A friend borrowed my bike an overcinched his panniers causing the exhaust pipe to bend in and burn a 1-2" dia hole in the airbox. He had some other problems on the trip and returned a limping bike back to me. Somehow we're still friends! He had though it might have overheated; had some problems making power at high load/rpm and subsequent starting issues

I got the bike back, double checked valve clearances and timing (I'd reset this in the past), put it all back together, and still reproducing sputtering at high rpm.

A) would a hole in the airbox be a possible culprit for that? should i replace the airbox?... I know additional airflow would lean it out, but I wouldn't think a max 2" hole would make it go from 'running alright' to 'limping'... I can't get it above about 30mph on a flat
B) if i replace it, how do i make sure i dont burn the new one up? Bend the exhaust pipes?

 

Just tape a piece of hard plastic over the hole and giv-er-a-go!
IMO, yes.

 

Fix the hole, create proper clearance on the midpipe, then you can start working on the problem.

I know you say his panniers caused the problem, and I'm sure it did - But for the record, especially on our KLX's, slapping on a slipon, and allowing its' midpipe to burn a hole in your airbox is caused by a malfunction between your ears. Check and fix clearances, or pay the price.

You only "bend pipes" after a complete loosening and repositioning of the entire exhaust system (including bending mounting tabs) proves ineffective or not effective enough. I had to bend my PC4 to get that last bit of "mo clearance".

 

I'm thinking that also a tip over or two pushed the panniers, pipe, etc. toward the airbox allowing the pipe to burn the hole. I think it sounds like your friend has more to his story than he's letting on.

 

Once you've exhausted your capabilities, perhaps your friend will take your bike to the dealership for parts replacements and repairs ?

 

I straightened up the exhaust pipes, taped the hole in the airbox, took a quick look at carb/bowl/jets, replaced the plug, and its still unhappy:
I'll check compression next i guess

My dude is a good friend and said 'whatever it takes to make it right i'll cover'. He was on a ride with a group, having trouble keeping up and nervous in traffic, etc, so he doesn't totally remember chain of events other than overcinching the panniers....

 

IMO, you have a problem with the carb.

 

Would he have remembered submerging it in water ?

Looks like you are about to become a "CVK Guy"- total dismantle (don't loose the needle jet !) , total blast cleaning, reassemble, bench check, test run....

Or you can fool around, over and over, with it until you finally decide to do the above, thus becoming a "CVK Guy" ..

Sorry for the attitude.. You could always take it to the dealership.