The stock screws look like philips but they are JIS. Therein lies the source of stripped heads - using a Philips driver.
Take a #2 Philips and file down the tip about 1.5 mm.

 

I always use needle nose vice grips to break the screws loose on carbs since they tend to seize. You don't have to crush the head of the screw, usually just a little pressure on the pliers is all it takes since they give you a lot more grip than a screwdriver. My $.02.

 

Allen heads and Fastenal has them for sure. You may have to buy a bunch, but they won't be that costly. You might be surprised how low buck they just may be.

Don't use stainless unless you use some anti-seize. Stainless may gauld into the body, I don't know. I do know they will if it is stainless on stainless or stainless on steel, maybe stainless on aluminum, not sure about zinc.

 

Yes - stick an M in front. M4x7x10. I forget now how I came up with that - that's why I was wondering if someone could confirm. I'll keep looking around here - but we don't have a Fastenal place. If someone on here was to buy a bunch of allen heads the right size, I would gladly Paypal you a few bucks if you'd slip some into an envelope & mail them to me. It's not just this bike I'd get them for, I've also got 2 carbs on a sled that I'm pretty sure are the same size and have an ATV kicking around too. I have always, in the decades I have owned anything with a motor on it, found the stock carb screws to be a huge PITA.

 

I just had a thought. I bought the Dynojet kit based on recommendations. The JD Jetting kits come with better float bowl screws. Maybe I'll shoot JD Jetting an email and ask if I can purchase the float bowl allen head screws only.

 

My local ACE Hardware has a very good selection of metric stuff.

If you have no Ace near you I could pick them up and ship. I bet around $0.40 or so per bolt.

 

Two methods that have saved me many times over the years...
1. Use a dremel w/ mini cutoff wheel to slot the screw for a large flat blade screwdriver.
2. Tap the top of a phillips screwdriver with a hammer as you try to remove the screw.


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use a (proper fitting) bit driver on a 1/4" rachet. You can get alot more downward pressure and torque on the screw.

 

This place is another online/mail order supplier of industrial parts. Shipping is very fast and I think only the actual cost. They've been around for years. The downside is you have to get packs of 25 or 50, etc.

McMaster-Carr

Item 92290A144 is probably close to what's needed (and I'm using). Metric 316 SS Socket Head Cap Screw M4 Thread, 10mm Length, .7mm Pitch. You can even choose the type of stainless steel you want (although I think the 316 is the way to go.) Recheck the part number and dimensions though since I dont have my order history in front of me.