Buying a used yfz guy said it needs an oil pump

[LxMxL97]

I'm thinking about getting this 05 yfz and the guy said it needs an oil pump I have a couple questions like how does he know what's wrong with it and is there anything I should be concerned about as in things being burnt up internally also how much work is it to get to the oil pump I was told the I would need to split the cases because (I understand these are completely different machine) on my 400ex it's right under the clutch cover

[blacknblue#2]

I would walk unless its dang cheap. More than likely its seized and he probably thinks it seized from oil pump failure. When it could be the wrist pin or lower rod bearing. Chances are it never had the oil mod done

[2001400exrida]

the yfz's pre 2007 all have oiling issues on the lower rod bearing. There is an "oil mod" that can be done on them where they put an oil squirter in there to help lube . On the 04/05/06 you can either flirt with disaster, invest in the oil mod, or put a newer model side case on. I personally ran my 04 for hundreds of hours with no oil mod. My 05 had it done already. It's a known issue with the older ones that they had oiling problems. He has most likely already done the damage on this one. Google search oil mod yfz or search for oil squirter yfz. It's something that many do as a precaution since so many have had the issue with the older ones.

[LxMxL97]

I'm probably going to steer clear of it since after all I am a honda guy Lol

[2001400exrida]

here's some info on the mod if ya get bored and wana read up on it. http://www.yfzcentral.com/forum/37-tips-n-tricks/79028-diy-clutch-cover-oil-squirter-upgrade.html

when i bought my first yfz i knew nothing about this and was lucky i guess. The 2nd one i made sure it had this mod before i bought it. Anything 07 and newer there's nothing to worry about.

[gtilley45]

The '07+ oil squirter and oil mod don't have anything to do with the bottom end or lower bearings. They both squirt oil on the wrist pin and bottom of the piston.

[2001400exrida]

The '07+ oil squirter and oil mod don't have anything to do with the bottom end or lower bearings. They both squirt oil on the wrist pin and bottom of the piston.

oil mod lubes wrist pin and lower rod bearing.

[gtilley45]

oil mod lubes wrist pin and lower rod bearing.

I disagree. None of the ones I've seen do anything for lubrication of anything other than the wrist pin.

Here's the '04-'06 oil mod with no jet installed (had this on my '04)
1718107327

Here's the '04-06 oil mod with jet installed
1718107328

Here's the '07 and up oil squirter.
1718107329

Those are the only "oil mod" methods I've seen on a YFZ.

[2001400exrida]

i stand corrected, although i was for certain that many engines had lower rod bearing issues as a result of no oil squirter, specifically the older models.

[gtilley45]

The wrist pin was the only thing I ever remember being a known problem due to lack of lubrication. I've heard of lower rod bearing trouble on YFZs but no more than any other quad. I ran my '04 for a couple seasons before I tore it down. I pu a WR crank and piston in it and had the oil mod done while it was apart. I ran that motor hard for 2 more years of MX and when I tore it down again, the wrist pin and bottom of the piston looked brand new. So I will say that the old style oil mod with just a hole drilled works. After seeing mine, all my buddies started getting it done on their YFZs too. That's why I was so certain, I've probably seen and helped tear apart/put back together at least 5 YFZ motors that had the oil mod done.