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Help! Crf450r died and locked up

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So a fee weeks ago i was out riding my 2010 crf450 i wasnt riding it as hard as i normally do, i come off around a corner, and it was fine rode around a bit longer then it die and basically locked up on me thought i seized it.. Odd for about 20 hrs since brand new gave it a few kicks it started but kept diein unless i gave it throttle long story short i got home and started pulling it down valves are tight.. Cant get any feeler in there.. Thinkin about replacing them cleaned the fuel filter etc, started first kick, tried to start it the other day, 30 kicks later it finally started, just asking for recommendations as to what "could have happened" i dont really wanna pull it down if i dont have to anyone had anything like this happen to them?

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Typically, once the valves start to move its not long before you have to replace them. Buy good quality valves or OEM as the cheap ones don’t last long at all. But, the bigger question is if you only have 20 hours why have your valves moved? Air filter might not be set correctly or somehow allowing dirt to get by. if you tear it down might consider replacing the rings as well.

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Yep. Once the valves start going out of spec, the seats and the shape of the valve get worn. It will need the seats cut and new valves. You might a well replace the fuel filter, make sure it is the updated fuel filter. It is not starting because it is that out of spec I would guess.

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I find it hard to believe that all 4 valves on a 2010 bike with 20hours since brand new would close up. Are u sure u had it at TDC when measuring the clearances?

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You never know. Perhaps the air cleaner has never been cleaned or oiled...

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Air filter was cleaned and oiled after every ride and if it was a long day every few hours, had all the marks lined up to check for tdc.. And as i said couldnt get a feeler at all in there, and yeah after 20hrs and this goimg on, its a little confusing and disappointing lol looks like i will be investigating more today check tdc again cover the basics see if i missed anything

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Take the air filter off and grab a clean white paper towel, put some rubbing alcohol on it and swipe on the inside of the airboot, looking for dirt. Also you can see the throttle body butterfly, check it for cleanliness. I bet dirt has gotten by, that's the only way the valves will go out so fast.

Edited by Eddie8v

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Will have a look when i go over to the shed just frustrating having it and not bein able to ride it well i could but i wont when its like this, i must been unluky as my mates yzf same year gets a hard life literally it hasnt had an oil change in almost 2 yrs it probably has 300ml of oil in it if its lucky and air filter gets cleaned once a year haha still runs like brand new

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If the valves really have closed up, it isnt bad luck, you're doing something wrong with your filter maintenance or installation. This isnt normal.

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20 hours? That's only 6 months of riding for a casual rider. That bike is four to five years old. It would have 150 to 200 hours for most of us. Does it have an actual hour meter? Was it put on when the bike was new or just before you got it? My guess is the previous owner fudged the true amount of hours.

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Ive had the bike for 2 years owner before me was a mate and he rode it 5 times, oils and oil filter changed every 3-5 hrs air filter every ride, exception long days ill clean it halfway through the day, gets cleaned in 98 octane fuel in 3 different buckets to remove as much dirt as possible then cleaned in soapy water and dried then sprayed with the foam filter oil, air box is cleaned as well whilst waiting for the filter to dry

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Something is def wrong with something if it's a true failure ater 20 hours.  I have changed intake valves several times but have never cut new seats.  Bike runs great.  Cutting new valve seats is not a must.  I'd just drop in new intake valves, make sure my filter is on securely, and ride it.

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Ill check the valves again shortly if i get an hour to myself today really wanna go out for a ride and dont really wanna ride the kdx or pitty around haha

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I'm not trying to insult you or your bike but my 09 has 120 hrs and the valves are still in spec. This was all MX. 20 hours doesn't make sense!

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No insult taken and tell me about it anything that could happen has gone wrong for me lol i could have simply missed something it does happen to the best of us

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maybe there are more hours than you suspect.. you know how many you put on, but can you be positive about prior owner ? no use worrying till you check valve clearance again. As some mentioned, once the intakes move, they are not long for this world. In fact 1 long (i do 2 hrs in the woods at a time) was all i got sometimes after the initial adjustment. So LONG ago i knew to order intakes and springs at 100 hrs, cause around 110-120 is when they would begin to tighten up. If it ever got close to zero, i would be lucky to get 1 more ride before needing adjusted again (and not worth doing that..just replace)

 

i am not a fan of the spray on filter oils.. but that's me. Also unless you are riding in some particularly dusty conditions, there should be no reason AT ALL you need to clean a filter after every ride.. or change oil every 3 hours for that matter.. Do some searching on this subject and save yourself some money and time.

Edited by MELK-MAN

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The valves tightening up wouldnt have anything to do with the engine locking up. If the engine just died, thats a completely different thing. Some of the Honda heads have a concentricity issue. Meaning that right from the factory the valve seat is off center from the valve stem. It doesnt take much of this condition to wear the coating off the intake valve and allow it to recede into the head prematurely. It can happen PDQ as a matter of fact.

 

Check the lash again, if its close up again, well...its valve job time. The fact that the thing only has 20 hours on it really doesnt matter. It is what it is.

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Well my intakes are in spec, according to the manual, but my exhaust valves cant get a reading at all, might send it into shop dont have time to do it myself work 90 hrs a week

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Odd to have the exhaust valves close up without the intakes also doing so. Are you sure that you have the piston at TDC on the compression stroke when taking your measurements?

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more likely youve got ur intakes and exhausts mixed up. Either way if any of them have closed up its time for a valve job.

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