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Discussion Starter #1 (Edited)
TROUBLESHOOTING 101 and vast technobabble

ok. theres a constant rash of simple shit on here that results of either not searching or not knowing mechanical stuff.. hopefully this will kinda guide you in the right steps..
I will probably amend this in time to include other issues but for now, basic troubleshooting stuff is outlined here with some info as to why the problem occurs. as well, it's a compilation of some write-ups i've done a few years back too..
About me.. I am a career blue-collar guy... lol i possess a degree in electrical engineering specializing in industrial motor controls, automation and programming. I owned/operated a shop in hagerstown, maryland for 5 years building high-perf cars and bike, was a lead tech at another small shop in WV for 2 more after that building race bikes and quads.. all of which placed on the podium first time out. after moving to NC i secured a job as a tech and fabricator for a local german car speed shop building $180,000 M3s and porsches. I also worked carbon fiber for the #38 ADT/Audi team (champion racing out of pompano beach, fla.) in 2002.. the car was a LMP900 class Audi R8.
what i've gained to share here over the years is some no-bullshit stuff. feel free to hit me up for info or greater dertail in some of this shit..

* for concise, barely technical info, please skip to "TL:DR?"..

too long.. didn't read..

ok now onto the real shit

why does my bike make a clicking/buzzing noise when i try to start it??

well, in the most simple form, you're seeing a doorbell effect... for the NOISE
low voltage from a weak battery or bad connection is the culprit.

to understand the noise means you gotta know how a bell works.. i'm not gonna explain that, but the explanation as to why a bike sounds like a machine gun a and buzzes will make sense.

theres a "design" voltage .. the 13.86 volts that all mobile stuff is based on.

the battery and all the electrical shit can tolerate that and likes it.. but the electrical shit DOES have a point where the power is just not enough to get the job done.

now, lets say you turn the bike on.. voltage is at 12 volts at the battery, but the battery is weak and doesn't feel up to the task of cranking the bike over..

when you push the starter button, you close a circuit that in turn, closes a relay.. that is an electrical switch.. a high-power relay is commonly referred to as a "solenoid"

this solenoid take the VERY high power that the starter is going to draw from the battery, and passes it thru thick wires and heavy contacts from the battery directly to the starter motor.. if that wasn't there, you'd have this friggin gigantic ass pushbutton on your handlebar that would have huge wires.. all big enough to handle the starter motors power draw. ( about 60 amps)

so.. hows that solenoid work? well, it's magnetic. theres a coil in there thats connected to the starter button.

that coil created a magnetic field when the start button is pressed. .that field draws a steel pin in towards the middle of the coil.. that pin, in turn, pulls a set of switch contacts closed, allowing the high power for the starter to pass..

as SOON as this happens, theres a huge load on the battery then to turn that motor over.

the battery, when not up to the task, cannot create enough power to spin the motor and keep everything else thats electrical, running.. the voltage drops rapidly and far.. sometimes to 8 volts.

that is far below the design voltage.. this, in turn means everything is weak. te starter motor is too weak to spin the engine.. but it doesn't care.. it's a motor.. its going to try anyway.

so, it draws all this power from the battery in an effort to overcome the mechanical load placed on it.

the battery's like "fuck this" and loses power instantly.. this, in turn, leaves the whole electrical system looking for power.. that solenoid that closed when you pushed the start button loses its magnetic field, and the switch contacts open because of that.
as soon as the solenoid opens up and kills power to the starter, the power instantly jumps back up in the battery and the battery is all like fuck yeah.

well.. you're still holding the start button!!!!!!

so, as soon as the power comes back up, the start button passes that restored voltage to the solenoid coil. it closes again.. passes power to the starter.. starter takes it all.
battery voltage drops again.. solenoid coil loses magnetic fiel. solenoid opens. power jumps back when start load is gone.
this happens almost instantly and as long as you hold the button, this cycle will repeat til the battery is so dead it can't even make the solenoid close anymore.

this rapid clicking of the solenoid opening and closing is what you hear.


-battery is dead. replace/charge battery. ensure clean, tight connections on all electrical stuff.

AND to dispel the FAMOUS myth that you'll destroy something jumping a bike with a running car.ABSOLUTE bullshit.. and heres why.

why you CAN jump a bike off a running car

ok.. so.. remember how at the top i mentioned theres a design voltage? 13.86 volts DC. the peak voltage is 14.40 volts for most stuff. anything over 15 volts and stuff starts getting mad. anything under 11 and things don't work. well, cars. light trucks, some diesels, bikes and other stuff.
being that a 12 volt battery in essence is a 12V battery, lets toss out voltage and focus on amperage real fast.
now, in general, voltage and amperage are inversely proportional.. the higher the voltage is, the less current will be used.. and vice versa.

so with this in mind, lets look at a battery in a car without the motor running.. it has a typical CCA rating of about 750 amps.. so, at a regular temp it'll produce 750 amps of current at 12 volts.

now, look at the YTX12-B thats in your bike.. delivering probably 10-12 amp-hours of power, it has a CCA rating of 180 amps.

180 amps. thats almost as much as the panel in your house is rated for.

so, you can see theres a considerable amount of current available in both batteries.. thing is that the car battery is WAY bigger and sometimes people associate size with voltage output, which isn't the case. both batteries have 6 cells. it's just that the plate area is substantially different.
BUT .. with that being said, it should be evident why you can hook a car battery up to a bike battery.. SAME voltage.. you figure, even with the car OFF, you have 750+ amps available.. with the car running.. you STILL have 750 amps or more available. the alternator has typically 10 times less current output than the battery it's charging.. the voltage is regulated at 14.40 VDC as well.. the main reason for shit getting blown up is usually reversing polarity of the batteries.. the ensuing arc and surge current tends to cause the damage.


-theres 10 times the power of the bike battery available inside the car battery whether it's running or not. if someone you know had something fried, someone crossed the cables and blew something up. the voltages are THE SAME. and electrical shit ONLY takes as much current as it needs. you cannot force-feed current (amps) like you can with voltage

ExTrEmE TrOuBlEsHoOtInG AHHHHHHHhhHHH :crazyloco

ok kids. todays lesson is very basic diagnosis of engine problems, their causes and what can be done about them.

as all yas know, theres a ton of things that can go wrong with these machines... comes with the territory in a way... you squeeze this much power out of a tiny motor, theres bound to be problems sooner or later...


coil packs
these tend to act like fuel starvation. this is VERY VERY prevalent on the '03-ish R6. the 636 has had some issues with this as well. look for burnt or cracked rubber along the length of the coil pack, and shiney marks on the plastic. brittle or cracked rubber can sometimes be patched with electrical tape. the insulation just breaks down from age, high electrical voltage, and heat cycling.
you can sometimes hear the current leakage thru the boot/insulation as an audible "snap" from the spark jumping to the valve cover, or spark plug tube
valves. on bikes equipped with on-board diagnostics, you can individually cycle the coil packs without the motor running to test the integrity of the insulation, or if the coil even works at all...

theres an easy, non-dismantle way to check exhaust valve seal. when the bike is at idle, simply take a piece of paper and hold it to the muffler. if the paper is blown away from the can, then theres a good seal on the exhaust valves, and no vacuum is escaping.
if the paper is sucked towards the outlet of the can, this is indicative of a leaking/ bad seat or a sticking valve. what you're seeing is the vacuum being generated by the pistons approach to b.d.c on the intake stroke.

this is usually from not running baffles, and having enough backpressure to ward off carbon buildup.
abuse and a badly tuned motor will cause valve damage as well. cam timing being out, ignition timing being out, or incorrect air/fuel can attribute to this. also, oil starvation and valveguide wear will cause this.

a valvejob is almost always the remedy for this.. better safe than sorry.. you can get lucky and clean the seats without a seat regrind every once in a while tho...

this is a lil more intricate, and cant really do to a bike you plan on buying used, like the exhaust valve test.
the easiest way to test both valves (I and E) and piston rings as well, is to do 2 things.. a leakdown test, and a compression check.
the compression check is done with a 0-300psi gauge (usually) and a special adapter to convert pipe thread to spark plug thread.
the reading on the gauge is the actual pressure of the compressed air in the cylinder. it caries from engine to engine, and age/size of the engine as well.
a compression check will instantly indicate an open valve.
--even trashed rings and a scratched bore will generate a bit of compression... a stuck valve will bleed off all the pressure so fast, it will barely register on the gauge.

a leakdown simply measures the combustion chamber's ability to maintain a set pressure over a certain time, and test the integrity of the valves and piston... goos all over check on motor health. as well as the compression... good general test procedure.

if you want to differentiate between a valve and possible bad rings, pour a bit of ATF (auto trans fluid) or motor oil in the cylinder bore (maybe 2-3 capfuls...) this is called a wet test, and should almost double the pressure if the rings ARE bad. theres WILL be a difference between a wet test and dry test even on good rings, so use judgement on this. if 3 pistons have 160psi dry, and 1 has 145 dry.. chances are the rings on that one are going downhill. the wet test will indicate a head gasket or valve leak if theres NO pressure difference.. the iol wont seal the head or valves... thus the reasoning behind this.

if a wet test puts the 3 pistons at 225, and the other at the same difference of 15psi or so, then go ahead and order new rings!!

on a final valvetrain note, very incorrect cam timing, or too big of a cam will keep the valves opened when they shouldn't be... oh, keep that in mind on a race motor..

theres a few reasons a bike will smoke, when and why are pretty much the indicator if you know how to read it.

if the bike puts out a puff of blue smoke (oil) on startup, then it stops... the valve seals are leaking. whats happening is the oil is seeping past the seal and dripping onto the top of the piston... where it just sits... waiting to come into contact with the first flamefront when you fire it up. once the excess oil is burned off (the puff you see) on startup, the oil that leaks into the chamber while the bike's running is usually so minute that you won't notice it. in this case, usually its just one, or a few seals.. not all of them, BUT you should replace all of them anyway. you'll see oil buildup in the intake port and on the valvestem, and heavy carbon deposits in the exhaust port of the offending cylinder

if the bike smokes under heavy load, and normal running, its usually a sign of failing rings.. do a compression check just to make sure tho..

very badly worn or torn seals WILL leak enough to smoke constantly...

a blocked crankcase vent will also cause this too!!!! the pressure buildup will force oil past the rings and seals, this is usually identified by no smoke on a cold start, but once the motor's internal pressure builds, it'll smoke at idle and on acceleration

if the smoke smells like antifreeze, it probably is... this will usually indicate a blown head gasket. to further test this, remove the radiator or fill cap and run the bike at idle. if the bike (when cold) blows the coolant out of the opening, you're seeing the compression pressure escaping past the head gasket and going to the water jacket and pressurizing the coolant passages.

a sticking injector, or carburation issues typically produce a lean - backfire on hard accelleration and decelleration. a "rich" gassy smell is a sign of an improper mix, of out-of sync butterflies (the little brass flap-valves in the throttle bodies or carb bodies)
a vacuum leak will cause the bike to stumble and when you reach around 120MPH, you're usually yelling at why the bike is decellerating like someone shut it off..

W.O.T intake velocities are roughly 120MPH. so, from 0-119mph (or so) you have nothing but vaccum present in the airbox. at 120+ the air is not starting to become pressurized in the airbox, and this intensifies a vacuum leak and will separate a vacuum leak from fuel starvation most of the time. (very low pressure f.y.i., typically less than 1 psi)
a vacuum leak will also cause a slow spindown (what i call it...) meaning that when you rev the motor to lets say 5000 RPM, as soon as you let off, it should lose RPMs and drop to idle almost immediately.. in the slow spindown case, the motor very gradually drops back to idle during the same rev test. this WILL indicate out-of-sync butterflies OR a vacuum leak.. only hooking up a manometer (sync gauge) will tell ya if its actually sync or a vac leak.

the slow spindown stems from the motor still getting air into the cylinder after the butterflies shut, and this makes that one (or more) cylinder(s) work harder and carry the rest of the load and will override the correctly functioning cylinders since the ones with the leak are now generating a bit more power than the rest..

incorrect fueling will cause stumble and hesitation from no-load to load, and under partial throttle conditions with constant load.. theres a ton of variables unfortuantely. detonation under load will indicate a incorrect fuel type, or wrong a/f ratio.

poor gas milage will indicate either a dirty air filter or something being out of adjustment..

when you remove the sparkplugs, they should be a light tan. this will tell you the a/f is perfect and everythings good with fueling.

float levels and throttle-body boot tightness is very important..

please, if i've missed anything good, feel free to add to it, or tell me i'm a douche and this sucks. either is welcomed! hope this helps you out!!


i'm.. workin on this.. lol

more technical stuff

WHY did a rod come thru my engine?

(this is pretty technical.. so.. read it slow... as well, i stole this off a buddy from bikeland, but i will probably add to this if it piques curiosity)

The Force of Gravity will find the weakest part?? I found a formula on Engine & Fuel Engineering, Max Piston Speed, Rob Hughs of Orient Express, 23 Mar, 04 22:17, an 26 Mar, 04 0:58 hrs.
example: ZX-12 83mm bore x 55.4mm stroke , J&E replacement piston 229grams
Piston Speed Calculater=11,500, 55.4 = 4180ft per min = 69.67ft per sec
11,500 / 60 = 191.66 revs per sec 1 /191.66=.0052175 / 4=.0013 =
1 / .0013 = 769.23076923 x 69.67= 53592.3076922 / 32ft per sec, per sec=1675 Gs

1675Gs @ TDC & BDC, it stops 2 times every rev. A 229gr piston wt = 1675 x 229=383575=
382575 / 454(1 lb) = 844.87 lbs PER PISTON or = 1 gram = 3.689 lbs ??

845 lbs stop & starts, 2 x per rev of 191 per sec . 1 piston wt 845lbs x 4 = 3380 lbs flying around @ 11500 RPM, plus wrist pin , rings and clips. !! Rods and crank made of some good stuff ??

Ok bore an stroke it to 1375cc- 86 x 60 @ 11500. Plug in 60mm= 75.459ft per sec
75.459 x 769.23076923= 58045.3846153 / 32ft per sec = 1814 Gs x bigger J&E piston wt =260 grams = 471640
471640 / 454(1 lb) = 1038.85 lbs PER PISTON or 1 grm= 3.995 lbs 4 x 1038.85= 4155.40 lbs
Think about this 4155 lbs swinging @ 11,500 RPM"s, Stop & Starting

You have added= 775.40 lbs to rotating assembly, @ 191 revs per sec ?? BETTER HAVE the BEST RODS, PINS AND BOLTS MADE?? INCREASE STROKE , RPM"s or Piston wt, G-FORCES go UP ?? Buy the Strongest and Lightest , the VERY BEST !!! OR GAMBLE ??

Pass it On, PS . 93 BMW F1, V10, 3 liter, @ 19,000rpm's pulls 10,000Gs, outer space parts


the parts inside the motor are subjected to ridiculous amounts of stress at speed.. if a bearing looses oil, heats up and blows apart, the ensuing shrapnel is coming out of the case with 2 tons of force.

Understanding combustion

(i cannot take credit for this at all. .lol credit goes to David Redszus.. thought it was pretty interesting tho.)

The internal engine combustion process has been studied for over 100 years. We have pretty good idea of what happens but it is more difficult to quantify and visualize the process. Following is a very simplified description; jump in anytime.

When the spark plug fires, an electrical arc jumps across the gap at a temperature of approx 60,000F which will ionize the air space in the gap. Fuel molecules will be decomposed into their elements (carbon, hydrogen, oxygen) and diatomic gases (oxygen, nitrogen) will also be decomposed into singular elements of N and O. When and if this occurs, the elements begin to change partners and form a series of new compounds consisting of various hydrocarbons, free hydrogen, OH radicals and nitrogen compounds. This process is referred to as oxidation which we call combustion.

The process does not occur smoothly, either from the perspective of time nor space. As the compounds in the spark plug gap combust, the temperature is raised to approx 4700F which causes the gas to expand and move outward. Some temperature and outward motion is lost due to heat being absorbed by the spark plug electrodes. This resultant delay is often referred to as ignition delay and every engine has it. The initial flame kernal diameter is the size of the gap.

Once past ignition delay, the expanding gas pushes the flame front outward. The combustion occurs along the surface area of the flame kernal. As it grows larger, the surface area is increased and the combustion process is accelerated. This growing fireball does not grow uniformly in time nor space. Some unburned mixture pentrates the flame front and is combusted after the flame front has passed.

The rate at which combustion occurs is a function of temperature, pressure and motion. Increased temperature will accelerate flame speed. Pressure is increase the rate at which heat from the burned gas is transferred to the unburned gas. This flame speed is called laminar flame speed. Mixture motion produced by piston to head position is called squish velocity and is added to laminar flame speed to produce a total or turbulent flame speed.

The time that it takes for combustion to occur can be expressed in units of time or crank angle degrees. Various terms can be applied such as burn angle, burn time, flame speed, etc. Laminar flame speed is a function of heat and pressure and is fairly constant while turbulent flame speed will increase with increasing piston speed.

Since a flame front is actually a thin (approx 2mm thick) moving surface, with unburned gas in front and burned gas behind (or inside), the flame front will cease when it runs out of combustible materials or loses heat. The combustion process will stop if the local mixture is too rich or too lean and when the flame front hits any cooler surface such as a valve, piston or combustion chamber. An aborted combustion process will produce partially combusted hydrocarbon deposits known as carbon deposits. Flame fronts cannot pass through each other since that would require one front to burn an already burned mixture. But rapidly expanding pressure waves certainly can pass through each other.

The usual source of a combustion pressure wave is due to detonation which is the rapid combustion of a volume of unburned mixture. An unburned volume of charge that combusts spontaneously will produce a pressure wave that travels at local sonic velocity and rides on any available particle motion that might exist. These rapidly moving pressure waves will bounce off of all chamber surfaces and will make the characteristic "rattle" sound of detonation. But actually, detonation or knock, will produce three knock frequencies, one in each direction within the chamber.

Normally detonation will occur after top center. If, however, the charge is ignited too early, combustion pressure can increase substantially before top center. When this occurs, the combustion pressure is trying to push the piston down while the piston is still on the way up. We call this pre-ignition which can have a spark source or a surface temperature source.

A fuel will never ignite as a function of pressure alone; heat must be present. But a combination of heat and pressure will change the point of ignition. This makes setting the correct igntion timing for a turbocharged system very interesting. Even if the mass of fuel being delivered is constant, the mass of air ingested will vary with engine speed and induction resonant tuning, so the air/fuel ratio will constantly change. Now the fuel mass curve must be modified to accomodate the changing air mass curve. And often it is not fully adjusted. But spark plug and piston surface deposits reflect the average over time, it does not reveal the true instantaneous combustion air/fuel mixture. Even Lambda sensors which measure the presence of oxygen (not air/fuel ratio) often present a time averaged value which does not represent the true process.

The above is merely an elementary overview of the combustion process. There is still much be be learned regarding combustion pressure curves, misfires, cyclic variations, fuel properties, etc. And power production.


gas gets sprayed.. hits a spark.. catches on fire.. raises pressures to over 1000psi in the cylinder and pushes the piston down for wheelie power. liquid gas won't burn. only the vapor..

octane is an anti-knock (detonation) agent.. keeps the motor from blowing up.

Understanding OCTANE

This is brought up so often it is laughable. Read your manual as it will clearly specify the octane rating needed. Use the lowest octane fuel you can without detonation (pinging) for the most power. While Kawasaki suggests 91 RON (which in the USA is 87 octane), some bikes experience detonation and 89 or possibly 91 should be used. Octane booster will cause a decrease in power and race fuel (non-oxygenated) will also hurt you in the power department unless you have an ignition advancer, raised your compression ratio, or are using forced induction. Long story short though: Use the lowest octane fuel you can. Octane in no way will increase power by itself.

more in-depth..

The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites.

The reason octane is important is because engines can produce more power if they have higher compression ratios. A 10:1 compression ratio means that the engine compresses the volume of air it sucks in - say X, into a volume on tenth that size. The problem is that when air compresses, it increases in pressure and this heats it up. A low octane gasoline is prone to spontaneously ignite prematurely in a high compression engine, which causes damage. If the gasoline ignites too soon, the power of the burning gas and air mixture will push down on the piston as it's still compressing, losing you power and over-heating the piston (as well as valves, head, and cylinder walls), eventually leading to catastrophic engine failure. This is known as pre-detonation, pre-ignition or "knock".

With a high octane rating, engines can run with higher compression.

In actual practice, an engine has to be tuned specifically for high-octane fuels to generate extra power. If you have an engine fully-tuned and optimized for 91-octane pump gas, adding 100-octane race-gas into it will yield little if any increase. However, if you were to take that engine and increase the compression, advance the knock and/or increase the boost, then you can take advantage of the higher-octane fuel. But this precludes going back to the previous lower-octane fuels.

why the hell is my gas cap whistling or making noise?

gas vapors evaporating off the liquid gas inside the tank are building pressure and need to vent. theres a small vent inside the gas cap that allows this to occur while still holding back liquid gas. in some cases the seals will vibrate or whistle as the vapors purge from the tank.

2,293 Posts
Discussion Starter #2
page 2

reserved for future expansion of this section.

889 Posts
review the "why do i have a buzz in my ignition area"
or "why does my tank make a screaming noise":crackup

Senior Member
27,825 Posts
Yeah those posts like, " why wont my bike start " are getting old. I love helping people but geez, we are not psychics around here:angry

2,293 Posts
Discussion Starter #6
the gas cap squeal. brilliant and will be added shortly

senior member
16,062 Posts
Please cover octane, if you would.
Explain how it works and why higher octane does NOT mean that it's "better" fuel and your bike won't break land speed records if you use "race gas" or avgas.
Thank you.

2,293 Posts
Discussion Starter #8
i shall, good sir.
i noted it real fast in the tl:dr part after david R's thesis on fuel. lol

but i will add a sidebar to that one just on octane.

2,293 Posts
Discussion Starter #10
winnn. take a look. if you'd like to see something else or have a link you want me to add, just let me know and i'll pop it in there

2,293 Posts
Discussion Starter #12

2,293 Posts
Discussion Starter #15

2,293 Posts
Discussion Starter #18
I guess.
It's better than the dollar menu.
Throw in desert and a piece of jewelry and I won't feel like a total whore.
done. and baby i swear it won't be wal-mart jewelry this time. i learned from last time and listened to what you had to say.
you're worth it <3

2,293 Posts
Discussion Starter #20
we can put this back on the rails... lol
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