keeping motor cooled

[mike11743]

I just bought a blaster, and as soon as i hit powerband when it was warmed up, the top end shattered into the bottom end. When i took it apart, it was running extremely lean and the plug was pretty white and almost melting.. It smelled like somethiong was burning up, so i assumed it was overheating. I got the top and bottom end rebuilt. now the plug is a dark black oily color, but does not foul. I know that air cooled motors are largely cooled by the gas, so if I am running lean, will it blow my top end. I have a 240 main jet, and stock pilot jet. I also have DG pipe and silencer, air box vents, and filter and filter wrap. If I keep the jetting at 240, will that do any engine damage?

 

[fastLANE]

if the plug is black and oily than you are running rich. If you are not fouling plugs than I would stay with that main jet so you dont blow up again. What jets were you running when you ran lean and burnt your sh*t up?

 

[mike11743]

same ones. I didnt change anything. I dont know maybe it started to run lean after it blew up? I just bought it, and god only knows what the previous owner did to it.

 

[fastLANE]

you probably had a bad air leak somewhere that cause the bike to run lean. During the tear down and rebuild, it was probably remedied.

 

[xxxxfloodedxxxx]

ya.. thats odd though that your running fine with a 240 with a aftermarket pipe an silencer.. but hey, whatever is workin for ya. rich is better than lean!

 

[mike11743]

I was thinking that ill just go up to a 265 just to be safe. Does this sound right with my mods?

 

[bigdblaster]

well if its black and oily now a 265 is gonna make it foul more than likely i would keep it where it is for now maybe warmer temps see what it does jetting is funny i had air box lid on and used a 290 put vents in needed a 300 took lid off and now im at 310 elevation play a big part in jetting ur blaster.but if it was me i would stay where ur at if its black and oily i would even maybe adjust the air/fuel screw but aslong as its not fouling ur ok

 

[HOBBYHORSE]

WHAT FUEL RASIO ARE YOU RUNNING?

 

[mike11743]

32:1 maybe more like 28:1 on this tank due to a new top end, but usually 32:1.

 

[HOBBYHORSE]

32:1 maybe more like 28:1 on this tank due to a new top end, but usually 32:1.

GO WITH 40:1, THAT WILL TAKE SOME OF THE OIL OFF OF THE PLUG SO YOU
CAN GET BETTER PLUG READING AND YOU'LL GET A LITTLE MORE THROTTLE RESPONCE. IF 40:1 DON'T PULL THE OIL OFF THE PLUG, GO 50:1
WE RUN 58:1 BUT WE ONLY RUN 300ft AT A TIME. GOOD LUCK!!

 

[fastLANE]

GO WITH 40:1, THAT WILL TAKE SOME OF THE OIL OFF OF THE PLUG SO YOU
CAN GET BETTER PLUG READING AND YOU'LL GET A LITTLE MORE THROTTLE RESPONCE. IF 40:1 DON'T PULL THE OIL OFF THE PLUG, GO 50:1
WE RUN 58:1 BUT WE ONLY RUN 300ft AT A TIME. GOOD LUCK!!

why would you tell him to mix leaner when his bike already blew up from running lean? I would think richer would be better , then fine tune it from there.Gives him the safety of only replacing plugs as apposed to cylinder bores as he dials it in properly. As you said , you only run 300 ft at a time... so you put a few seconds of stress on your motors at that, while he puts hours on it at that mix.....see where I'm comin from? That may be good for a drag bike but not for a "fun" bike

 

[HOBBYHORSE]

why would you tell him to mix leaner when his bike already blew up from running lean? I would think richer would be better , then fine tune it from there.Gives him the safety of only replacing plugs as apposed to cylinder bores as he dials it in properly. As you said , you only run 300 ft at a time... so you put a few seconds of stress on your motors at that, while he puts hours on it at that mix.....see where I'm comin from? That may be good for a drag bike but not for a "fun" bike

I run the same mix in my "fun" bikes. How much oil you have in your gas does
not determine how rich or lean it runs, that is determined by your jetting.
All the oil does is lubricate the top end, it has no cooling value. The gas does all the cooling, if you want it run even cooler, switch to methanol. Yes I run
only 300ft. now. But I've been racing two strokes for 35 years, so I've seen about every fuel setup from nitromethane to the old leaded pump gas, so i
wouldn't steer this young man wrong!!

 

[Blaster.240]

The oil to gas ratio has nothing to do with the engine running leaner or richer, so some one says richer or leaner it is refering to the air to gas ratio the leaner the more air than gas the richer the more gas than air. Also when you bought you pipe it should have came with a jet kit for the carb. Whenever you a pipe on or anything that has to do with the air and exhaust system you need to jet the carborator for the right setting and for an aftermarket exhaust you have to rejet the carb no matter what.