my first ride with some newly acquired tubular wheels and noticed the rear wheel was flat soon after hanging up the bike. small bit of glass in the tire tread. cut is small (maybe 2mm - 3mm) but leaks air fairly rapidly. i did some research: i either need to cut open, patch, sew up and re-glue. or try one of these tire sealant products.

unfortunately most of them require a removable valve core and i'm almost positive mine is not removable.

Vittoria Pit Stop is one of the only products i found that you can inject directly into a standard open presta valve (without removing the core) but the reviews are mixed as is the longevity of the fix.

anyone have any expert opinion / experience with a decent product or should i just slice open and attempt a repair?

thanks!

I tested the Vittoria Pit stop on a small cut in a tubular -- it worked ok. Not sure how long it will last since I did not ride it afterwords. I would try this approach first. Repairing a tubular is a chore and the results are not always what you expect. It takes a lot of practice.

Welcome to the club.
Learn how to sew them up.

If it's a decent quality tire with good tread still, sending it to Tire Alert for a new tube and base tape may be worthwhile:

https://www.tirealert.com/

If the op has a 200 dollars tubulars it worth the time and money to send it to those guys, but for a 25 bucks tubular is just better go and buy a new one. In the meanwhile the op can learn how to fix them, is not hard at all. Once he knows what to do in 15 mins thats fixed.

This is why tubular tires have become unpopular.

If the cut in the tube is the size of the tire cut then the stop leak may not work.

Once you have a roll off after a road repair you will give up on tubular. however it is not that hard to re-sew a sew up. i did it yrs ago when i couldnt afford new tires and sew ups were still kewl. try the new goo stuff if you just have too,but you will never be sure of it and you will never patch it after the goo leaks out all over the tire and tube.

Why i never have problems with tubulars?? I basically retire them just because are too old.

Always good to know how to fix them anyways, is not hard.

Could be true... going on 27 years without rolling one... I'll be sure and post here when it happens... don't abate your breath.
In fact, I don't know anyone who's rolled a sew-up, but lots of people who know someone who knows someone who did... operator error in every case. (so far).