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Post by ricardoguitars on Dec 20, 2014 22:37:54 GMT -5
One of the bolts that holds the muffler on the engine broke! I have no idea how it happened, it suddenly started to sound like a Harley when I was riding on the highway, it is loud and annoying  Are those bolts holding the muffler welded to the engine?, is it possible to replace them? do I need a new engine block?  |
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Post by ccr on Dec 21, 2014 0:31:07 GMT -5
unfortunately this happens very often on these scooters
but it's a simple fix unless you have stripped out the aluminium threads
at this time it would be a wise decision to replace both exhaust studs and bolts and a new gasket if your old gasket has been compromised.
fortunately its jut a 15 minute fix to replace them. be careful not to strip the aluminium from the engine
or you will be sending it to a machine shop to get it drilled out and thread repaired.
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Post by ricardoguitars on Dec 21, 2014 1:28:50 GMT -5
unfortunately this happens very often on these scooters but it's a simple fix unless you have stripped out the aluminium threads at this time it would be a wise decision to replace both exhaust studs and bolts and a new gasket if your old gasket has been compromised. fortunately its jut a 15 minute fix to replace them. be careful not to strip the aluminium from the engine or you will be sending it to a machine shop to get it drilled out and thread repaired. Can the bolts be replaced? Do I have to take the engine head apart? How can I take the remaining stud out and place a new one?  |
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Post by JerryScript on Dec 21, 2014 2:59:10 GMT -5
So long as there is enough stud left exposed to put two nuts on it, it is very easy to remove. Simple put two nuts on it, and then put your wrench on the nut closer to the engine, and turn it out against the nut near the end of the broken stud to remove it all.
If the stud broke off at the engine case, you will probably need to borrow an extraction tool from a store like PepBoys or AutoZone (they usually have loaners available with a deposit).
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Post by rcq92130 on Dec 21, 2014 14:06:07 GMT -5
You didn't mention - maybe do not yet know - the key issue here.
If your bolt broke off flush with the engine casing you have a real problem. If there is a stub still sticking out - enough to either get a few nuts on (as JS explained), or grab with vice grips, so you can unscrew it out, the fix will be quite simple. Just spray some WD40, wait, spray again, wait again, then unscrew.
Of course, you will have to remove the muffler either way - and maybe do so just to know if there is a stub remaining to grab on to. The muffler is removed with 2 attachment bolts (only one for you, since th other broke) and 2 nuts where it attaches to the head.
On the other hand, of the bolt snapped off with no stub remaining (no way to grab it and unscrew it) you need to:
1. drill a hole - carefully - down the centerline of the broken off bolt (might have to grind a flat surface to the bolt first so the drill bit doesn't just hop around). The drill size has to be correct for what comes next.
2. Buy or borrow an "EZ-Out" (Home Depot) matched to the diameter of the hole you drilled. Spray WD40 as above.
3. Screw the EX-Out into the drilled hole (it goes COUNTER CLOCKWISE - the opposite of normal). The "threads" on the EZ-Out go in the opposite direction to a normal bolt, and are designed to grip into the hole tightly.
4. Continue to screw "in" (i.e., counter clockwise) the EZ-Out, which causes the remaining bolt to unscrew since you are turning counter clockwise.
You then should have good clean threads remaining in the hole (unless you drilled on an angle and drilled outside the broken off bolt and into the crankcase). Just get a new bolt, put the muffler back on, good to go.
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Post by lain on Dec 21, 2014 14:13:16 GMT -5
I have a similar problem I have just been putting up with for a bit. One of the 2 studs that were in my block came out due to over-tightening which seems to be very easy to do when you are working on your scoot at night in below freezing weather. I have tightened the other bolt onto the other stud and its mostly flush but after it warms up it is very loud. I know what I need to do, but I just want to know if anyone has experience with loctite fix-a-thread? It seems to be used to repair threads on engine blocks of cars so I would think it would work here too? Just to be clear, the threads in the engine block that held the stud in completely stripped out and the stud just was able to pull out instead of unscrew. I have not tried anything else but this seemed like a good try because it is a well known brand that handles making glues and lubricants for threads.
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Post by rcq92130 on Dec 21, 2014 15:00:54 GMT -5
Locktite will **NOT** solve your problem. It only works where there are normal threads - not when the threads are stripped.
It's **possible** you can get at least a temp solution by (1) cleaning the hole REALLY WELL (i.e., lacquer thinner or maybe alcohol) (2) stuffing in some JB Weld (3) cleaning your new bolt well and smearing the threads with JB Weld (4_) sticking the new bolt back in.
That's MAYBE.
Othetr than aluminum welding and re-tapping new threads, your only other solution is to either re-tap new threads for a larger bolt, or, drilling and inserting a Helicoil of the correct size.
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Post by JerryScript on Dec 21, 2014 15:36:08 GMT -5
I believe lain is talking about a special product Loctite makes, it forms threads in a stripped out situations. However, I don't know that it will work on the exhaust, it is only rated to 300F. Here's a link to a video on using it from FixMyHog: www.fixmyhog.com/video/loctite-stripped-thread-repair-tip-005180/You can use helicoils by drilling the hole larger, inserting a helicoil, and then installing the new stud. Most auto parts stores have loaner kits. Here's a video on using them: |
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Post by geh3333 on Dec 21, 2014 22:55:13 GMT -5
I really hate the stock head exhaust studs , the 8mm studs are so much better .
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Post by toddmaples on Dec 23, 2014 14:03:29 GMT -5
You can use helicoils by drilling the hole larger, inserting a helicoil, and then installing the new stud. Most auto parts stores have loaner kits. Wish you guys would push GOOD thread repair solutions as much as you do HeliCoils... For the BEST thread repair solution for exhaust studs view my thread on fixing stripped holes. It cam be found by going to my started threads or searching my username. Or here: itistheride.boards.net/thread/6971/fix-stripped-hole-pics |
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Post by JerryScript on Dec 23, 2014 14:45:27 GMT -5
Absolutely, helicoils have always just stuck in my mind, I'll try to remember to suggest EZ-Lok inserts as well.  |
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Post by ricardoguitars on Dec 23, 2014 20:02:03 GMT -5
I took it to a muffler shop, they managed to weld a nut to what was left of the bolt, took it out and replaced for a new one.  |
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