Boging

duckhunter

New Member
Jul 11, 2011
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ok guys i recently blew the motor up on my 2005 blaster. i got it back about a week ago and was running pre mix gas and the fuel injection to brake in the new pistion. it sat in the garage for two days and when i went to ride it yesterday it started up fine but it has no power, once you give it gas it bogs very bad. i changed the spark plug and cleaned the carb, so im not sure what to do next, should i buy a new cdi? or what? thanks for the help guys.
 
Wait, If you ran pre-mixed gas and have the oil tank hooked up and running. I wouldn't call it fuel injection ... as the carb is the fuel delivery system and the stock oil pump just pumps oil into the mix.

Regardless, your first problem is that you should never run pre-mixed gas without an oil-block off kit installed.

Second, If you did this would not cause it to be lean, it would cause double the amount of oil in the mix which would make it extremely rich. I would hypothesize that the problem could be you fouled the spark when running it this way. I would atleast check this first. then drain the pre-mix out of the tank and put in clean gas if you are going to run the stock oil delivery system.

I personally would block the system off. Either way you really do not need to greatly change the mix for break-in. If blocked off you can pre-mix a slightly richer mix than 32:1 which is the best and recommended for your blaster but if you did your top end correctly and made sure to coat the cylinder and piston when re-installing I would not.

Edit: Sry did not read you already changed plug, have you made other changes that would need jetting changes?? and where in the RPM range is it bogging??
 
ok ill try that next, i was told double oil is best for breaking in new pistions but i guess they were wrong lol, but thanks for the help guys ill keep ya informed after i put fresh gas in.
 
Nope. Run your regular mixture and just make sure the quad is good and warm.
Warm quad
Ride at 1/4 throttle or less
Wait for quad to cool
Warm quad 1/2 throttle or less
wait for quad to cool
ect.....
 
Wait, If you ran pre-mixed gas and have the oil tank hooked up and running. I wouldn't call it fuel injection ... as the carb is the fuel delivery system and the stock oil pump just pumps oil into the mix.

Regardless, your first problem is that you should never run pre-mixed gas without an oil-block off kit installed.

Second, If you did this would not cause it to be lean, it would cause double the amount of oil in the mix which would make it extremely rich. I would hypothesize that the problem could be you fouled the spark when running it this way. I would atleast check this first. then drain the pre-mix out of the tank and put in clean gas if you are going to run the stock oil delivery system.

I personally would block the system off. Either way you really do not need to greatly change the mix for break-in. If blocked off you can pre-mix a slightly richer mix than 32:1 which is the best and recommended for your blaster but if you did your top end correctly and made sure to coat the cylinder and piston when re-installing I would not.

Edit: Sry did not read you already changed plug, have you made other changes that would need jetting changes?? and where in the RPM range is it bogging??

Actually doubling the amount of fuel in the mixture will also make the bike run LEAN because oil doesnt burn like gas does, and since oil is displacing fuel in the combustion chamber, theres less fuel in the mixture, more air, therefore lean.

Now thats not to say that would cause you to run TOOO lean, however, you never know. But yes, technically, reducing your oil to fuel ratio number effectively leans out the bike.

And usually bogging is a function of being lean.
 
i agree with luni, too much oil displaces the fuel and makes the mix more viscous, if you do run premix and injection, you MUST increase your jet size quite a bit to allow it to flow the correct amount of fuel,

its like sipping a super double thick milkshake through a cheapo littler straw, you going to battle, but use a bigger straw and its lekker!
 
But yes, technically, reducing your oil to fuel ratio number effectively leans out the bike.

Ok, just for clarification as I am not an idiot. I understand bogging is a result of being lean, but fouling and in some cases sputtering can mimic bogging. Now ... not that I don't think your correct but less oil to gas is a lean mixture ... thus double the oil to gas is a rich mixture. ???
 
something to remember is you have 2 kind of lean/richness on a 2 stroke, 1: your oil-gas ratio -eg 32:1 and 2: your fuel to air ratio eg 14.7:1 on a NA car. jetting only changes your air/fuel ratio and cannot account for the fuel/oil mix.

in this case, the fuel oil mix is VERY high/rich, probably around 18:1 thus if the bike is jetted properly for 32:1 fuel/oil, it will be LEAN in terms of fuel/air with a super high oil concentration. because: more oil in the gas= 1liter mixed fuel at the reeds now has a higher percentage of oil than it should this means its got less gas in it! so the bike may still foul plugs because its just chewing on oil but will bog because its short of actual gas to burn!

so you can experience oil rich fouling and gas lean shortages AT THE SAME TIME!--

simple solution: either premix or leave it to the injector...not both!

Complex solution: rejet with larger jets to allow the correct amount of gas through--side effects of this are that you still get heavy proportions of oil and will still foul plugs.

quite confusing ey?
 
For whatever reason in the 2 stroke world people have taken to calling oil ratio rich or lean. What youre talking about is oil to fuel ratio.

What Im talking about is stoichiometric, the perfect air to fuel ratio, and bottom line is, the more stuff you put in your fuel that ISNT fuel, it displaces the fuel and leans out the ratio. Oil doesnt burn like gas does, it isnt part of the stoich equation so, the more oil you put in your gas the leaner youre going to be on the burn.
 
bottom line is, the more stuff you put in your fuel that ISNT fuel, it displaces the fuel and leans out the ratio. Oil doesnt burn like gas does, it isnt part of the stoich equation so, the more oil you put in your gas the leaner youre going to be on the burn.

my point exactly, we just explaining it differently!
 
Your doubling the oil content of your mix. Say you were running 32:1 and the injector was set up for 32:1, your now running a 16:1 mix.
Your running leaner because you just took away 50% of the gas in the mix and replaced it with oil.
I would imagine the plug would foul out before serious damage is done.
 
ok well i drained the premix fuel outa the gas tank. i do have bigger jets too. i put regular gas in while just running off the normal oil injection system. i let the quad idle for a good 15 min with the new gas and it still bogs after 1/4 throttle. i changed the spark plug when i put the fresh gas in too. where do i go from here?