Top End Longevity with good oil!

[KXcam22]

I just took off the top end on my '92 for the first time.  Last ride I was able to bump start it down a steep hill which means (to me) compression is down a touch.  Barely noticable at the kickstart.  After 12 seasons of riding the lack of top end wear is amazing.  Cylinder is great, piston is still servicable and the power valve operates fine, no carbon to speak of.  I'm an ex-pro MXer and although I don't ride as hard as I used to, the bike still gets ridden reasonably hard. The bike has only been raced 8 times but I still figure I must have 500 to 700 trail hours on it.  The secrets: Run good 2-stroke oil and clean the filter lots.  The bike has spent it's whole life on a diet of 60:1 Belray MC-1 with 4 or 5 seasons at 70:1.  Kudos for good oil.  

In the past I had a similar experiece with my 1979 Maico 400 race bike.  In those days I ran 85:1 MC-1 (was the recommended ratio) and got over 50 MX races (plus 3 days/week practise) on a top end.  Since that experience I have always run it in everything I own, outboard, snowmobile, chainsaw, weedwacker etc, same 60:1 ratio.  I know there are lots of good oils out there, but the Belray MC-1 has been my long-term choice and it has proven itself once again.  Cam.

[hughes]

Good Info. I think a lot of guys forget about the importance of a clean air filter. Went to the local track this weekend and you would not believe how many bikes showed up at the track looking like they have never been washed I'm talking about mud not just some dust that could be easy to wash off. What I getting at is that if the bike looks like that first thing showing up at the track maintainance might be lacking. Today's dirt bikes are race machines that need coutinous maintainance. For oil I use Yamalube 2-R at 32:1 with Yamaha'a ring free. I have not tried to use a lighter ratio due to the fact my manual say's my 500 should run on 32:1. What do ya'll think?

[machine]

I run a "light" 40:1 of Maxima 927 ONLY!

[Arigato]

Yamalube 40:1.

[machine]

U guys might hate me 4 this!
But Yamalube in a Kawi hurts me!!!

Blue, won't mix with green!!!!

No, I know it's a good oil!!!!

[Timbowe]

100:1 amsoil has always been my choice.

[machine]

100:1  WoW!!!!!

[BigKX]

According to my engine builder, Yamalube keeps the crank bearings alive the longest.

[NastyNick]

50:1 BelRay H1R

btw, BelRays web site says this about the two premixes:

The diff betwix these two full synthetic ester based 2-stroke oils is simple. Bel-Ray MC-1 2-Cycle Synthetic Racing Lubricant must be pre-mixed at 50:1 and Bel-Ray H1R. Synthetic 2-Stroke Racing Oil is more flexible and can be mixed betwix 30:1 up to 50:1

So running MC1 at anything other than 50:1 is a no-no

p.s.  kind of a cool page for general 2-smoke oil info: http://www.belray.com/consumer/Q&A%20pages/q&a2s.html

[KXcam22]

Timbowe,
  100:1 amsoil is very popular with the snowmobilers here! At 180hp 3-cyl turbocharged 800cc they demand a good oil.  I though this discussion might be informative for the members who typically never run lean ratios.  Personally, I haven't run a ratio less than 60:1 since using mineral 2-stroke oil at 32:1 in my 1978 Husky 390.  Lots of piston seizures and blown rods in those days.  Since oil burns quite a bit hotter than gas, there is a tradeoff between lubrication and heat. With synthetic oils, the film strength is phenominal so lubrication is usually not an issue so you can reduce the amount of oil to reduce the heat.   At 85:1 my race bikes always ran great and lasted long.  Over the years I have run lean ratios from 60:1 to 100:1 and never had an issue with sezures or engine wear/life.  I ran 100:1 Amsoil (trying it out) for a season in my 2-stroke road race bike with good results.  My new yamaha 15hp ouboard specs 100:1 yamalube in the manual but I'll probably use my faithful MC-1 at 85:1.  Leaner ratios definitely makes an engine start easier.  In all I guess it's what oil you run and what ratio you are comfortable with.  For BigKX: When disassembling the engine, the 60:1 MC-1 leaves a nice comforting film of oil on the crank parts and bearings.  It's not quite a comparison but my kids PW50 & 80 would carbon up a few times a season with yamalube injector oil.  Removing the injector and running MC-1 solved the issue.

As an update, I closely inspected and measured up my top end last night.  The power valve components are all perfect with no wear and almost no carbon.  The piston is within spec, BUT .... there is a crack in the stock piston in the top surface of one of the piston pin holes. Glad I found it!  Anyway, some oily food for thought. Cam.

[machine]

Cam;
What would you run for a mostly stock KX5 in the high deserts.
@ around 2000/3000 feet alv. and @ around 75-85 degrees???
 

[reknelb]

I picked up some mobil1 mxt synthetic 2 stroke oil. Haven't tried it out yet, but I've heard alot of good things about it. Mostly that it doesn't carbon up the power valves. I was going to run 40:1, maybe I will try 50 or 60:1?? How much, if any, did running 100:1 mess with your jetting?

[alan]

I use Kawie Chem at 40 to 1 in El Paso desert  with 50/50 race gas + 100 degree at 4000ft. !

Alan

[KXcam22]

Machine,
 This is turning into a great discussion! It's great to learn about everyone's long term experiences with various oils.  Given my past experinces I can heartily recommend the Belray MC-1 at 50:1 or 60:1.  You might need to lean your jetting a touch.  Fuel mixture is (oil + gas:air) but the fuel/air ratio stays the same so when you reduce the oil amount, the gas amount must increase - which richens the jetting.  Your elevation, conditions and temp are about what I run in, using 60:1 and 94 octane pump gas.  

Nastynick: I ran the H1-R at 60:1 part of last season figuring it would be good for the powervalve. Ran fine BUT... spooge everywhere even with perfect jetting and 60:1. My silencer is gross, black mess dripping out.  Yuk.  Have you had this same experience?  The 12 years of MC-1 left almost no carbon on the powervalve or elsewhere.

I had a talk with a Belray chemical engineer last year.  I specifically asked about the 85:1 ratio which used to be the recommended ratio on the bottle in the 80's, but is now 50:1.  He related that they changed the recommended ratio due to public perception and not the oil.  People were scared to run the lean ratio of 85:1 so the 50:1 was adopted since it was more "palatable" to the public.  Further, in their testing ratios up to 100:1 did not produce significantly more wear than 50:1.  I started with the 85:1 but have since gone to a more reserved 60:1. Cam.

[NastyNick]

Nastynick: I ran the H1-R at 60:1 part of last season figuring it would be good for the powervalve. Ran fine BUT... spooge everywhere even with perfect jetting and 60:1. My silencer is gross, black mess dripping out.  Yuk.  Have you had this same experience?  The 12 years of MC-1 left almost no carbon on the powervalve or elsewhere.

I did have a spooge problem early last year after I did a rebuild on the motor at the same time, I installed a new reed system and moose spacer.  The bike ran OK, but didn't "yank my arms out of the sockets" like I expected it to after the rebuild.  It also spooged really bad.  I suspected jetting so removed the moose spacer and worked on jetting.  I finally got it right and the spooge stopped.  Now my K5 is SCARY FAST and I haven't seen any gunk yet.

Not to get too far off topic, but d**n! this bike is a screamer.  I hate stories about drag races on bikes, but I got one I have to share.  Most of my riding is in the mountains or on the track so  I put a FMF Gnarly Torque on it and left it at stock gearing.  The other day I was out riding with a bunch of my friends who all ride 4-wheelers.  My buddy Jeff was on his DS650 with NOS and a turbo (it's scary fast too) and he pulled up next to me while we were riding.  He gave me that look (you know, the one that says "go for it") and I hit the gas at the same time he did (and the NOS).  I don't know how fast we were going when I finally chickened out (coming to some curves), but when I chopped the throttle, I felt the front wheel hit the ground.  Didn't even know it was in the air.  I was in 2nd when we started and 5th when we stopped.  He pulled up next to me and give me a wierd look.  Later he told me I pulled that wheely for over 3/4 of a mile and threw rocks from the rear tire about 30 yards behind me!

Funny thing is, my K5 used to be his and he GAVE (yes, gave, free, except that I had to fix it up) it to me a couple of years ago.  Now he is eyeballing an 04 K5 at the local kawi dealer ship.

moral of the story:  JETTING is key and nothing beats the KX500!