Kickstarter shaft seal popping out

Mr. Afterbar
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Mr. Afterbar
The kickstart shaft seal on my '16 KX450F keeps popping out every time I take it out on the track. I've replaced it at least 4 times and same thing every time. I installed it using a deep impact socket the same dismeter as the seal. I've tried seating it all the way in and just short of bottoming it out as well. Even tried some loctite 518 around the outside of the seal once. My case breather hose is not obstructed. I'm baffled. Don't know what else to try. It didn't pop out during my last moto today for the first time since I've been having this issue, but I was taking it easy as I was spent and my hands destroyed. Has anyone ever had this issue or have any suggestions on how to remedy it?
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kb228
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kb228 8/5/2019 4:02am
8/5/2019 4:02am
strange issue. Never seen it before. Did you make sure theres nothing on the kick lever or shaft catching that seal and twisting it out?
Mr. Afterbar
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Mr. Afterbar 8/5/2019 6:00am
8/5/2019 6:00am
kb228 wrote:
strange issue. Never seen it before. Did you make sure theres nothing on the kick lever or shaft catching that seal and twisting it out?
Yep, no issues there.
charlie68
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charlie68 8/5/2019 10:03am
8/5/2019 10:03am
Is it an OEM seal or aftermarket seal you are using?

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dmm698
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dmm698 8/5/2019 12:23pm
8/5/2019 12:23pm
charlie68 wrote:
Is it an OEM seal or aftermarket seal you are using?
Mr. Afterbar wrote:
Only OEM.
Can you physically "suck" air through your breather hose? I dont remember the configuration of my 16 kx450 crank case breather as the bikes long gone, but I remember way back when buying an 09 kx250f for pennies because the valve cover seal and all the other seals woudl always pop out. Kawi used a hollow shaft that was press fit into the cases, and only had one cross drill in the shaft to align with the breather. If the idler sprocket ever grabbed the shaft and caused it to spin (which this one did) even the slightest amount, it would prevent the engine from relieving itself of crank case pressure.
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Paul_Pitzonka
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Paul_Pitzonka 8/5/2019 2:43pm
8/5/2019 2:43pm
I know the 2016 kx450f we’re breaking right case halves at the kick start gear... is it possible the inner case is cracked and causing the kick-shaft to “walk” the seal out?
Mr. Afterbar
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Mr. Afterbar 8/5/2019 2:58pm
8/5/2019 2:58pm
dmm698 wrote:
Can you physically "suck" air through your breather hose? I dont remember the configuration of my 16 kx450 crank case breather as the bikes long gone...
Can you physically "suck" air through your breather hose? I dont remember the configuration of my 16 kx450 crank case breather as the bikes long gone, but I remember way back when buying an 09 kx250f for pennies because the valve cover seal and all the other seals woudl always pop out. Kawi used a hollow shaft that was press fit into the cases, and only had one cross drill in the shaft to align with the breather. If the idler sprocket ever grabbed the shaft and caused it to spin (which this one did) even the slightest amount, it would prevent the engine from relieving itself of crank case pressure.
I’m not able to blow into it with the engine sealed up, but if I pull the oil fill plug, it blows right out.
Mr. Afterbar
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Mr. Afterbar 8/5/2019 2:59pm
8/5/2019 2:59pm
Paul_Pitzonka wrote:
I know the 2016 kx450f we’re breaking right case halves at the kick start gear... is it possible the inner case is cracked and causing the...
I know the 2016 kx450f we’re breaking right case halves at the kick start gear... is it possible the inner case is cracked and causing the kick-shaft to “walk” the seal out?
This actually happened to one of my friends ‘18 KX 450. No signs of that issue with mine. I didn’t pull the right side cover, but I might have to just to have a look.
charlie68
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charlie68 8/6/2019 5:12am
8/6/2019 5:12am
charlie68 wrote:
Is it an OEM seal or aftermarket seal you are using?
Mr. Afterbar wrote:
Only OEM.
So speaking strictly of the hard parts and why THIS seal would fail repeatedly, OEM seal at that, and not other seals, I would say the right case half is cracked and swells when hot and under stress allowing the seal to pop. I have used a kit containing 3 different spray cans designed to detect cracks but I dont remember what it is called.
Mr. Afterbar
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Mr. Afterbar 8/6/2019 6:47am
8/6/2019 6:47am
charlie68 wrote:
Is it an OEM seal or aftermarket seal you are using?
Mr. Afterbar wrote:
Only OEM.
charlie68 wrote:
So speaking strictly of the hard parts and why THIS seal would fail repeatedly, OEM seal at that, and not other seals, I would say the...
So speaking strictly of the hard parts and why THIS seal would fail repeatedly, OEM seal at that, and not other seals, I would say the right case half is cracked and swells when hot and under stress allowing the seal to pop. I have used a kit containing 3 different spray cans designed to detect cracks but I dont remember what it is called.
I have a feeling you may be right. I will have to tear it apart and have a good look. I was thinking last night that something might be warping when the bike gets really hot.
dmm698
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dmm698 8/6/2019 7:31am
8/6/2019 7:31am Edited Date/Time 8/6/2019 8:05am
Mr. Afterbar wrote:
Only OEM.
charlie68 wrote:
So speaking strictly of the hard parts and why THIS seal would fail repeatedly, OEM seal at that, and not other seals, I would say the...
So speaking strictly of the hard parts and why THIS seal would fail repeatedly, OEM seal at that, and not other seals, I would say the right case half is cracked and swells when hot and under stress allowing the seal to pop. I have used a kit containing 3 different spray cans designed to detect cracks but I dont remember what it is called.
Mr. Afterbar wrote:
I have a feeling you may be right. I will have to tear it apart and have a good look. I was thinking last night that...
I have a feeling you may be right. I will have to tear it apart and have a good look. I was thinking last night that something might be warping when the bike gets really hot.
https://www.amazon.com/Dye-Penetrant-Crack-Finder-Kit/dp/B00XLW4BRC

I used one of these kits we had at work to look at a 49mm a kit fork tube that was leaking from the lug once I removed the lug to realize there was a crack in it. I think i have a seal kicking around now that I think about it from my 2016 that started weeping on the kick start shaft at 40 or 50 hours that I never installed before trading it in. If i find it, you can have it just cover shipping.
charlie68
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charlie68 8/6/2019 8:00am
8/6/2019 8:00am
charlie68 wrote:
So speaking strictly of the hard parts and why THIS seal would fail repeatedly, OEM seal at that, and not other seals, I would say the...
So speaking strictly of the hard parts and why THIS seal would fail repeatedly, OEM seal at that, and not other seals, I would say the right case half is cracked and swells when hot and under stress allowing the seal to pop. I have used a kit containing 3 different spray cans designed to detect cracks but I dont remember what it is called.
Mr. Afterbar wrote:
I have a feeling you may be right. I will have to tear it apart and have a good look. I was thinking last night that...
I have a feeling you may be right. I will have to tear it apart and have a good look. I was thinking last night that something might be warping when the bike gets really hot.
dmm698 wrote:
https://www.amazon.com/Dye-Penetrant-Crack-Finder-Kit/dp/B00XLW4BRC I used one of these kits we had at work to look at a 49mm a kit fork tube that was leaking from the lug...
https://www.amazon.com/Dye-Penetrant-Crack-Finder-Kit/dp/B00XLW4BRC

I used one of these kits we had at work to look at a 49mm a kit fork tube that was leaking from the lug once I removed the lug to realize there was a crack in it. I think i have a seal kicking around now that I think about it from my 2016 that started weeping on the kick start shaft at 40 or 50 hours that I never installed before trading it in. If i find it, you can have it just cover shipping.
Yes! That is the stuff.
Mr. Afterbar
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Mr. Afterbar 8/9/2019 4:56am
8/9/2019 4:56am
charlie68 wrote:
So speaking strictly of the hard parts and why THIS seal would fail repeatedly, OEM seal at that, and not other seals, I would say the...
So speaking strictly of the hard parts and why THIS seal would fail repeatedly, OEM seal at that, and not other seals, I would say the right case half is cracked and swells when hot and under stress allowing the seal to pop. I have used a kit containing 3 different spray cans designed to detect cracks but I dont remember what it is called.
Mr. Afterbar wrote:
I have a feeling you may be right. I will have to tear it apart and have a good look. I was thinking last night that...
I have a feeling you may be right. I will have to tear it apart and have a good look. I was thinking last night that something might be warping when the bike gets really hot.
dmm698 wrote:
https://www.amazon.com/Dye-Penetrant-Crack-Finder-Kit/dp/B00XLW4BRC I used one of these kits we had at work to look at a 49mm a kit fork tube that was leaking from the lug...
https://www.amazon.com/Dye-Penetrant-Crack-Finder-Kit/dp/B00XLW4BRC

I used one of these kits we had at work to look at a 49mm a kit fork tube that was leaking from the lug once I removed the lug to realize there was a crack in it. I think i have a seal kicking around now that I think about it from my 2016 that started weeping on the kick start shaft at 40 or 50 hours that I never installed before trading it in. If i find it, you can have it just cover shipping.
Thanks for the recommendation on the dye kit. I’ll have to give it a shot if I can’t see anything when I pull the cover. I’ll take you up on that seal offer if you do track it down. I have a spare, but for a few bucks, I’ll take another. Thanks.
inthebadboycorner 8/9/2019 5:58pm
8/9/2019 5:58pm
Something else wrong inside engine and creates massive amounts of blow by, factory vent does not cope, try a lap without the filler cap, maybe put a stocking over the filler hole.
Mr. Afterbar
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Mr. Afterbar 8/21/2019 12:18pm
8/21/2019 12:18pm
inthebadboycorner wrote:
Something else wrong inside engine and creates massive amounts of blow by, factory vent does not cope, try a lap without the filler cap, maybe put...
Something else wrong inside engine and creates massive amounts of blow by, factory vent does not cope, try a lap without the filler cap, maybe put a stocking over the filler hole.
I tapped the same seal back in place a few times while out riding a couple weeks ago and it has magically decided to stay in place. No idea why this was happening, but it's fine now and I'm running with it.
charlie68
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charlie68 8/22/2019 5:13am
8/22/2019 5:13am
inthebadboycorner wrote:
Something else wrong inside engine and creates massive amounts of blow by, factory vent does not cope, try a lap without the filler cap, maybe put...
Something else wrong inside engine and creates massive amounts of blow by, factory vent does not cope, try a lap without the filler cap, maybe put a stocking over the filler hole.
Mr. Afterbar wrote:
I tapped the same seal back in place a few times while out riding a couple weeks ago and it has magically decided to stay in...
I tapped the same seal back in place a few times while out riding a couple weeks ago and it has magically decided to stay in place. No idea why this was happening, but it's fine now and I'm running with it.
Mysterious simple fix, good luck.
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