This may be a silly question but i have been looking all over the place and I cannot find a 77 xs500 specific rebuild kit for the carbs.

I believe I have the 38mm mikunis in it.

I have also seen that there are oversized jet rebuild kits that i think fit the 38's is this a good idea?

I am planning on putting a higher flow exhaust and air filters on the bike which I have heard you need to make the higher flow jets work properly.

Haver you checked with Speed & Sport Yamaha for carb kits? They have a website and seem to have lots of parts for old Yamahas.

Haver you checked with Speed & Sport Yamaha for carb kits? They have a website and seem to have lots of parts for old Yamahas.

You will need to re-jet for both of those things. You should get both and then re-jet, as you'll probably have to change again if you put one on then the other.

You can also get all the necessary parts from here:

http://www.mikesxs.net/products-37.html#products

I also suggest getting new gaskets if you're going to be taking the carbs apart, which you can also purchase from MikesXS.

The parts are relatively cheap, so you can purchase 2 different sized jets and see what fits your setup best.

Good Luck.