Jump to content
Sign in to follow this  

Aw crap! Carb thread stripped

Recommended Posts

Hey guys,

I was measuring the float height on my FCR-MX today / changing needle clip pos, and when I put it back together one of the float bowl screws felt funny as I tightened it. I gave it a little turn to snug it down and it spun free. Yup, stripped out the threads in the upper carb body. 👍

Am I screwed, or is there a simple fix for this? Sure seems like there would be a fix. A slighly bigger screw to bite into the existing hole, or a sleeve type deal, or something similar.

Anyone had this problem, and have a solid (not "should work in a pinch") fix for this?

Any tips, tricks, hints, or otherwise helpful information would sure be apprecitated.

PS - I have no one to blame for this but myself, as Im sure it is a result of my being lazy and using a power driver to put the screws in previously. 🤣 Woops

Share this post


Link to post
Share on other sites
Hey guys,

PS - I have no one to blame for this but myself, as Im sure it is a result of my being lazy and using a power driver to put the screws in previously. 🙂 Woops

👍🤣:lol:🤣

yeah, hand tools are groovy when working with carbs.

Crystal ball sees a bigger bolt, two drills, and a tap in your future.🙂

I've never done it to a carb, but at the risk of incriminating myself, I've done it to lots of other stuff. Including a certain S-10 2.2L rocker arm mount.

Share this post


Link to post
Share on other sites

Ouch! Put down the power tools and back away from the expensive carb.🤣

There is not a lot of extra meat there for a larger screw. They are 4mm... 5mm might be a bit big. A 8-32 screw is slightly bigger than a 4mm. You might just be able to run a 8-32 tap through the existing stripped hole and get enough thread. You'll need to pick up a 8-32 bottoming tap unless you are lucky enough to have stripped one that has plenty of open area behind the hole for a starter tap.

Good luck with the repair..... and remember nothing on a carb needs to be that tight. 👍

Share this post


Link to post
Share on other sites

Don't feel so bad, we all have to learn the hard way sometimes 👍. I damaged the crank case cover on a KZ-400 because I was too cheap to pay the extra $25 for the OEM kick start lever. I only realized the problem when the engine sounded different due to low oil level🤣.

All is not lost, you have several options. On the cheap side, you could clean it thoroughly and fill it it JB-weld. They say it can be tapped, and the carb bowl screws aren't working nearly as hard as cylinder head bolts.

If that's too cheesy for you (I wouldn't blame you), you can use aluminum solder. I've had very good luck with it. You will have to remove all plastic and rubber parts first, then heat it up with a propane torch, fill the hole, drill and tap. If you file it down, no one will be the wiser.

The ultimate solution is to TIG weld it. I'm sure you can find a local welder that will do it for $10. It will take him 30 seconds, if that. You will still have to drill and tap, but at least you know it will be done right. This is how I repaired the KZ-400 crank case years ago. I got the right kick start lever and eventually sold the bike.

Share this post


Link to post
Share on other sites

The ultimate solution is to TIG weld it. I'm sure you can find a local welder that will do it for $10. It will take him 30 seconds, if that. You will still have to drill and tap, but at least you know it will be done right. This is how I repaired the KZ-400 crank case years ago. I got the right kick start lever and eventually sold the bike.

Unfortunately the zinc content in the carb body would prevent any TIG welding repairs... besides the chance of warping the body, you'd have to disassemble the main venturi body from the upper float bowl chamber because of the internal rubber sealing gasket. Not for the faint of heart or short on special torx bits kinda folks.

If the bump up to 8-32 doesn't get it my next attempt would be to JB Weld the hole in and drill/tap for the original 4mm screws. JB Weld is some amazing stuff. 👍

Share this post


Link to post
Share on other sites

I think I'll go for the JB weld deal. It seems like keeping the same size screws all the way around might be easier for my peabrain to rememeber.

Thanks for the responses everyone.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×
×
  • Create New...