Exhaust threaded rod sheared off

bigdreamz2000 · Sep 29, 2009

Well, I've really messed my bike up. I had an exhaust leak around the gasket so I tried to tighten the nut. The rod must have had a fissure because with my small ratchet it sheared off like butter with no effort applied to the nut. Probally had <10ft/lbs of torque. It sheared flush with the casting metal. I tried to easy out the remaining rod but my easy out snapped. So I tried to drill it out and made a sloppy hole. Then my drill bit broke in the sloppy hole, so I had to drill out the drill bit. What should I have done when my threaded rod sheared off? I now have a very big hole in the place where the rod used to be. I filled it with JB weld since it says that it is able to be drilled and tapped. I have new threaded rod to go in but no tapping tools. I've never tapped anything, let alone a JB weld material. What will I need, any hints?

Venice Motor Bikes · Sep 29, 2009

I think a better way might be to drill the JB weld back out & use a Heli Coil!! That way you still have metal to thread the exaust stud back into!

noco · Sep 29, 2009

you should have jb welded it....could it have been possible to tap that bigger hole and use a bigger bolt?

freewheeling frank · Sep 29, 2009

look into the heli coils they work much better than jb, and really arent that hard to do

bigdreamz2000 · Oct 1, 2009

I am curious to see if JB weld can hold a tap. I did a little looking into tapping and I have what they call a blind hole. Meaning I cannot go through with the tapping bit (because I'd go into the piston), so I need a more expensive flat bottom tapping bit. If that doesn't work, I'll investigate a helicoil.

I'll post back when I get done.

Bikeguy Joe · Oct 1, 2009

If you think the JB will hold after you tap it, just JB Weld the new stud in place. No need to tap out the JB Weld.

bigdreamz2000 · Oct 1, 2009

Bikeguy Joe said:
If you think the JB will hold after you tap it, just JB Weld the new stud in place. No need to tap out the JB Weld.

I forgot to mention that I tried that. The hole being slightly bigger than the rod it was not possible to jam JB weld into the hole and then jam the rod into the JB weld. I was using the putty like stuff, maybe if there is some sort of more plyable, liquid like stuff I might be able to shove the rod in the hole and the excess could squirt out. I got the bottom tap M6 X 1.0 off of Amazon for a little over $7.00 and that includes shipping. Should be here in a few days.

MB-Monkey · Oct 1, 2009

Note to self make a post arguing the best reasons to use bolts instead of studs......

bigdreamz2000 · Oct 1, 2009

That's easy, because the pot metal would be very easy to cross thread. Plus it is easier to slide a part on then tighten a nut, rather than have to search for the hole thru the part, then hold it in place and start the bolt. A good compromise would be having the studs made more robustly.

donuts31 · Oct 1, 2009

Time sert, its idiot proof and I should know because I've used them many times on HT engines.

++ TIME-SERT Threaded inserts for stripped threads, threaded inserts, thread repair stripped sparkplug's, Ford sparkplug blowouts, threaded inserts threaded, repair stripped threads, stripped threads, inserts threaded inserts, Ford spark plug repair,

Kevlarr · Oct 1, 2009

Any tap can be made into an "expensive" bottom tap with a grinder.

BTW I don't know what you consider "expensive" to be, I just paid $10 for a regular 6mm tap because someone else cleaned the workbench and I couldn't find my old one.

bigdreamz2000 · Oct 1, 2009

I saw those on ebay but didn't know what they were all about. Thanks for the link the videos were helpful to understanding them. Another possible option but the kits look expensive...

Anybody know what size drill bit I should use before I tap with my M6?

Thanks!

Kevlarr · Oct 1, 2009

My tap said to use a 13/64 bit. If you can find metric bits it's a 5.5mm

aquarianmonkey · Oct 13, 2009

Sorry to hear about your problem. Tread repair kits are the best since jb weld is ONLY temperary when you do fix the hole toss those studs in the trash and use 5m machine bolts they are the best. My studs would back out no matter how much lock tight I used tossed the studs and now use 5m machine bolts. I plan to replace all the studs with 5m bolts since a 5m alan fits better in my pocket rather than a 10 mil wrench and 5m bolts are harder than the studs so the worst that can happen is the threads in the hole will strip rather than the bolt breaking flush.

Bikeguy Joe · Oct 13, 2009

Excuse my ignorance, but what are 5m machine bolts?

aquarianmonkey · Oct 13, 2009

5m machine bolts are bolts that are alan hex heads and are super hard. I get them at Ace hardware in black. They tend to be a little pricey about .79 cents a piece. They look nice and stay tight. Sorry I havn't any pics of them.

Bikeguy Joe · Oct 14, 2009

What does "5m" mean?

Pablo · Oct 14, 2009

Best bet (not sure what the status is): Grind out any old tools from the hole (easy outs are from the devil), drill and tap - or drill tap and use a threaded insert. Problem solved without that much hassle.

aquarianmonkey · Oct 14, 2009

millimeter. If you go to Ace there in the metric bolt bins I can't remember the pitch though. It might be 1.5. Standard bolts go by the dia. of the bolt and number of the threads, metric machine bolts go by the size of the alan hex and the thead pitch. I always just bring in the bolt I want to replace and size them up at Ace. I have been using these for the exuast for awhile and have had no problem I plan to use them in the intake also.

2door · Oct 14, 2009

aquarianmonkey said:
millimeter. If you go to Ace there in the metric bolt bins I can't remember the pitch though. It might be 1.5. Standard bolts go by the dia. of the bolt and number of the threads, metric machine bolts go by the size of the alan hex and the thead pitch. I always just bring in the bolt I want to replace and size them up at Ace. I have been using these for the exuast for awhile and have had no problem I plan to use them in the intake also.

What you have are Allen head cap screws in the metric equivilent to the ASME grade 8. They are not sized by what wrench you use but by diameter. The intake and exhaust manifolds will take a 6mm X 20mm X1. thread. Yes, they take a 5mm hex wrench (Allen) but the bolt size is 6mm. The 20mm length will work on almost any Chinese 2 stroke engine. I suggest using a flat and a lock washer on each bolt.
Another thing to look for is the weld bead around the exhaust or intake flange that is sometimes too wide and will not allow a bolt head or a nut to rest flush against the flange. That weld needs to be ground away so the fastener can sit flat against the surface and not bend the fastener when tightened.
Tom

Exhaust threaded rod sheared off

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