Delkevic Headers - the Long Way Round

Hello all, it's been four years since my VF4iR project, so it's time for one final project: Replacing the steel-and-catalytic-equipped stock exhaust with a nice stainless. The only contenders being MOTAD and Delkevic, I read and researched to find if the MOTAD is worth the extra dosh. They seem to be pretty evenly matched with positive and negative experiences, so I swung for the Delkevic, based on 'alilpsi's experience (his bike is much cleaner than mine ...).
Normally, this wouldn't rate a winter project posting, but as I've been going thru this, I realized that anyone contemplating doing this might want/need to know some of things I've discovered along the way.

My motivation was to lighten the weight (-3 lbs), better performance, and cooler running. Along with doing this, I'll be getting the pipes Jet-Hot coated to keep the heat in the pipes and off the motor.

I ordered the Delkevic headers (via Ebay) 2 weeks before Christmas, they arrived on Dec 21st. Upon opening the box, the pipes were bubble-wrapped nicely, but there were no gaskets - none, nada, including the rear header-to main-system joints - I fired off an email to Delkevic that night but knowing it was Christmas I knew it'd be a delay in seeing any action. Meanwhile, cursory observation and measurements confirmed that the new headers were larger diameter than the stock headers - by a good 4-5 mm. Also, the '00-'01 stock headers do a criss-cross plumbing upfront, the '98-'99 do NOT. The delkevics also do not criss-cross. So, I started digging thru online parts listings (servicehonda) and sure enough, there are different gaskets and clamps, between the early and late years of the 5G. Essentially, the Delkevics are replacement headers for the 5G early years, with added bungs for the O2 sensors. They will of course fit the later years, others have commented that they also fit the 6G.
So, a few pics before I stop for the night:

Work Stand: Best investment ever.

Rear pipes orientation:

PB Blaster to the rescue:

The catalytic hanger bolt was the worst to remove:

Yes, the front of the motor look like crap:


More later,

 

Can you post a pic of the cat?

My new 00 looks like it does not have one and I just want to be sure, don't know what a motorcycle cat looks like haha

 

Here is a pic.
http://1.bp.blogspot.com/_TaWn3qQlT3w/Ss9HyzaoavI/AAAAAAAAANM/rTWm4hJ2FyQ/s400/CB750police.jpg

 

I lol'd. Really though, if this bike has a cat on it I will just swap the headers from my 98 on.

 

Unfortunately I didn't take a pic of my 6th gen exhaust when I pulled it off, but here is a pic fo a 5th gen system and where the pipes all come together (the collector) is where the CAT would normally be.



You can see the CAT on the old Hypermotard. It is the extremely fat section of the pipe just in front of the rear wheel.



I installed a 5th gen header on my 6th gen to eliminate the CATs and because my stock header was damaged. It fit the bike just fine but the O2 sensor location resulted in what you see here which is a bit unpleasant. I'm still deciding on what to do in order to eliminate the cosmetic issue. The other issue I'm having is exhaust leaks at the head. The 5th gen pipe has a very narrow flange which is bigger in diameter to the 6th gen so I think I will need to get some 5th gen gaskets to obtain a proper seal.




Here is a picture of teh 5th gen vs 6th gen header pipe flanges with the 6th gen on the left. You can see that there is a notable difference.

 

Thanks Looks like mine has no cat

 

Interesting thread.

I miss the nice clean stainless headers on the 2nd gen....and my 1st gen I cleaned and coated the headers.

They're quite gross on my 4th gen.

 

If a header diameter is too large it decreases the exhaust gas velocity. This effects the exhaust scavenging during valve overlap, which could be detrimental when a VTEC engine is in two valve mode. The elimination of the cat is helpful at higher rpm's though.

:argue2: Not wanting to pick a fight or slam anybody's mods, just pointing out basic exhaust theory.

 

Here ya go! The big fat square block of steel-encased platinum.

So - if you have an '00, you *should* have a catalytic in your system unless, a) someone already replaced the system with an aftermarket system
or a early Gen 5 system (early: '98-'99; late: '00-'01). I don't think Honda built a non-cat version for Canada. Anyone ?

Geeez guys, one intro post and hijacked! Just kidding, NP. I'll try to get more progress posted up tonight.

Norcal: Absolutely correct on the header diameter. The Dels are the same as the early Gen 5 pipes so all should be good for me, albeit with minor PCIII tuning. Interesting to note the late Gen5 using a smaller diameter, don't know why ...

 

I have my ideas, but I have no factual proof

 

Disassembly continues: The two rear header joints and all eight header clamp bolts were sufficiently rust and crudded up, so liberal application of PB Blaster on all threads really helped the removal of them all. Only one stud came out with the header nut, fortunately I have a bunch of spares from a friend's donation. Starting with a Dremel wire wheel, I cleaned up the studs, then installed the new stud using red Loctite and jam nuts.:


The rear section was a tight fit and required much wiggle and prying open of the outer pipe to separate the two:


Here's a side-by-side comparison, and the stock weight:


Prior to receiving any gaskets, I opted to do a test fitting to check alignment. As you can see, the rear pipes are not quite centered into the lower main system, I may have to tweak one or the other end to get the fit correct. The stock rear pipes were really deep into the header system, the ring on the pipe is only a gasket stop:


I mentioned in my first post that I sent an email to Delkevic noting the missing gaskets. They responded almost falling over themselves with apologies!
So they sent me this!:

Two SS band clamps, 4 copper head pipe gaskets, and THREE! count 'em, Three sets of rear header to main system gasket seals!! The two boxes together are labeled 'for VFR800', the other box is for an R6, and has the dimensions on the box - no idea, they all fit, but the R6 ones are a slightly thinner wall. Meanwhile, I ordered the Honda spec gaskets for a '98-'99, and they seem to match the VFR800 ones that Delk sent.

Stopping here now, I need to take more pics of part compares

 

I could be totally wrong, but wouldn't a smaller diameter exhaust "fire" the catalytic converter quicker than a bigger diameter exhaust? It could just come down to an emissions thing.

 

As Norcal suggests, it is probably a tuning thing. The smaller diameter pipe may actually improved low RPM torque numbers on a stock head. The gasses may also stay hotter due to the reduced surface area of the pipe and that also aids scavenging.

 

Scott, really enjoying this thread. I have a 2000 and just placed an order for the Motad so this post comes right in time. It will be interesting to see the differences in the two brands if any. David Silver Spares has the Motad for $459 and I did not think that was too bad a price. Only $17 to ship to CT as well. Not sure if I will coat it, wrap it or leave it alone.

Primo

 

Those shiney pipes sure look good.

 

Final pics and measures before I pack it up to Jet-Hot. A nod to jethro's pic earlier, the stock and Delk header pipe flange faces; noticeably narrower on the Delk. This plays in to the next three pics: Honda vs. Delk copper gaskets. The Delk is a larger diameter by 1.7mm and mates with its flange with less interference. Also slightly smaller cross-section.


The Delk pipe on the left, stock on the right. The Delk is 35mm outer vs. 32mm for the stock. However, the Delk uses a thicker wall at 1.5mm vs. the stock 1.2mm


Note the two hash marks at 12 and 6 o'clock. When I first tried to test-fit the metallic gasket(s), both rear header pipes were quite out-of-round by more than 1mm. Using my calipers, I found the high point and marked at 12 and 6. Then using precise pressure in a bench vise :biggrin: I brought the difference down to ~ .3mm, which is just about what the stock pipes are. I also took a file and slightly chamfered the outer edge, taking off the cut-off burr to allow a smooth fitting of the gasket.


Honda's really improved their clamps! That's a pretty substantial alignment key vs. the older stamped bent nub.


And finally, the Delk weight: a mere 3.8 lbs less than stock.


So, a couple of things to start discussions about: If the stock pipes for a '98 are nominally the same size as the Delk, there shouldn't be a negative performance hit due to larger pipes - HOWEVER - I note that the ECM changed between the early and late years of the 5G so fuel mapping might change and/or ignition curve, but certainly to accommodate the O2 sensors. Cams also have different part numbers between early and late. If you haven't seen this, it's a Honda part number descriptor webpage:
Honda Part Numbers

Tuning: I'm thinking about how I want to tune (PCIII) this with the new pipes: with or without the O2 sensors. The O2's allow for better fuel mileage when on a long trip (more steady throttle vs. hoon riding), BUT, tuning the with the O2's in place means your tuning 'to' the O2, not for best power.
So I was thinking that I could tune it (Factory Pro at Nault's, Windham, NH) with the O2's unplugged, then plug them in. Thoughts, comments ...

Finally, as much as I like the look of the shiny stainless, 1) they won't stay that way, 2) they won't be seen, 3) they'll perform better and keep the engine cooler (I hope) with a ceramic coating.

Primo, I'll be interested in your experience with the MOTAD, you got them for a good price! Then we'll meet and go riding in VT!

Ciao for now,

 

I will keep you guys updated and would love to take a nice VT ride!!!

 

Okay, so I received the Motad header. It is a nice looking piece. Very shiny! It comes with the gaskets for the two rear pipes and two clamps. I had to purchase the four exhaust gaskets and I bought a new header to silencer gasket. No pictures yet. I also bought two oil pan bolts to seal the two threaded bung holes for the O2 sensors as I have a PC V and have them capped already. Pictures and story to follow. This weekend was spent putting my Daugherty set up forks back on the bike. Thank you Jamie!!!! I did take it for a quick cold ride and it absolutely wants to lean in quicker. I was actually amazed. The bike feels totally different. Sorry to change the subject!

Primo

 

Annnd we're back. After a 2 month hiatus to get sh&t done on this and other projects, I think I can start the last half of this project posting.

While the pipe was at Jet-Hot for coating, I did some mild cleaning of the on and around the engine just to get the road crap off of it. One of the other parts of this project was to get the centerstand powder coated because of rust and salt and stupid me not cleaning it off after a wet-salt-and-sand ride a couple of years ago, so my local pc painter did that up.

Finally the pipes arrived - actually it was about an 8-day turnaround - I was surprised at the speed. Jet Hot knows how to pack pipes:

and they do a nice job of coating too:

They also come with a limited lifetime warranty - full re-coat free with shipping within the first year if it comes off, free re-coat and return ship after that.

I put the painted centerstand on, because you have to before the header goes on,

and then started the test fitting of the gaskets and the headers BEFORE installing them on the bike: I think this is an important step to confirming how everything is *supposed* to fit prior to wrestling with it in place (which you'll have to do anyway so do the easy part first).
I started using the Honda sleeve gaskets, but they didn't sit firmly in the main system holes:

Look closely and you'll see the upper pipes are angled into the lower pipe - that's with the bolts down tight.
So a little more measuring reveals that the Del gaskets are 1.2mm larger in diameter than the Honda's:

and the full system fitted and tightened (and my water softener system :tongue: ).

The copper gaskets go in, and the rear pipes go on - not tight, just enough play to allow them to rotate slightly as needed.
Even tho' I show the left pipe first, it's easier to put the right pipe on first *then* the left (working from the left side).
Yes it's a close fit around the shock spring!


Swing the system around the center stand and lay it into position:


Fit the front head pipes into position and loosely attach the collar nuts, then swing the system up into the rear pipes and push them up all the way:


I'll stop here for tonight and hopefully put the rest up tomorrow night. It really does look the balls.

 

Very nice! You make me jealous.