Yz450 engine kickback can cause damage?

19 replies to this topic
  • Yamaha222

Posted August 15, 2011 - 01:00 AM


I looked for an answer to this question on here but I couldn't find a satisfying answer. I recently bought a new yz450. I came up on a video on YouTube saying that improper kickstart techniques can cause the engine to kick back. It also said that if that happens, that it could cause engine damage. This has happened to me before and I think I know now how to do it correctly however I would like to know more information about this. If anyone here knows what sort of engine damage this might cause, would someone be as kind to shed some light about this topic? I am wondering what all could happen to the engine if it kicks back? How do you know if you did cause damage? ETC... I feel a little worried knowing that I was doing something wrong from day 1 and I am a little paranoid now about that. Thank you in advance.

  • dgcars

Posted August 15, 2011 - 02:35 AM


It can cause, or at least contribute to failure of the stopper on the kickstart assembly. This can be pretty major, tranny damage & engine casings etc.....

  • grayracer513

Posted August 15, 2011 - 06:28 AM


The usual damage is to your foot. The YZ450 is capable of kicking back hard enough to break your foot or sprain your ankle right through the sole of a good boot.

Beyond that, damage can result to the starter assembly, the gear train through which it turns the engine, or the crankcase around the starter shaft. It can also result in the cam chain skipping, but this depends on the cam chain being faulty to start with.

  • Steel Panther

Posted August 15, 2011 - 11:13 PM


what causes this to happen? ive never heard/had this happen before.

  • dgcars

Posted August 16, 2011 - 12:44 AM


what causes this to happen? ive never heard/had this happen before.

Search kickstart stopper

  • Yamaha222

Posted August 16, 2011 - 02:33 PM


In the manuel it talks about it possibly causing the rider to get injured but it doesn't say What it does to the bike. Would the damage be instanteaneous or could it be down the road? Thanks for the help

  • Steel Panther

Posted August 16, 2011 - 11:04 PM


Search kickstart stopper

I was asking more along the lines of what improper ways of kicking can cause kickback, or if it is caused by worn/broken parts.

  • Yamaha222

Posted August 17, 2011 - 01:10 AM


Its from not having the stroke in the right position. According to the "how to", if you just whip out the kickstarter and start kicking like a 2T, it is incorrect. More so, is twisting the throttle, regardless of magnitude. You have to softly kick over the engine until you start to feel the most resistence, then you bring the kickstarter back up and give it a good kick.
This video is one i came across that gives all information but the possible damage a wrong start could cause...

has anyone had any engine problems due to a "wrong start"? If so what exactly happened?

  • grayracer513

Posted August 17, 2011 - 07:44 AM


The most probable cause of a kick back on a YZ450 is kicking an engine that isn't partially flooded with the throttle opened too far.

  • Yamaha222

Posted August 17, 2011 - 06:10 PM


Yea thats kind of what i thought too gray. I dont know if this is going too far off topic but are there any other tips or important things to know with a new 4 stroke or atleast with a yz450. Im new to 4 strokes and this site altogether so i know there are probably a lot of things i am unaware about. Without causing a stir about getting off topic, does anyone know about other significant information that is crucial to our bikes' longevity? I know people are going to say clean the filter and change the oil, but the info i would like to be added to this badass forum would be info that might be unknown to some people or atleast people new to 4 strokes (like not everyone knowing starting a bike incorrectly could cause engine damage).

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  • wags450

Posted August 19, 2011 - 09:53 AM


The usual damage is to your foot. The YZ450 is capable of kicking back hard enough to break your foot or sprain your ankle right through the sole of a good boot.

or push your foot forward while wearing regular shows hard enough to break your toes. Not that Ive had that happen :eek:

  • ack1961

Posted November 07, 2011 - 06:40 AM


I'm so glad I did a search on this topic here - I wish I had read this on Saturday.
This happened to me yesterday:
My WR450 is the first real 4T dirtbike. I have a couple of 2T's.
Yesterday, I wanted to start it up, and it wouldn't light using the e-start. I started to kick it like I would have done with a 2T (as someone mentioned earlier in this thread). After a few rapid kicks, it kicked back violently. Threw my knee up into my throttle hand (which was wrapped around my grip) and nearly broke my thumb. Split the side of my thumb pretty wide open. Ended up with 2 souvenirs - bruised knee and a badly cut/bruised thumb.

I went back outside (after getting the bleeding under control) and pushed the e-start. Lit right up. Rode it for a little in the yard. The bike seems fine, but I think I got extremely lucky.

The power in the kickback should not be underestimated - it can be violent.
I need to read more on the proper way to start a 4T.

  • dgcars

Posted November 07, 2011 - 07:18 AM


The important thing is the bike wasn't damaged......:busted::busted:

  • ack1961

Posted November 07, 2011 - 07:52 AM


The important thing is the bike wasn't damaged......:busted::busted:

couldn't agree more. I have 2 thumbs and two knees, but only one WR450.

  • usp4u

Posted November 08, 2011 - 09:39 AM


I had it happen on an '03. Had a brain fart and had the throttle partly open when I kicked. Broke the kicker shaft in half, which then turned sideways and broke the right side center case and right outer case. Sucked.

  • atomic410

Posted November 08, 2011 - 10:21 AM


or push your foot forward while wearing regular shows hard enough to break your toes. Not that Ive had that happen :busted:

yeah flipflops in the pits and kickstartin 450's is bad mmmm-kay

  • motorboy1128

Posted November 09, 2011 - 06:57 AM


put it at right after then decopmpression tick....then kick hard and fast. starts every time

  • YZPaGuy

Posted November 10, 2011 - 05:54 PM


I'll tell you exactly what can happen to you. The kick starter can come back up, go through your pants at the lower part of the back of your thigh and punture a 1/2" into you leg.

I was practicing starts and my bike wasn't starting right. Well it fired off when I didn't think it would, i dropped the clutch but didn't give it enough gas, I dropped my right foot because I knew it was going to stall just as the kickstarter came back up with the motor.

It hurt like a bitch but I figured it is a flat peice of metal it can't cut me. As I rode back to the garage I got a wet feeiling in my boot, I thought no way that is blood. Yea, by the time I rode 200 feet to the garage my boot was full of blood. I had fat and muscle sticking out of my leg. Had to go to the emergency room and get stitches! I've had it throw my leg up in the air to but it doesn't seem to have hurt the bike.

  • bad72ss

Posted November 21, 2011 - 05:26 AM


My brothers 04 was. Less then 30 days old when the kicker assembly left the engine . Yamaha covered it .. but the shop that fixed it did more damage. But that's another story

  • NEM44

Posted November 21, 2011 - 07:17 AM


Here's the Yamaha Video on it:

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