did a plug chop... need advice

[indianablaster]

i have been trying to jet my blaster ever since i got my top end put pack together with the .080 bore and stock 26mm carb, fmf pipe, open air lid, k&n filter... anyway i did a plug chop with a 340 main in it and this is the result... looks lean to me, but i don't know... it was a new plug, and i was in 4th gear wot when i killed it and pulled the clutch in.... also after i looked at the plug and thought to myself "man, for a 340 main and my mods, the plug looks way too lean". so i got worried and i did a leakdown test and it held 7psi for like 20min so its not got an airleak... am i gonna need to buy jets in the 400 range to get the results im looking for? i basically tried to do lil3mils procedure and this is what i got, so please chime in... also, i found this place on ebay that sells jets individually for cheap, but i want to make sure that they are for my carb... they look the same as the ones i got from vitos, and they say the fit most vm carbs, which mine is a vm26ss... let me know what ya think Mikuni VM TM Main Jet Hex Jetting Tuning VM4/042/400 | eBay

all the photos are of the same plug

 

[blasterdad]

I the fourth pic you can see a nice light brown ring around the insulator, looks about right to me. You can richen it up if it makes ya feel better, I get jets from a marina in town for a dollar a piece... they are a pretty common jet, just bring one with ya to compare.

 

[2smoker85]

looks good to me, its a mocha color, if u want to richen it a smurf hair u can, but ur good on the jetting and for jets i use jets r us.

the light brown ring around the insulator tells u ur good on jetting

 

[Awk08]

i'd like it a little darker to cover cooler temp days/nights

 

[Blaner]

are you ported? 340 is pretty big if you not, but hey everyones motor is unique! how does it feel??

 

[indianablaster]

Thanks for the replys... the plug i had been riding on inbetween the jetting passes has always been pretty wet and rich, but i haven't really ripped on it too much since i was still trying to figure what the main should be... but i feel safe to go riding now... 80 degrees and sunny todayI:I

are you ported? 340 is pretty big if you not, but hey everyones motor is unique! how does it feel??

nope no portwork yet, and yes i thought 340 was pretty big, but everything lower than this did not have anything that resembled the color brown... all the lower #jet plug chops had color but it was more gray and the strap was faint if at all visible... she rips through the whole range, no bogging...

 

[jlsparky7]

Sure u have a stock needle in it?

Color looks good to me, when the temps drop a little id go up one or two sizes.

 

[indianablaster]

its the needle that came with the vitos jet kit

 

[Awk08]

is the tors/oil injection removed, and if so is the injection port on the carb plugged ??? is the cap tight with a rubber seal in it
i say this big of a jet is compensating for an airleak somewhere

 

[Whitty21]

is the tors/oil injection removed, and if so is the injection port on the carb plugged ??? is the cap tight with a rubber seal in it
i say this big of a jet is compensating for an airleak somewhere

my exact thoughts

 

[indianablaster]

k gonna sound stupid... wheres the injection port... i "ass"umed it had been plugged when the previous owner deleted the oil injection... yes carb cap is tight with a rubber seal...

 

[Awk08]

injection plug is high up on the carb body, on the kicker side, little nipple that sticks out, if it is already plugged, you'll see the old hose with a screw or sumthin plugging it, or a small vacuum cap avaiable at any auto store

edit...and nothing is stupid, not asking and frying sh*t is stupid

 

[indianablaster]

k well ye i just see a little brass nipple where you are talking about with nothing plugging it.... ok.... sooooo... have i just been ruining my new topend? it has been running fine, but i guess the main jet has been lean since i initially did the breakin.... haven't ran it at wot too much except for doing plug chops... also when i did a compression check a few weeks ago it was at about 127psi... thoughts?

also thanks awk... your a stand up guy

 

[indianablaster]

ok so i plugged the oil injection port on the carb, now it definitely idles smoother... i did another plug chop with a 340 main in it... there are two bands going around the insulator... is it the one on top or the bottom that i should be looking at, or both.... i still have trouble reading the plug chops, so let me know what you think...

 

[scotj77]

how long did you run at wot? it looks pretty close to me I wouldn't worry runnin at that color if your plug chop was done correctly

 

[Luni]

How does it feel? With todays gas with ethanol (E10) its sometimes harder to get a good reading on a plug chop, its more likely to LOOK lean than actually BE lean.

Does it feel really strong? I missed your modifications, but 340 main is ALOT of jet.

 

[Blaner]

im not sure you are running them long enough, there isnt much carbon to judge on. but its not oily. does it still pull cleanly or is it breaking up on top end?

 

[indianablaster]

i warmed it up, switched to a new plug, started it up and went down the road till i hit 5th gear, then i held it at wot for maybe 5-10 seconds and killed it with the clutch pulled in... should i hold it at wot longer, like maybe 30 seconds?

edit: yes it still pulls clean all the way, no breaking up at wot... but i agree a 340 main seems really big for my elevation, temp, and mods....

 

[Luni]

Again, how did it feel? You jet by sound and feel as much as by what your plug looks like.

If youre lean it sounds hollow and out of breath, it bogs and sometimes if youre too lean it will detonate and youll hear the pinging. If youre rich it sounds overly raspy and it smokes alot. When you try and go to the higher RPMs at WOT it will spit and sputter and not pull cleanly. Sometimes being a tad lean is just a flat spot in the RPM range. Sometimes you gotta just use the butt dyno. Run it at a given jet, then toss a fatter jet in, if it feels faster, toss a fatter jet in, till you feel it start to break up.

Do you have any idea what size pilot you have in there?

 

[Blaner]

the longer the better. i still think 340 is big, with my mods and my stock 26mm, i used a 330 and the banshee needle and it was a touch richer than ideal. i cant believe you would need a 340 on an unported motor.

i know you said you have done a leak test and that its good but how is the seal between the carb and the intake boot? im still gunning for an airleak here than you are compentsating for. you can test by having the bike idling and spraying carb cleaner around the intake fitting and all over the carb for that reason, if the revs pick up, its pulling air somewhere on or around the carb.