Apr 7, 2003
Thought i would share this with everyone.
I always ran Yamaha R 32/1 in my sons kx 65 and yz 85.
Desided to try amsoil and on the bottle it siad mix 50/1 so i called amsoil and said my manuals tell me 32/1 you say 50/1 who is right?? They tell me there oil is really concentraded and should NOT mix 32/1. So i started to mix it 50/1 and within a two week period both motors blow up! Rod berrings in both of them. Well after the second bike another mini dad came up and asked what is going on i said another rod berring, he asked what oil and mixture, started to shake his head and said he had the same thing happen to his sons bike using and mixxing the same oil at 50/1.
All were 2003 bikes, airfilters cleaned religiously. Maybe it was something else but never had rod berrings go out in any other of our previouse bike.

Anyways just wanted to share that with ya



Oct 27, 2000
I've been running Amsoil at 50:1 in my son's 2001 KX85 and my 2002 KX250 with no problems. Both bikes were bought new and we ride or race every weekend.

I know some people have problems with the cranks in the KX mini's but we have been lucky I guess. I would have someone like Eric Gorr check out the cranks and see if he can determine what might have caused the problem.

Sorry you are having problems.
Good luck.


Jun 12, 2000
I used Amsoil 2000 for over 4 years. I ran it at 50:1 for 2 seasons and then 20:1 for almost 2. Never did we loose any parts due to lack of lubrication, We has a KTM 65, RM 80 (2), RM 85 (2), 250SX, 300MXC & TM125E (2). 9 bikes different styles of riding and alot of different fuel. I had a rod go in the 250SX, 300MXC and a RM80. All of these were on there 2nd season of harescrambles. All had 100 race hours plus on them.

Not that my rave is over. Lets talk about your rant. :)
That does stink what happened. I would call Amsoil and get someone that cares on the phone. They will say that it is not an oil issue but if you can prove it then they will back it up. I have personal experience with other products that they backed up without any issues (years back). I have heard alot of KX crank issues in the last 2 seasons regardless of oil. The YZ's are normally strong. If you talk to most Honest builders they will tell you that Dirt and Fatigue are the main causes of rod failure.


PS.. IMHO stay with more oil like 32:1 or Even 24:1 regardless of brand with these Lil screamers.


Feb 29, 2000
Agree with Mike S., stay with a richer mixture on the mini's. With the heat they generate and the rpm's being turned those little motors just scream for more oil.

The only time we have ever lost a crank was when we lost both exhaust springs on the pipe and it sucked in dust.


Sep 25, 2003
we have two 03 kx65's they seem to have a crank problem on the 03's
ours and everyone we talk to at track are only getting 30hrs or every other top end out of these lower ends, and this prob did not exist on other 00's or


Hot Sauce
Oct 28, 2001
I've read a few posts on here by deansfastway and he recommended sticking w/32:1 for the kx65.. Knock on wood, no probs.. I dont think i would ever go 50:1 on a motor at all, oils cheap.. Oh, we're using Redline..


Mar 30, 2002
We have always ran Golden Spectro 52:1 in our RM80(for sale), KDX200 and 220, KX250, PE175, and KE100. The bottle says 42:1, 52:1, or 62:1. Every thing OK here.
Top Bottom