[Archive] [Q&A] SBF CB400 Official Q&A Thread 2008

[PaLmEr]

Hi all

 

In an effort to keep the section organised for the benefit of all forumers, this thread will be closed on 1st Feb 2009 and the new Q&A thread shifted to here.

 

Please direct all new questions to the new thread with immediate effect.

 

Regards

Moderating Team

SBF CB400s

 

Links: SBF CB400 Official Q&A Thread 2009 (PLS ASK YOUR QUESTIONS HERE!)

[PaLmEr]

Some Common Q&A From Old Q&A Thread (Under Construction)

 

What is the purpose and function of repacking the muffler with fiber?

Repacking the muffler is generally to keep the noise level at a reasonable level.

 

 

Engine doesn't start or is difficult to start

(Contributed by Ah Pek)

Possible causes:

1) Starter motor doesn't rotate.

 

a) Engine kill switch OFF.

 

b) Fuse blown. Check main fuse.

 

c) Battery voltage low. Check and recharge battery.

 

d) Starter motor defective. Make sure the wiring to the starter is secure.

Make sure the starter relay clicks when the start button is pushed. If the

relay clicks, then the fault is in the wiring or motor.

 

e) Starter relay faulty.

 

f) Starter switch not contacting. The contacts could be wet, corroded or

dirty. Disassemble and clean the switch.

 

g) Wiring open or shorted. Check all wiring connections and harnesses to

make sure that they are dry, tight and not corroded. Also check for

broken or frayed wires that can cause a short to earth.

 

h) Ignition (main) switch defective. Renew the switch if it is defective.

 

i) Engine kill switch defective. Check for wet, dirty or corroded

contacts.

 

j) Faulty neutral, sidestand or clutch switch. Check the wiring to each

switch and the switch itself accordingly.

 

 

2) Starter motor rotates but engine does not turn over

 

a) Starter motor clutch defective. Inspect and repair or renew

 

b) Damaged idler or starter gears. Inspect and renew the damaged

parts.

 

3) Starter works but engine won't turn over (seized)

 

a) Seized engine caused by one or more internally damaged components:

Failure due to wear, abuse or lack of lubrication. Damage can include

seized valves, followers, camshafts, pistons, crankshaft, connecting rod

bearings, or transmission gears or bearings.

 

 

4) No fuel flow

 

a) No fuel in tank.

 

b) Fuel tank breather nose obstructed.

 

c) Fuel tap filter or in-line filter clogged. Remove the tap and clean it and the

filters.

 

d) Fuel line clogged. Pull the fuel line loose and carefully blow through it.

 

e) Float needle valve clogged. For all of the valves to be clogged, either a

very bad batch of fuel with an unusual additive has been used, or some

other foreign material has entered the tank. Many times after a machine

has been stored for many months without running, the fuel turns to a

varnish-like liquid and forms deposits on the inlet needle valves and jets.

 

The carburettors should be removed and overhauled if draining the float

chambers doesn't solve the problem.

 

5) Engine flooded

a) Float height too high.

 

b) Float needle valve worn or stuck open. A piece of dirt, rust or other debris

can cause the valve to seat improperly, causing excess fuel to be

admitted to the float chamber. In this case, the float chamber should be

cleaned and the needle valve and seat inspected. If the needle and seat

are worn, then the leaking will persist and the parts should be renewed

 

c) Starting technique incorrect. Under normal circumstances (ie, if all the

carburettor functions are sound) the machine should start with little or no

throttle. When the engine is cold, the choke should be operated and the

engine started without opening the throttle.

 

When the engine is at operating temperature, only a very slight amount of

throttle should be necessary. If the engine is flooded, turn the fuel tap

OFF and hold the throttle open while cranking the engine. This will allow

additional air to reach the cylinders. Remember to turn the fuel tap back

ON after the engine starts.

 

6) No spark or weak spark

 

a) Ignition switch OFF. Engine kill switch turned to the OFF position

Battery voltage low. Check and recharge the battery as necessary

Spark plugs dirty, defective or worn out. Locate reason for fouled plugs

using spark plug condition chart at the end of this manual and follow the

plug maintenance procedures.

 

b) Spark plug caps or secondary (HT) wiring faulty. Check condition. Renew

if cracks or deterioration are evident.

 

c) Spark plug caps not making good contact. Make sure that the plug

caps fit snugly over the plug ends.

 

d) Ignition control unit defective.

 

e) Pulse generator coil(s) defective.

 

f) Ignition HT coils defective.

 

g) Ignition or kill switch shorted. This is usually caused by water, corrosion, damage or excessive wear. The switches can be disassembled and cleaned

with electrical contact cleaner. If cleaning does not help, renew the

switches.

 

h) Wiring shorted or broken between:

i) Ignition (main) switch and engine kill switch (or blown fuse)

ii) Ignition control unit and engine kill switch

iii) Ignition control unit and ignition HT coils

iv) Ignition HT coils and spark plugs

v) Ignition control unit and pulse generatorâ–¡ Make sure that all wiring connections are clean, dry and tight. Look for chafed and broken wires.

 

7) Engine Compression low

 

a) Spark plugs loose. Remove the plugs and inspect their threads. Reinstall and tighten securely.

b) Cylinder head not sufficiently tightened down. If the cylinder head is suspected of being loose, then there's a chance that the gasket or head is damaged if the problem has persisted for any length of time. The head nuts should be tightened to the proper torque in the correct sequence.

 

c) Improper valve clearance. This means that the valve is not closing completely and compression pressure is leaking past the valve. Check and adjust the valve clearances.

 

d)Cylinder and/or piston worn. Excessive wear will cause compression pressure to leak past the rings. This is usually accompanied by worn rings as well. A top-end overhaul is necessary. Typical symptom will be white smoke coming out from your exhaust.

 

e) Piston rings worn, weak, broken, or sticking. Broken or sticking piston rings usually indicate a lubrication or carburation problem that causes excessive

carbon deposits or seizures to form on the pistons and rings. Top-end overhaul Is necessary.[/size]

 

f) Piston ring-to-groove clearance excessive. This is caused by excessive wear of the piston ring lands. Piston renewal is necessary.

 

g) Cylinder head gasket damaged, If a head is allowed to become loose, or if excessive carbon build-up on the piston crown and combustion chamber causes extremely high compression, the head gasket may leak. Retorquing

the head is not always sufficient to restore the seal, so gasket renewal is

necessary.

 

h) Cylinder head warped. This is caused by overheating or improperly

tightened head nuts. Machine shop resurfacing or head renewal is necessary.

 

 

 

My bike runs like #@!#@%@ at low speeds!! (Contributed by Ah Pek)

1) Spark weak

Possible Causes:

a) Battery voltage low. Check and recharge battery. Spark plugs fouled, defective or worn out.

 

b) Spark plug cap or HT wiring defective.

 

c) Spark plug caps not making contact.

 

d) Incorrect spark plugs. Wrong type, heat range or cap configuration.

 

e) Ignition control unit defective.

 

f) Pulse generator defective.

 

g) Ignition HT coils defective.

 

h) Fuel/air mixture incorrect:

i) Pilot screws out of adjustment.

ii) Pilot jet or air passage clogged. Remove and overhaul the carburettors.

iii) Air bleed holes clogged. Remove carburettor and blow out all passages.

iv) Air filter clogged, poorly sealed or missing.

v) Air filter housing poorly sealed. Look for cracks, holes or loose clamps and

renew or repair defective parts.

 

h) Fuel level too high or too low. Check the float height.

 

i) Fuel tank breather hose obstructed.

 

j) Carburettor inlet manifolds loose. Check for cracks, breaks, tears

or loose clamps. Renew the rubber inlet manifold joints if split or

perished.

 

k) Timing not advancing. The pulse generator or the ignition control module

may be defective. If so, they must be renewed, as they can't be repaired.

 

l) Carburettors not synchronised. Adjust then with a vacuum gauge set or

manometer.

 

m) Engine oil viscosity too high. Using a heavier oil than that recommended

can damage the oil pump or lubrication system and cause drag on the

engine.

 

n) Brakes dragging. Usually caused by debris which has entered the brake

piston seals, or from a warped disc or bent axle. Repair as necessary.

 

continue...

 

 

3 Poor running or no power at high speed.

 

Firing incorrect

Air filter restricted. Clean or renew filter.

 

Spark plugs fouled, defective or worn out.

 

Spark plug caps or HT wiring defective.

 

Spark plug caps not in good contact.

 

Incorrect spark plugs. Wrong type, heat range or cap configuration.

 

Ignition control unit defective.

 

Ignition HT coils defective.

 

 

Fuel/air mixture incorrect

Main jet clogged. Dirt, water or other contaminants can clog the main jets. Clean the fuel tap filter, the in-line filter, the float chamber area, and the jets and carburettor orifices.

Main jet wrong size. Th9 standard jetting is for sea level atmospheric pressure and oxygen content.

Air bleed holes clogged. Remove and overhaul carburettors.

Air filter clogged, poorly sealed, or missing.

Air filter housing poorly sealed. Look for cracks, holes or loose clamps, and renew defective parts.

Fuel level too high or too low. Check the float height.

 

Fuel tank breather hose obstructed.

 

Carburettor inlet manifolds loose. Check for cracks, breaks, tears or loose clamps. Renew the rubber inlet manifolds if they are split or perished.

[PaLmEr]

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[rapalla]

My front wheel currently got this squiking sound like something rub against something. I check it bot there is nothing rubbing. I suspect it's the front wheel bearing, coz when I hold my front tyre and move it from side to side I find it loose a bit. Is front bearing the couse of it???

[inspire85]

My front wheel currently got this squiking sound like something rub against something. I check it bot there is nothing rubbing. I suspect it's the front wheel bearing, coz when I hold my front tyre and move it from side to side I find it loose a bit. Is front bearing the couse of it???

 

 

Botak brake pad rub against brake disc oso will have squiking sound..

[weixiang]

Hi Guys/gals..

 

Attached a few pics inside, pls advise if i should go for repaint or relacquer..?

If relacquer i guess they still need to paint touch up my faded parts hor..??

 

http://img165.imageshack.us/img165/4193/sfcb4001wy3.jpg

http://img171.imageshack.us/img171/3994/sfcb4002nc2.jpg

http://img165.imageshack.us/img165/4878/sfcb4003ba0.jpg

[BIKER1605199362]

Hi Guys/gals..

 

Attached a few pics inside, pls advise if i should go for repaint or relacquer..?

If relacquer i guess they still need to paint touch up my faded parts hor..??

 

http://img165.imageshack.us/img165/4193/sfcb4001wy3.jpg

http://img171.imageshack.us/img171/3994/sfcb4002nc2.jpg

http://img165.imageshack.us/img165/4878/sfcb4003ba0.jpg

 

my suggestion... tank bra..... :cheeky:

[B.e.n.s.o.n]

Hi Guys/gals..

 

Attached a few pics inside, pls advise if i should go for repaint or relacquer..?

If relacquer i guess they still need to paint touch up my faded parts hor..??

 

http://img165.imageshack.us/img165/4193/sfcb4001wy3.jpg

http://img171.imageshack.us/img171/3994/sfcb4002nc2.jpg

http://img165.imageshack.us/img165/4878/sfcb4003ba0.jpg

 

respray bro....

[logen1836]

Hi Guys/gals..

 

Attached a few pics inside, pls advise if i should go for repaint or relacquer..?

If relacquer i guess they still need to paint touch up my faded parts hor..??

 

http://img165.imageshack.us/img165/4193/sfcb4001wy3.jpg

http://img171.imageshack.us/img171/3994/sfcb4002nc2.jpg

http://img165.imageshack.us/img165/4878/sfcb4003ba0.jpg

 

jus cover the black portion wid black stickers to cover the whole black portion.

do at Juzz Wheelz (Bukit Merah).not sure bout pricing.

den lacquer if u still want ya ori paintwork.

[I_Ride_A_Bike]

A useful and profitable thread for all.

 

esp. to those who gather at teckghee square for kopi etc...

 

"ah pek, i have ruffled your giant feathers! bollocks to be near!"

[GodSend]

IKER;4324447']my suggestion... tank bra..... :cheeky:

 

If the cost of respray is more then a Tank Bra's worth.. then i tink iker solution sounds gd....

[armyjeff]

hihi.. do any1 know e difference between vtec I & vtec II.

eg. the fc between them. which is better or e same or any difference or similarities between them... thx.. lots..

[weixiang]

alamak..i was hoping dun need to wear bra..!

hahaha....

 

wonder if can just respray affected area + relaquer..?

[PaLmEr]

alamak..i was hoping dun need to wear bra..!

hahaha....

 

wonder if can just respray affected area + relaquer..?

 

the effect will not be good. Recommended to do a full respray of the tank. While you are at it, maybe you would like to respray the tailboard and rims too, to give your bike a new lease of life.

[4DToToBig Sweep]

ONe got V Tec di aother 1s no lor:angel: :angel:

[Stardust83]

ONe got V Tec di aother 1s no lor:angel: :angel:

 

huh ? Vtec I and II both got Vtec lehz....

[Ah Pek]

Yah hor...may be a good place to start a reference for some basic trouble shooting and knowledge for S4 beginner owners..be it Vtec or non Vtec amchine.

 

Some of you guys are already quite up to it and can contribute just as much..one thing though..I'm not into bike comestic or help producing horsepower stuff. See how this thread goes for the next few days.

[BIKER1605199362]

ONe got V Tec di aother 1s no lor:angel: :angel:

 

Huh.. You comparing the correct bike or not??

then Spec 3 ? Got turbo ?? cause spec 2 got vtec..

 

huh ? Vtec I and II both got Vtec lehz....

 

LOL, my reaction was like ===> o_O o_O when i saw the reply...

 

 

Okie, basically to my understanding, Spec 2 Vtec opens at a different RPM..

I forgot what is the RPM... 6.3k for all gears except 6.8K for the last gear..

 

Then Spec 1 is 7k or 105KM/hr then vtec opens... basically is 7K for all gears.