2013 CRF 450 motor problem HELP!

levibrito830
Edited Date/Time 4/22/2016 6:03pm
I have a 2013 crf 450, has great compression. New top end with about 20 hours on it. Bike runs strong lots of power. But when I come in and shut the bike off sometimes ( not all the time) when I go to start the bike for another moto. The motor acts as if its seized. Kickstart is frozen. But if I take the bike off the stand and push it at a fast pace and bump it into gear, the kickstart is then free again and starts normal, Please help. Im petrified its the crank
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Paw Paw 271
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Paw Paw 271 4/20/2016 7:35pm
4/20/2016 7:35pm
I don't think it's the kick starter that is the issue. It sounds like it's the auto decompression device in the cam is not bumping open the exhaust valve so you have reduced compression for the kick starting.
Every time I have seen this in the past it was caused by a worn out cam chain that is causing a timing issue for the auto decompression device in the cam to work at the correct time.
When was the last time the cam chain was replaced?

Paw Paw
levibrito830 4/20/2016 8:01pm
4/20/2016 8:01pm
To be honest, im not sure. I personally havent replaced it myself, i had read somewhere that the timing chain being off one tooth can cause a similar issue.
levibrito830 4/20/2016 8:03pm
4/20/2016 8:03pm
Paw Paw 271 wrote:
I don't think it's the kick starter that is the issue. It sounds like it's the auto decompression device in the cam is not bumping open...
I don't think it's the kick starter that is the issue. It sounds like it's the auto decompression device in the cam is not bumping open the exhaust valve so you have reduced compression for the kick starting.
Every time I have seen this in the past it was caused by a worn out cam chain that is causing a timing issue for the auto decompression device in the cam to work at the correct time.
When was the last time the cam chain was replaced?

Paw Paw
To be honest, im not sure. I personally havent replaced it myself, i had read somewhere that the timing chain being off one tooth can cause a similar issue.
Paw Paw 271
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Paw Paw 271 4/21/2016 3:10am
4/21/2016 3:10am
That is also true, and can be caused by a worn cam chain.

Paw Paw

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jsmx97
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jsmx97 4/21/2016 9:34am
4/21/2016 9:34am
When it becomes seized, remove the crank bolt access plug and try turning the engine over by hand. That will be a good indicator as to whether it is an issue in the engine rotating assembly, or possibly a kickstarter/other issue. Regardless what the issue is, you should never force the engine past a seized point by force... figure out your problem, dont make it worse!
moto314
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moto314 4/21/2016 12:43pm
4/21/2016 12:43pm
I would pop off the valve cover and check the timing and the auto decompression on the cam. It's very easy to check.
Slosh 112
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Slosh 112 4/22/2016 3:36am
4/22/2016 3:36am
Auto decompressor for the exhaust, if the cam chain were one tooth out it would run rough as, it would be very obvious that its not running right.
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Slosh 112 4/22/2016 3:37am
4/22/2016 3:37am
Wouldn't think that it would be a cam chain being a relatively new bike, how many hours has it got on it?
Paw Paw 271
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Paw Paw 271 4/22/2016 8:18am
4/22/2016 8:18am
Most likely the cam chain is worn beyond normal service life. If that is the case the chain tension will not work correctly and have enough tension to keep the timing correct. Look at your service manual for the bike and I would check out the cam chain service limits.
I have seen this issue many times. I have also seen riders replace the OEM tensioner with aftermarket manual units when it was just a worn cam chain and then have major engine failures.
I am not telling you this is the only possibility, but the cam chain is a very neglected overlooked wear item.
I would also be looking at the valve clearances, timing and the auto decompression parts in the cam as possible issues, but I would replace the cam chain if the valve clearances are correct.
the pre-2008 Honda CRF450R's had a different style of a decompression unit that was an arm that require very precise adjustment to make it work correctly and many bikes suffered the same issue you are stating. IN those bikes the easiest fix was the proper setting of the auto decompression arm. The newer versions are operated by a pieces in the cam itself. If the cam timing or the exhaust valve clearances are not correct it will not work correctly.
If I recall correctly the recommended service limit of your cam chain is way under the 95 hours you have on the bike, but I could be wrong. I am thinking it is in the neighborhood of 60 hours.
Honda has also had issues with the new style being too aggressive and causing some stalling issues at low rpms and modifications have been made available to correct this issue.
Check out youtube.

Paw PAw
levibrito830 4/22/2016 3:00pm
4/22/2016 3:00pm
Paw Paw 271 wrote:
Most likely the cam chain is worn beyond normal service life. If that is the case the chain tension will not work correctly and have enough...
Most likely the cam chain is worn beyond normal service life. If that is the case the chain tension will not work correctly and have enough tension to keep the timing correct. Look at your service manual for the bike and I would check out the cam chain service limits.
I have seen this issue many times. I have also seen riders replace the OEM tensioner with aftermarket manual units when it was just a worn cam chain and then have major engine failures.
I am not telling you this is the only possibility, but the cam chain is a very neglected overlooked wear item.
I would also be looking at the valve clearances, timing and the auto decompression parts in the cam as possible issues, but I would replace the cam chain if the valve clearances are correct.
the pre-2008 Honda CRF450R's had a different style of a decompression unit that was an arm that require very precise adjustment to make it work correctly and many bikes suffered the same issue you are stating. IN those bikes the easiest fix was the proper setting of the auto decompression arm. The newer versions are operated by a pieces in the cam itself. If the cam timing or the exhaust valve clearances are not correct it will not work correctly.
If I recall correctly the recommended service limit of your cam chain is way under the 95 hours you have on the bike, but I could be wrong. I am thinking it is in the neighborhood of 60 hours.
Honda has also had issues with the new style being too aggressive and causing some stalling issues at low rpms and modifications have been made available to correct this issue.
Check out youtube.

Paw PAw
When I removed the valve cover this is what I discovered,
levibrito830 4/22/2016 3:04pm
4/22/2016 3:04pm
hey guys I took a video please text me 7749559091 and I can send the video, it hangs up in one part of the cycle, wondering if thats normal??
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Paw Paw 271 4/22/2016 6:02pm
4/22/2016 6:02pm
The auto decompression arm does move during rotation as a normal thing. If it however is hanging up in the extended position that will cause the compression to increase as the auto decompression lob will not come in contact with the exhaust valve.
This can be caused by dirt, trash or wear. I would remove the cam and clean it to see if that fixes the issue at hand.

I can't tell from the photo, but the cam does seem to be fully seated in the bearing which could also cause a problem with the auto decompression's operation.

Paw Paw

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