Jetting prob i hope

Zwiser

Member
May 25, 2010
1,510
16
80
Harrisburg,PA
Ok so i bought my 2003 blaster about 1.5 months ago it has a v2 reed cage with boyson power reeds in it, reed spacer, toomey b1, uni filter lid off, vitos super stock standerd piston, vitos degree key, and thats all that was in the bag of spare parts,reciepts,and manuels he gave me with it along with a bunch of main jets labled, 230, 240, 290, 300, and a few other carb jets and needles so im guessing theres a 280 or 310 in there but i dont know. and when i bought the bike it was like 60-70 degrees out and medium humdity and it run golden didnt smoke that much and ran great but now i can start it up in 1 or 2 kicks when the motors cold but it doesnt idle for anything and smokes bad but not like it needs new crank seals and when i go to ride it somtimes it will let me but most times it just bogs down and shuts off and when i do ride it has NO power. i just changed the spark plug and cleaned the carb and when the motors warmed up it takes like 10-20 kicks to start then it just dies so my ? is it jetting or somthing else and if it is jetting plz tell me how to adjust it so it will run right BTW the temp is 90-98 and high humdity and the tors are still on and the parking brake is gone but im not sure if its disconnected and oil injection is still there but im getting rid of it soon and it seems to be workin right because its takin oil from the container sorry if i confused u wth any unnessary info
 
What did the plug look like? I'm not an expert by no means and i'm learning as i go too, had somewhat similar issue and found i needed to drop my main down, plug was jet black. I just went down to the next size and will try it and do another plug inspection, But the plug electrode should be golden brown, if it's lighter ya move up if darker go down I'd only go down one size at a time, so ya don't lean it out and burn it up.
 
the new plug has 15 mins on it and its looks new but the part on the bottom is a little black but the old plug was black all around
 
Ok I would think you are a little rich. Try stepping down to the next jet size and and do another plug chop test-http://www.blasterforum.com/engine-13/spark-plug-chop-20247/

Have ya ever done a leakdown test on the top end? had it apart lately? if so ya should do that leakdown test. It will save ya jetting headaches as well as blowin it up if the leak is bad enough. Holeshotman sell the tool to do it and it well worth the $30.

http://www.blasterforum.com/do-yourself-20/build-use-leakdown-tester-10663/
 
Unfortunetly you can't really check jetting by running a plug and looking at it, because when you idle the bike to warm it up it could give it a false reading, that is why it says to use an old plug to warm the bike up, and then use a new one to do the test, and put the old one back in to get home. Otherwise riding the bike in the mid and low end ,where the jetting could be right or rich, will throw off the purpose of the chop, to check that you are right/rich in the top end, and not lean.
 
Kinda sounds like your idle jetting might be rich. How many turns out is the airscrew? It's not a bad idea to plug chops at 1/4, 1/2, WOT. This will tell you which areas are lean, ok, or rich. and that is the area you need to adjust. It's possible to run rich off bottom, ok in the middle rpms, and lean at WOT. Or vice versa.
 
Kinda sounds like your idle jetting might be rich. How many turns out is the airscrew? It's not a bad idea to plug chops at 1/4, 1/2, WOT. This will tell you which areas are lean, ok, or rich. and that is the area you need to adjust. It's possible to run rich off bottom, ok in the middle rpms, and lean at WOT. Or vice versa.


this is a good idea, but it is harder to judge 1/4, 1/2 throttle, that is why chops are most commonly done at WOT becuase that is consistent, not saying its not possible but much harder to get right, as any variance could give a false reading.
 
Throttle positions, 1/4 throttle is effected mostly by the idle jet, which is tuned by the airscrew. 1/2 throttle is effected by the needle hight. WOT (wide open throttle) is only restricted by the size of the main jet. All of these over lap onto the other as the throttle is opened up. Hope this has enlighten you. That's how we learn.
 
this is a good idea, but it is harder to judge 1/4, 1/2 throttle, that is why chops are most commonly done at WOT becuase that is consistent, not saying its not possible but much harder to get right, as any variance could give a false reading.

True it's not easy to judge were the throttle is. taping t wire to the thumb lever that sticks up and clears the housing like a flag pole and marks on tape on the cover would help be more percise.;)
 
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ok so i put the 300 and 290 jet in today it still smoked but the 300 idled for a little and ran ok but the 290 was worse and didnt idle btw the 310 that was in there didnt idle eather
 
question do you have to keep pressure on the thumb to keep it running, but the instant you let off it dies? even if you rehit the thumb. than you might wanna losen the throttle cable a little on the thumb throttle. opening the cover will show you what I mean, cause if the lever is pulled against the switch then the TORS is getting a mixed signal.
But if that's not the case then you need to adjust the screw on the TORS under your seat out just a bit so the idle is faster, and you may have to adjust the airscrew in or out depending if the revs hang or drop, out if it drops like a rock, in if it hangs. but you air screw should be in no farther than 1/2 turn from bottom or out more than 2 3/4 turns from bottom. and don't tighten it at bottom this will screw up the air screw. hope this helps you out.
 
yea i had to keep pressure on the 310 but i put the 300 in and turned the screw on the tors up and it idlse fine but when i go to ride it ill get like 15 ft then it bogs down and dies
 
Keep a notes of what changes you do ( one at a time) note changes from what's different with each change you do. if you change more than one thing at a time it becomes confusing what did what change. do it long enough you can look at your notes and change it depending on weather and be right in were you want it to be. unfortunantly this does take time. make notes of temp and humidity with your changes. I had a blaster that I was dumbfounded with tuning, but got closer every time. had to pump throttle to hit the powerband. But would beat the other blaster off the line.
the main jet should have no effect at idle thou, only the idle jet and air screw should. at about 1/8 throttle the needle plays in till about 3/4 to almost WOT then its just the main as it's hole is the restrictive factor for fuel.