well doing regular maintnenece, (oil filter, oil, plugs) i stumbled upon a very trace amount of oil on the magnetic drain plug and about 2 little flakes in the filter.

Im mot thinkin much of it as most of my quads have done this at about the 3-4 year mark, but by the next change they are clean and perfect.

Well, reading up on this i found a page that said you should do a topend and valve adjustment on the yfz 450 for preventitive every 30 hrs, to prevent a massive engine explosion.

Im wondering this because my 450 is at about 50 hrs and im seeing a little, i mean little amounts of metal in it.

what year yfz? 06 or older? have u done the oil mod on a older model?

same questions what danno asked. also. there is a screen going into the oil cooler reservoir, from the factory machining and install will have small peices of metal. Yfzcentral has a topic on that. if its magnetic, it could be a sign of main bearings starting to go. bugsy on the board had one on him lock up. all the bearings on these motors are ball bearing.

its an 04, i got it about a month after they came out with them.

and no i havnt done the oil mod, what exactley does it include or whats changed?

P.S. Dont get the first model year, all the seals except for the case were replaced within 6 months and this thing cooks batteries like crazy

but i love the quad

50hrs is way to long to go without a valve adjustment. not only are you hurting your valvetrain you hurting your bikes performance. set those valves to spec asap. logg onto Yfztech.com so u can see how the oil mod is done.

Just speaking of my experience with a CRF 450R but I went almost 4 seasons of riding at least 2 weekends a month before I ever changed the piston and I ride a lot.

The maintenance that they recommend is ridiculous. They say I suppose to do a piston change every 15 hours. As far as the valve go, I have had 2 450s and 2 400s and the valves have never moved on any of them. I don't buy the whole 4 strokes suck because of the valves. I check the valves once a season.

If your compression is good, then keep riding it.

if the bike is stock it will run longer without needing adjustment. run aftermarket stuff like cams and youll see that youll need to adjust more often.

we just did a valve adjustment and cam mod on a 07 yfz. not off by much but needed it.

I would say the manufacturer is a bit on the safe side at 30 hrs, and might be basing their time frame on quads that are being raced. but....

Having just completed a bottom to top rebuild of a 2005 YFZ450 major engine failure.

and with 2 more motors ( YZ and another YFZ ) with engine failures in my shop getting rebuilt.

I'd say I would rather do the top end and oil mod sooner than later.

You could save yourself serious $ by not having to replace: bent valves, cracked guides, new cylinder, new crank..... I think you get the idea.

just my .02

Tres you work on YFZ450's? How hard is it to do a valve adjustment? I have a full shim kit that I bought and am still terrified to do more than required maintenance...

scat, its fairly easy. once you get in there youll see how simple it can be.

I have an 06 Honda and I checked it last year when I put my cam in and just checked it last month and it's still within stock specs

ya i know how bad lack of oil is, my 250 had the pump go out and it seized up in the bottom of a bowl, about 2 hours later and the help of somedude in a sand rail it was back at camp, then 2100 dollars later it was going again,

and back to my question, what is the oil mod and how difficult is it?