2008 with 91hrs... stock

So as you can see it is time to do some work to the bike. I just didnt have the finances over the summer to do a rebuild but I am planing to over the winter (tax return). So my question is what all need to be done? Or who has done rebuilds around the same hours and what did you do. I did search "rebuild" and after 15min of searching I thought it may just be faster to ask.

I am planning on new: piston kit , Clutch (maybe Rekluse EXP) , Cams ( '06 more power?), Head gaskets, wheel bearings, Linkage bearings, Chain/sprocket (2nd set) , and do some more work with my suspension (I have Smart valve kit and oil)

I am looking to get some more power out of the bike so any suggestion would be great. I am planing on doing a pipe and getting my carb done.

Thanks guys

P.S.

Dont kill me about the hours, I already know. I'm just lucky I got a Yami.

There's no rule as to when you should do what to your engine, really. You could, of course, replace the valves, cylinder, piston, crank, etc., and it would be that much fresher, but if it doesn't need it right now, that's somewhat wasteful, no? If you're racing all the time, it might be wise, but it depends on how you use the bike.

On the other hand, waiting for something to fail often means "break", and you don't want that. A leak down test will tell a great deal about an engine's condition. Not everything, of course, but quite a bit can be learned by it. I know mine doesn't "need" any of that, and it has more time than that on it.

check some of my posts concerning "complete rebuild"...I am currently rebuilding my top end and valve train if you would like to confer with me? pm me here or email josh@thetwistedgrip.com

My '07 just locked the rod at 148.2 hours.

My '07 just locked the rod at 148.2 hours.

For curiosity's sake, what is your oil, type and level of riding, and your oil change interval?

For curiosity's sake, what is your oil, type and level of riding, and your oil change interval?

I knew this was coming. Let me start by saying this bike has been the best MX bike I've owned. And before this one, there were a lot. As I now move on to the new model of YZ450F.

Oil type: Shell Rotella 15w-40

Change interval: Every ride, whether on the MX track, or in the woods, the bike doesn't go out of the shop without an oil and filter change.

Level of riding: A Level/Ex-pro MX, AA in woods.

It should've went before that like every other bike, but it almost doubled the hours of any other machine I've owned.

Edit: Oh yes, bike was bone stock, except for carb mods, and the occasional FMF slip on for the woods with S/A. The rings were changed at 113 hours and everything was in spec, top and bottom. Valves have never been out of spec, not once. Bike always started within 5 easy kicks when cold (I'm a lazy kicker)

Edited by RJacks
Add on
My '07 just locked the rod at 148.2 hours.

I too would like to know.. that seems like relatively low hours, but i guess there's too many factors that come into play to judge that. I have seen some high hour machines out there running around. I once had a 04 250f with over 400 hours on the meter when i got it. (harescramble bike). I rode it for a season then rebuilt it and the thing looked great inside. Its still running on the stock crank to this day.

Level of riding: A Level/Ex-pro MX, AA in woods.

How long is your typical woods race?

How long is your typical woods race?

2 hours unless GNCC comes to FL. I've also done more 2-3 hour straight rides on the weekends than races.

Rotella really doesn't retain its viscosity that long. Seems impossible, but it if you test your next sample at 1.5 to 2 hours, you might be surprised. Most of the time it comes back a full grade low at 30 weight.

Not saying that's what caused it, but it is interesting.

I know there are LOTS of people with good results, but every person I know that runs or ran Rotella (including myself) has had some kind of engine or transmission failure. Coincidence? Maybe.:p I stopped using it long ago. I now run Maxima or Amsoil and change it at 3-5 hour intervals.

I know there are LOTS of people with good results, but every person I know that runs or ran Rotella (including myself) has had some kind of engine or transmission failure.
More curiosity: how many people is that, including yourself?
Rotella really doesn't retain its viscosity that long. Seems impossible, but it if you test your next sample at 1.5 to 2 hours, you might be surprised. Most of the time it comes back a full grade low at 30 weight.

Not saying that's what caused it, but it is interesting.

Say what you will, to each his own. I've used Rotella for years with no issues. On average I usually don't get more than 2 hours per change on it. The rest of the motor was still in spec.

What types of oil do you recommend gray? If there is something better I'd try it. I definitely don't blame the rod locking up on my motor on the oil. At the level I ride at, I can't believe that it lasted as long as it did with out anything except rings.

I personally use Amsoil MCF, but I consider Mobil1 Racing 4T to be as good. My main issue is the question of viscosity loss to shear in the trans. Most automotive engine oils don't have the additive package to deal with that, and even as little as 3 years ago, not very many "motorcycle oils" did either. It is finally becoming more common, though.

I have almost 350 hours on the rebuild on my 08 450F. I run Yamalube and always change the oil and filter every other ride. Bike still starts easy and runs strong.

I should add that I installed the new piston "wet," which I have since read on here is a bad idea. It has always made a little bit of blue smoke on startup, but still runs clean once it's warm.

I should add that I installed the new piston "wet," which I have since read on here is a bad idea. It has always made a little bit of blue smoke on startup, but still runs clean once it's warm.

You haven't read that from me. I install all my pistons with a drop of oil in each ring groove, the cylinder wiped with oil, and a smear of oil on the skirts. None of them smoke or use oil.

Typically, a puff of oil smoke on startup only is the fault of leaking valve guide seals.

I have almost 350 hours on the rebuild on my 08 450F. I run Yamalube and always change the oil and filter every other ride. Bike still starts easy and runs strong.

Would you mind if I ask what all you did for your rebuild.

Grey thanks for getting back to me so fast. I think I start using one of the oils you have named. I know have big the right oil is for todays cars, dont know why i didnt apply the same logic to my bike. Oh and I am a 4 lap B rider, meaning I am only semi fast for 4 laps and then hit the wall and slow down. I just started to ride the bike hard over the past 20hrs, before that it was babied.

I had to rebuild at 50 hours because the timing chain skipped and the piston hit the head, broke two valves, and bent the connecting rod. The rebuild consisted of a new crank, piston, and head, and of course timing chain and tensioner.

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