Carb Inlet seat valve threads stripped

2 Stroke Kart Engine Forums
1

If where the seat valve sits in the carby if those threads are stripped is it basically a paper weight or is there a chance it can be revived?

2

Which carb do you have? Could you post a picture?

1 Like
3

It’s for a ka100 hw33a tilliston carby I can send pictures later on

4

Gotcha, just to make sure I’m understanding correct your referring to number 27 that is stripped out, correct?

image
image1290Ă—2796 118 KB

I circled it in red.

1 Like
5

Yes that’s what I’m referring to

6

Yes, it’s tough to get to. I believe it’s a 8mm socket. May be a ten. You have to shave it down slightly on a grinder or lathe to get it small enough to fit over it to take it out. If it’s entirely stripped out it may be tough to get. The carb should run just fine as long as the needle slides in and out smoothly and there are no burrs. I’ve had the same issue on a Tillotson carb where I couldn’t take it out. It hasn’t hindered performance for me at all. A fresh set of gaskets and it should be just fine. If you wanted to clean it you could just spray some carb cleaner and let it dry. But from my experience and what you’re describing it should be nothing more than a “superficial scar” so to speak.

8

Its getting to much gas because those threads are stripped

9

I can get it out I mean the threads on the carby are stripped where it screws into. I got an 8mm grinded down already when I put the new seat in the threads on the carby stripped.

10

Can you drill, tap and put a small helicoil in? Worth a try, it’s a small investment before you bin it

2 Likes
11

I see, Andy a good suggestion, can you re tap it?

1 Like
12

don’t know maybe you cant knock it if you don’t try it

13

Yes, use a helicoil kit. You drill it bigger, tap it, then insert the new helicoil that will bring the thread back to the original spec. They sell multiple kits, just get the one that fits the original spec

1 Like
14

Any idea of what thread size it could be or maybe a range or where I can find that out so I can know what kit to buy

15

The bore where the needle seat threads into is not threaded all the way around, there are 2 machined channels on either side. If you drill it out, you’ll end up drilling into the channels, effectively ruining them.

1 Like
16

Is there any way to fix it then without a helicoil kit

17

Do you potentially do these repairs on carbs or not possible to fix

18

With the price of a new carb, I would imagine it would be money well spent to just replace it.

1 Like