Suzuki 800 Intruder Club & Forum
Welcome to suzuki800 Intruder forum

A UK Site Dedicated To The Suzuki C800, VL800, VX800, VZ800, VS800, C50, M50, Intruder / Boulevard / Marauder.

You will need to register before all the area's become visible, before doing so please enter & read the first thread in the Introductory area

It will only take a minute to register & it would be great to have you on board
This is a free to access and use site.
Suzuki 800 Intruder Club & Forum
Welcome to suzuki800 Intruder forum

A UK Site Dedicated To The Suzuki C800, VL800, VX800, VZ800, VS800, C50, M50, Intruder / Boulevard / Marauder.

You will need to register before all the area's become visible, before doing so please enter & read the first thread in the Introductory area

It will only take a minute to register & it would be great to have you on board
This is a free to access and use site.
Suzuki 800 Intruder Club & Forum
Would you like to react to this message? Create an account in a few clicks or log in to continue.

Suzuki 800 Intruder Club & Forum

A UK Site Dedicated To The Suzuki C800, VL800, VX800, M800, VZ800, VS800, C50, M50 Model Intruder / Boulevard / Marauder
 
HomeLatest imagesRegisterLog in

 

 Rear cylinder coughing very hard

Go down 
4 posters
AuthorMessage
Capt Willy
Prospect
Capt Willy



Rear cylinder coughing very hard Empty
PostSubject: Rear cylinder coughing very hard   Rear cylinder coughing very hard Icon_minitimeFri Jan 16, 2015 5:26 am

Gents,

I've got an issue and I'm looking for information for inspiration.  Here's the low down.

(The following has the front cylinder plug wire disconnected to run only on the rear)

Rear cylinder will fire and idle for a few seconds sounding pretty normal,  Very shortly thereafter, it starts to cough and belch thick, rich smelling, light gray/white smoke.  The cadence of the coughs sound like it's only firing on every 4th or 5th revolution and with each labored fire, there's an accompanying belch of smoke.

I pulled the rear carb, tore it down, and cleaned all jets, checked the diaphragm visually, and reinstalled it.  Compression, while low at 135psi, is the same as on the (healthy firing) front cylinder.

It runs a bit without choke, but will stall and then resist turning over again.  Have to crank it and give her a lot of throttle stroking.

I swapped the coils, and trimmed a bit of the wires.  I checked for spark, and both front and rear seem about the same intensity of blue/white.

The plug is dark and oily. I've tried the hotter NGK and their Iridium plugs - same thing.

Fuel is good 91 octane and non ethanol..

It feels like fuel starvation, but I can't see how.  I'm thinking it's cylinder walls or rings.  Or valves.  Or maybe both.  Something that doesn't involve cracking the motor would be preferable!

Your thoughts will be welcomed!

Ride safe.

Capt. Willy
Rochester, NY USA
Back to top Go down
simbo
* Site Guru *
simbo



Rear cylinder coughing very hard Empty
PostSubject: Re: Rear cylinder coughing very hard   Rear cylinder coughing very hard Icon_minitimeFri Jan 16, 2015 5:29 pm

Capt Willy wrote:
Gents,

I've got an issue and I'm looking for information for inspiration.  Here's the low down.

(The following has the front cylinder plug wire disconnected to run only on the rear)

Rear cylinder will fire and idle for a few seconds sounding pretty normal,  Very shortly thereafter, it starts to cough and belch thick, rich smelling, light gray/white smoke.  The cadence of the coughs sound like it's only firing on every 4th or 5th revolution and with each labored fire, there's an accompanying belch of smoke.

I pulled the rear carb, tore it down, and cleaned all jets, checked the diaphragm visually, and reinstalled it.  Compression, while low at 135psi, is the same as on the (healthy firing) front cylinder.

It runs a bit without choke, but will stall and then resist turning over again.  Have to crank it and give her a lot of throttle stroking.

I swapped the coils, and trimmed a bit of the wires.  I checked for spark, and both front and rear seem about the same intensity of blue/white.

The plug is dark and oily. I've tried the hotter NGK and their Iridium plugs - same thing.

Fuel is good 91 octane and non ethanol..

It feels like fuel starvation, but I can't see how.  I'm thinking it's cylinder walls or rings.  Or valves.  Or maybe both.  Something that doesn't involve cracking the motor would be preferable!

Your thoughts will be welcomed!

Ride safe.

Capt. Willy
Rochester, NY USA

Grey/White smoke sounds like water in the cylinder to me, How's the coolant look? is there any Creamy like substance in the Oil filler cap?.
Back to top Go down
G.Terence
Valued Member
G.Terence



Rear cylinder coughing very hard Empty
PostSubject: Re: Rear cylinder coughing very hard   Rear cylinder coughing very hard Icon_minitimeFri Jan 16, 2015 6:16 pm

Capt,
I concur with Simbo, it could well be a gasket. Drain the oil and look for water.

G. Terence
Back to top Go down
Capt Willy
Prospect
Capt Willy



Rear cylinder coughing very hard Empty
PostSubject: Re: Rear cylinder coughing very hard   Rear cylinder coughing very hard Icon_minitimeFri Jan 16, 2015 6:35 pm

First item - thank you both for your replies.

If the oil/water barrier is compromised would I not see cloudy oil through the viewing glass?  I will take a look and try to answer my own question.

It's not an unreasonable hypothesis (coolant in the cylinder) and it does fit the symptoms.  One item I failed to mention was the oil smelled of gas.  If coolant was hampering ignition, fuel from the power stroke would have to accumulate in the oil.

Any other input from you or the group would be welcomed...

Cheers,
Capt. Willy
Back to top Go down
v-twin
Very Valued VIP Member
v-twin



Rear cylinder coughing very hard Empty
PostSubject: Re: Rear cylinder coughing very hard   Rear cylinder coughing very hard Icon_minitimeFri Jan 16, 2015 6:56 pm

I am not sure on the fuel system on your bike (manual or vacuum pet cock) but if you can smell fuel in the oil it sounds like the pet cock is leaking and has over filled the carb float and then run into the cylinder and through the rings and into the sump. If that is the case be careful as you could hydro-lock the cylinder causing some serious engine damage (as the petrol cannot compress). Drain the oil and check for fuel and replace. Then sort the pet-cock out.
Back to top Go down
Capt Willy
Prospect
Capt Willy



Rear cylinder coughing very hard Empty
PostSubject: Re: Rear cylinder coughing very hard   Rear cylinder coughing very hard Icon_minitimeFri Jan 16, 2015 7:14 pm

Thanks for the note, v-twin.

If the petcock is leaking and is over filling the carb, I'd think the rear air box would be a wet gassy mess (which it isn't).  Also, wouldn't a petcock problem affect the front cylinder as well?

Regardless of the cause, I'll need to change the oil.  It's definitely smells of fuel...

CW
Back to top Go down
v-twin
Very Valued VIP Member
v-twin



Rear cylinder coughing very hard Empty
PostSubject: Re: Rear cylinder coughing very hard   Rear cylinder coughing very hard Icon_minitimeFri Jan 16, 2015 7:18 pm

If the petcock is vacuum operated she could be leaking through the vacuum line directly into the inlet manifold and into the cylinder, bypassing the carb totally!!
Back to top Go down
Capt Willy
Prospect
Capt Willy



Rear cylinder coughing very hard Empty
PostSubject: Re: Rear cylinder coughing very hard   Rear cylinder coughing very hard Icon_minitimeFri Jan 16, 2015 10:45 pm

Well, my understanding is the VS800 petcock is not vacuum driven - it has a fuel pump.  I doubt that's my issue here.

Good thought though...

CW
Back to top Go down
Sponsored content





Rear cylinder coughing very hard Empty
PostSubject: Re: Rear cylinder coughing very hard   Rear cylinder coughing very hard Icon_minitime

Back to top Go down
 
Rear cylinder coughing very hard
Back to top 
Page 1 of 1

Permissions in this forum:You cannot reply to topics in this forum
Suzuki 800 Intruder Club & Forum :: The Garage :: FueI Injection Modules, Fuel, Jetting & Modifications, etc-
Jump to:  
Slide Show
A random selection of suzuki800.com member bikes.
Latest topics
» Looking for a set of Leg wind deflectors for a C50 Boulivard.
Rear cylinder coughing very hard Icon_minitimeby Aikido789 Yesterday at 10:11 am

» 12inch apes
Rear cylinder coughing very hard Icon_minitimeby bernard chaddock Wed Feb 21, 2024 5:06 pm

» Saying hello from Cheshire
Rear cylinder coughing very hard Icon_minitimeby bernard chaddock Wed Feb 21, 2024 4:58 pm

» ola de portugal
Rear cylinder coughing very hard Icon_minitimeby fabio almeida Tue Feb 20, 2024 9:28 am

» Hello from Texas
Rear cylinder coughing very hard Icon_minitimeby icoolwecool99@gmail.com Mon Feb 19, 2024 9:47 pm

» VX800 vacuum hose(s) 1996
Rear cylinder coughing very hard Icon_minitimeby Billybop90 Fri Feb 16, 2024 7:16 pm

» Chrome Fender Tips - Volusia VL800, Boulevard C50T
Rear cylinder coughing very hard Icon_minitimeby SWEET Fri Feb 16, 2024 6:25 pm

» New to the site
Rear cylinder coughing very hard Icon_minitimeby VAI777 Tue Feb 13, 2024 3:32 pm

» oldies but goldies
Rear cylinder coughing very hard Icon_minitimeby redevil Tue Feb 13, 2024 10:59 am

» My new M800
Rear cylinder coughing very hard Icon_minitimeby Urko Sun Feb 11, 2024 11:12 am

» Just visiting for final drive info...
Rear cylinder coughing very hard Icon_minitimeby CS_0427 Tue Feb 06, 2024 2:28 am

» Hello from the Isle of Wight
Rear cylinder coughing very hard Icon_minitimeby Badger Mon Feb 05, 2024 11:27 am

» Waking up a Sleeping VX800 in Alaska
Rear cylinder coughing very hard Icon_minitimeby John Silver Sun Feb 04, 2024 7:05 pm

» Will be making my own exhausts
Rear cylinder coughing very hard Icon_minitimeby JagLite Sun Feb 04, 2024 2:26 am

» just saying hello to this site
Rear cylinder coughing very hard Icon_minitimeby Mack Sun Jan 21, 2024 8:34 pm

» New old guy
Rear cylinder coughing very hard Icon_minitimeby Badger Sun Jan 14, 2024 8:26 pm

» Intruder C800 2008 Service Manual PDF?
Rear cylinder coughing very hard Icon_minitimeby Fergal Mon Jan 08, 2024 10:43 pm

» Anchorage Alaska Saying hello
Rear cylinder coughing very hard Icon_minitimeby JagLite Sat Jan 06, 2024 4:34 pm

» Hello from Slovenia
Rear cylinder coughing very hard Icon_minitimeby Urko Sat Jan 06, 2024 8:58 am

» Come and say hello
Rear cylinder coughing very hard Icon_minitimeby 03580 Wed Jan 03, 2024 7:26 am

Log in
Username:
Password:
Log in automatically: 
:: I forgot my password