jetting need help

elitz14

New Member
Aug 1, 2011
17
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ireland
hi i have a 200cc yamaha blaster with a full factory 7 exhaust, standard airbox without lid, standard carb and need to know what size jet i need?? tanks
 
We cant tell you what jets to run, because every bike is different, but we can throw you a ballpark of jets you may need, id say from 280-320 and you may o may not need to change you pilot jet. Always start from the rich jet and go down from there.
 
Im running some dynojets main jet and needle, and a 37 mikuni pilot jet. My main jets are difernet number from yours. But id say im around that 280-320 range i told ya. How is it running right now? did you check the plug?
 
theres alot of factors, other than our suggestions, that will determine what main jet you need, the stock pilot and needle clip in the middle will be fine

elevation and air temps, along with mods help determine what main is needed
i have ran a similar setup in the past, and would start somewhere around a 330 main and work down, doing plug chops with each different size, your plug chop reading will tell you, and is the only safe way, which main is needed
it's prolly gonna end up at a 300+
so maybe buy a 330/320/310/300

heres some reading to help you understand..................

http://www.blasterforum.com/do-yourself-20/jetting-101-everything-explained-1625/

http://www.blasterforum.com/do-yourself-20/how-plug-chop-38674/
 
i moved the needle to the middle clip sounds alright and 320 main jet the plug is brownish

just looking at the plug after riding it does not tell anything, as all 3 jetting circuts are adding to the color of the plug, you could be way lean on the main, but as you slowly 1/4 throttle it into the garage, or leave it sit and idle, the pilot and needle circuts will add color to the plug
you need to do a proper "plug chop"
new plug, wide open into 6th gear, pull plug and read the "smoke ring" down inside the threads, < either cut them off, or use a flashlight/magnifying glass to look down inside
read, re-read, re-read again if needed the plug chop link above
 
I would assume 320 would be rich but why are you asking about jetting? Is it running badly? all of awks advice is good advice and the proper way to dial in your jetting.