a link that tells you about them http://www.csiro.au/resources/MudWasps.html

 

[Thevmaxrider]

WOOOHOOO, my second guess was right:eusa_dance: Will have to go smoke a Cuban cigar tonight.

 

[gleno]

Next time I'll check with you first :thumbs up:

 

[Thevmaxrider]

Next time I'll check with you first :thumbs up:

LOL!!! Not right all the time, just most of it:rofl_200:

 

[gamorg02]

jesus that musta been a pain in the ass... glad u figured it out tho! not sure if i woulda thought of that after a while, altho with supertrapps its hard for anything to get in, but whenever i put a bike to rest for a while i stuff any holes i can (thats what she said)....

 

[gleno]

jesus that musta been a pain in the ass....

I thought I was losing my mind and I'd stuffed up the carbs (hence second strip down). In the end I thought "Hang on, this things an air pump. Why is it pumping out of the inlets?"

Put my hand down to the exhaust outlet. NOTHING.

Had a look and it was walled up with adobe.

Clever little wasps.

 

[maleko89]

Wow,PITA!

I knew there was a reason I cover up my muffer outlets with bread sacks!

 

[HDKILA]

Wow,PITA!

I knew there was a reason I cover up my muffer outlets with ball sacks!

Mark...take it easy with those. :biglaugh::eusa_dance:

And I am glad you got it running right! It can be frustrating to go through things without results. I'm sure it felt good to find it!

 

[gamorg02]

now the next question... how hard was it to get the 'mud' outa there?

 

[cambo]

Drained old fuel. Refilled with fresh stuff.

Removed air box cover and checked the filter - all clear.

Removed, cleaned and reset the carbs - TWICE:bang head:

And if you nominated a blocked exhaust YOU WIN THE CIGAR :clapping:

I haven't seen a blocked exhaust since I stopped riding two strokes!!!

The little bugger (literally) pictured is a mud dauber wasp. This little dude had bricked up the exhaust outlets with a mud nest that was like concrete.

I didn't tweek to it till I removed the air box to observe the carbs blowing fuel vapour out of the carb inlets.

TWO DAYS for a friggin' insect house :bang head::bang head::bang head::bang head:

I even had one of these set up house in the hollow of my rear axle!!!!

If you are interested here's a link that tells you about them http://www.csiro.au/resources/MudWasps.html

I hate those things. We have wasps in MI that do the same thing. They blocked a water discharge hose on my outboard one year, and if I had not noticed it when I did, it could have caused serious damage. Now I always check for them. I wonder if mud dauber "vandalism" is covered by insurance?

 

[gleno]

now the next question... how hard was it to get the 'mud' outa there?

The mud is harder than an adobe brick but it broke away from the carbon on the exhaust pipe pretty cleanly. So it was the carbon that broke up not so much the mud. Used a wire rod to do the job but I'm sure there are bits in the silencer.

It's not a good idea to be standing behind this bike when you go to WOT :rofl_200:

 

[lankeeyankee]

OK,, The first problem is that its a Honda!
2nd problem its a 1980
Which leaves me to the problem of .....its a piece of shit.

You would be lucky if it sinks in a large body of water.

OK. Sherlocks.

This is a skills test for you petrol heads who want to test their motorcycle fault diagnosing prowess. :ummm:

This quizz is based on a true story.

I can usually sort out engine problems PDQ but I have just spent two days working on a friend?s Honda CX500 trying to figure out why the bastard wouldn't start.

Problem is now solved and the bike is now running like a gem. :clapping:

Now it?s your turn to put your skills to the test.

Let?s see if you can diagnose the problem. Are you up for it?


Bike: Honda
Model : CX500
Year: 1980
Odometer Reading: 53,000kms on the clock.
Picture: Attached

Recent History : Running fine prior to being parked under an awning for eight months.

Specs:

Engine and Transmission
Displacement : 497.00 ccm (30.33 cubic inches)
Engine type : V2
Stroke : 4
Power : 50.00 HP (36.5 kW)) @ 9000 RPM
Compression : 10.0:1
Bore x stroke : 78.0 x 52.0 mm (3.1 x 2.0 inches)
Valves per cylinder : 4
Fuel control:OHV - Carburetor, Kei Hin CV 35mm Venturi Bore
Cooling system : Liquid
Gearbox : 5-speed
Transmission type
Final drive : Shaft drive (cardan)
Physical measures
Weight incl. oil, gas, etc : 221.0 kg (487.2 pounds)
Chassis and dimensions
Front tyre dimensions : 3.25-19
Rear tyre dimensions : 3.75-18
Front brakes : Dual disc
Rear brakes : Expanding brake
Speed and acceleration
Top speed :176.0 km/h (109.4 mph)
Other specifications
Fuel capacity:17.00 litres (4.49 gallons) 87 Octane

OK ARE YOU READY?

START YOUR ENGINE.

The battery is fully charged.

You crank the starter, the engine turns over and and it splutters to life. It's running very rough and finally splutters and dies after about 10 seconds.

You hit the starter again and it splutters, almost starts and dies again.

Using the choke gets the same result.

You continue to crank the starter trying all the combinations of choke and throttle until the battery gives battery gives up.

While the battery is on the charger you pull the plugs. They are wet and sooty.

You clean and gap the plugs, replace the re-charged battery and check for spark by grounding them plugs to the rocker covers and cranking the starter.

You have a big fat spark at both cylinders.

WHAT DO YOU DO NEXT?

 

[gleno]

OK,, The first problem is that its a Honda!
2nd problem its a 1980
Which leaves me to the problem of .....its a piece of shit.

You would be lucky if it sinks in a large body of water.

:th_image003:Thanks Yankee. You just made me $20 bucks.

You are so predictable I bet the Honda owner you wouldn't be able to stay out of this one AND you would say pretty much what you just did. :clapping:

Be sure to watch out for my next thread. I've got more mods to pay for. :rofl_200:

 

[lankeeyankee]

No problem Gleno just speaking my thoughts in all honesty..

I like Honda offroad products and cars, but I am just not impressed with there motorcycles.. They make good solid reliable equipment but it just cant hang with its competetors.

I am a racer and into speed so Honda motorcycles arent for me. Not saying they arent good bikes so all you honda owners dont get all wound up! LOL

Hoot Hoot !!