03 crf450r main crank bearings

quick question for those who might have a little more knowledge on the fact.....I bought a bottom end from someone and when taking the fly wheel off i noticed there was a little play in the crank....not much at all and it has a hot rods crank in it....Im wondering if i can get away with just putting new main bearings in it or should i replace the crank... crank looks to be in perfect shape????

I've done that several times. The bearing on the left side seems to give up prematurely. If the rod is ok, you can get a main bearing kit from hot rods, but the race for the left side requires the timing gear to be pressed off and back on.

thank you for responding.... i apologize but when you say timing gear to be pressed off and back on what gear are you referring to???

I think Shawn is talking about the bearing race on the LS of the crankshaft assembly behind the lower timing chain gear.


And you are talking about the LS main bearing in the case, so you'll have to find out which one of those are causing the looseness.

thank you i got you..... i was talking about the left side main bearing.... how often do the ls bearing race go???? and I'm only asking bc its a hot rods hd crank and i alright have a lot of money into the bike and don't want to buy the crank... what is everyones best opinion to do???

Your least expensive option is to replace the bearing race with a main bearings kit from Hot Rods. Most people dont bother though, they replace the whole crank. When you do the main bearings kit, youre not having to replace the connecting rod. The main bearing kits arent that much money. So youre basically into it for gaskets, the bearing kit and 20-30 bucks to have the gear pressed on and off. The bearing race you want to replace is behind the timing gear thats pressed onto the crank on the left side.


Even if the race looks ok, dont just throw a new bearing into the cases and cross your fingers. It wont last.

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