Now what? Stripped butterfly shaft screw

I determined that my butterfly shaft seals were the cause of a throttle issue, and have dug into the carbs very meticulously to fix the problem.

I spent the time it take to watch 2 lengthy movies, accompanied with a trusty file, and removed the peened backs of my Mikuni butterfly screws.

One by one I removed them with the appropriatly sized JIS type screwdriver, and all was going wonderfully, untill...



The last of the 8 screws stripped because of my haste toward completion of this vile task. :evil:

In any case, what do I do to remove this worsed of engineering feats?

 

Get yourself a set of these:

http://www.sears.com/shc/s/p_10153_1260 ... 000P?mv=rr

But be sure they're THIS type; with a reverse-drill end and a little "EZ-out" end; and proceed very carefully. Quite often the "reverse" drill biting in is all it takes to walk the screw out and you don't even need to flip it around and use the "extractor" end.

They come in various-sized sets; you need a set like this with the tiny ones in it. If you can't get your drill in there, use a driver extension or a "tap" driver.

 

Thanks for the link.
Sounds like a wonderful tool, but a miserable predicament. I'll have to give it a go.

 

What size ... what position ... Carb is it?

I might have the Throttle Shaft and Pllate
Or, ...
A Carb Body to swap for sale.

I'm PM you.

 

Either get a longer screw and nut, and then loctite the nut onto the back of the screw in that location (ugly, but works), or, we should have good used throttle shafts available....need to know which carb it is, all the shafts are unique on the 550's......

 

+1 I have that set, it has really surprised me on some tough deals.

 

Im going to try the screw extractor that fitz mentioned first, but if I bugger it up, I'll definitely be in the market for Carb #1 on the 550 rack.

Thanks for the quick replies, mates.

 

Not a uncommon problem.
I have had good sucess drilling the head off then using a 1/16 or 5/64 dit drill through the center of the screw. After the head is off most of the time the 1/16 bit will catch and run the screw out through the other side with no dammage to the threads.

 

Just before leaving for the store to get the extractor kit, I tried the 1/16th bit, and it worked like a champ! 8) Thanks for the tip, and the input from everyone.

 

Pick up the extractor kit when you get a chance, you'll need it eventually.

Good save.

 

Now that you have it out, double-check the threads in the hole and make sure they are clean. If so, great. If not, clean them and chase them with the appropriate sized tap before installing the new screw. Otherwise, you run the risk of having it seize up on the way in.

Dave

 

Brilliant reminder there, Dave.

In fact, I should take a very close peek at the threads on all of the butterflys, just to make sure everything is smooth sailing come reassembly.

 

be careful chasing those threads you want to get a tap with as low a "H" number as possible, like a "1" or the screw will be a loose fit, not good
all about taps

 

Thats a fascinating read. Not exactly more than I want to know, but perhaps more than will be useful in the foreseeable future. It's quite clear why I've been told to have a professional do any tap/chase work for me. Given that awesome write-up, it would make just about any technically minded person into a professional on the subject though.