Exhust if i take the baffles out of some after market pipes will it hurt the motor on a 98 650 yamaha v star like the back pressure the pipes are cobra stright pipes

cutting or drilling can cause motor damage as this will lower back pressure change the pipes also will need to re jet carb best to ask dealer what else you may need to do or the manufacturer of the pipes will have info on your bike

You need to have the timing checked.

Not at all Patrick. Just keep in mind that you do want
some back pressure and not all out "straight pipes" of
course....so start small. I'd say roughly 3/8".
And since I don't know the length of your baffle, I can't say
how many to drill.-but I have done this for a friend that was in need of help and I created my own baffle for him and it turned out great.

But in your case ,-Hypothetically speaking Let's say the baffle was
12" long...I would drill 3/8" holes, straight through and alternate
meaning sideways...then the next straight down. And I would drill every 3 inches.

I'm Guessing your looking for a 'lil more power and performance
and if you do it right, you can also increase the fuel mileage.
Please let me know how everything turns out, and on top of that,
Don't be afraid to first Build an exact copy of your baffle so
you can interchange " creations " till you get what you're looking
for.
Remember...the more exhaust that can escape the cylinder,
will help Pull more air and fuel into the cylinder.

No it won't hurt anything as long as your pipes are long enough. If they're way too short, you'll burn your exhaust valves up. As long as the pipes reach at least the front of the rear wheel, you should be fine running it straight piped. It'll make her sound good too. You'll be pleased with the sound change

The backfire is normal, the only cure is to put the baffles back in.

baffles are on a bike for a dual reason one it cuts down on noise and the other real important one is proper back pressure your valves will get no commpression relief if the air can just escape to fast your bikes motor will get hotter faster damage depends on how your valves are set and the choice of spark plug you run i would say for your peace of mind if you want a loud pipe get power cones to give back the pressure your motor needs and then you can run a free exaust flowing pipe that back fire is your valves already going out of adjustment they are not closing right and extra air is sneaking in during the intake /exaust transition i hope this helps you

To remove you just find the spot welds that hold them in and drill them out or you can use a hole saw bit that just fits in the end of the pipe and drill out that way,But once removed you may need to adjust the carb and possibly the timing due to the lower back pressure on the motor,Without the adjustments the bike can run too rich or too lean and cause poor performance.(Although this don't apply to all bike,I just wanted to make you aware of the possibility)

that seems to be what they do, i too have a 650a and have jardines on with baffles, it still pops and cackles when you roll off the gas. are you running no baffels? when i took mine out i noticed a drop in power as i had removed the requierd back pressure for optimum performance. you can get small baffles to slip into straight pipes from jc whitney for about $5 each.
anyway back to the backfire. my local bike shop shrugged their sholders when i asked them about mine saying it's what they do. you will get used to it and you will find a way to kinda not make it do it so much. i actually have grown to like it now, except when there are cops about.

happy safe riding

there will probably be a couple or rivets close to the end of the muffler. drill out or chop off with a chisel. pull out baffles. but beware it will be loud. i did this to my dragstar/v star and ended up putting them back. you could just remove some of the fiberglass packing from the baffles, the cops will give you sh*t if you run straight thru. aftermarket pipes would be the real way to go, you may need to re-jet the carbs though. my bike also lost power with no baffles as engines need back pressure and all pipes are designed to give this.
hope this helps