Nuts!

Post by **ericalm** » Thu Jul 11, 2013 12:35 am

Specifically, exhaust nuts. I've had three professionally-installed ones come off the header studs now, all after very hardcore long/at high (for Stella) speed/demanding rides.

This weekend I was afraid I'd punched a hole in the exhaust. It was sounding pretty 2-strokey. Then the noise got louder, with a little backfiring. Finally looked under the cowl — no nuts! I had a couple that fit, so I fixed it up in a couple minutes.

Haven't heard of anyone else having this issue. Maybe it's just my studs. Maybe I'm just prone to losing my nuts.

Anyways, my mechanic is going to get me some lock nuts. Hm.

MrChet · Post by **MrChet** » Thu Jul 11, 2013 3:34 am

I was about to lose the Sito+ on my 2T as it was so loud and obnoxious.

Having just installed a Prima on my Buddy I decided to check the nuts on the Stella and sure enough, they were loose. After tightening things up, the bike is back to a pleasant (but still loud) popcorn popper.

I think they they are prone to vibrating loose. Let me know how the locknuts work. Failing that I may try a longer bolt with two nuts.

fisher1 · Post by **fisher1** » Thu Jul 11, 2013 3:44 am

Most racing sanctioning groups require either safety wires/bolts or safety wires/washers to secure critical fasteners.

http://www.solomotoparts.com/Progressiv ... e-Washers/

http://www.solomotoparts.com/Progressiv ... fety-Wire/

SYMbionic Duo · Post by **SYMbionic Duo** » Thu Jul 11, 2013 4:00 am

could always double lock nut them.

Post by **ericalm** » Thu Jul 11, 2013 4:25 am

MrChet wrote:I was about to lose the Sito+ on my 2T as it was so loud and obnoxious.

Having just installed a Prima on my Buddy I decided to check the nuts on the Stella and sure enough, they were loose. After tightening things up, the bike is back to a pleasant (but still loud) popcorn popper.

I think they they are prone to vibrating loose. Let me know how the locknuts work. Failing that I may try a longer bolt with two nuts.

The studs on the 4T have space from two nuts each.

fatcharlie · Post by **fatcharlie** » Thu Jul 11, 2013 8:13 am

I'd either put a bit of blue loctite or a lockwasher on there before using a locknut.

Here is my reasoning: Most locknuts that you find are either Nylock style or a torque lock style... Nylock has a bit of nylon or plastic built into the nut that helps keep it from vibrating loose... Plastic on an exhaust system doesn't work too well once it melts.

A torque lock style is a slightly out-of-round nut that grips the stud or bolt tightly, only problem being is that I've seen them gall threads in the past... add this to some heat and rust (which is very likely on an exhaust) and next thing you know you're extracting the studs from the head because there are no threads left.

A split lockwasher would work... but you really should replace them anytime that the exhaust is off, especially with the repeated heating/cooling cycle that would just end up annealing the material eventually rendering the lockwasher useless.

Blue loctite allows you to remove the fastener with hand tools, and should keep the nut from backing off... it will build up a bit on the threads, but nothing that can't be handled with a few strokes of a brass brush... generally you don't even have to do that. Plus a bottle of blue loctite will probably last long enough to tear down the whole scooter, loctite EVERY fastener and still have some left over.

SYMbionic Duo · Post by **SYMbionic Duo** » Thu Jul 11, 2013 6:08 pm

Blue Loc-tite will not work. exhaust studs get too hot for it.

az_slynch · Post by **az_slynch** » Thu Jul 11, 2013 6:19 pm

How about some M6 Fuji Lock nuts?

Worst case scenario, safety-wire those suckers on.

Post by **ericalm** » Thu Jul 11, 2013 6:38 pm

SYMbionic Duo wrote:Blue Loc-tite will not work. exhaust studs get too hot for it.

This was my thinking, too. It'd just burn off.

If I did get lock nuts, they'd be the all-metal kind.

az_slynch · Post by **az_slynch** » Thu Jul 11, 2013 6:47 pm

The technical data sheet on Loctite 242 lists a temp of 482° Farenheit to break the bond free on stuck parts. I'd hope the flange isn't that hot, but it's pretty darn close to the exhaust valve.

fatcharlie · Post by **fatcharlie** » Thu Jul 11, 2013 8:14 pm

It will get hot enough to change the structure of the loctite... basically like if you burn red loctite with a torch and remove the fastener...

You won't get the satisfying crack when removing a fastener that has been "loctited" in... but the remaining stuff on there should provide enough resistance to keep the nut from rattling loose.

Your mileage may vary... but I've used it on a turbo manifold with good results. No matter what you end up doing, it'll still be better than having the nuts come loose.

SYMbionic Duo · Post by **SYMbionic Duo** » Thu Jul 11, 2013 8:57 pm

I know from experience that loctite wont hold very long. lost both nuts on my buddy even with loctite. switched to deformed lock nuts and haven't had a problem.

fatcharlie · Post by **fatcharlie** » Fri Jul 12, 2013 6:56 am

SYMbionic Duo wrote:I know from experience that loctite wont hold very long. lost both nuts on my buddy even with loctite. switched to deformed lock nuts and haven't had a problem.

Locknuts it is then... good to know, because I would've tried the loctite.