Exhaust bolt help
 

I've had an unfortunate situation happen with my exhaust. I went out to start my scoot on a VERY cold day only to have BOTH exhaust bolts fall off into the grass to be lost for good, I just need to know the size and thread so I can buy new ones down at the store. Needless to say it's not good to run without an exhaust for obvious reasons (aside from the noise, which actually is pretty cool) like burning out a valve or "piston slap". The only reason I started the bike was to keep a charge on the battery during some extremely cold weather this week. I'm thinking I'll fetch a battery tender next time :)

I do not know the size off hand, but someone will chime in.

But, I think your talking about the nuts right?

If this is what your talking about i suggest using two nuts on each bolt that you can get from any hardware store. Mine have not come off since I started doing this.

Those were the first parts I lost, I miss them. I don't remember the size but I do remember I pulled a similar sized bolt from somewhere (front wheel assembly can't remember what though) and it was the same. I took that bolt to the hardware store and grabbed the nuts (metal ones, they sell, off the shelf, don't start...) I think I left spending less than a dollar Hope that helps

They are either an m6, m7 or m8 with m6 and m8 being the most common. Check your local hardware or parts store and get some metal locking ones to replace the long acorn style that were originally there. The metal locking ones are like the nylon insert nuts but they are designed for high temp locations. After losing 2 sets of the acorn nuts I switched to these and haven't had a problem since.

If you are talking about where the exhaust flange connects to the head then those are not bolts but studs which are attached to the head first so the aluminum threads in the head will not get worn and stripped out from being spun while having the load of tightening the exhaust flange applied. You need a new set of exhaust studs, washers and nuts to repair this. If you are fortunate they were not in tight enough and spun out when the extremely cold engine was first started however they may have also been installed too tight and when the engine heated up poped out due to thermal expansion stripping the threads from the head. You may need to drill and tap them out to the next larger size if that was the case.

Not sure of size, but this is how I matched it - take the nut holding your under seat bucket. Same size nut

I assumed he meant just the nuts yes rocky is right they are studs...

Seen a number of folks ruin salvagable heads using bolts instead so played it safe and spelled it out. It's all part of the learning process. If I think back to almost 50 years ago when I first started wrenching there are more that a few things that I would not repeat and will probably deny ever happened. Things that garnered an "Oops! Did I do that?"

Same here man same here...

not sure what bolt exactly you are referring to mine has a few different bolts. I just replaced one on my Genuine Roughhouse it was a M8 1.25. Probably not all the same size but that's at least a starting point.

Thanks guys, I did just mean the nuts, not the studs. That would require a "Grab-it" tool and a good variable speed drill to pull out. I just had what sounds like a normal experience losing parts

Seeing as it's so damned cold here now (we usually don't get this cold) I'll wait until mid-week to go get the parts and put them on

UPDATE: Problem solved! It got warm enough to brave driving the scoot to the hardware store so I did. For those of you who have questions about size and thread here it is: 6mm, 1.00 pitch thread. I used the double up method as someone else suggested. You'll need either a 10mm nut driver or deep well socket to tighten them down. Now my scooter is nice and quiet.

Cool glad to see you back on the road. Thanks for the info

Soo..basically...you literally "Froze your nuts off"..:lmao: All kidding aside..they should be M8X1...some are M8X1.5 Instead of using plain nuts...I use metric size threaded rod couplers...they are longer and give more thread area for the stud to grip onto..meaning less chance of stripping the nut. Also since they are 2-3 times longer than a nut...they are easier to put on due to the cramped quarters under the engine....and keep water and road residue off the threads so they do not corrode. Just my 2 cents....:nod:

Hi
I surely hope you put a bit of the blue loctite on while installing them, as it should save you the hassle of them falling off once again
http://www.loctiteproducts.com/p/10/...r-Blue-242.htm
Take care and ride safely
Yours Hank

I use red loctite for all aircooled engines. It's for higher temp applications

So then...I am the only one that uses the longer threaded rod connectors vice thinner nuts that can strip more easily?...just curious...:shrug:

I ordered a few of these sets a while back to have on hand.

http://www.ebay.com/itm/SCOOTER-150C...bdd8f2&vxp=mtr

@ Hank: Yup, I used a generous amount of Loctite and just so people understand I doubled up leaving less chance of stripping, falling off etc.... You can literallty freeze your nuts off here lately, it's been a colder winter than we hoped for BUT I'm still riding, just harder starts in the morning

Double up the nuts is a great idea and works well. As for the cold...same here..it is actually so cold....you can SEE people fart...:lmao:

I tend to use the 6mm stainless locking variety. Then like Sammy Squirrel, "You always know where your nuts are"

I've never had an issue using the standard nuts with split washers.

LOL
now THAT'S cold!!!

Correctly tourqued to spec the hardened steel nuts designed for exhaust flanges generally work best. Milder general purpose nuts will corrode faster and become more problematic over time.

I was thinking about drilling the acorn nuts and adding a bit of safety wire. loctite is nice but I use antisieze to help parts not corrode and be frozen when I do wish to disassemble them later.

How about we all just check the nuts once in a while? I have an '03 scooter with close to 9000 on it and the exhaust has never leaked because every 2-3 weeks I go over it and check/tighten any fasteners I can get at without taking it apart. Most guys and gals wait til there's a problem to start getting proactive. That's too late.

The only reason in my mind that they fell off was because the cheap metal they use for mounting bolts contracted during cold weather. That said I agree that checking things every so often is a good idea. If I had thought to do that I might have prevented the issue all together. Seeing as the problem didn't make itself known until the thing fell off the manifold, I wasn't concerned but yes, I will check more often now that I know what the cause is.

These nuts need to be removed and re-installed about once a month.
This is to prevent rust from seizing them (oh yes, oh yes) and to ensure they don't work themselves loose.
Loc-tite will burn and may cause further seizure issues.

And if you don't want to replace the cylinder head, do NOT tighten them back up without a torque wrench!

Torque to 8 ft.lbs.

Mine are 10mm