Need help with jetting plz new to forum

[DBro563]

I just bought a 02 blaster with a fmf gs fatty pipe, fmf PC2 silencer, K&N air filter, air box with lid and snorkel still on, and oil injection is blocked off and I mix 32:1... I took the carb apart today and the main jet was a 240. Is this to small? I live at 600 ft above sea level and in Iowa so temp range from 0 - 100° F. Should I go to a 260 main jet or mix my gas and oil at 40:1? Any help would be greatly appreciated.

 

[Markblaster]

Do a plug chop.
http://www.blasterforum.com/threads/plug-chop-video.65534/

 

[Blaaster]

Stay at 32:1 it is proven to be best for recreational riding.

25:1 if you race..

I would be doing a plug chop starting with a 270 main jet...

 

[DBro563]

Im going to go to my yamaha dealer today and pick up a 260 and a 270. I've got about 30 hours of riding it the way it is and it seems to be fine and I haven't fouled any plugs. But I feel it should be a little snappier

 

[BanzaiBlaster]

With an intact airbox lid you're still on the lean side. Whether or not you decide to remove the lid grab 260-290 mains.

 

[DBro563]

With an intact airbox lid you're still on the lean side. Whether or not you decide to remove the lid grab 260-290 mains.

Awesome thanks bro

 

[DBro563]

If I take the lid off i should account for going up 1 for that also rite?

 

[BanzaiBlaster]

Could be more. If you remove the lid start at 290 and plug chop down.

 

[DBro563]

Im going to keep the lid on it just becuz were I ride at gets really muddy and theres alot of water. Going to change the Jets out now. Wish me luck lol. Thanks for your guys help.

 

[DBro563]

Update.... put a 270 in and I don't bog down when at dead stop then WOT.. had to adjust the air screw and idle screw a bit but seems to be running way better. Only thing that got me a little confused is she anit smoking like she was but that could be cuz she's almost out of gas.... not sure. I wouldn't think a bigger main jet would take away from the oil she's getting.

 

[Blaaster]

Set thecidle soeed as follows...

Idle adjusting.
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 .
if the air screw ends up being more than 2 1/2 turns out the pi;]lot is too big.
if the air screw is less than 1/2 a turn out the pilot is too small

 

[Blaaster]

Then plug chop to confirm the jetting...

This is the process of confirming that you are using the correct carb settings
for a efficient and healthy engine…
the process can be done at wide open throttle to confirm the main jet or at
1/2 to 3/4 to confirm the needle position.

Before you make the plug chop run it is important that the float level is
correct, the idle is set correctly and there are no air leaks in the system,
otherwise the smoke ring may lie about the AFR.
WHEN ALL OF THE ABOVE ARE CORRECT PROCEED WITH THE FOLLOWING.
Warm up motor to operating temp.
Fit new maker specified plug, ride WOT ( or 1/2 to 3/4 throttle for the needle
) through the gears and hold that throttle opening in 5th or 6th gear for 10
seconds, or as long as you can safely.
Switch off the ignition and pull in the clutch, apply brakes to come to a stop
quickly.
Take the plug out and replace the old one for the ride home.
Carefully cut the threaded end off the plug to expose the insulator.
There should be a smoke ring of a cardboard or biscuit colour around the
insulator.
If it is non existant or a very light colour, you are lean and require a larger
main jet.
If it is a lot darker you are rich and may go down a size in main.
I prefer to run a little on the darker side, I may loose a little power but it is
worth it for the peace of mind that I won't need a rebuild so soon.
You have to get up a reasonable speed so that you can get the engine to pull
strongly.
Then hold it Wide Open Throttle (WOT) for 10 secs or as long as you can.
The idea is not to get speed but to make it pull strong at full throttle to get
onto the main jet circuit.
I find I can safely do it on a short run by applying the brakes some.
If you have not enough room you can use 4th or 5th gear with good results.