[Discussion] Typical prices for Phantom repairs & mods

[singaporebikes.com]

hi there bros. i notice some phantoms outside. they mod their handle bars to a very straight one. and changed the mirrors to those rectangular shape ones. tht makes the phantom really smaller and nicer. does any bros know where to get those handlebars . ? and how much would tht cost? please help . thank you very much. !

[Simsci]

I am a trained vehicle mechanic from the then SVI way back in 1970-71 and was also VM/HPM instructor.

Regarding the two issues herein, carburetor sweats and backfire with throttle closed after high speed (or for "engine brake' during downslope drive/ride).

1. Carburetor "sweat": (warm air around engine/atmosphere condensed) due to venturi actions in carburetor, high velocity of air/fuel mixture rushing/flowing through cools down the carburetor body. This situation is the same as the condensation on the outside of a bottle/glass of ice cold drink. This is normal.

2. Engine "backfire": (unburnt gases in exhaust) when throttle is closed too suddenly after high revs, the air/fuel mixture became "too rich" for a complete combustion. The air/fuel mixture ratio for idling is richer than all speed except during cold starting. At that high rpm and the load driving the engine, yet with throttle at "idling" position, there will be incomplete combustion in the chamber. So, the unburnt gases flowing out of the chamber will eventually be ignited by hot exhaust gas creating that pop/explosion known as backfire. To reduce this backfire, do not closed the throttle fully suddenly.

Edited May 4, 2013 by Simsci

[sawfly]

I am a trained vehicle mechanic from the then SVI way back in 1970-71 and was also VM/HPM instructor.

Regarding the two issues herein, carburetor sweats and backfire with throttle closed after high speed (or for "engine brake' during downslope drive/ride).

1. Carburetor "sweat": (warm air around engine/atmosphere condensed) due to venturi actions in carburetor, high velocity of air/fuel mixture rushing/flowing through cools down the carburetor body. This situation is the same as the condensation on the outside of a bottle/glass of ice cold drink. This is normal.

2. Engine "backfire": (unburnt gases in exhaust) when throttle is closed too suddenly after high revs, the air/fuel mixture became "too rich" for a complete combustion. The air/fuel mixture ratio for idling is richer than all speed except during cold starting. At that high rpm and the load driving the engine, yet with throttle at "idling" position, there will be incomplete combustion in the chamber. So, the unburnt gases flowing out of the chamber will eventually be ignited by hot exhaust gas creating that pop/explosion known as backfire. To reduce this backfire, do not closed the throttle fully suddenly.

 

now finally something enlightening on the sweating! thanks for info on this!

regarding the backfire though, when i went for svc the mech said is because of the air valve inside that causes popping, and in the honda common svc manual it says its because of "sudden" lean conditions when throttle suddenly released... now im confused cos you mentioned its an over rich condition when returning to idle!

 

he said no need to change though.. cos even if change air valve later one year later the backfire issue will come back... costs 65$ =X

[Simsci]

Oh, pls don't get confused.

Gradual throttle widening (opening for acceleration) more and more air/fuel mixture (by volume) is drawn into combustion chamber for ignitions to increase engine rpm. But, in situation when the throttle is suddenly (not gradual) closed, there is a sudden "choking" effect resulting in lesser air/fuel mixture entering the chamber, so the engine rpm drops in instant response.

 

If the bike/car is ridden on a level gradient with clutch (not automatic transmission) engaged, there is corresponding vehicle drag (engine brake) causing the load (rider/driver) to be "thrown" jerk forward.

 

In other words,

Simultaneously, with throttle shut and engine in operation, suction from combustion chamber is not felt at the main fuel jet, now air/fuel mixture came from the idling/transfer or progression/regression circuit instead, which has a "richer" ratio but lesser in volume as compared to the main jet channel when throttle is open.

The load (rider & bike) which is still in forward motion momentum is "driving" the engine which is retarding due to lesser (not lean) air/fuel mixture drawn into combustion chamber with throttle closed.........thus resulting in engine braking action. And, this is also the time when "back-fire" occurs if there is any unburnt gases in the exhaust due to many other reasons, including improper air/exhaust valves gap setting, valve seats worn, improper ignition timing, carbon deposits in/on parts exposed to high compression/high temperature or too-low octane fuel used.

 

The fuel carburetor with its well calibrated air and fuel jets for the various circuits and in-built adjusting mechanisms can provides optimum performance without those "back-fires" if the engine including its carburetor are supported with proper service and maintenance. When cleaning the carburetor, do not use any hard object to clean the ports and jet holes. Any widening of these calibrated components will results in altering the air/fuel mixture ratio and with that the engine performance and fuel consumption.

 

I hope it is not too technical and this helps.

[sawfly]

Oh, pls don't get confused.

Gradual throttle widening (opening for acceleration) more and more air/fuel mixture (by volume) is drawn into combustion chamber for ignitions to increase engine rpm. But, in situation when the throttle is suddenly (not gradual) closed, there is a sudden "choking" effect resulting in lesser air/fuel mixture entering the chamber, so the engine rpm drops in instant response.

 

If the bike/car is ridden on a level gradient with clutch (not automatic transmission) engaged, there is corresponding vehicle drag (engine brake) causing the load (rider/driver) to be "thrown" jerk forward.

 

In other words,

Simultaneously, with throttle shut and engine in operation, suction from combustion chamber is not felt at the main fuel jet, now air/fuel mixture came from the idling/transfer or progression/regression circuit instead, which has a "richer" ratio but lesser in volume as compared to the main jet channel when throttle is open.

The load (rider & bike) which is still in forward motion momentum is "driving" the engine which is retarding due to lesser (not lean) air/fuel mixture drawn into combustion chamber with throttle closed.........thus resulting in engine braking action. And, this is also the time when "back-fire" occurs if there is any unburnt gases in the exhaust due to many other reasons, including improper air/exhaust valves gap setting, valve seats worn, improper ignition timing, carbon deposits in/on parts exposed to high compression/high temperature or too-low octane fuel used.

 

The fuel carburetor with its well calibrated air and fuel jets for the various circuits and in-built adjusting mechanisms can provides optimum performance without those "back-fires" if the engine including its carburetor are supported with proper service and maintenance. When cleaning the carburetor, do not use any hard object to clean the ports and jet holes. Any widening of these calibrated components will results in altering the air/fuel mixture ratio and with that the engine performance and fuel consumption.

 

I hope it is not too technical and this helps.

 

wow... im actually confused becos of this in the service manual.. =S

 

http://dropproxy.com/f/254

Edited May 6, 2013 by sawfly

[Simsci]

Hi sawfly,

Agree with you, you are confused.

The attached diagram/s is about EECS - to provide an alternative source of air (oxygen) to the hot exhaust manifold (not combustion chamber) during normal deceleration (gradual, not sudden) in normal engine operation. Its purpose as named is to maintain a cleaner emission from the engine. But, if the vacuum tube is at fault (clogged, leaking or missing), other problems, including backfires, are possible.

[sawfly]

Hi sawfly,

Agree with you, you are confused.

The attached diagram/s is about EECS - to provide an alternative source of air (oxygen) to the hot exhaust manifold (not combustion chamber) during normal deceleration (gradual, not sudden) in normal engine operation. Its purpose as named is to maintain a cleaner emission from the engine. But, if the vacuum tube is at fault (clogged, leaking or missing), other problems, including backfires, are possible.

 

Err.. how about the air cut off valve in the pic on the left? Its not part of the secondary air system for emissions control. .

 

edit: im including this for reference.. see 8-7 for the air cut off valve..

 

http://downloads.hondatech.info/Moto/Common/Honda_Common_Service_Manual.pdf

 

the air cut off valve is located on the carb.. thats why i confused when they say it activates to *cut off* air during close throttle conditions where it will suddenly become lean.. by cutting off air it will richen the mixture and prevent a lean mixture backfire resultant from the high vacuum state that causes a misfire..

 

 

 

 

Sent from my GT-I9300

Edited May 8, 2013 by sawfly

[Simsci]

The ACV is a "governor" in a seperate circuit (different from the EECS) of the air/fuel intake system.

 

As appended in page 8-7 of the Service Manual:

AIR CUT-OFF VALVE (ACV)

When the throttle lever is turned in the "close" direction and engine braking is applied (effected), the fuel mixture becomes lean. An ignited air/fuel mixture is discharged into the exhaust pipe, resulting the afterburn. To prevent this afterburn, the air cut-off valve shuts the air passage to the slow jet to temporarily make the fuel mixture rich.

 

With the throttle valve closed and the vacuum in the main bore increased, vacuum in the air cut-off valve also increases and moves the diaphragm to shut the air passage.

 

With the vacuum in the main bore decreased, the spring moves the diaphragm backward and opens the air passage.

================================================================================

Copied and pasted, from another source:

The ACV is an extremely important part of the air/fuel intake system that is frequently missed even by competent mechanics, most of whom are not aware of its existence or how it functions.

 

The valve is a "air blocker", along with the carburetor, serving to restrict air flow and increase the air/fuel mixture ratio when the carburetor slide is in the lower rpm range up to throttle fully closed, so that the engine will start and idle smoothly and during sudden acceleration and deceleration, meaning with the throttle at any position.

 

When typical starting requires heavy and prolonged choking to keep the engine running, when stalling and uneven operation occurs during normal running temperature and when "back-fires" while the throttle is closed while cruising to effect engine brake, most tinkerer will starts "adjusting" the air screws and try overcoming the "problem", only making the matter worse along with reducing their fuel mileage.

 

Running with faulty ACV can cause severe engine damage or failure. When the ACV is not functioning, the engine pulls nearly total air in the low RPM range through the carburetor into the combustion chamber. The air/fuel ratio is extremely poor resulting in pre-ignition, generating an enormous amount of heat, with no power, which is trapped a longer period of time in the cylinder before the exhaust valve opens.

Edited May 8, 2013 by Simsci
highlighting colours.

[Simsci]

Sorry.

Edited May 8, 2013 by Simsci
Duplicate post.

[sawfly]

The ACV is a "governor" in a seperate circuit (different from the EECS) of the air/fuel intake system.

 

As appended in page 8-7 of the Service Manual:

AIR CUT-OFF VALVE (ACV)

When the throttle lever is turned in the "close" direction and engine braking is applied (effected), the fuel mixture becomes lean. An ignited air/fuel mixture is discharged into the exhaust pipe, resulting the afterburn. To prevent this afterburn, the air cut-off valve shuts the air passage to the slow jet to temporarily make the fuel mixture rich.

 

With the throttle valve closed and the vacuum in the main bore increased, vacuum in the air cut-off valve also increases and moves the diaphragm to shut the air passage.

 

With the vacuum in the main bore decreased, the spring moves the diaphragm backward and opens the air passage.

================================================================================

Copied and pasted, from another source:

The ACV is an extremely important part of the air/fuel intake system that is frequently missed even by competent mechanics, most of whom are not aware of its existence or how it functions.

 

The valve is a "air blocker", along with the carburetor, serving to restrict air flow and increase the air/fuel mixture ratio when the carburetor slide is in the lower rpm range up to throttle fully closed, so that the engine will start and idle smoothly and during sudden acceleration and deceleration, meaning with the throttle at any position.

 

When typical starting requires heavy and prolonged choking to keep the engine running, when stalling and uneven operation occurs during normal running temperature and when "back-fires" while the throttle is closed while cruising to effect engine brake, most tinkerer will starts "adjusting" the air screws and try overcoming the "problem", only making the matter worse along with reducing their fuel mileage.

 

Running with faulty ACV can cause severe engine damage or failure. When the ACV is not functioning, the engine pulls nearly total air in the low RPM range through the carburetor into the combustion chamber. The air/fuel ratio is extremely poor resulting in pre-ignition, generating an enormous amount of heat, with no power, which is trapped a longer period of time in the cylinder before the exhaust valve opens.

 

wow... wall of text.. but i unds liao!! thanks for clearing up!

just wondering now when the mechanic say replace air valve.. dunno if its ACV or the EECS air valve though.. looks like i should just go replace the thing liao!

[Simsci]

Replacing it is the correct move! Enjoy your ride!

[sawfly]

Replacing it is the correct move! Enjoy your ride!

 

Yeap! Thanks for the advice lo! =D

 

Sent from my GT-I9300

[dhomosapien]

--deleted--

Edited December 3, 2013 by dhomosapien

[TianLei]

Anyone Re-wrap seat before?

At where?

[Simsci]

Will this do?

http://www.singaporebikes.com/forums/showthread.php/230024-Custom-Bike-Seats

[ahch0ng]

Hi, I'm a complete noob so please forgive me for asking this..

How much does it cost to install the metal tubes (I'm sure I can find this topic somewhere in here, but I do not know what it's called so hard to search) onto the upper part of the fork, similar to those on the fire edition phantoms? And, are they easily available, legal, etc..?

 

Thanks

 

i think u are looking for those fork guard...

 

lim ah boy shld be selling them

[dhomosapien]

i think u are looking for those fork guard...

[ATTACH=CONFIG]278158[/ATTACH]

 

lim ah boy shld be selling them

 

Thanks. Yup that's the one. How much should the cost roughly be? Scared kena carrot.

[kzone]

Wah dats nice.. Is it specific for phantom? LAB install as well?

Btw, anyone knows where to get a complete respray including the frame? All the places I went only do tank n fenders

[jtzx]

Wah dats nice.. Is it specific for phantom? LAB install as well?

Btw, anyone knows where to get a complete respray including the frame? All the places I went only do tank n fenders

 

just DIY a fork guard could do the trick. cause extra metal means bike heaviler and drain more petrol as well..

[kzone]

Not really a DIY person... If its the custom 4 material, shud be light enuff. Gonna renew my Coe soon. Thought of doing a makeover

[Spark_135]

Not really a DIY person... If its the custom 4 material, shud be light enuff. Gonna renew my Coe soon. Thought of doing a makeover

 

The metal wont weight more than 10kg i suppose. At most is 5kg or less, rough estimate. Won't cause much of increase in FC If DIY just make sure its smooth design, dont add air resistance can liao.

[wizardtan]

Hi where can I install hazard light & high beam switch? Thanks

[TianLei]

Anyone Re-wrap seat before?

At where?

Done at aunti sop.

$50 include the back support.

Price vary from the cloth you choose to wrap.

[jtzx]

Eugene sadderllary at jalan besah. around $40

[reaper_y]

Hi where can I install hazard light & high beam switch? Thanks

 

Hi, bro wizardtan. Most workshops will be able to do that. They just need to be willing and have the necessary parts.