Where do I find anew one of these? Help

[Snikare]

I was taking apart my throttle shafts to replace the seals. However upon trying to remove the screws that hold the butterfly in, they stripped. And then to top it off the screw remover drilled itself through the side of the screw destroying the threaded hole. Now I need to replace the rod too. But, I can't find a replacement. Can anyone help me find one?

Do you have a set of bs38 carbs that you would part out? I need it in a hurry!

Thanks for any consideration.

 

[Snikare]

Forgot to mention what year is from. This is for a set of '79 BS38 carbs. The rod in question is from the left side carburetor.

 

[TwoManyXS1Bs]

Depending on the severity of the damage, there may be a way to save it.
The original butterfly screws are M3-0.5. A #5-44NF screw is slightly larger, by about 0.007" in diameter. This kind of refit would be a machine shop task...

 

[Snikare]

Thanks. I've thought about actually having the hole closed with silicon bronze and then tapping it. But the heat may actually warp it...

And just an FYI, I measured the screws and it seems that they are actually M3- 0.25 fine pitch threads. Those aren't easy to find. Going up a size may be doable. I may be able to drill out and tap an M4 in house. It would be nice to get a new one though. If anyone has parts around, I'll take them off your hands!

 

[TwoManyXS1Bs]

Found these two left bodies on eBay.

Item: Yamaha XS650 #1 Left Side Carburetor Carb BODY 1978-1979 Fitment ONLY XS 650

URL: http://pages.ebay.com/motors/link/?nav=item.view&id=351519002736&alt=web

Alt URL: http://www.ebay.com/itm/Yamaha-XS65...Y-1978-1979-Fitment-ONLY-XS-650-/351519002736


Item: CARBURETOR LEFT SIDE MAIN BODY CARB 1977 YAMAHA XS650D XS650 XS 650 650D D 77

URL: http://pages.ebay.com/motors/link/?nav=item.view&id=381038234824&alt=web

Alt URL: http://www.ebay.com/itm/CARBURETOR-...A-XS650D-XS650-XS-650-650D-D-77-/381038234824

 

[TwoManyXS1Bs]

MikesXS carries the butterfly screws.

http://www.mikesxs.net/parts/yamaha-xs650-screws-throttle-shaft-pk-4-oem-256-14922-01-00

And 5twins found suitable McMaster-Carr replacements:



The screws I recently removed from mine are a 0.5mm pitch, which is indeed rather fine, about 50 TPI...

 

[weekendrider]

You can get Allen headed screws for that application.

 

[Snikare]

Strange. I just checked ebay and found nothing under my searches. And when I went to the hardware store the 0.50 pitch screws didn't fit...

I'll take a look at the eBay stuff now. Thanks!

 

[TwoManyXS1Bs]

If you're considering oversize screws, here's a diameter progression:

M3 - 0.118"
#5 - 0.125"
#6 - 0.138"
M4 - 0.157"

 

[Snikare]

Wow. That's great info. Thanks 2many!

 

[TwoManyXS1Bs]

Critical update to this thread.

After checking my original throttle-shaft/butterfly-plate screws, and comparing them to my new MikesXS screws, found that the MikesXS screws have the WRONG countersink angle of 80°.

The McMaster-Carr screws mentioned previously have the correct 90° countersink angle.

Using screws with the wrong 80° countersink angle will have the screwheads protruding above the mount surface, restrict clamping force to just the inner portion of the screwhole, and reduce the screw's contact area with the countersink. All this could encourage future looseness of the butterfly plate.

You can get Allen headed screws for that application.

Thanx, WER. I just ordered a set of DIN7991 stainless screws. (90° countersink angle)

 

[Snikare]

This is great. I'm going to do the same. Thank you!

 

[TwoManyXS1Bs]

Follow-up reference. Notice the fit comparison in here:

http://www.xs650.com/forum/showpost.php?p=197433&postcount=101

 

[weekendrider]

You're welcome. A hex/allen is easier to work in that tight space.(4 me).

 

[Snikare]

I got screwed by the guy selling a carb body in Texas. He said it was in excellent condition and asked a premium price for what the pictures looked to show a good carb body. Upon recieving it I found that the threads were totally stripped on the end of the throttle shaft and the nut was just barely hanging on.

Now that I'm loking for another one again on line, they're hard to find just what I need. Not that I want to go this route, but what is the best replacement option when it comes to new aftermarket carbs for a 79 special?

any suggestions?

 

[TwoManyXS1Bs]

I got screwed by the guy selling a carb body in Texas. He said it was in excellent condition and asked a premium price for what the pictures looked to show a good carb body. Upon recieving it I found that the threads were totally stripped on the end of the throttle shaft and the nut was just barely hanging on...

Well, CRAP! That outfit looks to be L&A Ventures/Spyderscycleworks, out of Houston. They do carb rebuild work. That must have been one of their rejects, and dumped it on you.

The throttle shafts are plated brass. A good welder/machinist (or skilled/experienced hobbyist) would be able to restore that stripped/threaded end. Should be no shortage of those types in your area...

 

[Snikare]

Yeah. Sounds like that's exactly what happened. I'm sure I could even thread the end and make it work, but I was hoping for a straight swap with a nice piece at $70.. If I'm gonna do a fix job, I may as well fix the throttle shaft I have already. Which is exactly what I just did.

 

[scabber]

The Keihin CVK carbs from the EX 500 are a good replacement.