i want to run the best oil in my 400ex
Klotz Mx4
Pro Honda GNA
Pro Honda HPA

 

The best oils are the ester synthetics. My first preference is Redline MC. Second is Maxima Ultra. Maxima Extra, Klotz, or Motul would be a third choice if I couldn't find the others. All these are expensive....but so is a rebuild!

Honda GN4 is a basic petroleum oil, and not up to what your engine is going to dish out. Honda HP4 is a petroleum/synthetic blend, and a good step up from GN4.

From your list, spend the extra money on the Klotz!!! A second choice would be the HP4 (but not HP4M).

 

Lots of good reading:

http://www.thumperfaq.com/oil.htm


http://www.sportrider.com/tech/146_0308_oil/index.html


http://www.sportrider.com/tech/146_0310_oil/index.html (Note the increase in torque/horsepower with Maxima Ultra!).

http://www.maximausa.com/techn...news/LubeNews2002.pdf


http://www.p1-performance.com/pdf/oildoc.pdf

 

i have noticed many threads about using the hp4m oils with a wet clutch system.i have owned a 2001 400ex since new in december of 2000.it was broke in for around ten hrs of ride time in snow on original oil and then changed to pro honda hp4 WITH MOLY.i rode that thing close to every weekend for at least 4 hrs a weekend.did a valve adjustment about every 30 hrs,changed the oil once a year.i have countless hours on this machine.i have replaced lots of bearings,a swingarm,3 sets of tires,plastic,brakes.but my clutch NEVER had a problem until 2010!it would feel like it was slipping about 3 hrs into a ride when it was very hot and i was using it alot in tight woods.but i could still pull a wheelie with just the gas.i disassembled it that winter and friction plates were still slightly thicker than replacement specs.i did replace it anyway with oem clutch parts and filled it back up with moly.i will only use hp4m oils.

 

Power Sports - Bob Is The Oil Guy