Help jetting my blaster

[Kameron]

I have an older blaster that I have put together and I need a llittle help on jet size. My bike has a recently rebuilt wiseco lower end and full fmf exhaust. Also has a fox performance ignition coil and Boysen race reeds. the I have a 260 in it now and it hardly moves. Do I need to change jet? Also I have never adjusted the carborator needle. also the cylinder is on its last bore at 80 over. Kn air filter as well.

 

[ZSPOT]

I haven't been involved with Blasters very long, but a 260 seems pretty small for those mods. I have a 260 with only an FMF pipe, silencer and a UNI.

 

[Kameron]

Yea that's kinda what I was thinking. It raps hi like it's starving for gas so that's what I was guessing might be wrong. I was hoping someone on here has the same stuff don'e to give me a ballpark on what jet size would be close

 

[Awk08]

Thank that fixed my throttle problem but n bike is acting like it doesn't have any power. Is a 260 jet too small for a blaster bored 80 over with full fmf exhaust a performance Fox ignition coil and Boysen race reeds?

yes a 260 is likely too small, stop running it before it fries !!!!!!
depending on elevation and current tempoeratures, FMF's usually require between 270 to 300 main jets.
the only way to know for sure is to start with the 300 and work down doing plug chops till correct............
http://www.blasterforum.com/threads/how-to-plug-chop.53237/

while you have the carb open to change jets, check/set your float level
http://www.blasterforum.com/threads/float-heights-and-how-to-adjust-them.50565/

needle in the middle clip position

and tune your airscrew like this
http://www.blasterforum.com/threads/adjusting-your-airscrew-pilot-jet.51060/
do not get that confused with some short version being called "idle speed adjustment"
that lacks the info about the airscrew turns revealing if your pilot is correct.
do it just as explained in the link above

 

[Kameron]

Thanks will do

 

[Kameron]

300 jet in bike and still no low end power. I have power once i get in top of gears thou

 

[dirtysquared]

300 jet in bike and still no low end power. I have power once i get in top of gears thou

Did you clean your carb well?? Take out all the jets and clean them, spray out all passages with carb cleaner, then blow out with compressed air?

Make sure you have the correct needle in the carb and that the clip Is in the 3rd slot.

 

[Kameron]

Carb is clean as all hell an I have never touched the needle.

 

[Larry's Shee]

300 jet in bike and still no low end power. I have power once i get in top of gears thou

Considering an FMF is more low end pipe you have something else going on.
What size are rear tires and what is your gearing?

 

[tbrooks]

I haven't been involved with Blasters very long, but a 260 seems pretty small for those mods. I have a 260 with only an FMF pipe, silencer and a UNI.

The only mods that matter for jetting are mods to airflow, like exhaust, air filter, air box lid. How the fuel is mixed also makes a difference though. According to the info given here, zspot, you should have a higher jet than Kameron! However temps and elevation also play a role in this, and there is no mention of the airbox lid being in place, modified, or removed.

 

[Kameron]

Airbox cover is on and I just put a 300 in it

 

[ZSPOT]

The only mods that matter for jetting are mods to airflow, like exhaust, air filter, air box lid. How the fuel is mixed also makes a difference though. According to the info given here, zspot, you should have a higher jet than Kameron! However temps and elevation also play a role in this, and there is no mention of the airbox lid being in place, modified, or removed.

Thanks for the heads up! After purchasing a few weeks ago, I'm still in the process of rebuilding almost everything to my liking and learning how the Blaster's tick. While working on the carb, I noticed the jet size, but haven't gone much further. Air box lid is on for now, and Kansas gets HOT AND HUMID in summer. LOL

 

[Kameron]

If my bike is running rich then carb needle needs to move up to adjust needle down right

 

[Blaaster]

Moving the clip up the needle leans the mixture.

Usually middle slot is ok for most applications!

 

[tbrooks]

Yes normally best in middle slot. I found at my elevation of 3400ft, with my fmf I had to move my clip down one slot to richen the mix. However there are 3 circuits to our carb and each can run rich independent of the other. There is the Idle circuit, needle circuit, and main circuit. Needle controls 1/4-3/4 throttle,main is 3/4 up, at what position is it giving you problems?

 

[Kameron]

Never adjusted the needle so whatever it is stock and the bike is running too rich

 

[Herpderplol]

Never adjusted the needle so whatever it is stock and the bike is running too rich

how do you know someone else never adjusted it?