Hey guys I just replaced my carb,cleaned fuel tank replaced spark plug,new petcock,New air filter and my bike runs a lot better but it has like a miss and slight backfire.Any info would be greatly appreciated.thanks

What jets are in it?
Any other mods?
Cold start ok?
Idle normally?

The carb is brand new not sure what jet size.Hard starting in cold weather here in wyoming.idles a little rough kind of a slight sputter. I have not made any adjustments to the mixture screw.It is a 92 with supposed 540 original miles.Had a lot of rust in tank I cleaned it.

Stock jets no mods starts kinda hard about 40 degrees starts better warm.has like a little backfire at times or like a slight Pop when I shut it off.its not flooding not sure if float is to high? I want to check the valves got to get a feeler gauge. thanks

By brand new, do you mean never been used, or is it used and brand new to you? Did you set the idle after carb installation, and after warming up the bike? I assume your using choke when starting it cold. +1 on checking your valve clearance's.

I bought it brand new also new to me.I didn't do any adjustments.I use the choke. Getting ready to pull it back off today and remove the plug to set the screw I will post if I make any headway. I appreciate your feedback.

That being a new carb, I really doubt what you are experiencing is carb related. Outside of possibly maladjusted throttle or choke cables. Or idle setting. No harm in trying the pilot screw adjustment. Main thing is to just not crush it when closing it, before backing it out. Be sure to count the turns when closing it, just so you know where it was factory set. I think I would be looking in to other maintenance items. Like valve adjustments, cleaning the exhaust baffle etc.

When I purchased it the guy replaced the intake manifold I decided to check it this morning and he didn't replace the oring it is broken.Makes me angry he needed the money so bad that he didn't tell me he didn't replace it. I texted him and still no response.Does anyone know where I can just purchase the oring.Also I removed the brass plug and screw was set at 3/4 turn.Waiting to replace O ring before going further.Thanks for all your help. I will keep you posted.

The O-ring depends on the make of intake manifold that was installed. If it's a genuine Yamaha item, then you need the O-ring for that specific part. If it's a lower cost clone, then the O-ring for that particular clone will be required. In this situation Google is your best friend..

Best I can tell so far is it comes with carb kit the guy I bought it from got the part from a dealer so I will call them in the morning see if they just sell it.thank for everything.