Oil and Gas Question

I have received mixed advice on Transmission oil. So I am asking you guys. Are their differences between the synthetic/non synthetic oils sold by the manufacturers (Yamalube, Pro Honda) and the major brand oils (Pennzoil, Valvoline, etc). I would believe that using a high grade synthetic (Racing 20/50) and regular oil changes would do just fine.

Also in the jet ski world, in is common practice to mix aviation fuel with premium to get a cost effective high octane gas. Is there a problem with this practice for YZ400/426?


Regarding oil - there are many opinions on this issue.

Here are the things people agree on:

(1) Change it often

(2) Don't use an oil labeled "Energy Conserving" on the API donut

(3) Synthetic is OK

Personally I have used automotive Mobil 1 15-50 for over a year. I used to change it every other ride but now I change it every third ride. I clean/inspect the oil filter every other oil change.

I think using a high quality oil and changing it often will be just fine.

I have no opinion on race gas since I just started using it myself (not diluted).

I run Valvoline 20-50 and change the oil every 3 rides and inspect the filter every other also. With the fuel, I run a mix of 110 and 93. I've used this combo for quite a while and have had nothing but good effects from it (nice burn and power)

Av gas is and never was designed for auto or motorcycle engines. The cetane rating (the rate at which fuel vaparizes in the combustion chamber) of av gas is designed for altitude at elevated temperatures, airplanes heat the fuel before it enters the carb to prevent icing. Mixing av gas with pump gas is an OLD racing trick that did not work then and does not work now. With the availability of quality race fuel or even just quality pump gas(sunoco 93 works great in my 426) mixing is not nessesary. It will actuall raise your octane rating but will probably cost you power since a fair amount of the av gas may not even burn on each cycle.

You make a good arguement and further are making me question my use of AV gas. Years ago I had a boat motor mechanic rant and rave about running AV gas in boat motors. Not so much an octane boost he was hyped about but the cleanliness of the fuel. Claimed AV gas didn't have the laquering properties associated with the detergents in automotive fuels. Also thought it did not 'go bad' as quickly and if left sitting in the carb would not leave a sticky mess if it evaporated.

Long and short of it I've been driving to the airport for the last 10+ years paying extra to burn up that 'special' fuel in all my small engines: lawn mower, weed whacker, chainsaw, pressure washer, hedge clipper, both boat motors and of course my 426. In fact I've never run regular gas in any of these.

That drive to the airport has gotten real old. Maybe it's time I revisit this issue. Has car gas gotten cleaner in the last 10 years? BTW-my car/truck are diesel so I wouldn't know. Or have I been following the rant of a lunie? Stuff runs great, never had any problems with it.

Av gas does not go bad as fast as pump gas, that is true. I've read that it is formulated for 30,000ft, and is not the hot ticket for cars or MX bikes. A bottle of Sta-bil from Walmart is a lot cheaper than AV-gas too. :)

In addition to still having lead in it, blue 100LL, Av-Gas also has other additives that can damage seals and such that are not made for aircraft engines. I just use Chevron Super or Mobil Premium; the Mobil has more detergent in it. The bikes run perfect, no jetting or plug fouling problems.

As far as oil goes I have some bikes using moto specific Mobil 1 MX4T full synthetic and Castrol ActEvo 10-40 synthetic. I don't use auto oils in my bikes. Coincidentally, I am also one of the guys who has not had clutch problems with the YZ450.

Hope that helps,


Funny you have good luck with Mobil gas. When I use Mobil in my 426 it runs great bug needs a new plug each new day (won't start). Any other brand I've tried is OK. Maybe the Mobil near me buys cheapo gas somewhere? Or better yet, maybe the 450 is better with plugs! :)

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