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Luigic81

Looking to buy '06 yz450, what to replace immediately

11 posts in this topic

low hour bike, all stock, I have heard that the following should be addressed if the previous owner has not done so already:

1. Cam chain should be replaced

2. Upper steering head bearing

Additional things that may go out soon

1. water pump seal

2. fork seals

3. Shift stopper

Anything else?

The cam chain will be easy, as far as the steering head bearing(s), I dont have a press, so I'm assuming I would just remove the complete steering head, purhcase bearings and have a place like Napa press them on for me? Or if you are diligent about greasing the steering head bearings do they need to be replaced at all? (i'm not a pressure washer guy)

Water pump seals I have done before, so thats no biggie, I guess I would just wait until my oil looks milky and then it's time to change her out.

Fork seals are self explanatory

Now the shift stopper.... I replaced the one on my '05 YZ 125, so is it basically the same problem with this bike? You are replace the bearing style stopper with a solid roller type? Where these known to go bad like the 125 ones?

Thanks!!!!!!

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Why replace all that stuff if it doesn't need it?

If it has low hours (and it was maintained well), most of that stuff should still be good.

you should be able to tell via inspection/symtoms whether it needs those items, accept for the cam chain . . . perhaps good to swap it out for cheap insurance.

My '08 450 I bought used DID need some steering head bearing work. (yep it was powerwashed by previous owner.:-o

I replaced the upper one only. Used a punch to get the race out (from the underside, of course.)

The new bearing set comes with a race, which is an interference fit. I didn't have a press, so I carefully got it started evenly using a small wood block, drove it in most of the way, then used a large socket to carefully drive it all the way home (making sure to avoid the actual bearing surface.)

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not being a smart a$$ but why not buy a newer bike that needs nothing but someone to twist the throttle?

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The only head bearing that requires a press is the lower bearing on the stem. Have it changed at a bike shop if you don't want to use one of the gorilla methods soon to be suggested. As far as the races in the steering head, they can be driven out with hand tools.

Your oil will never become milky due to a failed water pump seal. There is a gap between the oil seal and the coolant seal that is open to the outside specifically so that coolant leaking past the seal can escape without contaminating the oil.

As to the indexing arm:

http://www.thumpertalk.com/forum/showthread.php?p=4922391#post4922391

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thanks for info guys, I am buying this one becuase it's setup for supermoto and comes with an extra set of dirt wheels/front brakes. It will mainly be a sumo bike for me as I have my 125 for MX.

I hear what your saying, and I would definatley wait to replace the fork seals, water pump seals, and steering head bearing until they failed, but I would just go in assuming that those would fail in the near future.

I would do the cam chain regardless as cheap insurance, I'm gunna be in there to do a leak down test and check the valves anyways...

How about the shift stopper? Is this similiar to the one on the 125? apparently it was a big deal on those bikes, and if they went out, it wasnt pretty.

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Very helpful thanks :)

So sounds like the cam chain and shift stopper should be done right away, and then the other stuff I can wait on.

so back to the water pump seal, does this bike have a weep hole to let you know when the seal is bad?

I've only done them on 2 strokes and it always mixed with the trans oil and made it milky.... thanks

The only head bearing that requires a press is the lower bearing on the stem. Have it changed at a bike shop if you don't want to use one of the gorilla methods soon to be suggested. As far as the races in the steering head, they can be driven out with hand tools.

Your oil will never become milky due to a failed water pump seal. There is a gap between the oil seal and the coolant seal that is open to the outside specifically so that coolant leaking past the seal can escape without contaminating the oil.

As to the indexing arm:

http://www.thumpertalk.com/forum/showthread.php?p=4922391#post4922391

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so back to the water pump seal, does this bike have a weep hole to let you know when the seal is bad?

I've only done them on 2 strokes and it always mixed with the trans oil and made it milky.... thanks

Uh,....

Your oil will never become milky due to a failed water pump seal. There is a gap between the oil seal and the coolant seal that is open to the outside specifically so that coolant leaking past the seal can escape without contaminating the oil.

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I have an 06 I have tried to wreck. I have replaced everything about now except the frame and suspension almost ( not really just pushing the idea) and must say this has been my best bike ever.

I am looking at a new Yz, but I am scared it won't be as reliable.

issue's I have had is rear wheel bearings and clutch

I am on plates set 6 and basket 3 clutch hub3 and springs 3.

I still love my bike.

Oh and the hot start got stuck once and had me scratching my head for a long time.

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Uh,....

Sorry maybe I should state the question differently,

"How would you know if your water pump seal went out on this bike?"

Would you just be pissin coolant out the overflow?

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Depends on the severity of the leak. A slow leak might go unnoticed other than that the coolant level keeps dropping unless you pick up the odor of hot anti-freeze. The escape passage exits below/behind the water pump. If you can't really see any coolant leaking or find it wet, dust the area with baby powder. The trail will be obvious.

Remember, the whole system only holds a little more than a quart.

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