2004-2006 oil jet mod?

[diesel_dean1]

Appereny the common killer of these year yzfs and yfzs was they had unsufficient lubricant to the lower end. In 2007, yamaha engineers changed the cases around so there was a little jet to keep the bottom end lubricated. I've read that sometimes the effects can be expensive and brutal, costing easily 3 grand to repair. Has anyone ever done this oil jet mod done? I want to know where I can get this so-called jet and high pressure oil pump and do it myself.

[grayracer513]

Well, you haven't read accurate information, or you've misinterpreted it.  The oil jet you read about doesn't feed the bottom end.  In fact, it doesn't "feed" anything.  

 

The Gen1 ('03-'05) engines didn't even have one, nor did any YZF prior to that, and frankly, those engines have an unassailable reputation for reliability.  The purpose of the oil jet, which was first added to the YFZ Quads in '05, is to help keep the piston crown cooler by spraying an oil mist on it from underneath.  The nozzle is located in the cylinder mouth of the case on the right side.

 

When the Gen2 engine came out in '06, the oil jet was also included in that bike, and has been used ever since.  The only time that I know of where it has been recommended to be upgraded is in cases of using high compression pistons on Gen4 ('14 and later), and possibly Gen3 ('10 -'13) models, not the earlier units. 

[diesel_dean1]

Well, you haven't read accurate information, or you've misinterpreted it. The oil jet you read about doesn't feed the bottom end. In fact, it doesn't "feed" anything.

The Gen1 ('03-'05) engines didn't even have one, nor did any YZF prior to that, and frankly, those engines have an unassailable reputation for reliability. The purpose of the oil jet, which was first added to the YFZ Quads in '05, is to help keep the piston crown cooler by spraying an oil mist on it from underneath. The nozzle is located in the cylinder mouth of the case on the right side.

When the Gen2 engine came out in '06, the oil jet was also included in that bike, and has been used ever since. The only time that I know of where it has been recommended to be upgraded is in cases of using high compression pistons on Gen4 ('14 and later), and possibly Gen3 ('10 -'13) models, not the earlier units.

Oh okay, so should I put my bike back together and ride it? I took it apart to see if I could do it and I also needed to do clutch plates so I said why not. Thats a good relief. Because I've been riding it around and after I read it I took my bike apart. Oh well. thank you greatly for your input!

[mrjata]

I did this on a YFZ I had.  The machinist who did it and has done a bazillion of them explained the issue as a wrist pin oil spray feature since the old slash system didn't work.  Took a high volume pump too. Yam fixed it in later years

[Gunner354]

Well, you haven't read accurate information, or you've misinterpreted it.  The oil jet you read about doesn't feed the bottom end.  In fact, it doesn't "feed" anything.  

 

The Gen1 ('03-'05) engines didn't even have one, nor did any YZF prior to that, and frankly, those engines have an unassailable reputation for reliability.  The purpose of the oil jet, which was first added to the YFZ Quads in '05, is to help keep the piston crown cooler by spraying an oil mist on it from underneath.  The nozzle is located in the cylinder mouth of the case on the right side.

 

When the Gen2 engine came out in '06, the oil jet was also included in that bike, and has been used ever since.  The only time that I know of where it has been recommended to be upgraded is in cases of using high compression pistons on Gen4 ('14 and later), and possibly Gen3 ('10 -'13) models, not the earlier units. 

It was my understanding when I purchased a 450 quad in 07 for my son that it was the first year Yamaha added the oil jet.

Edited March 5, 2016 by Gunner354

[grayracer513]

Well, we're both apparently wrong on that point.  I had my YZ genealogy backwards.  And I don't pay too much attention to quads.  The oil jet was introduced in the '06 YZ450F along with the Gen2 engine.  At that time, the YFZ450 quad still used the Gen1 engine.  If yours has the external oil lines feeding the head and the trans, it has no oil jet.  The YFZ didn't get that feature until '09, and then only on the EFI YFZ450R models that used the Gen2 basic engine.

 

Either way, Yamaha's published reason for the jet was crown cooling, not wrist pin oiling, although it obviously contributes to the latter.