Vf700-750f, Exhaust note?

I am really curious how one of our vf7f's would sound with straight pipes slipped onto the collector. Surely the collector box provides some sort of dampening and possibly kills that sweet v4 4->2 sound.

Guess I will find out soon enough, I have already loosened and sprayed the clamps as well as unbolted the mounts, mufflers should be ready to pull by the time I get back out there and get the carb rack on.

I will post a short vid of how it sounds, in the mean time if anyone has heard a vf700-750 with straight pipes behind a factory collector , I would be interested to know how loud it was.

IIRC I found a thread where a guy rode a vf750 home with one muffler/pipe/can missing and it was obnoxiously Hardly Hog loud. But that might have been on a later model without the center collector box.

I already pulled the airbox inlet snorkels, so that I can hear a little intake sound. I want to able to hear the exhaust note , not break out the earplugs, scare inattentive drivers as you pass loud, but at least as loud or louder than the valve train.

Regards
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Ever since I got the 4>2 Vance & Hines pipes in '84, I have found the sound to be "unusual" at best. The cadence or firing order never sounded like a hot bike even though it went like stink.

 

The collector box obviously let's all the exhaust run together to an extent, at least enough to balance the pressure waves. But not sure how it's designed internally . I would imagine that the majority of the left cylinders exhaust pulse is picked up by the left pipe, same for right.

Definitely got some experimenting to do.


Later
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Front two into one, rear two into one.

 

Is the pic of the V&H setup?

 

Yes, right after I had them ceramic coated. They had lost most of their original coating and were rusty.

 

Was thinking it would run to left two cups and right two cylinders but really if you think of the two banks front/rear makes more sense. Saw someone is able to get these built for $300-350, too bad the money tree is down to singles on the branches

 

Well? How does it sound? I plan on having straight pipes as well. Is it a good idea to modify the air box by removing the snorkles and maybe the plastic panel that mounts to the frame in front of the snorkles?

 

Every picture of the HRC 750's were like the V&H, front two and rear two.
Air box mods don't work, has to do with making sure all 4 carbs get the same amount of air.

 

Those mufflers were a bear to get off, I even have a new used collector to put on, think I will have to pull the whole exhaust as a unit then wrestle off the mufflers.

However I did drill the rivets in an effort to get the baffle out, and believe it or not it made it loud enough for me.

If I were to drill it just for sound I would probably do 4 1/4"-3/8" holes centered in between the rivets.

Here is a clip of the exhaust with the rivets drilled.
https://youtu.be/6CkjH9Vfz1c
[video]https://youtu.be/6CkjH9Vfz1c[/video]

Let me know what you think, it smooths out a bit once it warms up, but I don't like to let it sit and run any longer than it takes to come off the fast idle. After that it's fairly gentle riding until the engine and coolant is up to temp, then it's all good to give it the gusto if that suits the mood.


Later
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I understand about the airbox, definitely gonna loose power if you pull the velocity stacks going to each carb off. All I did is remove the inlet tubes on each side of the air box.
Doubtful it will help with power , but I always liked hearing the intake sound especially on anything with a manual trans. Love the sound of accelerating at WOT but moderate RPM when you can really hear the intake sound.

Call me crazy....most do

Later
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Finally got the end "cap" off . The rivets not only hold the end cap but the small exit pipe extends on into the pipe.
After about an inch it attaches to a 2 1/2" X maybe 8" long glass pack. At the other en of the glass pack is another 2 inches of 1 1/2" pipe that inserts into another disc that is mostly open (has just enough material to hold the back of the glass pack)


Internal glass pack



The holes as you can see are not factory, the end cap suffered alot of abuse until it was finally contorted enough to get 2 pry bars behind opposite sides. That said not to worried about the ultimate fate of the muffler as it will likely be replaced either with stock pieces or another can altogether.

Here is what is inside the pipe after the end cap and glass pack are removed. Behind the broke piece are two 3/4" pipes that come out near the lower left edge, these are perforated piles that extend on into the main body



Mine obviously was damaged by removing and reinserting the glass pack.
A good word of advice is if you have nice factory mufflers don't take them apart unless your are prepared to make them worthless to anyone other than possibly yourself.

I knew that it was going to be hard to get apart and possibly damage the pipe, but after finding more than a few cans from $50-$100 per set as well as a decent factory right pipe for less than $50. What can I say curiosity got the best of me.
My loss your gain.


After seeing this, if I were to mod my factory pipe I would take a 7/16" drill and drill 3-4 equally spaced holes from the exit hole at a steep angle through both layers of the glass pack. If that didn't give me enough sound ( drilling through the glass pack isn't going to allow more airflow).
Then next thing I would look to do would be.... Use a 12" drill extension with a 1/2" bit on the end to drill straight back and through the internal baffle. This is likely to increase flow and reduce back pressure by adding an additional 1/2 hole to the 2 3/4" pipes that allow flow through the baffle.

What will it sound like? At least the stock mufflers will still look stock from the outside. I wouldn't recommend this unless you are already planning to replace the factory mufflers anyway. That way if it sounds horrible, or causes you to loose bottom end at least you can put on the A/M cans or unadultered factory muffs.
Later
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