MooseMoose

I'm of the 3 bungs camp. Here's the deal, I think the ONLY person here who has a quad of sensors on a VFR is @CandyRedRC46 , and he already has a TBR exhaust. I seriously doubt any of us are going to do more than one, or two, of these lambda sensors. It would be best to just sniff down the exhaust and get the 4 cylinder average, just like we're all going to do. PCIII folks are going to dyno it with a sniffer in the tail, rapidbike MTB and PC Autotune folks are going to stick with our current sensors. As for the question of whether 4 sensors will destroy the flow, I understand the concern. But @CandyRedRC46 had one in each downpipe and has posted impressive dyno runs. We're talking RC45 race bike level numbers on a 6th gen. 120hp is pretty impressive for a VFR. I don't think that's a problem, though if he's still paying attention maybe my tagging him will let HIM tell us of his reasoning. That said, I still don't think it's worth the effort for this particular exercise as most of us just want a nice header that isn't rotten or a chinese piece of marginal quality. A little gain in the high end is a nice benefit, I think most of us will be happy to see it, but the last 2% of horsepower or mileage you get from PERFECTLY balanced cylinder fueling can be left on the table. Oh, also, note that a map on one bike is not going to be the same as a map on another. They may be close, but fine tuning each cylinder on a test bike won't match a differen't bike's airflow, fuel injector condition, etc. If you're looking for a base map for PCIII or non AutoTune folks, I doubt it'll really be helpful for folks who want to build a map for their own bikes. After 20 years, they're all kind of snowflakes, especially with wear and mileage.

It IS a concern, though I don't know how much. And the corroding is a concern. Somewhere in the Honda manual it says to NOT use carb cleaner on the throttlebody as the bores are coated in a molybdenum something or other to prevent corrosion. I didn't mention it because you're well past that stage, but yeah. Make sure to do anti corrosion. Also very smart to do the o rings. Mine were a crusty mess. It's a 5th gen, and 20 years takes its toll on rubber, regardless. They're a cheap, easy change if you have the throttlebody off anyway.

Absolutely! Mine was a leaky mess as is. I yanked that BEFORE I did the MTB and my idle changed a touch, which tells me it wasn't exactly working per spec anyway. You can argue about flapper mods, and I can see both sides, but I will ALWAYS recommend yanking the PAIR, regardless. But if it's letting fresh air in you straight up won't get the right readings. Probably run rich and fluctuate based on how you're riding and how much air those valves are leaking in.

Yes. Same as for the 5th gen 00-01 bikes. The sensor goes in separately, after the merge. There's a checkbox on the software to fudge the data if you leave the stock sensors in place, and they remain in place so nothing silly happens at the ECU. On my 5th gen I just had a local shop pop a bung in the mid pipe as close down stream of the merge as I could fit it.

You might want to replumb that thing, too. My vacuum lines were pretty crusty and leaking enough to throw a code on the MAP sensor, so I had to re-remove the throttle body and run new vacuum. It's not hard. Just did it one line at a time so I never got lost. So, since you've made the mess already, you might as well.

Hi Anonymous, Thank you for your donation of --. We look forward to improving the forums with your donation. Thanks VFRDiscussion

Yeah, seems that's the case. I think I have 4.9, but I'm going to look just because I want to know. It's all moot, the system works well right now and I expect it'll be perfect with the new exhaust either way. The benefit really comes in that I can swap cans, or fit a silencer plug, or do whatever repairs as I fix up the bike and have no need for a new dyno run. Even imperfect but pretty darned close beats the heck out of dropping a couple hundred on dyno runs to make rich and lean maps every time I fix something.

I'll search for it. I got mine a couple of years ago so I'm on the cusp. Now I wonder. Thanks for the info.

I'm doing the same, currently, on a delkevic system. Had a bung welded into the pipe just behind the collector, where the two stock sensors are installed. As an aside, how do I know which sensor I have? I just bought the MTB kit and installed it, but didn't realize they have a newer, better sensor. Not that it matters much, but now I'm interested to know. Whatever, on the new headers I will definitely do something similar. Need an exhaust bung on the midpipe as close to the collector point as possible -- whether wade does that for me or I deal with someone nearby. it is super nice to have. Taking the silencer plug out of my can or putting it back in is mindless. It just works.

Well, you know where his bias lies! Interesting work. I applaud the tenacity it takes to do this many things this well.

Kerosine IS diesel. It's a matter of refining, Kerosine being just a little lighter an oil than diesel, but it is fundamentally the same sort of thing and should have very similar properties with regards to how it affects an o ring. That said, I don't know. Maybe RK is coming out with a special formula chain cleaner, or maybe we have been using the wrong thing to clean our chains for a long time and just don't know it. Wouldn't be the first time I used something that worked but might not have been the very best.

That's a good ride. With a little TLC it'll take good care of you. Mine was similar vintage. 01 with 20,000ish miles when I bought it. They're pretty on the outside, but sometimes dirty underneath. You'll find you need to clean lots of stuff whenever you do maintenance. And little things definitely show age. For example, my o-rings were pretty crusty so I suggest you change them out when you decide to replace hoses or if you ever pull the throttle body. I did a clutch, I think sitting for a long time is not good on a wet clutch and a bike that old without many miles may have sat for some time. Other than that, most of my maintenance has been to make it better for me, not required. It's a surprisingly nice bike for a 20 year old design. Enjoy!

Yeah, I think you are right, though I only know that by reading here so...

https://commons.wikimedia.org/wiki/Police_motorcycles_by_brand#/media/File:Japanese_HONDA_VFR800P_police_motorcycle.jpg It's the Japanese Police version of the 5th gen VFR. Has raised bars, bags, and fittings for crash bars, etc, but is fundamentally the same as the VFR800 Super fun youtubes of the VFR800P in action, too. Like this: