VF500F Aftermarket Exhaust Systems from Back in the Day

Thank you for the post.

5x5 on the 'skew'.

 

A bit more intel on the VF500F 'Droner' engine (source: Big-bang Firing Order, Wikipedia)

 

In doing a bit more research on 360 degree cranks I came across this interesting post on Classic VFRs:

MarkJHarris
27-06-2007, 12:39
Time to simplify things folks....

A 180 degree crank is just like a bicycle crank and pedals. One goes up while the other is down. When you apply that to a 90 degree V4, it does get more complicated. But suffice it to say that when the front bank are both half way up their strokes, the rear bank at at TDC and BDC. With a 360, you'd have to take the left crank off and re-fit it so it matches the right side. Try riding it without clips or SDs would be a bit difficult and your tummy would feel it in no time too.

The actual firing order for the 180 engines, i.e. VFR750 and 800 is BangBang...bang........bang you can hear it if you listen. The VFR400R and RC30/45 engines are far more regular in beat, more suited to high revs.

On an RC45 it goes rear left, front right, rear right, front left. BangBang.....BangBang.....BangBang......BangBang.. ...lovely.

Both bikes do sound quite different, even though the engines are almost identical. Remember that the RCs and indeed NCs don't have collector boxes, the exhausts run 4-2-1, with the fronts paired and rears paired.

The VFR800 has one rear and pone front paired before entering the box then a solitary exit pipe.

The RC has a far angrier tone at fast idle. Then again the road bike pipes are far too small and the gas speed is silly, which explains the lack of top end.

With my Akropovic 4-2 conical racing on, it sounds amazing, if a tad loud for the neighbours!

The wail off walls as you open it up is almost embarassing though, hence it's back to the O.E. pipes for now.

These sound descriptions help quite a bit in understanding the rhythm of the engine/exhaust of a 180d vs 360d crank.

 

An interesting 4-1 exhaust installed on an '85 (note the length of the rear headers).

This image was taken from the SuperTrapp Forum. SuperTrapp says that while the muffler is theirs (a universal muffler) the rest of the system is not.

Has anyone seen one of these systems before?



My 85 Interceptor: What system do I have? - SuperTrapp Industries Support Forums

 

So ic I can't help but wonder if you've got something in the mist with you collecting all this data are we gonna see a special exhaust system from you?

 

Thanks Matt. I think others are a few classes ahead of me on this! I've been gathering intel as part of a goal of creating a library for VF500F owners. Hopefully this will be of help when sourcing/fabricating exhaust systems for the VF500F.

 

I've mentioned this before and was laughed off for the idea......but what is the problem with running the headers to 4 small individual mufflers? A 4-4 system?
Maybe crunch the numbers so the pipes are too lrg and still give enough backpressure?

 

In a word, scavenging.

From what I have read, 4-2-1s are the best exhaust systems for the VF.

 

Although you lose the scavenging effect, a 4-4 system is probably the safest bet for the DIYer. Trying to get the phasing correct on a merged system is tricky and requires a good deal of time on the dyno and various design tweaks to get it right. If you want to just weld something together and be done with it a 4-4 might not be a bad choice..... providing you don't mind the four mufflers.

Here's an example of what not to do: YouTube - supersport1958's Channel

 

other than using a few peices of pipe to make a 180 what was wrong with that? just asking

 

Based on my knowledge and experience with V4 exhaust, that looks like a configuration that will have some real problems. The stock collector box does a pretty good job of evening out the flow, so it might not be terrible. I would be very surprised if it doesn't have a negative impact in performance compared to stock.

 

Great thread, lots of useful information, I have a VF1000F that I want to do the exhaust on (I have to change the oil pan so it has to come off anyway), I liked the picture of the cut open stock collector box (its good to see whats inside) a fellow in europe is making a replacement for the collector box (I'll try and attach a picture). Jamie and anyone else let me know what you think of this.
Sorry no picture at this time, I'm at work and I'm blocked from uploading pictures. Later.

 

There is a company in Europe that has made a small run of pipes for the kF but the concept may well work for the 500 as well. There was a group buy on another forum and here is what the guy who started the interest said aboyt the guy making the collector.

"Tubular in construction and then boxed in.This guy really knows his stuff about bike exhausts,it is all he does.He is in last months classic mechanics mag with a new Triumph thruxton that he made some pipes for.Dynoed against the Triumph's own fancy pipes he had 5-6 bhp more for the whole rev range and even Triumph were that impressed they wanted him to make the pipes for them,he showed me the paperwork from the Triumph factory.The tubular collector will free up a fair bit of power in the midrange as the std one is so restrictive when you look inside.
Please dont anyone be concerned about quality or whether it will fit because he is the best in the business."

I would take that as more cred than anyone just theorizing on the subject. If someone is making pipes as a living and getting good reviews, I would feel confident in their ability to understand exhaust flow and the trade offs that pertain to a given bike setup. 100's of custom made exhausts vs. 0 says a lot to me.

Here is his setup for the F. You cut the stock fronts to slip in. The cross over pipe looks odd but I'm no expert so I'll take his word for it over someone with 0 pipe making experience saying it won't work.


It sure looks like it would flow freely but you would need slip-ons for each side so no 4-1.

 

I'm not sure that I like how the rear primaries merge in, or should I say how they don't merge in. Maybe that's why the crossover is so large. I also agree that exhaust performance is not easy to judge by looks alone.

I'm not a big fan of two pipes either, so a dual exit doesn't really appeal to me.

 

Thank you for the post.

I agree it is a bit of an odd looking design but as I'm not an expert in these systems this could very well be the bee's knees for the 'big bang' VF engines.

If I could ask, do you have the contact information for this fabricator? I would like to write to them to see if I can glean some more info on how this system works.

 

Seems to me there more than a slight bit of interest in the vf exhaust market.

 

I'm not sure of any contact info. Here is the post about this pipe.

Honda vf1000.com Owners Forum - STAINLESS EXHAUST INTEREST

You may have to join then contact the author. The pipes are made by OS Pipes in the UK.
Stainless steel motorcycle exhausts, silencers and associated parts manufactured in Staffs England

They don't do email but have a phone # on their site. Their pipe work and muffler work is indeed impressive. If not OEM style then certainly OEM fit and finish. Putt around at some of the bikes they've done in the sample section. I think most good exhaust shops can bend some pipe but doing quality motorcycle mufflers is a different beast altogether.

The above collector appears to be basically a V&H system joined with a crossover pipe. so maybe there's something to the design. Here's a V&H for a VF700


The rear is quite short compared to the front. V&H either felt this was the hot setup or was trying to mimic the Race bike versions. It is naive to believe that all pipe mfg'ers in the 80's were producing pipes with amazing power increases. Bet that many were rushed out to meet consumer demand regardless of performance gains, with aesthetic appeal, ease of manufacturing, or both being more important than performance gains.

 

Thanks hop. I agree that many systems are more about aesthetics & ease of manufacturing than actual performance.

With this in mind, the V&H system probably isn't the best model as it paired the 1|2 and 3|4 cylinders, which from everything I've read (and seen in photos) isn't the way to go. Pairing the 1|3 and 2|4 being the best setup for the 'big bang' (360 degree crankshaft) VFs.

On this topic here is an interesting read on aesthetics versus performance:

Pipe Jetting

 

I noticed that the factory race bikes of the first gen (big bang type 360* crank) split the front and the rear cylinders apart. Treating them like two separate engines, sort of. The factory collector has 1&3 and 2&4 cylinders pointed out the same side, respectively. The exhaust piece Hopit88 shows the same with a balance pipe (which I like).

I do know that using H,X or Siamese balance pipes on cars (American muscle) will produce more mid range power. It also looks easy to make. I wonder why the factory racers separated the front and rear. For top end may be.? Hopit88 what is the diameter of the V&H pipes? They also look easy to fab. It would be interesting to find out how and why each design worked. Anybody know?

 

Thanks for the read. It confirms what I've thought all along, many people are more concerned with sound when buying a pipe. I thought the subject of the "tuned exhaust" was interesting. I know we've all heard how vital pipe length is in header design and that with all the proper calculations you can get a pipe to perform but what some don't realize is that "tuning" is specific to a given RPM range and it may be a VERY small rpm range at that. In racing, that rpm range is usually top end since, hopefully, that's where you will be most of the time. On the street, we like more mid range for passing or accelerating without having to down shift. The part I found fascinating is, once you add a baffle, all the "wave tuning" you tried so hard to achieve, goes out the window. No baffles in race bikes but Joe Blow's race replica pipe on his GSXR does so his benefit is greatly diminished. So what can we gather from this article? It seems to say that you don't HAVE to have a specially tuned exhaust to make your bike perform a little better, in fact, if it has a baffle, there's no point in even trying to keep pipe lengths equal. If you can drop some weight by ditching the stock exhaust, add a good breathing filter and play with the fuel delivery a little, you can make your bike perform better than stock. And if not better but just as good, then super. Stock collectors are getting rustier and rustier as time goes by so anything that keeps these things on the street is cool in my book. That is exactly why the above collector was commissioned, to keep a bunch of guys in the UK on their V4's.