premix ratio

[cbxracer30]

70 to 1 in my drag bikes for the last 8 years ,the bikes my boys race get alot more than just track time on them ,  I used to run AFT powerlube but now we are running Motorex 2T Power . My buddy just got a new 300 KTM and he said it calls for motorex mixed 60 to 1 , but he run Amsoil Dominator 50 to 1 . CBX

[Big Yac]

when I first started riding I ran Suzuki CCi in my YZ 125, that oil was junk.  I then switched to MC-1 at 50:1 and the 125 ran great.  When I got my KDX 200 I kept running MC-1 @ 50:1, it too ran great.  When I got my 500 new in 99 I ran a tank of MC-1 and it fouled plugs like crazy.  I switched to Maxima SuperM and adjusted jetting (I'm sure this is what cured the fouling), still running at 50:1 and the bike has ran great since.  Top ends look fine and you can still see the cross hatch in the bore, not alot of carbon build up either.  50:1 is fine.

[andydunne]

50:1 jeez I thought that would be way too lean.
I presume its only ok to run 50:1 plus with a top quality oil?

[Motorrad]

50:1 jeez I thought that would be way too lean.
I presume its only ok to run 50:1 plus with a top quality oil?

technically... rich..

[The Flyin Hawaiian]

I used to run 50:1 in my old 88 500 with no issues. I run 40:1 in my 02 500 mainly because my wife runs 40:1 in her KX250 and we share the same cans at the races. Just easier for us. Runs fine on that also.

[Polar-Bus]

FYI, injected PWC's  run about a 100:1 ratio  ! Think about it there is no dirt out on the water, and PWC's see fairly consistant lighter engine loads.

[kwakman]

im sticking with 32:1 as it wont hurt on the road. some good info on that maxima page.K.

[81cr450]

im sticking with 32:1 as it wont hurt on the road. some good info on that maxima page.K.

I agree whole thoroughly 32:1 & safe, besides plugs are alot cheaper than motor builds

[alward25]

What keeps getting overlooked is that different oils have different concentrates. This results in a differant mix ratio.  The more you have to add, the thinner the premix.

[Big Yac]

What keeps getting overlooked is that different oils have different concentrates. This results in a differant mix ratio.  The more you have to add, the thinner the premix.

and I guess I should have added to my post, something that an earlier one did, 50:1 should be fine using a quality oil, not something you've picked up at Tractor Supply or whatever for $1.99 a bottle.  If in doubt just go along with what the oil manufacture recommends.  Really though, about any brand name oil, Maxima, Bel Ray, Golden Spectro should be fine at 50:1 in a 500.

[Polar-Bus]

im sticking with 32:1 as it wont hurt on the road. some good info on that maxima page.K.

I agree whole thoroughly 32:1 & safe, besides plugs are alot cheaper than motor builds

A common misconception is that you will foul a plug quicker running 32:1  vs say 50:1 . This is technically false.  It's the jetting that determines if and when a plug will foul not the oil ratio .  Engines need to be jetted richer when running richer premix ratios ex. ( 32:1). The added oil content slows down the flow of fuel through the jets, adversely a leaner ratio like 50:1 can be jetted leaner as the fuel will flow faster through the jets. All the bike mfg's  advise 32:1 based upon the assumption that you are a expert level MX racer who will be holding the throttle WFO for 30 min straight out for two motos on sundays. Kawasaki also prudently advises a 32:1 ratio (and overly rich jetting) because they don't want to see your brand new KX###   blown up the first month you own it.  This is why KX's generally run pig rich from the factory (especially when ridden by a weekend sport rider) . It's all preference, 32:1 is fine (your just wasting $$ buying extra oil IMO)  and 50:1 is fine as well. I'll say it again,   more importantly than premix ratios is the need to keep your air filter clean !

[81cr450]

The leaner oil mix does need to be jetted leaner for sure as it increases the amount of fuel by a pecentage, depending on ratio. Its mixed by the gallon, you have a gallon whether its 24:1 or a 100:1. The 100:1 is more fuel & less oil you lean it out due to more fuel being there to burn.

Any watch kx500 youtube videos. Listen to the sound, "Most" people dont rev them. The moment the powervalves start to open, shift. They should mix 100:1.

When you pull your motor down look at the width of the oil band in the bottom of the case, all the drainback from whats coated your parts. Thank for the tip on this by the way, you know who you are.

This pool, or the oil retained is what loads up & fouls plugs if your running to rich of oil ratio. Like when you let your girlfriend drive it & then you have to "blow it out" cause shes not spinning it high enough  to match the load to the oil mix ratio. Ideally you'd have 100:1 at idle, 50:1 when the powervalves open, 32:1 @ WOT & if WOT is sustained for more than 30 seconds the ratio drops to 24:1. Like the chart posted on maxima, mix being rpm / load based you need to figure it on your rpm range. A track bike being one end & a dune / desert bike being the other.
 Sounds like it would help if people posted mix ratio & type of riding as well, plug life, & time hours between rebuilds

[royceymon@hotmail.co.uk]

i run 40:1 with rock oil fully synthetic racing synthesis 2 ,ive run the same oil since 87 never had any problems even on the kx500s i had all run with thier necks rung! not only more oil less fuel through the jet but i dont run too weak on the oil front for the cooling properties and lubrication ,i dont have any plug problems or oiling up .
 on the single ring piston im running at the mo the ring is wore out already , i think ive only done about 10 hours max i know someone who knocks one out after 5 hours! so i guess 10 hrs is good
defo agree filter more important than anything

[Big Yac]

just like using a quality premix is important, a quality air filter oil is important too.  You want something that wont get sucked into the engine or restrict air flow yet be easy to clean.  Myself, I like Maxima FFT.  It comes out thin like water so you can get it spread around and then after a few minutes it get nice and tacky.  Bel Ray seems to make a good foam filter oil too.  I know they say not to use gas to clean your filters but I use kerosene followed by a rinse in soapy water and then clean water and the filters look like new.  I clean the filter after every ride.