I usually use the regular Honda GN4 10w40 in my 2004 rancher. is it alright to change to Honda's synthetic blend or synthetic or do I have to flush the engine or something?

 

Just drain the old and pour in the new. No flushing necessery. You cant go wrong with either of the oils the tyou mentioned. Synthetic is the only way to go!

 

No flushing necessary. Where these old wive's tales get started, I have no idea???

I would certainly recommend Honda's HP4 Synth Blend (without moly), over their GN4 which is just a basic petroleum oil. From the smell of it, I suspect that HP4 contains a fair bit of ester.

One of the dirt bike magazines ran a CRF450X for 200 hours on HP4 (HP4M with moly in the engine side and HP4 without moly in the transmission side), then they took the engine apart and looked for wear. All they found was a little scuffing on the cylinder wall....pretty good when folks are predicting that the 450 engines will grenade after just 15 hours!

My personal favorite however is Maxima Extra, an ester based full synthetic. I run it in everything, including my Ranchers. http://www.maximausa.com/products/4s...synthextra.asp

Some oil info, in case you haven't seen them already: http://www.thumperfaq.com/oil.htm

http://www.maximausa.com/technical/l...beNews2002.pdf

 

Thanks for the help