air box cover jetting?

[outcrydrummer]

I have a pretty much all stock 02 blaster.

Has a fmf gold series sst pipe. the carb was rejetted by the shop that installed the exhaust for the previous owner.

I seem to be running a little rich. Not a ton rich but enough to fowl a plug every now and again. I'm running the same premix and oil that the previous owner was.......maybe a slight change in elevation or air quality???

But anyways I was just wondering how big of a jetting change it was for the air box removal?? If its not a huge jetting change I was going to run the blaster without it for a day with a brand new plug and see if that fixed the issue......and gain a free mod in the process

Thanks

 

[Surfrjag]

good thinking. it may work but would still be nice to know what jet is in there. i would at least check it first. guessing around 280-300 in a stock carb would be about right

 

[brandoz28]

do a plug chop with the lid on, and then go from there. sounds like its pretty rich as it is, grab a couple extra plugs, and do a couple chops

 

[Surfrjag]

or i was thinking you could start drilling holes in the lid until the plug chops are good.. little at a time i guess

 

[Awk08]

or i was thinking you could start drilling holes in the lid until the plug chops are good.. little at a time i guess

we do that on my buddies blaster, he used my old lid with 8- 1" holes drilled in it
but we only had a 300 main jet at the time, we used duct tape to cover the holes, then uncovered them 2 at a time until the plug chop read good,
there are still 2 holes covered
during the cooler months he re-taped 4 of them to richen the A/F mixture

easy jetting changes using only duct tape to control the airflow instead of tearing the stock carb off to change jets

 

[outcrydrummer]

Sound advice.... Thanks!!!!!

I may just hold off til next week to try it if its that much of a jetting change.
It's pretty dang rich...... I rode for about two hours on a fresh plug the other day and it was fouled. Straight black and still wet when pulled. It smokes a little on the heavy side as well......not crazy smoke just mix oil smoke. You can feel how rich it runs when you first start riding as well. 1st and 2nd don't want to do jack squad until its completely up to operating temps.

 

[Blaaster]

You did not mention what ratio, or oil you are running.

Stupid as it may sound, but if you add more oil the premix, you can lean out the mixture.

Changing from 32:1 to 25:1 leans it out about 1 jet size.

Although there is more oil in the mix, the AFR will be leaner and will burn hotter and the plug should not foul.

I run 25:1 bean oil, at a richer than optium AFR, and never one fouled plug.

 

[brandoz28]

You did not mention what ratio, or oil you are running.

Stupid as it may sound, but if you add more oil the premix, you can lean out the mixture.

Changing from 32:1 to 25:1 leans it out about 1 jet size.

Although there is more oil in the mix, the AFR will be leaner and will burn hotter and the plug should not foul.

I run 25:1 bean oil, at a richer than optium AFR, and never one fouled plug.

I've done it the opposite way, going to 40:1 when I didn't have a jet to go a little richer.

 

[dksix]

If you are going to hold off til next weekend, I have a lid that already has the 8 1" vent things in it (the foam is long gone), that I could send you to work with. $7 shipping should cover it, if you want it just let me know. I can send it out from work on Monday and you should have it in NC Wednesday or Thursday.

 

[outcrydrummer]

I'm running 32:1 Super M maxima oil with 93 octane fuel.

I went riding today and it didn't run right all day. Kept being real boggy and just snappy at all....just fealt real rich.

So at the end of the day I took of the airbox cover and it ran great. I'm letting the outside temps cool down a bit ( 103 here today ) and then I'm gonna do a plug chop on it and see what the deal is.

I couldn't hear any detonation and it took a lot of the smoke I had out of the equation. Hopefully its a good plug chop so I don't have to drill out a bunch of holes in my cover

Thanks for the offer on the cover but I'd just assume save you the hassle. I have a holesaw kit here at the house and a drill so its not a big deal.

Thanks guys

 

[outcrydrummer]

Hmmmmm

So I did my first ever plug chop. Warmed up the quad on a already used plug. Then put in a new plug, ran it down through the gears and then held it wide open in 5th for 5 seconds then killed it.

Cut the threads off and found no brown circle or discoloration at all.......br8es njk plug??? Any ideas???

Also I think it's actually running a lot better now. My first start after sitting for a while and running it rich was puffing out some serious smoke. Seems like it was clearing out everything left behind from before.....or now I have a different issue lol.

 

[Blaaster]

No ring, no ride, toooooo lean.

 

[outcrydrummer]

Yeah figured as much lol.

I got the airbox lid back on. Guess it's time to start drilling holes until I get it right lol.
under better light I did see some discoloration on the plug it just wasn't the coffee stain I was hoping for. Definitely was on the lean side.

Oh well..... back to the drawing board................... Too bad reading the plug on a 2 stroke isn't as easy as a 4 stroke lol.

 

[Awk08]

you'll be lucky to get any color in just 5 seconds,
try 20-30 seconds at wot, and see what she tells ya

 

[outcrydrummer]

Oh ok. I don't know if I have anywhere where I could run it at wot in 5th or 6th for that long.

If it was too lean wouldn't I hear some sort of detonation? Is there a way to tune them according to exhaust temps with a temp gun? I use to tune nitro rc cars and trucks by engine and exhaust temps. Seems like a 2 stroke dirt bike motor works on the same principles.

 

[dnoftz]

Got a ? what is this detonation sound? Sorry i know this is off the topic.

 

[outcrydrummer]

Got a ? what is this detonation sound? Sorry i know this is off the topic.

Detonation is what happens when you run to lean.......your cylinder temps are way up there and the fuel / air mix is exploding before its suppose to. Normally you can hear it through what sounds like a pinging coming from your head.

I did another plug chop and had a ring this time. A little lighter then what I want so to correct slightly I'm going from 32:1 mix to 38:1 mix. It wasn't so lean that it was white or chalky just like a light mocha colored ring. Sure runs a lot better though. Before it was so rich that you really couldn't do much with 1st thru 3rd.....would be boggy and wouldn't really open up.

Thanks for all the help guys. Once again, amazing site with amazing people. Rep to all

 

[Blaaster]

If it was too lean wouldn't I hear some sort of detonation?.

Mild detonation caused by a slightly lean mix, is very difficult, bordering to impossible to hear.

One size to small on the main, or the needle on a leaner clip setting, can create enough temperature increase in the combustion chamber to, slowly but surely, fry the piston crown.