Broken Kickstart shaft

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Jan 29, 2001
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#1
Anyone ever sheer off their kick starter shaft ?

We're not talking about stripping the tynes off.. I mean busting the shaft right in half.

I did that Sunday on the YZF. When hot I usually don't use the decompression release, just kick.... Well, you guessed it... SNAP
:eek:

Any idea why something like this happens ?

-B
 

zcookie49

Seven OUT!
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#2
snapped

Thats sucks man... Hope you werent stranded or anything... anyhow, I use the decompression all the time in the drill, the compression is feirce, i almost brke my shin making the mistake of kickstarting with a nike on, i still have a popeye sized bump on the shin... anyhow, I know the shafts are somewhat over $100, your manual may show you how to install them. ......
I know the 98 yz400's were snapping for people were trying to start them like a 2 stroke. I'm sure you will prob use the compression lever more often now...That just sucks... I read on another forum of someone rigging up a YZ125 or 250 starter on their bike for they were about 5'9" as well.. good luck and keep the post going with update if you dont mind..
 

penguin

N. Texas SP
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#3
if you tried to slap at the lever like a 2-stroke that would explain it. You should always use the compression release on the YZF or risk the consequences. The fourstroke staritng technique can be a real learning experience :(
 
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#4
I take blame for this one...

Ya... I have a tendency when the engine is hot to not use the compression release when starting the bike. I weigh 200 lbs and rarely have a tough time kicking it over. I assumed the shaft could handle the torque... my mistake.

We were a good 20 min from the trucks and there were 2 horrible river crossings I had to navigate through before I could load the bike up. After about 10 tries I managed to bump start it then road home scared to death I would stall at the bottom of a hill in a mud bog. Fortunately I made it home without stalling.

I'll certainly use the relase from now on.

The shaft is $120 and I'll have the shop do the install. Shouldn't take more than an hour.

This bike has sure given me a lot of opportunities to build character.:think
 
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#5
I know it's too late now, but we always tell our first time four stroke racers if they're kicking the bike so hard it's leaving a mark on the kicker where it's hitting the footpeg, they're not doing it right.

I've seen bikes with less than 20 hours on them that have a 1/4" indent in the kicker where it's slamming into the footpeg. Man, something's gotta give!
 
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#6
Thanks DualSportr...

That's good advice.... I'll start kicking a little gentler from now on.... Using the CR lever, saying my prayers and eating my vitamins :D

Damn... whoda thunk... so many things to master before you even hit the trail.... :)
 
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#7
CR Lever...

How does that work?
Is it using the stock knuckle?
Does it come down on the foot peg better than the stock lever?

Thanks,
- Sean
 
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#8
Ooops.... we got cross wired there...

CR lever = Compression Release lever

Sorry if it sounded like Honda CR KickStart lever....

Just trying to cut down on the typing..... instead I had to type this .... So much for shortcuts :D
 
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#9
Holy moley!

I was reading this post and went out to look at the kickstarter on my 3 month old yz250f -- huge gash halfway through the shaft! I alway use the compression release. This thing is going to break sometime in the futrue for sure. Any alternatives to the $120 stock lever? Any way to repair this before it breaks?
 

zcookie49

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#10
any solutions

Now is it your actual kickstart shaft, where the peice hits the foot peg, for they have placed additional metal there to compensate this.....I did the same in the beginning, i lost half the metal on the added lip on the kickstarter. When I replaced my bars and grips, I took one of my old grips, cut out a portion and placed it on the rear of the foot peg where the kick starter hits, i used 2-3 zip ties and adhered it to "cushion the impact" of the kickstarter to the peg. Now granted, this shouldnt be necessary, but in my mind it is preempative maintenance.... I thought I had my routine down pat, no problems for a long time, then yesterday at the track, started bike up, then popped off choke for prob 30 secs, rode into a muddy berm, and stall.. I tried all my tested routines and it just wouldnt grab, went up an pull started it real quick behind a 4 wheeler for it was hot and i didnt want to screw around with it... I am now thinking that if the bike is not properly warmed up, and stalls, the bike cant figure out if it is in hot start mode or chok3. it is really weird, for no gas given to flood it out.. oh well.. maybe the grip on the foot peg might work for you...
 
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#11
The reason we'd look for damage on the kicker was to see how hard a rider was kicking the thing at the end of the stroke.

The rubber bumper will add life to the kicker, but may not protect the shaft very much.

Basically, you should be through with your kick before it hits the peg. If you're still pushing with enough force to leave marks (from the peg), then it may be too much for the shaft and the internal gears.

Just think about what happens when the kicker hits the peg -- imagine it in slow motion. All the force that was rotating around the center point (shaft), is now transferred to a pivot point (the footpeg), leverage pushes the shaft up, and can bend or crack it sooner or later.

Of course, Yamaha should take some of the blame for this, as they installed a little 125 kicker on the thing. It makes you want to kick it hard and fast.

Look at the kickers on the XR400, or the mile-long thing on the XR600. These took a long time to complete a kick, and so your power was gone by the time you came to the end of the stroke. These rarely broke kicker shafts. Of course, they don't see an MX track either!
 

BadgerMan

Mi. Trail Riders
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#12
I would inspect the shape of the upper third portion of the kickstart lever by comparing it to some other YZ’s and WR’s. My lever was warped or bent as delivered which caused it to wedge inside the stop cast on the foot peg. It missed the footpeg stop completely at the bottom of the stroke causing a lot of damage to the stop cast on the lever (sounds like others have the same problem). When the lever wedges inward at the end of the stroke it would also apply some strange forces to the shaft possibly causing it to fail. I purchased a new lever that had a different bend near the top and it lined up perfectly with the footpeg.
 

ochster

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#13
BadgerMan, you are correct! I have seen a couple where there is a misalignment with stop. And it forces the shaft to flex as the kickstarter is "wedged" against the peg.
 

BadgerMan

Mi. Trail Riders
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#14
The contact point between the lever and the peg is far enough away (from the pivot/shaft union) so it won’t generate a lot of leverage relative to the shaft when it bottoms out. However, if it wedges in-board it seems it will inflict forces that will try to bend the kickstart shaft. Take the aluminum casting portion of your lever off the steel pivot and line it up to some other levers looking for a difference. Mine was warped so bad that it stuck in the down position the first few times I started the bike. If it is warped, tell your dealer you would like it replaced. If you don’t address the root cause of the problem you may eventually break another shaft.