Ongoing top end issue...

[02Bansheeee]

For the last few months I've been having issues with getting full power out of the 3/4 to WOT range. It begins to sputter as if it is lean. Last weekend I did a leakdown, and had a airleak between the cases. I sealed that up and replaced the seals while I was there. Got bike all back together, did a leak down, 100% sealed up.. 6lbs for 6 minutes (didn't drop a bit). Took it for a ride and it was doing the same thing. I'm at roughly 600ft elevation, and the temperature here is around 75-90°f. It currently has 32.5 pilots, needle in the middle position, and 330 mains. Did a plug chop and the plugs were completely white as if NO fuel was getting there ( I had 310's in at the time)... not much better with the 330's. so I swapped carbs with someone else with 27.5 pilots, needles in middle position, and 300 mains and I had a verrry light brown reading on the plug... best I had gotten so far. So I swapped in my 330 mains into those carbs and once again it was back to white.. I'm frustrated and stumped. So far I have adjusted my float level to the proper setting, checkedy carbs for cleanliness, looked at reeds for cracks or gaps through the intake ( looked tight with little wear ), replaced crank seals, and I will be putting some huge jets in tomorrow or Thursday to see if that gives me a reading... does anyone have any advice on what the hell could be going on?? I'm fairly stumped. Modifications I have are factory air box without lid and a K&N, stock carbs with stock tors (unhooked), pro design intake ( ditched the boost bottle though because it went through grommets every week), stock stroke crank, 64.75 cylinders, stock head, 115 psi compression, Toomey T5's. 

[bigweav81]

Have you tried a 280-290 main? Cleaned carbs really well? I've seen electrical components cause a break up rpm as well.

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[02Bansheeee]

Thanks for the reply, but no I haven't. I believe the problem is a lean issue so I haven't backed down on jetting, only up. I have cleaned carbs well. I have thought about swapping coils but still wouldn't my plug be wet if an electrical issue was present?

[trickedcarbine]

Timing?

[trickedcarbine]

Better yet, what's the full motor set up? What fuel/oil and mix ratio? Timing? Water pump is in good shape and the motor isn't overheating?

[02Bansheeee]

Funny that you ask about overheating... the last ride I took it on to try to test the jets I noticed a little bit of coolant on the swingarm coming from the hose on the overflow bottle. I also noticed a faint smell of coolant, I'll go check the coolant in a few minutes. But I ordered a chariot billet impeller today because of what I noticed, I'm 100% positive it's a stock impeller in the water pump but not sure of the condition. Dumb question, but could that cause my issue? I have a stock woodruff key and flywheel, mix 32:1 with yamalube 2R, and full engine is 64.75 bore and pistons, 115psi compression last time I checked, stock stroke aftermarket crank (not sure of brand, bought it with it in it), stock head, Toomey T5, boyseen reeds, pro design intake with boost bottle eliminated, stock carbs, airbox w/o lid and k&n. Thanks for the reply!

[trickedcarbine]

Verify it's cooling. You've thrown enough fuel at it. 

[02Bansheeee]

Will do, I will get back once I find something out

[02Bansheeee]

My billet impeller should be in today but I have figured out the issue. Ended up being the ignition coil. I swapped with another quad and it ran perfect