Redone the topend on my 06 450f

Just thought I would let you guys know that I put a piston and rings in my 06 450f. It had a total of 50 hours on it when I did it last week. Everything looked pretty good inside after 50 hours,the cam chain looked good,valves were in good condition but they did have alot of carbon built up on them along with the piston so I just scraped all the carbon off the valves and had to re shim them (only one size) The piston and rings looked good also but since I was in there I went ahead and replaced them also The cams were in execellent shape. I guess the 06 will hopefully be good for another 50 hours..... Your do you guys think I should stretch it to 60 hours next time?

I have 105 hours on my '06. The only thing I have done is check the valves at 80 hours, and they were still in spec.

My bike is running fine, too. :crazy:

I have 105 hours on my '06. The only thing I have done is check the valves at 80 hours, and they were still in spec.

My bike is running fine, too. :crazy:

wow...ditto, I checked mine around 75 and have not done a thing since them and Im pushing 100.

wow...ditto, I checked mine around 75 and have not done a thing since them and Im pushing 100.

Yea!....But!....When I checked the valves in mine before I tore down the top end they were in spec......After I scraped all the carbon off the valves and put in the new piston and rings and then checked the valve clearence, they were off (to loose), I guess the carbon was holding them in spec. I only had to reshim after cleaning off the top of the valves.......Something yall might wont to consider.

True, but...mine starts 1st or second kick every time...and I obviously havent taken the carbon off my valves...so I dont have to worry about that one..haha

But I will check everything soon since its getting cold here.

Yea!....But!....When I checked the valves in mine before I tore down the top end they were in spec......After I scraped all the carbon off the valves and put in the new piston and rings and then checked the valve clearence, they were off (to loose), I guess the carbon was holding them in spec. I only had to reshim after cleaning off the top of the valves.......Something yall might wont to consider.

I can see how you might get a build up of carbon on the exhaust valves, but why would you get it on the intake?? Or, by "valves", were you referring to only the exhaust side?

I think 50 hours is waaaay conservative to tear into these, ESPECIALLY when your valves are measuring in spec and there's no excessive noise or indication that something is wrong.

How's your preventative maintenance? Oil change intervals, filters (air and oil), riding conditions, fuel used, etc etc. I think these are more important to focus on than whether you can "stretch" 60 hours out of your piston and rings next time.

I've got over 100 hours on mine and zero probs. Good maintenance, that's what I believe in.

I would question your results on your valve clearance measurements after you put it all back together. Correct torque of the cam caps is crucial, and inconsistent technique of the feeler gauge measurement can yield a useless maintenance practice.

Yea!....But!....When I checked the valves in mine before I tore down the top end they were in spec......After I scraped all the carbon off the valves and put in the new piston and rings and then checked the valve clearence, they were off (to loose), I guess the carbon was holding them in spec. I only had to reshim after cleaning off the top of the valves.......Something yall might wont to consider.
You might want to check those valves again.
Yea!....But!....When I checked the valves in mine before I tore down the top end they were in spec......After I scraped all the carbon off the valves and put in the new piston and rings and then checked the valve clearence, they were off (to loose), I guess the carbon was holding them in spec. I only had to reshim after cleaning off the top of the valves.......Something yall might wont to consider.

There's something not right with what you are stating. If you merely scraped the carbon off the valves surfaces in the combustion chamber it should have absolutely no bearing whatsoever on the measured clearances. If you took the valves apart and cleaned off any deposits on the inside of the valves, if anything, that should have tightened up your clearances as the valves will now seat deeper into the head.

As Grey said, re-measure your clearances.

I put a top end in mine after I bought it used an heard all that racket coming out of it. Of course it didn't need it either. I checked and shimmed the valves while I had the head off. I did it on my workbench instead of doing it on the bike. Then I checked it on the bike after I put it together, no difference. It sure was easier on the table rather than on the bike. I think I went one size down. They were just off the edge of the spec. The thing had been raced for a season. Hours = ??

and for the small cost you might wanna put a new cam chain in there for safe measure. food for thought. ski

The cam chain should be replaced annually as a cheap precaution. Likewise, the valve springs whenever the opportunity presents itself.

The cam chain should be replaced annually as a cheap precaution. Likewise, the valve springs whenever the opportunity presents itself.
Why not just replace the topend once a season to be on the safe side and not have to worry on takeing a chance on the motor blowing up.......It would be better to spend about $150.00 on a piston kit than to spend $2000.00 plus dollars on a whole new motor.:crazy:

If you are campaigning a race bike, racing and practicing seriously on the same bike, it's probably a sound enough idea. But then, you might also want to replace the crank, too. There have been more big end failures on high hours YZF's than piston failures by far. If you ride it like that, it should have more than 100 hours on it in the year, and it probably still won't really need a piston.

You might want to check those valves again.

You checked them again and they were to LOOSE????????

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