KZ440 bogs on hard acceleration and full throttle

Hi there!

Posting this in the engine section because I think this is somehow related to air/fuel just not sure if it is actually a carb issue or exhaust issue.

I've got a new to me KZ440 that does NOT have the original airbox but I made a custom airbox like in this post: www.kzrider.com/forum/3-carburetor/59956...om-air-box-for-kz440 which worked great until recently when I took the bike apart for painting. Since I've put it back together it doesn't run as well as it did before (ran great even with the new airbox).

While the bike was apart I noticed the exhaust kinda felt/sounded like there was a pipe banging around in there disconnected, wasn't sure if that was going to be an issue. I also noticed two holes in the crossmember pipe and I patched those up.

When I first put the bike back together it seemed to run fine but I noticed a knock when accelerating in too low a gear and exhaust leaking from the flange. I read that the knock is probably from leaky exhaust and I tightened everything up. I'm not 100% if this is when the problem started, but it kinda seems like it.

Stuff I've done to try to address the issue:
- Replaced the plugs. Old plugs had right cylinder beige good looking plug and black sooty plug on left cylinder.
- Checked spark. Looks nice and white to me
- Checked coil. All readings OK
- Checked timing and timing advance, both seemed spot on
- Cleaned carb. Pine Sol dip, fine brush through all the holes, rinse and blown with air gun. Rubber diaphragms look great, everything looks clean.
- Checked for carb air leak. Sprayed wd40 around boots between engine and carb, no throttle increase. Plugged vacuum line to tank and ran on Pri, still had issue
- Tinkered with mixture screw, currently set at 1.5 turns out, have played with it between 1 and 5 turns in 1/2 turn increments and while there is some change in overall performance, all settings still have the "bog down"
- Checked float levels. Both bowls are about 1-3mm below the seam between the bowl and the carb body using the clear tube test.
- Checked carb sync with U tube manometer, they are synced
- Tried to shim the pin. Made the bog down worse
- Tried to restrict air flow through the air filter. Made the bog down worse.

I've read lots of stuff about pods on KZ440s being finicky but not so much about people who've put the custom airbox on. Those people seem to have no real issues. And I had the custom airbox on for a long while before disassembling the bike and it seemed to run fine (albeit I was not really impressed with the power).

Any ideas? How do I test the exhaust to see if it's clogged or blocking airflow? I put my hand in the way and it seems fine when idling. It is pretty old and rusted so can I just go ahead and clean out the insides and turn them into straight pipes?

Take the exhaust off and point them to any particular recalcitrant neighbor silly

Just the mufflers that is, never can be too clear can we?

2 or 3 am I highly recommend

Thansk for the quick reply! Can you take "just the mufflers" off with these bikes? It looks like the whole exhaust is one solid piece...

Haha, I know that you are jazzing me and that's okay because I'll give it right back. You go through a long drawn out dissertation off utter bs and expect me to take it seriously.

If I didn't know any better I would think this KZQ

I mean sheeit, I was born at night but not last night

Well I listed all the shit I did because I didn't want to waste anyone's time telling me to "clean the carbs" or "check the spark". This is my first bike and it was an honest question.

How'd you know that they'd ask that. I don't do emojis sorry

Did you possibly waste a bit of your time getting a manual and seeing if you actually didn't need any help at all or was this the lesser of all effort.

Be honest, it's okay, I don't judge, just curious, that's all

Reason i ask is simply because i think i can achieve anything as long as i have good honest information.

What precludes you from obtaining a manual when most likely you can download it for free?