Switching Oil Types - Petroleum base vs. Synthetic

[RaptItUp]

I am going to switch from Yamalube to Maxima Full Synthetic and had a couple of questions for anyone who has done the same thing.

Those who know only reply.

1- Is it necessary to get all (I know you can't get 100%)of the old oil out of the engine before I put the synthetic in. It seems that I only get about 2 out of the 3 qt capacity out every time I change oil.

2- Any danger to clutch plates with a slight mixture of the 2 types in the crankcase.

3. If I need to get all oil out what is the best way to do it.  I noramlly drain the crank case and the oil tank.

Thanks....

[TRX450R_Racer]

No problems just change to the new oil and don't worry about anything.

[backinsaddle]

If your motor has a lot of hours on it, it's not always the best thing to switch from petroleum to synthetic.  In a car for example, once you hit 50-60-70,000 miles and you have been using petroleum based motor oil during that time, most mechanics that I know will recommend NOT switching over to synthetics.  I'm not positive about this, but I think petro based is a "thicker" oil, and once the motor breaks in, your ring/piston/cylinder wall and other clearances develop based on the clearances needed for petro oil.  Switching to a "thinner" synthetic oil you may have some slop in those clearances which equals less horsepower, possible leaking, etc.

Someone else chime in if I got this wrong.

As for getting all the old oil out, someone recommended recently to put an air hose in the filler hole and blow out any remaining oil...may not get all of it, but it's supposed to get most of the oil out that normally doesn't drain out on its own.  If you have 3 qt capacity, and are only getting 2 qts out, you need to get most of the rest of the oil out, unless you change the oil regularly-a little left is o.k., but 1 qt isn't.  It's not going to damage the motor mixing oils that I'm aware of, but different oils don't always mix well and you may end up with foaming oil, plus I've noticed if you don't consistently use the same brand of oil, sludge seems to develop more quickly.

Hope this helps.

[RaptItUp]

I do see your point about the thicker petroleum based oil.   That's a good thought.

I would estimate 50-60 hrs on the motor.  No racing, but some hard trail riding.  I have changed the oil pretty regularly (avg about 5-10 hrs), so I doubt that it should have any substantial wear.   I would like to get most of the old oil out so I don't 'pollute' the Maxima with used Yamalube.  Maybe I might try the air compressor trick.   

I'm open to any other suggestions.

Thanks,