Suzuki RM250 $$ Best 2 stroke oil?

[racin4ds]

Originally Posted By: sunruh
Originally Posted By: quarterliter
I've heard great things about motul kart racing GP premix. Formulated for the super high revving karts under race conditions. Granted it's 20 bucks a quart but I think it's worth it


its really funny that you say "super high revving"....no 2stroke of 60/65cc revs even as high as the modern 4sroke engines of the 250/450mx and 600/900+ of sportbike designs. the bigger the 2smoke piston, the slower the max rpm.

the 250smoker the OP has only goes to 9k.....yet my 250f (4stroke) still has another 1300 rpm to go before it hits max hp.



Ummm I've raced the KT100 Yamaha 2 strokes in open karts that spin 14,500 every lap. I can assure you there are tow strokes larger than 60cc spinning way higher than your 4 stroke ever will.

 

[sunruh]

im sorry you have a slow turning kart

for 2007 (yes thats 7 years old now) the YZF-R6 came with

"is a tachometer with more realistic 16,500 RPM redline for 2007."

 

[Jarlaxle]

I recall older 125cc 2-stroke karts spun past 16K. (And below 12K was basically lugging them...)

 

[yaris0128]

Opti-2 has blown my mind for a 2 stroke oil. Leaves little to no ash behind and my little 66cc engine runs like a champion. I do a lot less top end clean up rebuilds with Opti-2 over even Amsoil.

 

[Cujet]

It is true that 2 strokes generally don't rev or redline as high as modern 4 and 5 valve, short stroke 4 strokes.

What also remains true is that 2 strokes in proper tune, make more torque and HP than comparable 4 strokes.

For example, a well tuned 250cc motocross 2t will make 45HP and 28Lb/ft torque. A well tuned 250cc 4t motocrosser will make 40HP and 20Lb/ft torque.

Here is a dyno chart of a 450 4t, a 250 2t and 4t.

Interestingly, highly tuned Kart 2 stroke 125cc engines make well over 50HP!

 

[Cujet]

I've owned a number of big bore 2 strokes. I currently ride a KTM 380EXC with minor mods. A very well tuned 380 (not mine) will make 60HP (at the wheel) and 38lb/ft torque.

But, the real champs of HP are the 500cc 2 strokes. Some stock models made 65RWHP (prior to factory de-tuning) and there are modified units (with aftermarket 500cc cylinders) making over 100RWHP!

I simply love the well tuned, big bore 2 strokes. Everything else feels weak to me.

 

[sunruh]

Originally Posted By: Cujet

What also remains true is that 2 strokes in proper tune, make more torque and HP than comparable 4 strokes.


of the same size displacement, yes.

Originally Posted By: Cujet

For example, a well tuned 250cc motocross 2t will make 45HP and 28Lb/ft torque. A well tuned 250cc 4t motocrosser will make 40HP and 20Lb/ft torque.


define "well tuned". as my 250f 4t makes more hp and torque than that. however, mine is not eom stock anymore.

Originally Posted By: Cujet

Here is a dyno chart of a 450 4t, a 250 2t and 4t.


exactly which 450f, 250smoke and 250f did you take the from because NONE of the 250f's make that little oem nowadays. as can be seen in the DirtRider mag 250f shootout. and if i remember right, all of the 450f's are above that as well.

Originally Posted By: Cujet

Interestingly, highly tuned Kart 2 stroke 125cc engines make well over 50HP!


yes over a range of what 500rpm? or is it less?

 

[02SE]

Originally Posted By: Cujet


I simply love the well tuned, big bore 2 strokes. Everything else feels weak to me.


I agree completely. I still have my old '95 KTM 550 MXC. In it's current guise it's running higher compression, and has had some porting work done. It makes my buddies CR 500 feel weak.

I think it's almost more dangerous to try and kickstart, than it is to ride. Occasionally the uninitiated will make fun of the old dirt bike with the stock purple seat. Until the old, heavy, 2-stroke roosts their latest 4-stroke wonder.

 

[sunruh]

a little 550. you should try the ATK 620 or 700 Intimidator.
the pics of comparing the 500 piston to the 700 piston are like a coffee cup to a coffee can.

and there are a few "built" 450s that will easily run with that old ktm.

 

[02SE]

I've ridden them. The factory is only a short distance away from where I live. When I'm home that is. Most of the year I'm traveling around the country.

Anyway, I did mention the higher C.R. of my old KTM, I just didn't mention how high it is. Pump gas doesn't cut it.

It weighs about the same as the ATK's, and has no trouble running away from those bikes in stock form.

 

[Cujet]

Originally Posted By: sunruh
Originally Posted By: Cujet

What also remains true is that 2 strokes in proper tune, make more torque and HP than comparable 4 strokes.


of the same size displacement, yes.

Originally Posted By: Cujet

For example, a well tuned 250cc motocross 2t will make 45HP and 28Lb/ft torque. A well tuned 250cc 4t motocrosser will make 40HP and 20Lb/ft torque.


define "well tuned". as my 250f 4t makes more hp and torque than that. however, mine is not eom stock anymore.

Originally Posted By: Cujet

Here is a dyno chart of a 450 4t, a 250 2t and 4t.


exactly which 450f, 250smoke and 250f did you take the from because NONE of the 250f's make that little oem nowadays. as can be seen in the DirtRider mag 250f shootout. and if i remember right, all of the 450f's are above that as well.

Originally Posted By: Cujet

Interestingly, highly tuned Kart 2 stroke 125cc engines make well over 50HP!


yes over a range of what 500rpm? or is it less?


2014 dirt rider 250f dyno test results:

KTM 250 sxf 36.98
YZ250f 36.66
KX250f 35.67
CRF250r 34.68
RM-Z250 34.50

How'd you get more than 40HP out of your 250f? Big bore?

I rode a big bore, well modified, 290cc WR250f in Ocala National Forest. It was much nicer than a stock bike, due to the added grunt. However, near 40HP or not, it was still heavier and felt like half the power of my 380. Probably because the 380 makes much more mid range torque.


Back to the oil question. For dirt bikes, I universally recommend 32 to 1. I'm not at all sure there are huge differences in engine lifespan between quality oils, such as any EC-D or FD oil. I am 100% convinced there are differences in lifespan when very lean oil ratio's are chosen. (like 100 to 1)

Dirt bikes are subject to varied conditions. One possible condition is high RPM with the throttle closed. Such as going down a long hill. Lean oil ratio's don't work well under such situations. It's wonderful to think that a film of oil remains in place for a while. It's another thing to see a video of 2 stroke oil migration. You quickly realize that the oil gets washed off under certain situations.

 

[sunruh]

Originally Posted By: Cujet
How'd you get more than 40HP out of your 250f? Big bore?


cdi, cam, porting. im at 42.1 and that is not even near the top of the heap.
the national bikes are making 48ish. no its stock bore and stroke.

Originally Posted By: Cujet
I rode a big bore, well modified, 290cc WR250f in Ocala National Forest. It was much nicer than a stock bike, due to the added grunt. However, near 40HP or not, it was still heavier and felt like half the power of my 380. Probably because the 380 makes much more mid range torque.


well the wr is known as the pig. there are tons of weight adding items on it over a yz.

 

[Blaze]

If you want the least amount of piston and bearing wear etc personally I would use something that has castor oil as an additive. I believe Maxiam (sp?) has something close.

 

[sunruh]

maxima has castor927 which has castor oil in it
and k2 which is 100% synth

 

[FastGame]

Klotz

 

[Panzerman]

Just imagine if they put the time and technology into two strokes that they do four strokes, what kind of monsters we would have. Four strokes are a failure overall, what they were designed for. They do run well and fast, but the expense associated with keeping them that way is out of a lot of budgets. Kawasaki is losing their butts, they have dropped almost all their racing programs. Average people just cant afford to race four strokes, too expensive to rebuild, buy and replace.

 

[sunruh]

in the outboard boat motor world there is direct injected 2smoke motors. they rip!

the problem is when you have some insanely stupid ceo of hugecompany (tm) cough honda cough that says they will never build a 2smoke again. well, there is only 1 way to change that and it ends with a knife in the gut.

 

[FastGame]

Originally Posted By: sunruh
in the outboard boat motor world there is direct injected 2smoke motors. they rip!

the problem is when you have some insanely stupid ceo of hugecompany (tm) cough honda cough that says they will never build a 2smoke again. well, there is only 1 way to change that and it ends with a knife in the gut.


WTH ??? ends with a knife in the gut ?

In the snowmobile world 2 cycle really rips, but 4 cycle is taking over. 2 cycle has 1 major limiting factor...crank seals.

 

[racin4ds]

Originally Posted By: FastGame
Originally Posted By: sunruh
in the outboard boat motor world there is direct injected 2smoke motors. they rip!

the problem is when you have some insanely stupid ceo of hugecompany (tm) cough honda cough that says they will never build a 2smoke again. well, there is only 1 way to change that and it ends with a knife in the gut.


WTH ??? ends with a knife in the gut ?

In the snowmobile world 2 cycle really rips, but 4 cycle is taking over. 2 cycle has 1 major limiting factor...crank seals.




And why in the heck does the crank seal limit a two stroke??? Uh.. I'm not seeing it. Two strokes were killed because of the useless EPA

 

[FastGame]

Originally Posted By: racin4ds
Originally Posted By: FastGame
Originally Posted By: sunruh
in the outboard boat motor world there is direct injected 2smoke motors. they rip!

the problem is when you have some insanely stupid ceo of hugecompany (tm) cough honda cough that says they will never build a 2smoke again. well, there is only 1 way to change that and it ends with a knife in the gut.


WTH ??? ends with a knife in the gut ?

In the snowmobile world 2 cycle really rips, but 4 cycle is taking over. 2 cycle has 1 major limiting factor...crank seals.




And why in the heck does the crank seal limit a two stroke??? Uh.. I'm not seeing it. Two strokes were killed because of the useless EPA


All the super hotrod boosted (turbo) 2 cycle sleds I've seen seem to have problems with their crank seals. I've been to many frozen lake/grass drags and this was common. Maybe I jinks the the 2 cycle guys ??? 4 strokers don't have that crank seal thing and they can run higher boost. Also boosted 2 cycle has other issues with the way charge flow is controlled.

But yes the EPA is the #1 killer of 2 cycle in general.