rebuild/jetting question?

NJblaster94

New Member
Jan 12, 2012
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NJ
I just rebuilt my 04 blaster top and bottom end.. it had a stock top end so i went with a vitos forged super stock piston that requires jettiing, besides the piston it also has a fmf fatty and powercore, with vforce3 reeds, and open air box....... my question is should i heat cycle the quad to break it in, then jet the carb?? or should try and jet the carb while heat cycling it??
 
#270 - #280 main jet, I would plumb for the #280, needle in the middle slot. Far better safe than sorry!

Make sure that the float level is correct and the idle is ajusted, you can do this on the first of the 3 - 5 heat cycles.

Then take it no more than 3/4 throttle for 2 tanks of gas.

If at any time you get a lean bog, stop and increase the main one size.

If it babbles and burbles and fouls a plug, decrease the main jet.
 
Im having some problems trying to get mine running also. I rebuilt the top end and have bored it to 68mm and running wisco piston, vito's reeds, stock air box and fmf fatty pipe and powercore 2 silencer. need base line of what jets to run?
 
Im having some problems trying to get mine running also. I rebuilt the top end and have bored it to 68mm and running wisco piston, vito's reeds, stock air box and fmf fatty pipe and powercore 2 silencer. need base line of what jets to run?

Firstly do a leak down test, a must for a fresh rebuild.

The Fatty calls for a #260 main

#260 - #270 main jet, I would plumb for the #270, needle in the middle slot.

Premix at 32:1 add one size bigger main.

Make sure that the float level is correct and the idle is ajusted, you can do this on the first of the 3 - 5 heat cycles.

Then take it no more than 3/4 throttle for 2 tanks of gas.

If at any time you get a lean bog, stop and increase the main one size.

If it babbles and burbles and fouls a plug, decrease the main jet.
 
Altitude is just as important a factor as modifications, my friend. What may be "just right" at sea level could be too rich at 3,000 feet. And what's "just right" at 6,000 feet would be disastrously lean at sea level.
 
hey just leetting everyone know that i tore into the carb that was already jetted for the quad when i got it and it had a 370 main and ran perfect , so i might move up to a 400 if its to lean.
 
Altitude is just as important a factor as modifications, my friend. What may be "just right" at sea level could be too rich at 3,000 feet. And what's "just right" at 6,000 feet would be disastrously lean at sea level.

Unless user stated, all recommdations I offer are based on sea level elevation as are many recommendations from other members.

hey just leetting everyone know that i tore into the carb that was already jetted for the quad when i got it and it had a 370 main and ran perfect , so i might move up to a 400 if its to lean.

Sounds like a major air leak to me.

If you need a #400 main jet you better make sure you are underwater in the Pacific trench.
 
when i ride the quad this weekend ill do plug chop and post the pic... but i did my heat cycles last weekend and ran a couple tanks of gas through it its doesnt bog at all, and has a wicked powerband.