Looks like I need a new crank, but I have a question??

[jkiserracing]

My 450r started to smoke a little when I started it. As it turns out my rings are getting bad so I decided its time for a new top end. Cylinder is still fine. Upon further inspection....the bad news...I need a new crank. Is there anything I could have done to have caused that (or not done for that matter) I am not the original owner. Im the 2nd and I do know it was bought new in 08 (its an 08) and the guy did not ride it very much. I bought it in 2012

Since I have owned it, I maintain it very well as I have all my quads.
Im very particular and keep it extremely clean and maintained.
Oil and filter change every 2-3 tanks of gas.
I use Maxima oil.
Only engine mods are CRF cam and head gasket.

[CJM]

Just happens, bearings wear out and thats that. Did you find shavings in your oil/oil filter?

[DnB_racing]

Jkiser..what part of the crank is bad? if its the big rod bearing, it can happen as CJM said, but if its mains vibrations can cause that, a out of time counterbalance can cause that...

I say this out of experience, was off by one tooth and was very slight vibrations felt when I wore my sneakers moving quad around, but couldn't feel vibrations when wearing thick boots, my mains wore out prematurely, but I was seeing some very fine dust partials in my oil

but what part of crank is bad this will help narrow down if you have other issues

[jkiserracing]

Well Im not sure what part is bad exactly. I did not find any metal shavings. This was discovered once the cylinder / piston was taken off. I do a majority of any work on my quad EXCEPT motor work. The guy who works on my motor says he can feel some play in the crank. While its apart it would be best to go ahead and put the new one in. I can agree with that though....no need in putting in a fresh top end only to be tearing it back down sooner than later. This motor does have a good bit of time on it too.

[Peterson-Racing]

I don't think you need a new crank. Just rebuild the one that is in the bike now. You can rebuild that one and save a good chunk of money. If you guys can't do it I will do it for you. 160.00 total shipped back to you. It will be as good as new and way cheaper. I have been doing crankshafts for 22 years and rebuilt ones are just fine.


Well Im not sure what part is bad exactly. I did not find any metal shavings. This was discovered once the cylinder / piston was taken off. I do a majority of any work on my quad EXCEPT motor work. The guy who works on my motor says he can feel some play in the crank. While its apart it would be best to go ahead and put the new one in. I can agree with that though....no need in putting in a fresh top end only to be tearing it back down sooner than later. This motor does have a good bit of time on it too.

[jkiserracing]

Well......I definitely like the sound of that!! ^^^