Japanese spend years & years making their bikes the best they can be. Overly tuned bikes won't last long, & for such little extra power it's just not worth it when standard they are so fast as they are.
Dude has a point. e.g. the intake cam mods, sprocket mods, and airbox mods are but some of the things that tear an engine up quickly due to the effects these mods have on the fuel/air ratio.
+Oscar v Engines are designed to drive and not be driven. The dyno wheel is probably 700+ pounds and has a bunch of inertia. Depending on the bike and the fuel and ignition system several bad things can happen. With fuel injection, for instance, the throttle position sensor is reading zero, but the MAP and/or MAF sensor thinks the engine is running wide open because the engine is being driven at nearly full RPM. The ECM incorrectly calculates fuel/air mix, timing, fueling requirements, etc., and may tell the system to spark at the incorrect time and the injectors may pulse as though they are wide open. This can cause a load of fuel to enter and ignite at the wrong time, causing damage. If carbureted the bike is still gulping fuel/air mix and, again, if there is a throttle position sensor, the timing may be way off. By pulling in the clutch the rear wheel can continue to spin at full speed while being disconnected from the engine which will let it idle down normally.
Honda vs Yamaha, Ford vs Chevy, Pepsi vs Coke. It NEVER ends. We all have our favs so no need to diss ANYONE in the game. I've owned and ridden for decades Honda, Yamaha and Suzuki bikes and to tell you the truth I love Honda most. Back in the 80's their V-4 engine was a breakthrough in design. It powered the Interceptor and Magna models and was one of the smoothest and most powerful engine of its' day. At 12,000 rpm my mirrors still held a sharp image and was a VERY reliable engine. I learned to ride on my Dad's 1971 Honda CB350 and my Father used to love to show me the cigarette trick. Meaning while idling he could balance a cig on end on the gas tank, with no vibration. That was 40 years ago!. Honda is NOT a manufacture that should ever be shat on because it's one of if not the largest in the game, for a reason. Love yours to death, I'll respect that, just don't diss on mine and expect no response. That's all.
The maximum cylinder pressures of petrol engines can go up to 30 bar(a) or more. The minimum cylinder pressure is only 0 bar(a) (vacuum). Which means that the maximum pressure difference across the piston can only be 1 atm ( assuming the crankcase to be atmospheric). So the magnitude of the negative pressure is not critical, its direction is. During deceleration the rod bolts are subjected to severe tensile forces and stretch / break when overloaded.
True, a slipper clutch was not designed to prevent broken rods. My argument is that without the added benefit of a slipper clutch that the sudden burst of piston speed and piston stop could have caused the rod to snap off at the small end without ever touching a valve. As a factory technician you should know this. Do I dismiss that this could have been caused by valve float, absolutely not. It could have even been cam chain slack on deceleration that caused the valve timing to be off.
There are many variables involved. The simple fact is that the centrifugal force of an 875LB dyno roller spinning over 100mph does have the ability to snap a connecting rod at the small end due to rod stretch IF the dyno operator downshifted too aggressively. You can see this very same issue on V8 engines with a much lower piston speed and the driver selecting the wrong gear when downshifting. Of course there are other variables but it does happen, and that is a fact that you cannot argue.
@desibro08 if your bike is untuned it will foul the plugs and ultimately cause damage to the engine. this is why your bike should be tuned. dyno tuning is simply a more precise way to tune.
@DragonFlyback256 Yeah i didn't hear any downshift either. But doesn't the sound from the engine sound a bit too consistent for it to throw a rod? Then again, i guess it wouldn't develop that kinda smoke if it just ruined the valves.
@hybridracers Having worked for factory superbike teams you should be well aware that before the use of slipper/back-torque limiting clutches (which a stock CBR600 of this year lacks) that it's not the sudden acceleration of piston speed that causes the connecting rod failure but rather the sudden deceleration or attempt there of, that snaps the piston off at the small end of the rod. Oh, and those are chunks of the crank case & oil pan under the bike when the pull is complete. Not a valve.
Being a bike technician and personally dynoing hundreds of bikes I can tell you that dyno's do not cause engine damage when used correctly. However, the centrifugal force of the 875lb drum spinning can have an adverse effect on a motorcycle if not handled correctly. The person running the bike on this dyno downshifted immediately after a run which more than likely snapped 1 or more of the notoriously week connecting rods in the CBR 600. Be picky about who dyno's your bike and with what dyno.
For the non technical people, what basicly happens, the piston moving up and down so fast without the compression slowing it down, will pull too hard on the conrod. conrods are designed for press force, not for pulling force.
Racing curcuit environment is totally different from a dyno in some basement...Where you do 2-3 dyno runs without proper cooling, with the bike still...much more stressfull for the engine.
So you mean to say that I might blow up my engine when I drop the throttle at 11.000rpm at the end of a fast part of the racing circuit, in preparation for braking?
You're not an idiot man, in fact you are the only clever one to ask... I can't explain it thoroughly right now but in plain terms, as i remember it, when the engine revs up with full throttle, positive force is created in the combustion chamber (BMEP, google it)...when you release the pedal completely, the opposite is caused, sort of a "negative" BMEP, which at low rpm is not bad, but at high rpm causes great stress to the connecting rods mainly. I hope i explained it correctly :)
Definitely yes, you should put the gear on neutral and let it slow down on its own (if you are on 5th) or just shift to a higher gear and then let it rev down.
Never back throttle at high RPMs and let the motor run down to idle. It creates a large vacuum in the cylinders and stretches rods and sucks in valves.
Your not a motorcyclist. He did not downshift twice after the second power run. For an accurate dyno reading, the engine must be allowed to rev down to near idle whilst the driveline is engaged as this process measures drivetrain powerloss. The engine failed thru no cause of the dyno operator.
@Hardwyre Alot of bikes pop its kinda normal switching to aftermarket exhaust. This bike was running too rich.wIch isn't a bad thing, just gives you lots of carbon build up and poor gas mileage. Something else was wrong here.
@desibro08 You own a bike? Or even ride one before? You get addicted to the power very quickly and when you can ride better you want something more out of your toy. Plus it's hella fun to mod and wrench on the bike. My previous 06 gsxr 600 went from stock 102whp to 120whp after full bolt ons and slight head work with compression upped to 13.5:1. Along with shorter final gearing, weight reduction and Ohlins suspension...bike was so fun to ride that I kept it for 4 years. Stock is boring.
"project bike 99% finished currently not running but probably just needs a new spark plugs and battery, bike ran awesome last time it was used but been sitting for a while should be an easy fix i just don't have time"
@surrynet i was the only person in my class to pass certified dyno drive test. The next day I got in an Argument. All vehicles had to be dyno tested that were brought in. My question what about vehicles unsafe to drive. . The companys said all vehicles. I quit the job after one week. Later they recinded the mandate.
seems to me that 1) a rev limiter is needed for that test rider and 2) an external fan source wouldn't be a bad idea either. I've never raced but, I have been in the motorcycle industry as a tech. Just from what I am seeing and hearing here the engine is running a tad lean (lean misfire on deceleration) which will build heat as fuel does contribute to a cooler running engine and having run dyno tests one should always have 1 fan (at least) blowing air past the motor. Just sayin...
@ThaRealGecko because when you are on the road you have air blowing through the radiator. on a dyno you have to try and replicate it. looks like these guys didn't do that well of a job.
***** well as a bike mechanic i know honda officially blows. It even did it in your whack ass video. Dont have a specific brand i like. I just dont like honda. Everything else is sweet.
***** not that they are hard to work on. They can be a pain just like any bike. But honda cbr is just made cheap thats why it blows. Nothing reliable about it. Yamaha badass all around. 2014 kawasaki zx10r keeps up with the bmw s1000r. So thats why i think honda blows. Ive been around them for a while. Would you like to see a vid of my shop with nothing but hondas in there for the most part. Most of them are 08 600's because they have a recall on the crankshaft and piston rings. Couple suzukis due to the fact they recalled 250,000 front brake components. So yes apparently im a shit mechanic. Thats why i got all these bikes to fix. Hell bring yours by. Ill fix it too so it wont blow up on the dyno buddy
i have a yamaha. every kawasaki ive ever worked on valves were fine. yamaha too. i was giving the man sh*t just joking with him. i dont care what kind of bike it is. you should know as well as me that things blow up on a dyno. i dont like honda because of the way the fram is designed. motors are great.
Anthony Heflin hahahahaha a yamaha fan?, a user from youtube have a CBR600F4 with 250000 miles, my friend has a CBR 07 with 97.000 km. A tuning bike like this 600 is unreliable, but a stock honda (except a crf) is extremely reliable
You can hear the engine go 'pop' and all the metal inside smash apart. Why would you spend time looking at the side of the engine after, watching the oil drain out... Only way to fix it now is to strip down and see all the smashed pistons and big ends..
@neephius nope it blew, oil was running all overf the dyno. didn't you see the smoke pouring out of the exhaust before the engine locked up? why the hell didn't he push the clutch when shit went wrong?? lol
@HunterCO1 yes you will beat me in life as i do two degree at university with a mining scholarship. fouled plugs are one of a few results. you can either have too much oxygen or too little. too much oxygen at high temperatures causes oxidation of material such as the piston rings, the chamber, the piston itself(corrosion). I didn't say it will blow the engine up in an hour but it's not good for it causes more wear in general and accelerates the loss of power.
i dont see any fans around, people forget that even water cooled bikes go bang if they dont have airflow. either that or its a typical hero's 600 that gets thrashed & not serviced. I have a 200hp zx12 & i avoid dynos if i can, it gets way too hot.
Still waiting for the crash? As in to crash into, onto, or off of something. I did see a cbr600 blow up, or explode, or grenade an engine, throw a rod, etc.
@makexxx I didnt ask for more bullshit I asked for specifics so I could determine what the compression is try again. Bore, stroke, deck height, piston dome volume and cylinder head volume how hard is that it tells the truth.
@desibro08 Nah, it's worth to me and thats what all matters. I take all my bikes to track (ROAD TRACK!) to have more fun. You never get the money back what you put into aftermarket stuff, and decide to sell the bike later with all bits installed. But it sure as hell is fun to have nicely modded bike... But ya opinions are opinions. I can't even start to think how much I would have money right now if I would never modded anything I owned.
Put it on neutral gear and also it would be could to rev up a bit 3-4 times after that so it can be lubricated and cooled properly. Like in this video: watch?feature=player_detailpage&v=BvGymn_NAKU#t=17s
