Kawasaki Dirt Bikes Forum

masterlink:
Make sure u really mix ur fuel well!! A slug of lean "oil to fuel" mix will wipe out a top end quickly. I always add the oil to the container first, then pour in the fuel and shake with a little dance number that I made up.  also todays pump fuel is for the birds. I think u'll have better luck if u give ur bike a steady diet of race fuel.

DLHamblin:
Not necessarily.  This could be a topic unto itself.  Running race fuel in a stock or near stock bike is wasting the race fuel and may actually make throttle response less than with pump gas (same if you run straight AV gas).

Most stock (and near stock bikes) may benefit from mixing some race gas (up to 50%) with pump gas to help with the quality of the stuff we get now days, but its not necessary to run 100% race gas (other than it smells good...).

I have found my YZ250 and son's YZ125 seem to run better on 25% race (105 Octane) 75% pump (93 octane) mix than straight 105 octane race gas.

one of my friends told me that he used to run jet fuel through his 2 stroke is he full of it or would that increse power or make the bike run better
i have several Qs about running higher octane


u know the octane boost that they sell at the bike shop is it a good idea?

does higher octane cause premature wear in the top end ?  


the quick reply button can be found outside the text box on the bottom left corner about an inch down look for your pointer to turn into a hand and you found the donkey

Full of it.  Jet fuel is kerosene - basically Diesel.  The engine won't even fire up.

The rule is - use the lowest octane fuel you can use that doesn't detonate.  That's where your best throttle response and power will be.

The race fuel is more consistent than pump fuel.  It also has a higher oxegen content.  That's the primary advantages, above and beyond the resistance to pre-ignition.

Don't waste your money on the octane in a bottle crap.

Bottom end

80/85 - in the hands of a pro kid, maybe a season.  
125 - a couple seasons for a reglar rider, 1 season for a racer.
250 - typically a couple seasons or more.  
Since when is Dirt blue??!!!

the top end in my bike was two years old, i havent got it apart yet im on my way to finish right now so what more is there to good i mean goood maintance on a two stroke? i change the oil about every 2-3 hours lube the chain run good oil i did it about like my sled, i guess i dont know how much more you can do  
LIKE A MIDGET AT A URINAL, YOU GOTTA KEEP ON YOUR TOES

got it apart have pics for ya but the stupid computer wont let me load them. it dont look too bad though, a small scuff in the jug but it dont look more than a thou deep. gonna take it to work and hone it out, how much play is there supposed to be in the rod, i have no idea, thanks for all the info too guys!! you rock any thing else i need??  
LIKE A MIDGET AT A URINAL, YOU GOTTA KEEP ON YOUR TOES

side to side some play is ok, up and down (without spinning the crank) should be next to nothing. double check your manual on how to inspect the freeplay.
pictures will give us a better idea what happened.  
expert ragdoll, helmet tester, chiropractors dream
06yz125,kx60(2)

No, you aren't going to hurt anything with race gas.

But, there are different types of race gas.  I use Turbo Blue Unleaded 105 octane.  When you use any of the more exotic oxygenated fuels you will generally have to rejet the bike so depending on where your stock jetting is you may have some running issues.  
Dave H 2006 YZ250
(2008 YZ 125 son)

skipkh:
Full of it.  Jet fuel is kerosene - basically Diesel.  The engine won't even fire up.

The rule is - use the lowest octane fuel you can use that doesn't detonate.  That's where your best throttle response and power will be.

The race fuel is more consistent than pump fuel.  It also has a higher oxegen content.  That's the primary advantages, above and beyond the resistance to pre-ignition.

Don't waste your money on the octane in a bottle crap.

Bottom end

80/85 - in the hands of a pro kid, maybe a season.  
125 - a couple seasons for a reglar rider, 1 season for a racer.
250 - typically a couple seasons or more.

Skip,

I typically run the 25% mix of Turbo Blue Unleaded 105; its a non-oxygenated fuel and the denisty is close to pump gas so the jetting doesn't get monkeyed with like some oxygenated fuels will do.

I do it for a bit of detonetion protection and also because it (Turbo Blue) is more consistent as you said.

I ran a tank or so of straight turbo blue.  It smells good but I found no gain over the mix.

Also, if you guys do run oxygentated fuels don't let them sit for long periods in the bikes tank/carb as they have been known to gunk up faster that non-oxygentated fuels.  
Dave H 2006 YZ250
(2008 YZ 125 son)

skipkh:
Full of it.  Jet fuel is kerosene - basically Diesel.  The engine won't even fire up.

The rule is - use the lowest octane fuel you can use that doesn't detonate.  That's where your best throttle response and power will be.

The race fuel is more consistent than pump fuel.  It also has a higher oxegen content.  That's the primary advantages, above and beyond the resistance to pre-ignition.

Don't waste your money on the octane in a bottle crap.

Bottom end

80/85 - in the hands of a pro kid, maybe a season.  
125 - a couple seasons for a reglar rider, 1 season for a racer.
250 - typically a couple seasons or more.

DLHamblin:
Skip,

I typically run the 25% mix of Turbo Blue Unleaded 105; its a non-oxygenated fuel and the denisty is close to pump gas so the jetting doesn't get monkeyed with like some oxygenated fuels will do.

I do it for a bit of detonetion protection and also because it (Turbo Blue) is more consistent as you said.

I ran a tank or so of straight turbo blue.  It smells good but I found no gain over the mix.

Also, if you guys do run oxygentated fuels don't let them sit for long periods in the bikes tank/carb as they have been known to gunk up faster that non-oxygentated fuels.

The U4.2 I buy says to drain from bike after each use. I usually run VP red which is 105. I've looked for Sunoco fuels but can't find any locally, and I can remember years ago there was CAM2 available, although I don't recall what octane that was. The U4.2 is nice for the 4 stroke but the draining part can be nerv-racking.  

Ya know - for all the complaining I do about how much we have to re-jet to compensate for our altitude (5800' where I live, 7500-9000 where I ride), there is a good side!  We don't worry about pre-ignition.  At our altitude we lose 20% or so of our effective compression.  I could run 87 octane in my YZ250 and it wouldn't care

Dave - I like your idea.  25% mix, no oxygenation, and insurance against pre-ignition - it sounds like pretty darn sound advice to me!  
Since when is Dirt blue??!!!

Masterlink: Cam2 is Sunoco Purple now.  110 octane. Same blend, same great smell!, just different name.  Lucky, they sell it at regular Sunoco gas stations here in Central FL!  I think they want you to drain U4.2 because it is kinda tough on yellow metals if it sits.  

allright guys i dont know how to put pics on here, but its not the worst ive ever seen i was told it was probably from going the same speed for too long,darn i wish i could show you a pic, but yeah theres no play up or down just side to side, what ind of piston + rings should i get?? i was thinking pro circuit??  
LIKE A MIDGET AT A URINAL, YOU GOTTA KEEP ON YOUR TOES

Go with the original piston/ring from the bike manufacturor - they hold up the best.  
Since when is Dirt blue??!!!

yamadog:
Masterlink: Cam2 is Sunoco Purple now.  110 octane. Same blend, same great smell!, just different name.  Lucky, they sell it at regular Sunoco gas stations here in Central FL!  I think they want you to drain U4.2 because it is kinda tough on yellow metals if it sits.

Wow! Yamadog I didn't know it was 110. What do u run it in? I don't think I have the comp ratio to run 110.  Have u tried the u4.2 I have mixed feelings about it. It makes my 4 stroke start so nice, but it doesn't seem to make power until my bike gets really warmed up. (If that makes any sense)  

I put up a thread on how to load pics. I asked Dave to sticky it. Dont know if he did. Search ( clickable thumbnails using photo bucket)  

i figured out the pics kinda just gotta pu em on myspace, but my batts are too dead and it didnt save the pics, ill pick some up tomarrow, off sub i work with a guy who aparently has no idea about dirtbikes (thought a two stroke meant two cylinders) whos gonna sell me a 2000 yz250 for two hundred!! its blown up but who cares!! im goin to look tomarrow let you know what i come up with PEACE  
LIKE A MIDGET AT A URINAL, YOU GOTTA KEEP ON YOUR TOES