how many hours?

vet45
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vet45
Edited Date/Time 7/13/2012 4:42am
does anyone have any useful or documented information on how many hours a crank can safely run before a rebuild on a 2009 YZ450F? rider is pro level....crank is still within specs at 60 hours.....??
thanks in advance for replys
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Rob_Miller
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Rob_Miller 7/6/2012 7:45am
7/6/2012 7:45am
Normally I wouldn't post on this because I can't give an honest answer as in to how long you could safely run it. But i do know I've seen them go a lot longer than 60 hrs. How the bike is maintained is going to be the deciding factor in how long the motor is going to last. These bikes are made to have the piss ran out of them. My oil is changed in my 08 CRF450R every couple of hours. I'm at 48 hrs on the bike now, all moto. Everything is still in spec. Like anything else though, freak accidents happen. Sometimes parts wear out, just because they do. I know that this post doesn't answer your question as in to how long you can go. Maybe it gives ya some confidence in the bike though. If everything is still in spec and having no signs of wear, you should be fine. "If it aint broke, dont fix it!" I ride with guys that rebuild their bikes all the time, just because they feel like it, and have the money to. They usually have less problems than I do. I feel like the less times a motor is torn apart, the better. Rebuild them as necessary, and only when necessary.
pete24
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pete24 7/6/2012 5:43pm
7/6/2012 5:43pm
crank is in spec, as in how? you wiggled it from the top f the case with the cylinder off?, if not and u took it out pressed the rod off and measured the inside dia, and the pin, then at that point why wouldnt you just put a new rod on? the wiggle test doesnt work for a pro, good thing its a yamaha cuz anything else you would be 30 hrs over needing a crank( at the pro level)
vet45
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vet45 7/7/2012 6:35pm
7/7/2012 6:35pm Edited Date/Time 7/7/2012 6:36pm
thanks for your input, i was amazed at the lack of information regarding service interval hours for cranks. we do top ends between 17-20 hours. cranks at 60. i did see that on eric gorr's site he used 75 hours as a bench mark. at the pro level you do not prescribe to "if it aint broke, dont fix it". thats the point of a good maintenance program, most all driven by budget. most factory and well financed satellite teams have a maintenance cost of $950.00 per running hour (rebuild every moto). not many can do that. regarding the crank within spec., the side to side clearance at the big end of the rod and the end play can be measured and give you an idea if its worn out but theres really not a measurement to tell you how long its safe.
i have no reluctance to split the cases on our motors, its the best way to see whats going on an.
mx5471
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mx5471 7/7/2012 7:00pm
7/7/2012 7:00pm
If you are a wrenching at a "pro" level, you wouldn't be asking questions on this board, you would be answering them.

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vet45
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vet45 7/10/2012 7:18pm
7/10/2012 7:18pm
i wrench for my son who rides at the pro level. i do not make my living as a pro mechanic. i have wrenched for many years and found that i learned more by asking questions . even though i have built and rebuilt many many motors, i was looking for reasonable service interval information regarding crankshafts and hopefully from a source that has documented data.
I dont pretend to be a know it all, thats why i asked for information.
at least pete and rob (who replied above) were trying to be helpful, im not sure what the intention of your post was.....?
Rob_Miller
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Rob_Miller 7/12/2012 3:30pm
7/12/2012 3:30pm
vet45 wrote:
thanks for your input, i was amazed at the lack of information regarding service interval hours for cranks. we do top ends between 17-20 hours. cranks...
thanks for your input, i was amazed at the lack of information regarding service interval hours for cranks. we do top ends between 17-20 hours. cranks at 60. i did see that on eric gorr's site he used 75 hours as a bench mark. at the pro level you do not prescribe to "if it aint broke, dont fix it". thats the point of a good maintenance program, most all driven by budget. most factory and well financed satellite teams have a maintenance cost of $950.00 per running hour (rebuild every moto). not many can do that. regarding the crank within spec., the side to side clearance at the big end of the rod and the end play can be measured and give you an idea if its worn out but theres really not a measurement to tell you how long its safe.
i have no reluctance to split the cases on our motors, its the best way to see whats going on an.
My bad, for some reason when i first read your post and started typing I was thinking that you had bought the bike from a pro-level rider and I was assuming that it was being raced/ridden locally or something of that sort. Disregard my post. lol.

It does seem odd that there isn't more documented information on it. Hopefully somebody knows. I bet that if you asked a pro race mechanic they would have a pretty good idea. I know that they rebuild their riders bikes all the time anyway, and they don't wear the parts out usually between builds, but I bet they've all seen testing and such as in to how much their parts can take. Best of luck to you and your son!
CamP
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CamP 7/13/2012 4:42am
7/13/2012 4:42am
vet45 wrote:
does anyone have any useful or documented information on how many hours a crank can safely run before a rebuild on a 2009 YZ450F? rider is...
does anyone have any useful or documented information on how many hours a crank can safely run before a rebuild on a 2009 YZ450F? rider is pro level....crank is still within specs at 60 hours.....??
thanks in advance for replys
Brian, the Tisco Team guys are replacing their 450 cranks at 50 hour intervals.

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