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VF500 Exhaust


GazVF500

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GazVF500, I'm very interested in how you are making out with your 4-2-1 exhaust system. Any updates on this projectThx!

Interesting you mention that. I have now got a box of stainless bends waiting to be chopped up, I'm just trying to work out exactly the best way to calculate the lengths required.

I've seen a very common equation for the lengths required, but with no derivation or evidence to back them up.

Once I've done this I will update this post!

Good deal! I look forward to seeing what you design.

On a side note, I've added a sketch to help clarify the exhaust sequence.

I've read that 4-1 systems or 4-2s (paired 1|3 and 2|4 with a staggered exhaust) are the best systems for the VF500F based on the pulse sequence.

Any thoughts would be most appreciated.

Thx!

vf500fexhaustsystemsketch01-10-11.jpg

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  • 2 weeks later...

Right, finally had some time to crack on with the exhaust. I found a good source for stainless steel bends, in 316L grade - www.allstainlesssteel.co.uk for anyone who's interested. They only sell pipe in 3m sections, though, which was pointless for me.

The diameters I'm using (basically driven by what was on the bike as OEM and what is available) are 1.25" OD for the primary ( 2 x 4-into-2s), 1.5" OD for the secondary (2 x 2-into-1s) and 2" OD for the tailpipe (as that's what the silencer needs).

So far I've bought 15 off 1.25" 90 degree bends, 4 off 1.5" 90 degree bends, and 2 off 2" 90 degree bends, all seam welded hygienic grade stainless.

I'm only at the tacking-together stage at the moment, but think I have a pretty good idea of where everything is going to go, remarkably similar to my original sketch above! Been working on the back 2 cylinders today, as they seem to be the most challenging to route, but think I'm doing quite well! If all goes well I should make a start on the front pair next weekend.

I need to get some straight pipe sections, as I've got most of the bends cut, just need to fill in the gaps! I've "borrowed" InterFester's collector design from his photo above, hope he doesn't mind!!

And lastly, I know, I know! If there are no pictures, it doesn't exist.......... When I've done some more I will certainly post some up!

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And lastly, I know, I know! If there are no pictures, it doesn't exist.......... When I've done some more I will certainly post some up!

Thanks for the update, I'm looking forward to seeing the progress on this very interesting project!

If I could clarify, your design is a 4-2-1 system?

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Yes, 4-2-1 system, joining both front cylinders and both rear cylinders first, then front and rear banks.

Tuned lengths kind fo go out of the window as they're fairly impossible to package!

I'm trying to keep the 4-2 parts of both banks the same length, but there's going to be a difference front to back in the 2-1 part because I can't hide the extra length in the back.

It looks like I'll be able to keep the centrestand too, which is nice.

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Yes, 4-2-1 system, joining both front cylinders and both rear cylinders first, then front and rear banks.

Tuned lengths kind fo go out of the window as they're fairly impossible to package!

I'm trying to keep the 4-2 parts of both banks the same length, but there's going to be a difference front to back in the 2-1 part because I can't hide the extra length in the back.

It looks like I'll be able to keep the centrestand too, which is nice.

Sounds like you are making good progress on the design. Kudos on working the design around the bike's centerstand. It is nice to have the option of using/keeping this.

On a side note, will you be using the mounting points on the oil pan?

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  • 6 months later...
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I guess I missed the most recent updates, 'bout time you got busy welding. :biggrin:

So it's been a few months, how does it look? Surely you have pictures by now.

I recently purchased a really nice '84 VF500F so I can start moddin'. I really should leave it alone but I know I won't. I can justify mods if they are easily reversible right?

The more I think about it, the more important fit and sound are to me. I still plan to pair 1/2 and 3/4 for fit and easy plumbing sake. They aren't 360 degrees apart but they aren't super close either, at least 270 degrees. Besides, if they all merge into one then they are all gonna share all the pulses.

I'm looking forward to working with smaller diameter tubing, lot's tighter designs can be done the smaller it is. 2"OD gets to be tough.

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Yes, I really should be welding now!

I have made some (very slow) progress with this, but should have something to show for it soon!

Pictures as soon as I have them!

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  • 2 weeks later...

Thanks for all the info. I was going to ask questions regarding firing order for the same reasons and was trying to work out how to route the rear bank so that they would be the same as the front. If I have read this thread correctly, then it does not seem to really matter as long as the longest (front are either 1.5 or 2X the length of the shortest). Am I correct? I don't really need to worry about the centre stand as this will be going onto a Vf1000r.

I purchased a manufactured collector box from one of the members of the UK VF1000 forum members and will try that first before attempting 2 x 2 into one sets.

Thanks for the thread.

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  • 2 months later...

Right, back from the dead! Finally got some time to finish the exhaust, its' fully welded but I need to clean it up a bit as it's not that, er, pretty at the moment!

So anyway, here are a couple of pics so you can see how I've routed it!

DSC00828.jpg

DSC00823.jpg

And here it is fitted to the bike with the end can, I've made it so that it is a snug fit with the footpeg bracket

DSC00824.jpg

Hope you guys thought it was worth the wait, lol!

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Very nice! I hope you set up a jig so you can make a few more...

Love to hear a sound clip once its fired up. Great work :fing02:

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Hey, you got it done! A lot of folks just talk and never build, but you finished it.

We would love to hear it when it is running.

I'm guessing with that Micron can meant for a much larger bike that it'll be quite quiet.

Is the can E-legal or roadrace only? Even a roadrace can is going to be quite quiet, given it's size and the 500's displacement.

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Thanks for all the feedback, guys! As you can see, I'm a little way off firing the old girl up!!

As for making more, I'm not sure I'd go through the pain again :-)!

It'll be interesting to see how it runs when it's finished - there's a DynoJet centre just down the road so I can check the mixture, hopefully!

Managing to make some progress now, this week I got the forks rebuilt (you can see them in the last pic), and the brake calipers refurbished. My CBR6 F2 wheels are ready to go on, just need to work through the rest of the bike and get her back together.

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Looks great GazV! Now hurry up and start the engine so we can hear it. JK, worth the wait.

Duc888, those cans look right at home on yer 1KR. Sometimes mixing old and new really works.

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I'm guessing with that Micron can meant for a much larger bike that it'll be quite quiet.

Is the can E-legal or roadrace only? Even a roadrace can is going to be quite quiet, given it's size and the 500's displacement.

The can is not e-marked, but as I understand it for UK MOT (yearly roadworthy inspections) regulations the can doesn't have to be, it just can't say "NOT FOR ROAD USE" or cause your ears to bleed. I'm not too sure how loud it will be, it's 2" bore straight through. If it's too bad I'll get it a dB killer/baffle.

Duc888, I bet the VF1000 sounds great with those on!

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Interfester, thanks for the feedback.

Gaz, they are not too loud, just a nice low growl. They MOT place that did mine said it was mostly up to the testers discretion. Like you said "as long as they don't make yer ears bleed".

Give me a shout if you get stuck and I'll give you the address of the place that does mine.

Next job on mine is to fit some drilled discs and rear sets.

cheers

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Nice work. That exhaust looks great!

A before and after dyno would have been nice, as i have heard that making an exahust for the V-4's takes alot of science to keep the exhaust pulses from running into each other and hurting performance.

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Looks cool. I can tell you from experience that they are not fun to build from scratch. Mine are 2, 2-1's. My first try had the rears way too short. I ended up adding about 10 inches to them before they merged into one. The fronts are about 27 inches before they merge. Making the rears longer dropped the mid-range down a few k's. It flows really good mid to high now but definitely lost some low end, not a huge deal with a 1000cc V4.

I'd say I'd like to see your fronts a bit longer but can't do much about it now. The fact that you have all four merging might help. You can chase your tail trying to get it right at all rpm's but even the best pipes will have a dead spot somewhere so I wouldn't sweat it. Proper jetting will get you far. I sand blasted and applied a ceramic coating myself which has held up really well so far. Just spray it with any spray gun and bake.

Can't wait to hear it.

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I'd say I'd like to see your fronts a bit longer but can't do much about it now.

If I could ask, is the goal to have the front and the rear tubes the same length before they merge?

It seems exhaust building involves as much folklore as science. I think everyone has heard that pipes must be equal length. How much of that is true is unclear. The Sudco 4-1 for an R that's hanging on my wall has unequal length pipes(fronts are longer). My comment was speaking more to the front length before a merge regardless of rear length. I'm only speaking from experience with my exhaust which is a 2 x 2-1 system and clearly different form Gaz's. My rears were very short before the merge. When the bike was idling, you could feel the difference from the fronts to rears. If you put your hand over the end cap of the fronts(right side), you could feel a steady flow of slight pluses. If you did the same over the rear side, you felt larger pulses and not so steady. I tore off a small piece of paper and held it right in front of the right(fronts) side end cap, the paper fluttered out in a steady arch. The left side(rears) however would swing back and forth, blowing outward then sucked back in to the opening. This had everything to do with length before the merge into 2. Now this was at idle, half to full on the gas, my bike pulled hard and didn't pop on deceloration but I had lost lower rpm power. By lengthening the rears before the merge, I gained back some of that.

This may all be mute if they all eventually merge into one but this was just my experince. I know some have added a simple crossover pipe to gain some midrange, but again, who knows where to add it and what diameter. This is probably like an oil thread, there will be a million opinions most backed up with "what they heard".

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Very impressed with your handiwork! I've heard many talk about making an exhaust for a V4 but very few actually have done it.

I also would like to see your front head pipes somewhat longer but like what you've done.

My exhaust on the R is also 2 X 2 into 1 and also the header pipes are not exactly the same length. Seems to work well though.

Also have a 1000 Interceptor with a Holeshot 4-1. Seems a little softer in the lower rpm range.

Well done.

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