Another question from the new guy!

[deestroyer11]

I have a 2003 Blaster that i just had the motor rebuilt bored .40 over new crank, bearings and seals. It has a FMF Fatty Gold series complete exhaust and k&n air filter. I believe the motor has been gone through before because the stock carb has a 290 main jet i believe. It had a 350 jet in it. I bumped it up to a 390 and it was still running lean. I now have a 420 in it and it is still lean. Is this normal? I don't want to hurt the motor. I just started riding and i don't know much about these 2 stroke and 4 stroke engines. If anyone could give me some advice it would be greatly appreciated.
Thanks,
Tony.

 

[liljatownboy]

um are you premixing? if not oil pump may have gone out and hows it ideal air leak maybe

 

[deestroyer11]

Yes i am pre mixing 32:1 I think the pump went out before and thats why the piston broke into pieces which is why i had to rebuild it.

 

[deestroyer11]

It idles fine...

 

[liljatownboy]

why u think its running lean? and whats the air fuel screw at and needle whats that at?

 

[deestroyer11]

Im not sure what the needle is at. The mixture screw is out 1 1/2 turns. The reason i say it is lean is the pro shop that i had it done at says that when i put it in 3rd gear and give it full throttle it should bog down and then drop the jet one size at a time until it doesnt bog down anymore.

 

[liljatownboy]

well dont go bye that go by what the plug looks like. to tell u the truth idk how your bike is even running with a 420 in it we have never gone that high on a jet

 

[liljatownboy]

and you have a a/m pipe so i dont see why it would bog

 

[deestroyer11]

Ive recently been told that these guys at this pro shop do not know a hole heck of alot. But its the only place close so they stay in buisness. And yes it has a 420 in it, it starts with the first kick every time. It idles fine, i start it, give it a couple pumps on the gas and then it wil sit and idle. I run it down the road and it seems like it gets to a certain rpm with me holding the throttle steady and then it takes off, it must be then that its in its power band. The plug is dark brown but the nickel plated pipe is turning blue right outside the motor, I was told that means its running hot/lean.

 

[Blasterdude27]

Ive recently been told that these guys at this pro shop do not know a hole heck of alot. But its the only place close so they stay in buisness. And yes it has a 420 in it, it starts with the first kick every time. It idles fine, i start it, give it a couple pumps on the gas and then it wil sit and idle. I run it down the road and it seems like it gets to a certain rpm with me holding the throttle steady and then it takes off, it must be then that its in its power band. The plug is dark brown but the nickel plated pipe is turning blue right outside the motor, I was told that means its running hot/lean.

No its normal for a pipe to brown or blue, a 230 main is stock you should run around a 270.

 

[jahrastapark]

i run a 350 and nooone knows why. its a mystery. havent had it at a shop recently though

 

[deestroyer11]

So do you think im hurting the motor in anyway with it having a 420 in it?

 

[Blasterdude27]

So do you think im hurting the motor in anyway with it having a 420 in it?

No I don't think so..

 

[liljatownboy]

thats just gonna drink gas out the ass

 

[just_ride_595]

lean with a 420 size main is rare i'll give you that. it sounds like its running fine, esp with the plug color which is for the most part exactly what a well jetted engine's plug should look like. no chance of an air leak?

 

[03blasteryfs03]

head gasket or base gasket or reed boot or gasket