Rebuild to a 240?

Deutschy33

New Member
Dec 19, 2012
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Northampton, Pa
Hey everyone, buddy showed me this site and you guys seem to know your stuff lol. I have an 02 blaster should be bone stock with oil injection and only has an aftermarket dg pipe on it. Long story short i think i blew the rings on it/overheated and there was a slight chip in the side top of the piston. A buddy is rebuilding it for me and asked if i wanted i wanted to go to a 240 kit rebuild. I know the price difference is only a few hundred bucks and the horsepower is a decent increase. Has anyone done this swap and is it worth it. Also wanna know what else i should do if i do the swap, i am gonna put the oil delete on with this but i heard a few things like: change the mix ratio and to stay away from certian brands for the rebuild kits. Any suggestions on what brand or what to do with the swap would be appreciated. Thanks, Lee.
 
Ill share the little bit i have gatherd while being here.

Wiseco crank aren't the best, but there pistons are awesome.

Vito's make decent stuff, you can buy a full top end 240 kit on ebay.
 
skip the 240 unless you have the plans and wallet for the necessary supporting mods to make it worth while...
different pipe/carb/intake.

the most bang for the buck has proven to be a ported stock cylinder and head mod. which will work with the stock carb, but that dg pipe is still going to hold you back some on either of those options.
 
dont do it, bore it .020 or .030 over port and pollish, the 240 kit isnt worth it and please dont take off that oil pump, ive been working on these for a long time, me and my friends have tried all kinds of things and the best is leave the oil pump alone! the blaster does not run like other 2 strokes as in the oil ratio its not constant, so premixing doesnt work, the pump on idle pumps the perfect amount of oil, then as the engine speeds up the oil ratio changes to compensate, with pre mix theres one ratio its either guna be too much oil on idle, and foul plugs left and right, or not enough oil on top end and blow up, so save yourself the pain and money, and just bore it over a little.
 
dont do it, bore it .020 or .030 over port and pollish, the 240 kit isnt worth it and please dont take off that oil pump, ive been working on these for a long time, me and my friends have tried all kinds of things and the best is leave the oil pump alone! the blaster does not run like other 2 strokes as in the oil ratio its not constant, so premixing doesnt work, the pump on idle pumps the perfect amount of oil, then as the engine speeds up the oil ratio changes to compensate, with pre mix theres one ratio its either guna be too much oil on idle, and foul plugs left and right, or not enough oil on top end and blow up, so save yourself the pain and money, and just bore it over a little.

Boy is this statement going to poke a stick into an hornets nest.

Whilst I am in favour of retaining the oil injection system, premixing is the best thing since sliced bread.

"with pre mix theres one ratio its either guna be too much oil on idle, and foul plugs left and right, or not enough oil on top end and blow up,"

Where did you glean this piece of usless information from or did you just make it up?
 
blaaster, really?? is your oil pump still on? if so crank it up pull the hose off the carb, let it idle watch the oil come out of the hose, rev it up and WATCH the oil, it pumps more oil the faster the engine runs, the blaster does not run on one constant ratio, it constantly changes. and as far as premix yea it is great, for machines built to be premixed, the blaster was not. but ur basically sayin take a a fuel injected car with a supercharger, take the supercharger and fi system off, put a 2 barrell carb on it and you made it better. makes no sense.
 
Go easy on him Blaaster. He's a newbee.

Here's the deal...
Pre-mix works just fine...always has. Pretty fool proof. Just find the oil you like and the fuel to oil ratio you like and PROPERLY JET THE ENGINE! No problems. In colder weather? Better jet fatter for the denser air (cold air is denser,which leans the mixture),and the most important thing...DON'T FORGET TO PUT OIL IN YOUR FUEL! This would fall under "Operator Error",and I have persaonally witnessed it. One time it was grabbing the wrong gas can,because it wasn't marked "pre-mix" and the second time it was gas with no oil mixed in. It can happen. Fix for both problems... SLOW DOWN.


Here's the other deal...
The Yamaha "Autolube" oil injection system is pretty fool proof too. However, when you think you have invented something thats fool proof,along comes the "new and improved idiot".
Just make sure to PROPERLY JET THE ENGINE! No Problems. In colder weather? Better jet fatter for the denser air (cold air is denser,which leans the mixture),and DON"T FORGET TO PUT OIL IN THE OIL TANK! This too falls under "Operator Error" Imagine that. You can see the traslucent tank from 200 feet away. Is it low or full? Just look. It really is that simple
Now if you have had the system apart for any reason, you need to "BLEED" the system its quick and simple to do.

And YES... you can run oil injection with engine modifications.
 
blaaster, really?? is your oil pump still on? if so crank it up pull the hose off the carb, let it idle watch the oil come out of the hose, rev it up and WATCH the oil, it pumps more oil the faster the engine runs, the blaster does not run on one constant ratio, it constantly changes. and as far as premix yea it is great, for machines built to be premixed, the blaster was not. but ur basically sayin take a a fuel injected car with a supercharger, take the supercharger and fi system off, put a 2 barrell carb on it and you made it better. makes no sense.

It pumps more oil because it draws more fuel at higher rpm's... It pumps more to keep the same ratio. Why not just cut out the middle man?
 
It pumps more oil because it draws more fuel at higher rpm's... It pumps more to keep the same ratio. Why not just cut out the middle man?

Cuz the middleman sometimes gets in a rush and forgets his oil,
cuz the middleman sometimes gets his gallons and ounces mixed up,
cuz the middleman sometimes finds himself at a backwoods gas station with no oil,
cuz the middleman isn't as smart as the crowd that designed that autolube pump!
 
blaaster, really?? is your oil pump still on? if so crank it up pull the hose off the carb, let it idle watch the oil come out of the hose, rev it up and WATCH the oil, it pumps more oil the faster the engine runs, the blaster does not run on one constant ratio, it constantly changes. and as far as premix yea it is great, for machines built to be premixed, the blaster was not. but ur basically sayin take a a fuel injected car with a supercharger, take the supercharger and fi system off, put a 2 barrell carb on it and you made it better. makes no sense.

Why on earth would I take the oil injection pipe off, cut the lubrication supply and then rev up my motor.

Oil starvation sure sounds like a dumb party trick to me.

The oil injection system delivers oil at the correct amount in relation to engine revs, low rev = little oil, high rev = more oil.

That tells me that the oil supply is at a constant ratio, in relation to revolutions at about 20:1 at every engine speed.

On the other hand if one is basing the ratio on throttle opening then the oil/fuel ratio is constantly changing.

Now I am confusing myself.



Lets not get into a discussion on fuel injection and superchargers as it bears no relation to oil injection.
 
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I also prefer the extra oil at 20:1 because it promotes much better ring seal,which = a tad more power. Just my opinion.
Plenty of lubricant to lube everything too. Also,he oil tank seems to last forever.
 
20:1 does increase compression a little due to the prescence of a little more oil pooling in the bottom of the crancase to be splashed around.

I choose to run bean oil at 25:1 therefore cannot use the constant ratio oil injection system, as bean oil cannot be used for injection.
 
Hey everyone, buddy showed me this site and you guys seem to know your stuff lol. I have an 02 blaster should be bone stock with oil injection and only has an aftermarket dg pipe on it. Long story short i think i blew the rings on it/overheated and there was a slight chip in the side top of the piston. A buddy is rebuilding it for me and asked if i wanted i wanted to go to a 240 kit rebuild. I know the price difference is only a few hundred bucks and the horsepower is a decent increase. Has anyone done this swap and is it worth it. Also wanna know what else i should do if i do the swap, i am gonna put the oil delete on with this but i heard a few things like: change the mix ratio and to stay away from certian brands for the rebuild kits. Any suggestions on what brand or what to do with the swap would be appreciated. Thanks, Lee.

Let us get back to the topic in hand!

It is perfectly ok to use oil injection with a 240.

If you choose to run premix then 32:1 is what most of the folks base the jetting on in BF.

Any other oil/fuel ratio will require a change of main jet.

Tip of the day, remember to leak test the motor after rebuild and prior to starting the motor.
 
Back on topic...

My suggestion would to get a stock jug and have it ported and have the head cut with a new chamber and squish band. You will be amazed at the difference. I believe that you would notice more of a gain from that than a 240 big bore kit. The advantagees are...

#1... Stock cylinders are available every where
#2... You lots of over bores in a stock cylinder
#3 The prices of blaster parts are inexpensive.
 
I had A 98 blaster stock bore with a 3mm stroker fmf fatty/ power core 2, p&p, and some other mods. It had some good all around power you could not kill that bike.
 
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