I know mods have been talked to death but this may be a bit different.

2009 bike at 2,000 ft above sea level. I ride to 4,500.
I removed the air valve thing and plugged the ports.
KDX200 snorkel
Factory filter, oiled w/filter oil, it was almost dry from the dealer
125 main
38 pilot
N1TC clip in 2nd slot from top.
7/64" drill to slide
Kouba T screw set at 1.5 I did the turn to turn and set in the middle method
Idle at about 1,400
Smoothed up the weld on the headpipe
13t front
The bike ran SLIGHTLY better than stock. It had quicker throttle response and reved up to about 9k rpm in 5th gear on the highway where it struggled to reach 8k stock. Plug, black on the edge of the threads and white/tan on the electrode. The exhaust seemed a little warmer than usual on a 40 mile test run through FS roads and highway. I was dissapointed that I had to use a bit of throttle to start the bike after it was hot.
Now, I took the stock exhaust can apart at the rear. I found that the 1/2" hole in the first plate idea is a bunch of crap! Yeah it may help but You'd never notice it. That baffle plate has slots cut in it and there opened up to resemble fan blades. There's already lots more open than the little tailpipe opening. The only thing the 1/2" hole in the center may do is make a direct path to the tailpipe and maybe increase the sound slightly THUS increasing POWER right!! I opened up the slots a little more and drilled a hole in the center of that baffle. I then removed the little tailpipe and welded in a 1" pipe. The pipe is attached to the end cap and the first baffle inside. I think this baffle acts like a damper for sound or perhaps vibration. It sure doesn't effect flow. I think the flow is mostly blocked deeper in by the baffle with fiber around it. It can be opened up a touch without harming it's purpose.
I ended up with a nice exhaust tone. Very much like the factory sound only a bit louder.
OK. After a test run today, my headpipe is really getting hot. Not glowing but blue. The bike revs a bit higher and will redline in neutral where it wouldn't go passed 8.5k before the mods. It still needs some throttle to start when hot.
WHY is the headpipe so hot? Can opening up the exhaust cause a leaner condition? Think I'm to lean? Will the third slot be enough? Why the starting issue? I've thought about a Twin Air filter. How would this facter in?
Well, I still need to hit some power robbing hills but so far the difference in power from stock is only slightly noticable. I know a true aftermarket exhaust would show more improvement but I don't want to trade the sound increase even from a Q4 for it, esp. at $300.
On a possitive note, I went in to tell my wife I was going to test ride again. I was really suprised when she asked if I'd ride her down the driveway! I ended up riding her several times. She'd never shown interest before. She admitted that she may ride on the FS roads but not the highway. I think I just need to suprise her with a bike. Anyone got a used TW200 for her!

 

FWIW, those fan blade things are your spark arrester, Krizman style. Drilling a hole in the middle defeats the spark arrester and won't pass the forest service stick test. Maybe not a concern but just saying...

Your head pipe shouldn't be running too hot unless the air inj isn't blocked off upon removal. Cap the air pipe or plug the hose that feeds it.

Your having to start with throttle, was that at 4500' ? I find the N1TC needle too rich up high unless I drop it to 1, it gets all blubbery off the bottom. At sealevel it likes clip 3. Probably why someone came up with 2 as the standard?

125 main was lean at wfo on my bike, I ended up with 132.

 

I did plug the air inj. and rechecked it.
Throttle to start is at 2,000ft.
Is going to the third notch the same as a larger main jet?

 

Why do you think the pipe is running too hot? I've never seen a spec for how hot a head pipe should run. Anyone else know of one?

If the plug reading is good, the bike runs good, there is no problem. It's a single wall pipe right up by your leg, it's gonna be hot. Expect it. Until I got my exhaust coated by JetHot the radiant heat could almost burn my leg in shorts or jeans - yes, I do ride in shorts at times and it could make my leg red. After the coating job more heat is held in - a good thing for exhaust gas speeds - and it is noticably less "burning" although still noticable radiated heat is there. It is carrying exhaust up to over 1000 degrees away, what would I expect.

There is no comparison to street bikes since most run double wall tubing or at least exhaust shields.

 

Before any mods the pipe was not nearly as hot.
Would you think the kdx snorkel and 125 main would be leaner than stock?

 

what were the mods then?

 

My main concern is the hot headpipe and having to give it throttle on a restart. I can see where moving the clip will help with restart. I'm also wondering about float height.

 

Sorry Punkenduro, the bike had a Big Gun pipe with quiet insert, KDX snorkle, aftermarket filter here's a 128 main and bigger PJ run. Looks super but got the bike running better with a 300 exh system (ebay end cap) and going up to a 132 and back down to a stock 35 PJ. Sorry no graph on the last mods. I believe the large headpipe diameter of the big gun made it go lean at low rpm when the throttle was wacked on the dyno, why the 40 looked better.

 

Barely ran better than stock?

You can see my mods in my signature, my bike was a completely different bike after the mods.

I don't know much about the headpipe heat problem, but my bike has the same "give it a little throttle to start" problem since the mods. I have like 300 miles on it and it runs great other than that. I think it has to do with the big snorkel.

 

I have more or less the same setup as BigSky, when the bike was new I noticed the radiant heat from the head pipe was more than any other bike I've ever ridden, searing hot. I've never seen a pipe turn so many pretty colors so quickly, blue, then purple, then a sort of coppery color. I ended up wrapping it with ceramic tape, mostly to keep from burning down the forest if I rode through tall dry grass, or dropped it in pine needles. Helps with the percieved heat as well.