Yonaka Civic Si Coupe Exhaust won't bolt up...

JT Si

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I finally got around to installing the dirt cheap Yonaka Civic Si exhaust I pre-ordered a while ago and it doesn't bolt up.

The mid-pipe flange is so thick the factory frontpipe studs are not long enough to thread the nuts back on.

I looked around at other exhausts and they all appear to have solved this problem. 27Won gives special stepped nuts that recess into the flange to achieve threading. Takeda has milled the flange corners thinner around the holes so the factory studs like through sufficiently. Another brand made the flange out of thin metal similar to the OEM design.

Yonaka did provide hardware, but it's just a bunch of regular nuts and bolts. I'm going to contact them ASAP but I don't have any idea how they expected this to bolt up.

Does anyone know if the frontpipe studs are easily removable? It didn't look like it, and that's the only way I can think of to make this work - remove the frontpipe's studs and drill the holes out large enough to feed the Yonaka bolts through.

If that's the intended installation, that is far from "bolts up to OEM" as advertised.

Does anyone have any ideas? There were no instructions provided on the website or in the box.

I tried searching for nuts similar to what 27Won provides but I came up short.


As a side note the hanger for the mid-pipe doesn't fit the OEM hanger correctly, either. I'm starting to regret buying cheap. :doh:
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boibuddha

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There are tiny welds that hold the front pipe bolts. Smack it with a hammer a few times and wiggle the bolts around, they will break loose.

I've seen this come up with some other cheaper exhausts as well. They either expect you to have an aftermarket front pipe or they glance over the small details, such as this.
 
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JT Si

JT Si

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There are tiny welds that hold the front pipe bolts. Smack it with a hammer a few times and wiggle the bolts around, they will break loose.

I've seen this come up with some other cheaper exhausts as well. They either expect you to have an aftermarket front pipe or they glance over the small details, such as this.
A little disappointing. Do you know if there's a problem reinstalling the OEM bolts/studs to reinstall the factory exhaust after breaking the weld and removing them?
 

boibuddha

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A little disappointing. Do you know if there's a problem reinstalling the OEM bolts/studs to reinstall the factory exhaust after breaking the weld and removing them?
I don't see it being an issue since the welds are pretty small. If anything, using OEM bolts might even help hold the head of the bolt (if the bolts are located in their original location) while you attach the nut to it.

Sorry for the late reply. I hope you managed to get the exhaust on. Don't forget to share a sound clip too.

Cheers.
 
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JT Si

JT Si

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I don't see it being an issue since the welds are pretty small. If anything, using OEM bolts might even help hold the head of the bolt (if the bolts are located in their original location) while you attach the nut to it.

Sorry for the late reply. I hope you managed to get the exhaust on. Don't forget to share a sound clip too.

Cheers.
I haven't yet. I'm waiting to hear from Yonaka about the hanger post being too short to seat the hanger.

I'm on the fence about whether I want to install it now or just get the frontpipe I was planning on getting later to do it all at once.
 


ebatr24

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I recommend the PRL or RV6 front pipe both excellent quality. If you are looking to go cheap you can even go PLM which is a copy of the PRL and will come with its own bolts to mount to the exhaust. Otherwise just get some hardware man, not really that difficult. I cut the hanger on mine but, that's because I am not sure it was intended to fit as I put this exhaust on my Type R lol.
 
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JT Si

JT Si

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I recommend the PRL or RV6 front pipe both excellent quality. If you are looking to go cheap you can even go PLM which is a copy of the PRL and will come with its own bolts to mount to the exhaust. Otherwise just get some hardware man, not really that difficult. I cut the hanger on mine but, that's because I am not sure it was intended to fit as I put this exhaust on my Type R lol.
I was eyeballing the PRL since that thread about the FK8 review group got me looking at their Facebook page and someone there PTP wrapped one. It looked fantastic.

Honda Civic 10th gen Yonaka Civic Si Coupe Exhaust won't bolt up... FB_IMG_1590505444850
 

ebatr24

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Yeah the PRL is a great piece, so is the RV6. You really can't go wrong with either.
 

Rustlinjimmies

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I've heard multiple sound clips of that exhaust and it sounds so good for the price I would do it if they made them for the sedan but they don't have any plans on releasing any other exhaust this year :confused:
 

PdxJose

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Interesting, I just picked up the same exhaust but locally. I hope the muffler shop doesn’t encounter any problems installing it
 


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JT Si

JT Si

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Interesting, I just picked up the same exhaust but locally. I hope the muffler shop doesn’t encounter any problems installing it
They probably won't. Yonaka indicated they expected heating up the studs and hammering them out, and that a shop shouldn't have a problem.

I'm just waiting on the PRL frontpipe I ordered to get here so I can avoid the whole thing.
 

PdxJose

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They probably won't. Yonaka indicated they expected heating up the studs and hammering them out, and that a shop shouldn't have a problem.

I'm just waiting on the PRL frontpipe I ordered to get here so I can avoid the whole thing.
I had the exhaust installed thins morning, they mentionEd the hardware that was included didn’t help but they were able to get it on using some of their own. I don’t know if it’s because I got the exhaust used and the previous owner didnt give me the proper hardware but yeah. I hope you don’t run into any more problems. I really like the sound, way better than it stock or any other muffler delete. I think you’ll like it. Even more with the FP you’re waiting for!
 
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JT Si

JT Si

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I had the exhaust installed thins morning, they mentionEd the hardware that was included didn’t help but they were able to get it on using some of their own. I don’t know if it’s because I got the exhaust used and the previous owner didnt give me the proper hardware but yeah. I hope you don’t run into any more problems. I really like the sound, way better than it stock or any other muffler delete. I think you’ll like it. Even more with the FP you’re waiting for!
You bought the one that was modified for the Type R that was for sale in the PNW group, didn't you?

It looks like the hardware that was included from the factory is sufficient, if you can remove those frontpipe studs or if you have an aftermarket frontpipe. I think it was because it was second hand and modified.
 

PdxJose

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You bought the one that was modified for the Type R that was for sale in the PNW group, didn't you?

It looks like the hardware that was included from the factory is sufficient, if you can remove those frontpipe studs or if you have an aftermarket frontpipe. I think it was because it was second hand and modified.
Yup that’s the one I bought. Are you part of that group too?
 


 


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