Exhaust cap-nut replacement/mod. |

Bluefront
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Modded Xingyue ITA150

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Exhaust cap-nut replacement/mod. Jun 14, 2011 13:56:52 GMT -5

Post by Bluefront on Jun 14, 2011 13:56:52 GMT -5

If you lose one of these cap nuts that hold on the exhaust header, you'll have trouble finding one locally. Online they can be very expensive.....as much as $12 ea.

Here's a cheap replacement.....they're called "extenders", available in various thread sizes at Ace Hardware $1.69ea. This one happens to be 8mm. The reason a long nut is better than a normal nut....easier to install in an awkward area. The OEM cap nut is on the left....

I never have liked cap nuts in any application. They look neat and hide the threads of the stud/bolt, but they trap moisture and can rust solid. And since the end is closed, you can't spray any rust-buster on the threads.

So I switched over to a set of these extenders. And I drilled a set of holes near one end.....

The holes.....used for a safety-wire. When wired together after the installation, they won't fall off. Pretty neat. I coat the threads with adhesive silicone to prevent loosening, and spray some lube into the openings from time to time.....works well.

Last Edit: Jun 14, 2011 13:57:35 GMT -5 by Bluefront

loganhes Great Big Guru Dawg Posts: 473	Exhaust cap-nut replacement/mod. Jun 14, 2011 14:37:27 GMT -5 Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by loganhes on Jun 14, 2011 14:37:27 GMT -5 that is a great idea Bluefront...thanks!
	2011 Kymco 150cc Super 8

quicksilver
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Exhaust cap-nut replacement/mod. Jun 14, 2011 19:07:48 GMT -5

Post by quicksilver on Jun 14, 2011 19:07:48 GMT -5

The nice thing about cap nuts is that they do prevent water getting to the threads where as the extenders, water can get to the nuts very easy.

If you are worried about not being able to remove the nuts later on, use something like neverseze to coat the threads. This would displace moisture and prevent rusting.

Last Edit: Jun 14, 2011 19:10:21 GMT -5 by quicksilver

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Bluefront
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Modded Xingyue ITA150

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Exhaust cap-nut replacement/mod. Jun 14, 2011 21:05:30 GMT -5

Post by Bluefront on Jun 14, 2011 21:05:30 GMT -5

^^^^^That certainly is the theory about cap nuts anyway. But moisture always seems to find a way inside the things, then stays there and starts the rusting process.

I usually replace cap nuts on my own machines whenever I find them. If a person were to break one of the exhaust studs, replacing it will be tough. These extender-nuts can get a squirt of lube easily enough....just part of on-going maintenance.

biggwill69 New Puppy Dawg Posts: 1	Exhaust cap-nut replacement/mod. Nov 24, 2012 2:07:38 GMT -5 Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by biggwill69 on Nov 24, 2012 2:07:38 GMT -5 How do you take a broken stud that broke of with the cap nuts I have a 150cc sunny scooter

50cc Great Big Guru Dawg www.scootdawg.net Posts: 385	Exhaust cap-nut replacement/mod. Nov 24, 2012 9:05:24 GMT -5 Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by 50cc on Nov 24, 2012 9:05:24 GMT -5 Wiring them together is the smartest thing I've seen in a while!! Wondering if I can do the same with the two engine mount nuts..
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urbanmadness
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Exhaust cap-nut replacement/mod. Nov 27, 2012 22:05:21 GMT -5

Post by urbanmadness on Nov 27, 2012 22:05:21 GMT -5

When my buddy lost his exhaust nuts, we just used standard nuts with lock washers. The original cap nuts worked loose and he lost them on the road some where along with the donut gasket, so we improvised. if you use standard machine nuts on the exhaust studs, use lock washers too. A squirt of lube during oil changes is always a good call as they do corrode.

There's your problem.... something's wrong with your suck, squeeze, bang, blow!

Deleted
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Exhaust cap-nut replacement/mod. Dec 18, 2012 12:14:45 GMT -5

Post by Deleted on Dec 18, 2012 12:14:45 GMT -5

I really appreciate this tip as I have one half held on by a regular nut because the price of those cheap caps pissed me off, remember to bring the old cap with you so as to match up the thread, that is very important.

On a side note I found it best to check these nuts with a torque wrench (8-9 ft.lbs.) regularly as they like to come loose, popping in the exhaust can be an indication of this.

And the reason why I highly recommend using a torque wrench is...

Nov 24, 2012 2:07:38 GMT -5 biggwill69 said:

How do you take a broken stud that broke of with the cap nuts I have a 150cc sunny scooter

You may have a problem, is there anything of the stud left sticking out?
If so, you can TRY grabbing it (you only get a FEW chances so make it count) grab it FIRMLY with some vice grips and see if you can turn it out.

It would help, to get better clearance, if you have a motorcycle lift.
Probably you're now looking at removing several plastic body panels also.

The Vise grips are far from perfect but due to the cramped space on a gy6 exhaust I found nothing worked better thou there do exist a number of special stud extraction tools and sets where I blew some more of my money.
If I recall correctly, I grew gray hairs dealing with this problem.
Yes, I even bought a set of left-handed drill bits, but I did tried.
Better off already, buy yourself a 3/8" torque wrench.
You'll need it anyway...

Because if that doesn't work I'd start ordering a new cylinder head.
Which is what I had to do, set me back several days waiting for parts...
The good news is the head cost about $30 and the actual repair took an afternoon...
You'll need a gasket set as well, cheaper to get a whole set ...
Don't forget the studs, and the caps.

Some people and you can try but I don't advise drilling it out and re-threading because there exist oil passages within that cylinder head and if you go just a little too far with the drill or the re-thread tool you could get metal shavings inside the engine, not to mention an oil leak...
I know all about this as well.

Don't forget to get the NCY $6 performance exhaust gasket:
www.ebay.com/itm/SCOOTER-150cc-GY6-NCY-RACING-PERFORMANCE-EXHAUST-GASKET-/160932957145

Last Edit: Dec 18, 2012 12:49:16 GMT -5 by Deleted