If you look at the owners manual for these machines, it does not list Honda's own synth blend oil (HP4) as a recommended oil. In addition, if you look at the back of the HP4 bottle, it says that it is NOT for use in bikes with automatic clutches. They do however recommend Honda's own GN4, which is a pure petrolium oil.

OK, so my question is whether it is logical here to infer that A HONDA AUTOCLUCH IS NOT COMPATIBLE WITH ANYTHING BUT PETROLIUM OILS??? Synthetics have many advantages over petrolium, so I would prefer to run a high quality synthetic, or at the least a synth blend. But, if Honda's own HP4 is forbidden, does it mean that all synths or synth blends are also forbidden, or is it just something about HP4 in particular that makes it incompatible? (I have heard rumors that even HP4 which says "without moly" on the label, does have some moly in it???)

I asked the dealer, and not surprisingly they are no help either. They said they just put GN4 in EVERYTHING, no matter what. (Personally, I think GN4 would be toast pretty quick in a high revving CRF250/450 or the 450R engine! GN4 use to be SG, but is now SJ so I no longer run it in anything, not even my generator!) Their hunch is that their own HP4 is to "slippery" for use in an autoclutch, but they also admit that in all these years, I am the first one to ever bring up the question, and they have never even thought about it.

So what do you think, and what are your experiences??? I have 6 bikes with autoclutches, so I don't want to be runing around with a bunch of slipping clutches, because I used the wrong oil. My preference would be to run a synthetic, perhaps Mobil 1.

 

Tricky question.. All I can say is I run either Castrol Grand Prix 10w40 or the GN4 in the Foreman, and change it when it's looking dirty (no hour meter). I can say that I've seen all kinds of engines with some pretty ugly oil in them and little or no bearing damage. If you're concerned with the oil breaking down more quickly, just change it more often than you normally would. I agree that the synthetic offers better protection, but the auto clutch factor has to be considered as well. I think the fact that Honda recommends only the GN4 when they could be selling the pricier synthetics says that they either have evidence that the synthetic causes problems, or they simply don't know either and are taking the safe alternative.

I was going to run synthetic in my Foreman, went through the same debate you are, and said "I'll take my chances with the GN4, keep a close eye on it in hot weather and let the engine warm up a bit before loading it heavily in cold weather." An oil temp gauge might be a good idea if you're really concerned about cooking the oil.

 

reconranger, the following has been "cut and pasted".

"Valvoline ATV oil contains a proprietary blend of premium base oils and advanced additive technology to help you get the most from your ATV.

Valvoline ATV Oil provides:

Extreme Condition Performance - Thermally stable formula maintains proper lubrication to protect engines under extreme conditions.
Wet Clutch Protection - Optimal frictional characteristics for high torque, smooth shifting and proper protection of the wet clutch.
Corrosion Resistance - Advanced additives help protect against water, deposits and other corrosive materials to keep engines clean.
Maximum Horsepower - Proper additive balance for maximum horsepower.
Minimal Wear - Increased anti-wear agents minimize wear from metal-to-metal contact.
Shear Stability - Shear stable viscosity improvers better resist oil film breakdown."

Valvoline ATV oil is SG rated. It also has the ratings required for manual transmission lubricants, but I can't remember what they are. I ahve been using it for a few years in both our ATVs with no problems.

 

Spectra-From what I can tell, Valvoline ATV is petrolium oil just like GN4, so I wouldn't expect any problems there. I have been running Maxima ATV Premium, also a petrolium oil (API SG/JASO MA), with no problems either. But, if you look at the technical data for synth vs petrolium, the synths are just way ahead of petrolium.

I was wondering what Honda oil your owners manual recommends for the Rubicon (which has a centrifugal clutch). I am betting it only recommends GN4, and not HP4???

 

I use Amsoil 10W-40 Motorcycle Engine Oil. It is a pure synthetic and is compatible with the wet clutch. I have had no problems with it.

 

james-You run Amsoil (Group IV PAO Synthetic), but in what bike??? Is it a bike with a fully manual (hand clutch), or an autoclutch Honda??? The owners manuals on Honda full manual clutch bikes (450R, 400EX, 300EX) do recommend using Honda's synth blend oils, so if your bike is one of those (or another manufacturer), that doesn't count.

Actually, there was a guy who posted a while back, who said he worked formulating oils. He said HP4 is just a blend of Mobil 1 (PAO Synthetic) and petrolium oil.

 

GN4 for the Rubicon. I was told full synthetics didn't work well in the Hondamatic trans too, but there are poeple here who use it with no problems.

In the 5000 miles on our Rubicon, I have only added oil between oil changes twice, and it was very little both times. My friend recently purchased a 04 Rubicon and with a few hundred miles on it, it is no faster than mine. So I think for 5000 miles, everything is still ok.

I do believe in synthetics. If I had a manual clutch, I would ge straight synthetics no problem. I use full synthetic gear oil in the diffs.

 

sorry, I thoght that I had done my signature..I need to do that. I'm running the Amsoil in an 04 Rancher 4x4 ES and an 04 Recon 2x4 ES.

 

the big deal is to stay away from friction modifiers with wet clutches. follow the rating in your manual and on the back of the oil bottle and you can run whatever brand you want.

 

I'm using Mobil 1 MX4T. It's has no friction modifiers. Made for wet clutches. Check out there web site.