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Discussion Starter · #1 ·
I have performed several searches, so please direct me if I have missed obvious information due to lack of knowing the right terms.



Before I make an offer on a '79 CX500 Custom, I need to know if I can rectify this problem.



The crossover part (collector) is gone. This bike, otherwise stock, is fitted with gutted Harley pipes and lacks all low-end power. It does not have the crossover part. The chassis has the threads for this part intact, in fact the threads for it near the center-stand are clean and fresh meaning the part has not been missing for very long. But as I understand it, this part is hard to find intact and I wonder if there is a way around it.



I won't make an offer on this otherwise all-stock bike if I can't get it to perform as the Honda engineers intended.

And I did do a search, but I don't see that anyone has found a workable solution to the collector missing.



Please tell me a way around this exists! Because otherwise I know I can bring this bike back to a street-worthy status, and this old engine should be back on the road again.



My "rescued" '86 VFR needed a crossover pipe to re-gain midrange power from the aftermarket Supertrapp exhaust installed when I got it. That was cheaply and easily accomplished by a local automotive exhaust welder. But this CX500 exhaust seems to be far more detailed.

Again, assuming I searched with as many terms as I could think of and found nothing, is there a known way around this problem?



Many thanks for any info.....
 

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We typically call that the H box, and they can be found on Ebay on occasion, but condition of them are always used. To my knowledge, it is not something available new. Some are in pretty decent condition, but usually with some rust as that is a very weathered area.



There are some folks who modify to exclude the H box, but other modifications to carbs, jetting and exhaust have to be accounted for to get the bike to run decently.



If your goal is to put it back as designed, find the best looking used one on a web sellers' site and cross your fingers. You can't fix the insides, but you can tidy up the outsides.

*edit* to add, if you have a wrecker yard in your area, sometimes they turn up.



Joel in the Couve
 

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As Emeril would say, BAM....there ya go!!! Thanks Bear! I did not know that.
 

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Hi Mate. Some aftermarket ones are available. Try these guys in the UK.

Aftermarket collector



DavidSilverSpares.com or CMSNL.com


Hmmm..... seller says "Out of Stock".



To the OP are you sure that the H-box is all that has been changed on the bike? Any carb mods to your knowledge? It may be

easier to rejet and modify the intake to match, ot stuff those pipes for more back pressure, than find an H-box.

Good luck.
 

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1978 CX500 "The Grub", 1983 GL650I "Nimbus"
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The crossover part (collector) is gone...

I won't make an offer on this otherwise all-stock bike if I can't get it to perform as the Honda engineers intended.

And I did do a search, but I don't see that anyone has found a workable solution to the collector missing.
Assuming I can separate it from the mufflers, I have a collector from a Custom, but I'm not sure what year. (Anyone know if it matters?) It was given to me by another forum member, so it's yours for shipping.





R
 

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There are a couple on UK Ebay,



http://shop.ebay.co.uk/i.html?_nkw=...ust+box&_osacat=0&_trksid=p3286.c0.m270.l1313



I don't know if they post to the USA.



Note:I bought a new,"Standard" Cx500 h-box(The Custom boxes are different) last year and the after market down pipes on the bike were a little longer going into the front of the H-box so I had to hack saw of a couple of mm off the Manifold Down pipes.When I checked them against an OEM pair I have they were indeed longer at this point so make sure everything fits no matter what you get and adapt where needed as things can vary.



It would be better if you can source them in the US as the pound is very strong against the dollar at the moment raising prices.Some one in the US must stock them?
 

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Discussion Starter · #9 ·
It seems to be a pretty finely-tuned exhaust...seems it would be pretty hard to tune this bike any better than Honda made it.



The seller finally agreed to my offer as of last night, so I'm really glad you folks responded with the links and photos, and advice. Much appreciated. I should pick up the bike by this weekend.



Randall, if you don't want the part, I'll see if the part number matches for the different years. What year is yours? This is a '79. If it will work, I'll send you something cool local from around here, to thank you.

If it won't fit, I still think the overseas offering is a good option unless I score a good used one.



The cutaway diagram posted above says there's steel wool in there. Will that need to be re-packed, like fiberglass muffers?



Lastly, these cans are gutted. I think I will need to source some HD cans to get the right performance without a bunch of tuning, right? I was searching the site and saw that the Dyna cans are good. That really hits me hard, because I bought a Dyna years ago and the nearly-new cans hung on the wall for years. I scrapped 'em after I sold the Harley and moved on to "performance machines" like old Hondas! Now I wish I had 'em back....



So stock Harley pipes will offer the backpressure I need, right?



Thank you all again for all the help...
 

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I've never worried about any steel wool being in there so don't worry.As there are several versions of even Harley 883 exhausts(I have two pairs one of which you can see right through but have a small baffle plate in,the other pair you cannot see through so have more of a baffle.

They do affect the performance but how and how much could only really be tested on a,"Dyno".They work well enough and most the exhaust balance is taken care of by the Collector box/H-box.

My MPG goes down with with either set of my Harley's on and more with the straight through ones.I got a few MPG back with this little mod,



http://globalcxglvtwins.hostingdelivered.com/viewtopic.php?f=9&t=324&p=1667&hilit=harley#p1667



The full stock system is of course the best or a Motad 2 into 1 system for overall performance as they have been designed to the engine and of course Honda,like most bike makers,have the equipment,experience and knowledge to get them tuned exact but the Harleys are of good quality and pretty easy to fit and take off.Some people say they have had no effect on their MPG however that has not been the case for me.
 

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Discussion Starter · #11 ·
Thanks Shep. I've never re-packed a muffler....



As tempting as the Motad is, Randall might have exactly what I need. It looks like some parts he can't use will fit my '79...when I finally get it home.

Weather's been stormy so Hubby needs the truck to get to work. It's our only 4-wheel vehicle. My job is much closer so I just put on the wet weather gear and take the bike.



I can't wait to get this thing home.....
 

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1978 CX500 "The Grub", 1983 GL650I "Nimbus"
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The mufflers I'll be sending to Coffee_Brake appear to be straight through. Is this typical for the Custom?



I don't see any evidence of alteration. When I look down the throat, all I see is a narrow tube, which I assume is perforated along its length to interact with the resonance chamber in the cone? The mufflers on my Standard are indirect, like the illustration above.



Was the Custom exhaust open to give a tone more in keeping with the cruiser-esque styling?





Thanks,





R
 

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I can't speak for the Customs per se but I have a set of,"Stock" exhausts on one of CX500s now that on one side you can see through but the other you can't.They are from different makers/after market e.g mixed over the years.They behave the same so I think there is even some variations in,"Stock" exhausts.They both have baffles in,just a slight difference internally.



HTH
 

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The stock mufflers I had on my custom you could see right down through them. The baffles had holes all down the inner tube. Here is a pick of what the baffles look like





 
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