Help with an 08 Raptor 350

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Roman84

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Hi, I bought a raptor 350 a few days ago, It bogs down, sputters and backfires through carburator.
It came with a chinese carb, and the bike had that issue so I opted to mount the original carburetor in it.
The following is what I have tried:

1) Completely dissasembled and cleaned the mikuni carb, replaced the needle valve set and float, needle set, adjusted float level to the right height per manual, pulled out and cleaned all the nozzles and jets and put new o-rings, springs and seals.
Current Setup:
Jet Main: 142.5
Air: 70
Jet: 165
Pilot: 22.5
2) Calibrated intake and exhaust valves per manual
3) Took care of leak on the exhaust (Read online that this could cause it, sounded odd but fixed it anyways)
4) Timing chain marks are lined up, when on TDC, crankshaft T lined up with casing mark, and camshaft sprocket line with the head casing mark.
( the camshaft mark is lined up but when the tensioner pushes in always turnes the camshaft sprocket line slightly of center clockwise) I tried moving the sprocket on chain to see if I could get it to line up perfectly but that is the closest position, so it’s like 1/16” off from the casing mark on the head) maybe the chain is stretched?
5) Read about the Parking brake switch and the reverse switch infamous problems.
The previous owner seems to have removed the parking brake, the only connector by the left head light is the one coming from the clutch, there is no open connectors where it should’ve been for the parking brake.
The reverse switch I tried grounding it but it makes no difference, the bike still sputters and backfires through carb.
6) Compression on motor is good and everything looks stock.

Getting ready to pull the head out to check the intake valve to make sure it’s sealing properly, but wanted to ask, maybe someone has any other ideas on what to try before I do this.

I have just worked on automotive weber and dellorto carbs so the problem sounded alot like carburetor issues but I can’t find what else could be wrong with it, everything seems good.
Any help is appreciated!

Thank you,

Roman

(A link for the video as I can’t open it on the site)
https://youtube.com/shorts/D7iWMJ5W7us?feature=share
 

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