My plugs look lean

[indy_500]

It's a 99 XC 700. Stock jetting is 190 mag and 185 pto and i'm running 190 on both sides. They don't look super scary lean but a lot leaner then i'd like. When i let off the throttle, it kinda makes a puffing sound (almost like a super mini-backfire, this sound is really hard to explain). But, when taking off it's not boggy and everything runs fine basically. It idles at 2500 but if i let it idle for a minute or 2 it will go down to 1800. Is my air screw turned up slightly too much? I only got over half throttle once today and put on 35 miles, it was 10-15 degrees out also. Pics coming in a bit. There is no visible air leaks but on my air box by this rubber pull tab, it's splitting the upper part of the box from the lower, my dad's is the same way but his plugs look perfect. The Pto side is actually looking leaner despite the richer jetting. The pics i took i believe are pretty close to the same color (i don't think the flash affected it too much) The left side is the pto and the right side is the mag in the picture. Could the fuel pump affect this or the reeds? the carbs are CLEAN believe me, could i have accidentally adjusted something?

 

[snootbiscuit]

only look at the white porcelin part of plug, should be chocolate brown or tan for ideal burn. i doubt if that crack would matter much. were your carbs ever dirty? are you running iso? are you runnin ethynol?

 

[harvest1121]

Sea and Snow cures all

 

[indy_500]

only look at the white porcelin part of plug, should be chocolate brown or tan for ideal burn. i doubt if that crack would matter much. were your carbs ever dirty? are you running iso? are you runnin ethynol?

I am running a little bit of sea foam and a little bit of oil (not running either in my dad's sled, could it really have leaned it out that much?) What exactly do you mean porcelin part of the plug? The white thing under the "tip"? one side of the porcelin part looks black and the other is almost white. I am running NGK BR9ES and the sled calls for champion rn3c or something like that

 

[indy_500]

any more opinions? should the plugs look richer?

 

[mjkaliszak]

Indy looks too lean to me. I kind of like " fat ". When running seafoam it will decarberize . ( JIMO ) I would get my hands on the manual and start with the stock set up, mains, pilots, screw turns, needle position everything.THEN... Get some fresh plugs, good gas no additives, run the sled around a little, find a straight, haul arse, get close to your garage or checkpoint , hit the kill switch, and coast in letting all the fuel burn up in the cylinders as you coast to a stop. Then pull the plugs and check color. Their are actually plug charts with pictures for comparison from the manufacturers ( Google it ). That' how I was taught by a couple of T-cat performance guru's back 17 yrs ago. These guy's had 2k clutch set-ups and used to run the lakes. Also had about 20 years on me back then. I may be a little off on my technique, BUT I believe that is a good place to start .
I'm no POO off-ic-ian-oto so most of what I have learned is from lumps on the head, and busted knuckles.

 

[mjkaliszak]

I do mean everything... plug gap, oil pump alignment , ect.... leaking exhaust, good springs to the can, leave no stone unturned .... If you want to go down the " performance " road. With my old T-cat, I used to dremmel slots in the pipe & can spring mounts and double up on the springs. Just some dumb old tips I picked up on along the road to the school of hard knocks. I'm done rambling now.....

 

[indy_500]

I do mean everything... plug gap, oil pump alignment , ect.... leaking exhaust, good springs to the can, leave no stone unturned .... If you want to go down the " performance " road. With my old T-cat, I used to dremmel slots in the pipe & can spring mounts and double up on the springs. Just some dumb old tips I picked up on along the road to the school of hard knocks. I'm done rambling now.....

the springs do look bad (i put hi temp silicone beads on all the springs so they don't vibrate) i replaced the exhaust gaskets and took the ypipe off once more after replacing so maybe it didnt seal? i put hi temp silicone in all the joints, maybe the grafoil seal is bad? the huff-puff sound it makes letting off the throttle sound slike exhaust problem. I'm not very experienced with the oil pump so i'm kind of afraid of going there. I also don't know how to adjust needle position. Could i possibly need to turn down the air scew?

like i said, i jetted richer, shouldn't it look a lot more richer? i have about 75 miles on the plugs. What about fuel pump?

 

[srt20]

nevermind edited post.

 

[indy_500]

Are those plugs brand new??

brand new 75 miles ago

 

[srt20]

I'll tell you my opinion, I dont think those are lean at all. The plugs are new. They have good dark patches on em. Hard to tell but doesnt look like any blistering. I personally wouldnt mess with it at all. Unless you plan on riding in -30* F. My IQ plugs have more color all the way around, but they are older plugs. But the color isnt as dark as the patches on yours.

Also you need to look down into where the porcelean meets the body of the plug. Any specks? White? If not your fine. Im willing to bet its dark and wet in there.

You said you were over half throttle once, right? You werent even touching the main jets at less than half throttle. You cant judge your main jets by how you were riding. You check main jets by WOT runs, like the other guy said. Also most sleds are leaner in low-mid throttle than in WOT. Less heat, less cylinder pressure=less burndown.

 

[indy_500]

I'll tell you my opinion, I dont think those are lean at all. The plugs are new. They have good dark patches on em. Hard to tell but doesnt look like any blistering. I personally wouldnt mess with it at all. Unless you plan on riding in -30* F. My IQ plugs have more color all the way around, but they are older plugs. But the color isnt as dark as the patches on yours.

Also you need to look down into where the porcelean meets the body of the plug. Any specks? White? If not your fine. Im willing to bet its dark and wet in there.

You said you were over half throttle once, right? You werent even touching the main jets at less than half throttle. You cant judge your main jets by how you were riding. You check main jets by WOT runs, like the other guy said. Also most sleds are leaner in low-mid throttle than in WOT. Less heat, less cylinder pressure=less burndown.

last part there really made sense. I really do not need a sled this big (lol, seriously) i was just ditchbangin, i only went WOT once and that's when me and a few buds raced in deep pow, i guess i probably went over half throttle, but only WOT once, or at least close to WOT once. Just a lot of dinking around in some yards and and "ok to me" pow today for 35 miles. I can't get WOT in my yard so i guess that's a problem

 

[szotty]

you could try to move the needle a half notch with a small washer or buy new needles i had to do that almost daily on my race bikes to get the plugs right where i wanted them if i were u do that and if dont know how look it up very easy to espically on sleds compaired to motocross bikes same with my old 440 xcf so it ran tip top only takes few mins

 

[indy_500]

i figured out how to adjust the needles, i still don't understand why they would've been messed with anyways. Could it have moved itself althought the needle is notched?

 

[szotty]

NO there are clips in the needle to hold it only way it moved was by adjusting . air temp altitude wet/ dry weather/ pressure can make a a difference thats why there trying to move almost everything to efi to help with the constant adjustments needed to run at perfect performance, remember set up great for 10 degrees it will be off alitte at -30 and 40 not one set up for perfection in all just a round about

 

[snowbuff]

Indy - IF you have flat slide carbs in it, you should have a fuel screw AND an air screw. The fuel screw is the one with the thumb wheel. Turn that one out 1/4 turn and that will help with your idle comming down quicker.

If you don't have flatslides ... NEVERMIND!!!

Also, Like srt said, don't worry about your mains. You haven't used them yet.

 

[wishbone]

Is this kehnin carbs or Mikuni? If your mikuni and under 200 on mains for a 700 twin I think theres a mistake. My 600 twins I'm runnin 400 mains, 420 stock. Ditto the plug check with that little run time and no WOT.

 

[snootbiscuit]

I could not see pics till now. looks like a good burn to me! they dont look lean! again, only look at white porcelin part of plug in the center, dont bother reading any other part of plug!!

 

[mjkaliszak]

Let me clarify. The burn looks un-even. A lot of white porcelin on the 1 plug. This could be due to SF, since it is a decarbonizer. Just saying. Maybe it's the pics , yes the 1 plug has a decent look to it. Maybe it's my eyes, maybe it's I'm full of shatt. Sorry if I'm confusing. I like coffee brown , even burn, a little fatter the better in my book.

 

[doomsman]

Are you still losing anti freeze? That will clean a plug.
Also here is a good chart'

http://www.dansmc.com/spark_plugs/spark_plugs_catalog.html