Full system versus modified header

[tomacGTi]

I hate being sick because it means downtime and downtime means needlessly searching Ebay...

So recently I acquired a full Vance and Hines Supersport exhaust for the little bike, the same that Pitter had awhile back. I ran into the same problems he did with fitment because V&H use a 2 1/8" pipe on the collector versus the normal 2". All of this isn't so bad as you can get adapters or just a 2" OD pipe will fit into the V&H collector. I opted for the latter and used my existing slip-on like he did.

I would have used the V&H mid and muffler but I could not get the can apart to clean and repack no matter how much I tried. It was rusty as hell inside and I was sure the packing had been in there for an eternity, it looked like the whole system was stored in a wet basement for the past 15 years. The interior of the pipe is big, like 2 1/4" but has a built in silencer that goes in about 6". I know that the downsize to 2" all around isn't desirable but my hearing and annoyance factor is.

The #4 headpipe had a hole ground into it that I tried to repair but it blew through (guess acid-core solder has its limitations). To fix it right, I'm going to have to cut out the material and weld in new as the steel around the hole is super-thin from being ground as well as rust. I know as soon as I put the torch to it, it'll blow right through so I'm using some purpose-made manifold and pipe repair epoxy now and if that holds, I'll be happy. No need to whip out the sparkle gun.

Here are some initial impressions I had in the very short ride that I did.

-My previous factory header I removed the perforated reducer in the collector and ground down the welds in the primary pipes. I gained good flow all around and in comparison to the V&H header is about 1mm smaller diameter in pipe but substantially smaller in the collector box. The factory outlet at the collector necks down to under  2" ID whereas the V&H maintains at least 2" ID (outlet is 2 1/8" remember).

-If you obtain one, you will need longer header flange bolts. The stock ones are about 10mm too short, they'll only grab about 2-3 threads.

-With the jetting unchanged from the modified factory setup (it would run out of steam at 10k in 5-6 gear) there was some lower midrange loss (4k-7k) but significant gain from 8K on. I wasn't able to really get it on the pipe to see if the jetting was close at all up top till the initial repair let go but to 10k in 4th gear it felt stronger.

-I'm not looking forward to another round of jetting but I think I'm at least close. I have a feeling the mains are within one but the concern to me is if the loss down below can be jetted around or if it's to be expected from the 4-1 larger pipe. It'll suck for the street but scream at the track. There's no free lunch and in worst case, I'll put the stock header back on.

-Noise wasn't much different versus previous setup. If anything, it seemed to be about the same at idle, just a little deeper.

I'll update when I get a chance to put some miles on it. Should be an interesting experiment. For ha-has:

-117 main
-3.5 turns
-3 needle with shim (Dynojet)
-V&H header into Cobra F1s muffler with 2" core
-Uni filter in modified box: 52mm snorkel

[Chris H]

Good to hear you feelin better.
Will be interesting to see if it makes any difference. I got the Beet 4/1 and have not had any probs with poor mid range. If its running out of steam it usually a sign of runnig weak but only a plug chop will show for sure. It would be worth trying with the needle up and then down a notch regards the mid but as you well know its a hole in the head when you gotta keep strippin it down and building it up- why dont they make bikes so you can change the jetting easy!!

[tomacGTi]

I decided to go to the folk's house to use the welder, I figured I'm not messing around with ceramic putty to fix a hole that I can fix right, forever. It was raining anyway, why not?

Glad I did too as when I removed the paint around the area there were at least 4 hidden pinholes near the main puncture. Half hour later and a coat of paint, it was just like old. Gotta love old, neglected, ground-out thin wall tubing.

Some more notes as I took the time to futz with the factory header as I had it off the bike.

-If you choose to gut the collector, you can remove the inner reducer to where the 2" tube is welded to the collector body. This will open up the collector significantly from stock (45 to 49mm). You will need reinforced Dremel wheels to do this as the metal is very hard and you'll even chew through a couple of those in the process. Going beyond the weld doesn't get you any more, just be sure not to cut the outer pipe as well. Grinding the midpipe tube weld flush doesn't hurt either.

-The divider inside the collector is there for a purpose. The reason why the collector box is so long is because it does indeed act as the 2-1 for the pipes so contrary to popular belief, the factory setup is 4-2-1 stock. The divider goes from where the 4 pipes enter to where the 2" midpipe is welded to the box. You can remove the perforated metal easily from the far walls by prying and twisting it out near the tubes but I don't know if it will gain you anything at all.

-Grinding the weld material inside of the headpipes is where the most gain can be made. There is a significant amount and bringing it just flush will open up another 25% that was previously obscured.

-The difference between this and the V&H header is mainly primary tube size (about 2mm bigger on the V&H) and the 4-1 versus the 4-2-1. The other major difference is weight, though not by as much as one may think. I didn't take it to a scale but I would guess 2-3lbs max. The tubing is far more robust on the OEM pipe and can withstand alot more abuse. The small area I repaired today pales in comparison to some of the dents in my OEM pipe.

Hopefully when the weather breaks I can finally take the bike out for a ride and see what the hype is all about.

-Randy

[tomacGTi]

Here are some initial impressions after a quick ride the other day:

-Power does come on later in comparison to a 4-2-1. Bottom end to early part of the midrange are affected. It isn't as sharp as the old header and you have to roll on the throttle gently. Bit softer from 4-6k for sure and doesn't like being lugged at all.

-Power hit comes on hard at around 8k and continues up through the upper revs. Normal power peak I've found is around 10k and the design helps bring the power up above that.

-Jetting for the most part has remained the same as my modified stocker. I'll either need to get to the dyno or really get it up on the top end to sort it all out but for the most part, it's good enough.

I'm looking forward to the track day come June to see what it can do. If you're just riding around town and zipping through traffic, I think the modified stocker is the ticket. More of the power is aimed towards the bottom end of the tach and you don't have to rev it like an R6 to get around. The 4-1 is a beast when it gets going and that's the major difference.

Since the jetting seems close between both pipes, I may just be tempted to swap around headers for the occasion. We'll see, I'm not normally that ambitious and it is a slight PIA.

-Randy

http://youtube.com/watch?v=ZvWQKTY1tKU

A vid I found of the V&H in it's unadulterated glory. Dear God that's loud!