GreginDenver

If you're going to install LED bulbs in the turn signals you need to replace the flasher relay with one of these: https://www.superbrightleds.com/moreinfo/motorcycle-accessories/electronic-led-flasher-relays-for-motorcycle/787/842/

Yes, he (the guy who did that Honda N600 build) is currently active on the VFRWorld forum. His screen-name there is "ccrunner". He's currently working on another "Bike Engined Car" conversion which is a late 1950's Berkeley sports car and he's using another 5th Gen VFR800 engine.

Guess I'll have to start reading up on the various boxes available for the 5th Gen, unless you're going to tell me that there's a clear winner in the group, an obvious choice that everyone agrees is the way to go.

Hope this isn't a dumb question, here goes: It seems to be assumed that every VFR getting one of these exhaust systems will also have some sort of tuning box/device. I haven't gotten into tuning either of my 5th Gen VFRs, is it a necessity with this exhaust? I was just going to buy the exhaust as a replacement for the ugly, rusted OEM exhaust that's on my '99 without any thought about tuning the bike for more horsepower. Am I thinking wrongly about this thing?

I'm wondering if "race-prepped" motorcycles are the best source of modification ideas/guidance for people who ride motorcycles on streets.

If one engine has VTEC and the other does not do you think these two engines might need a different airbox configuration?

I heard that the EPA fired their motorcycle intake noise regulation from the "grassy knoll".

Great job! 2019 is an "odd numbered" year, so I'm looking forward to the coming summer when the Iron Butt Association run their Iron Butt Rally. I would never try something like this but I really enjoy tracking the action day-to-day to see how it goes.

It sounds like you're just gonna double, triple and quadruple down on your "noisy intake" idea. And not only that, you're gonna go all conspiracy theory (Honda doesn't want us to know this stuff... black-helicopters, chem-trails). And you're doing this in spite of the fact that Honda very plainly explains (in Chapter 21) that the VFR800 airbox is not restrictive at all. I mean look, read, understand... here it is in plain black and white:

Okay, let's talk/debate... Maybe, before we start talking actual technical issues, we should try to work out a couple of what I'm seeing as "barriers to communication". First, you seem to be very strongly self-convinced that the VFR's airbox was designed the way it is for noise abatement reasons. I find this to be very strange, I've read a a lot of the published literature on the VFR and have never seen any mention of this, where in the world did you get this idea from? Second, it seems that you want to discount the information in the Service Manual Chapter 21. Why do you think Honda went to the trouble of including the Chapter 21 information? Can you give me a good reason why I shouldn't take Chapter 21 at face value?

You're not getting me (can't tell if you're doing it on purpose or by accident), but let me be clear: I'm completely disagreeing with you on this subject. Once again, reading Chapter 21 of the Service Manual will completely debunk everything you (seem to) believe about Flapper Valve and Snorkel modifications. I'm totally willing to discuss this situation in depth, issue-by-issue, if you would like.

Okay, just in case I'm missing something here: You're saying that performing a mod to make the flapper valve stay open during low Rpm/low "demand" situations (instead of closing as it was designed to do) somehow delivers more horsepower in the higher RPM/high "demand" conditions (during which the flapper was always programmed to be open anyway)? I'm confused.

By the way, doing "the usual snorkel-flapper mods" isn't really a great idea. Yeah, there's a lot of back-and-forth argument on this subject but I can tell you that 99% of the guys (maybe even 100%) who argue in favor of this modification have not read Chapter 21 of the 1998-2001 Honda VFR800FI Interceptor Service Manual, which is entitled, "Technical Features". If you were to carefully read (and understand) the information Honda has provided in this chapter you would realize that disabling the flapper valve and messing with the snorkel is a counterproductive effort. I'm not going to try and explain the whole situation here in this post to your forum thread, but the most important piece of information contained within Chapter 21 is that the VFR800 ECU runs in two different modes, depending on "demand" (which is closely, but not completely, related to throttle position). In conditions of low demand the ECU makes its fueling decisions primarily based on information provided by the Manifold Absolute Pressure Sensor, and in conditions of high demand the ECU makes its fueling decisions primarily based on information provided by the Throttle Position Sensor. Now I'll leave it to you to carefully read and understand the Chapter 21 information and by doing so come to an understanding of why the snorkel and flapper are installed on the engine (and why the Honda engineers programmed the flapper to open and close when it does).

Here's a bit of information that hasn't been mentioned yet in this thread: the 5th Generation VFRs breath pretty heavily through their crankase ventilation system, which dumps the oily blowby gases into the bike's airbox. As a result of this the intake valves can end up with a good bit of carbon build-up on them. If you're going to take off the throttle body, for something like getting at and replacing the thermostat or to remove the injectors to send out for cleaning, you should look at the intake valves to see just how much carbon is stuck on them. Both of my two 5th Gen VFRs are low-mileage but both of them have a good bit of carbon build-up on the intake valves. I'm currently looking into various ways of cleaning them up. Another possible cause of fueling problems is a fuel pressure regulator that is beginning to fail.

I own an example of both "sub-generations" of the 5th Gen VFR800, a 1999 bike and a 2001 bike. I don't know if you've noticed this but something happened to the VFR800 clutch pack internal parts arrangement when Honda changed the 5th Gen over from the first half of the 5th Gen (the '98-'99 bikes) to the second half of the 5th Gen (the '00-'01 bikes) Here's the 5th Gen VFR800 clutch question I've been asking myself (but as of yet I haven't been willing to do the work to find out the true answer): What happened to the "Judder Spring Seat" (part number 22125-ML7-000) and the "Judder Spring" (part number 22402-ML7-000)? You'll find the Judder Spring and the Judder Spring Seat are listed on the parts fiche diagrams for the '98 and '99 year models of the VFR800, but these parts are not listed on the '00 and '01 year models parts fiche diagrams (even though the parts providers often use the same drawing of the clutch parts for both 5th Gen sub-generations, which shows the Judder Spring Seat and the Judder Spring). You'll also notice there are differences in the number of Clutch Plates and Clutch Friction Disks: The '98-'99 bikes have 8 Clutch Plates and 9 Clutch Friction Disks, while the '00-'01 bikes have 7 Clutch Plates and 8 Clutch Friction Disks. The part numbers for these Clutch Plates and Clutch Friction Disks are different for the '98-'99 bikes and the '00-'01 bikes. If the '98-'99 clutch pack includes all of these extra parts (the Judder Spring Seat and the Judder Spring and 1 more Clutch Plate and Clutch Friction Disk) my guess is that the plates and disks in the '98-'99 bikes must be thinner and the plates and disks in the '00-'01 bikes must be fatter. Or... Honda changed the "stack height" inside the clutch basket (which would explain the need to change the number of disks and frictions and do away with the Judder Spring Seat and the Judder Spring). Further evidence that something was changed in the "stack height" of the clutch, the part number for the Clutch Center (the part of the clutch that transfers power into the bike's transmission) is different between the two 5th Gen sub-generations. This is the part you would have to redesign if you were going to change the overall height of the of the clutch internals. Could it be you're working with a clutch that the prior owner somehow miss-matched parts or accidentally deleted parts (for your '98-'99 5th Gen sub-generation)?