I would think they'd be fine but check that they're compatible with fuel.
If they've never been off before they can be very tough. Try wriggling them up and down and concentrate on pulling one of the end ones out first. It might help to warm the intake manifolds with a hair dryer to soften them but I've never tried it myself. You shouldn't need to lever against anything. If you can get to the intake manifold clamps you can try removing those as well and see if they come off more easily. Make sure the clamps are very loose as the carbs have a lip around them.i have tried to remove these carbs but just can't seem to get them off. i have an actual Honda CBR900RR service manual and have followed the steps, but with no result. i tried using a screwdriver style pry bar but i didn't apply very much pressure in fear of cracking the magnesium valve cover, i had thought about putting a piece of aluminum plate over the valve cover and try more pressure with the pry bar but i thought that magnesium will crack easily, is there any other suggestion? THANKS!!