Newbie question....again

[Maniacmotomouth]

Ok I know jetting questions get redundant, but my brain is fried I guess. I have a stock blaster with uni filter and no lid....at a 250 jet, the plug chop look ok maybe a little lean, however at 260 the bike won't even idle unless I turn the air screw in all the way, I guess I thought that meant I was still running lean so I bumped up to a 270, sAme results. So I went back to a 250 and it will idle with the air screw ~1 turns out. Does this mean I am running rich? Sorry to ask the same questions that have been asked a million times

 

[Blaaster]

The air screw does not alter the mixture of the main jet in any way, you can mess with it all day, it only is used to obtain the idle speed.

Float level, pilot jet, and air leaks is the area you should be looking at.

Idle speed adjustment..


Set float level, make sure that all jets are clean and fuel flows freely from the float bowl drain when the screw is cracked open.

Start with air screw 1.5 turns out.

Set idle screw so that it has some sort of idle. With TORS it is the big screw under seat on top of unit. With no TORS is is the brass screw midway down carb body.

Warm up motor and then set idle screw for a faster idle, 2000rpm+

Adjust air screw either way to get the fastest idle.

Adjust air screw a little at a time leaving 10 secs or until the motor responds.

Re adjust idle screw for desired idle .

 

[Maniacmotomouth]

Then why will it idle with the 250 in there and won't at 270? That makes no sense if the main jet is no even being used at idle. Air pressure held for 15 minutes

 

[Blaaster]

You disturb the carb when you change jets, could the float be rubbing or sticking somewhere.

If the needle and seat is in poor condition, fuel level may fluctuate.

 

[Maniacmotomouth]

My plug chop. Looks a little dark? Should be lighter? Just redid this one

 

[jus_me]

Not that I am doubting you but I have to ask. This was a hard pull in 5th or 6th gear and pulled in clutch and shut right off? Fresh new plug after warm up? Like blaaster said main jet has nothing to do with idle.. you aren't missing the little washer under main jet are you? and float is set correctly? Something is a miss.

Edit: And yes your plug looks rich if proper plug chop procedures were performed.. You can actually plug chop different circuits in the throttle if you make marking at different increments. Blasters seem pretty happy with no pilot change and maybe a clip move up or down on the needle and of course main jet changes are most common and necessary.. Even a power jet can be added but we don't need to get into that..

 

[Blaaster]

For a correct plug chop, the float level must be correct, the fuel delivery must be adequate, the washer under the main jet and preferably the slosh baffle in place.

 

[Maniacmotomouth]

Everything was in place for the plug chop. Thats why I replyg chopped and re-adjusting everything to spec

 

[jus_me]

You have a new air filter also right? I know you got one, but did you put it in? B8es plugs? Newer fuel?

 

[transmental]

Seems like youve tried numerous things to get it right... but for what i see i bet its not going to be any the air screw nor the jet. Start way behind your intake all the way to your exhaust silencer and make sure it is leak free. Clean carby and set float level and make sure float valve is moving freely. If premixed make sure the 2 cycle feed is plugged on the carb... air screw 1 1/2 just like said before... make sure needle is in middle or one richer only possition. Needle runs up and down freely with a good spring to it... clean reeds... check oil...id think a 250 jet is good to start...

 

[Davo]

For a correct plug chop, the float level must be correct, the fuel delivery must be adequate, the washer under the main jet and preferably the slosh baffle in place.

Just a question, What significance does the washer under main jet have? Makes me wonder about one of mine. I do not remember seeing that. .... guessing the point fuel is pulled threw based on float height. ...... it would be #10 on a OEM layout.

 

[transmental]

Main jet does not have any sort of washer... it haves a plastic shield guard thing that goes right over and around the main jet... like the one shown on this vid... do not know what the vid is about but it shows it how the mai jet and plastic guard go..Yamaha blaster main jet replacement:

 

[Maniacmotomouth]

Actually it does, I have a 98 and when you pull off the plastic shield, and then unscrew the main jet there is a washer under that main jet. Didn't come out the first time I rebuilt carb, but it did come out when I jetted the other night. And yes it's in there. I took carb off and checked everything, reset float height and put needle in middle clip. Got dark on me so I'll have to plug chop maybe tomorrow at lunch. Full speed 6th gear pull is no fun without a headlight.

 

[transmental]

if everything is i place then good... nothing works best on this blasters than a clear mind and a new day...