PAIR valve blockoff

How would you cut the Holes in the box - and how big ? I have cut the Quads Box , but (and although the rules apply the same to both engines - I am hesitant to cut or modify theVfr , I love it so much and the quads parts go to hell after 4 weeks tough riding anyway )

I saw some guys removing the Snorkel going Into the Airbox as well .

Good idea? Bad idea ? I'm hesitant about this one . And this together with the Zorst mods is going to basically make a 200 km Ride close to Unbearable !!

..........And suffice to say that the pipes were meant to be a bit more agggressive than The stock ones - I would have prefferred a BOx with Baffles . I notice though the importers failed to mention that they simply import them minus Baffles ..... Disappointing , really .

 

Try it for yourself it's an easy Mod to pull out and re-install.
I tried the Snorkel Mod for about 3000km's before deciding to re-insert again.

On the Positive side it sounded great and it felt like there was a little more HP up top.
On the Negative side found the motor felt a weaker down low and created a Mid range 5>7.5K flat spot right where I like to ride around in. :frown:

Other possible Negative - Speaking to other Viffer's when debating whether to re-install had also heard one say the with snorkel removed water had got into the airbox during sustained heavy rain.

 

Def -

Ever seen a compass with an exact-o blade tip? That's what I used on a few o f mine. Make the circle and keep going round adding a bit more pressure till you can basically press it through with your thumb.

I don't have a VFR yet, so I cannot comment on how many of these holes I would make. I usually make about 4-5 in front and 3-4 in the rear respectively. I like to look at the size of the air box first. Make the holes about the size of a quarter. Sorry, using U.S. currency as a guide for measure here. 5 in front and 4 in the rear is usually what I do, but I know guys that practically make swiss cheese out of their air boxes and they work fine. It's like putting a velocity stack on a car engine. Cutting about 4 holes in the top is also a good idea along with the front and rear for relief of pressure that can build up. Cutting a couple in the bottom of the air box at low points can alleviate any water or moisture that gets inside the box and provide an escape hatch for it. Notice with all these holes you're pretty much talking swiss cheese at this point anyhow, but the flow through is amazing as described above - a home made velocity stack.

Removing the snorkel works, but not as well in my opinion. As John says, it runs the risk of water leaking in if you leave it off and the bike sits outside as mine does. I like having the snorkel connected. A more finished look to it. Most people don't think about this, but when you do either type mod that I describe above you should use a fine bug screen type mesh and attach it flush and tight to the inside of the air box, or to the outside of the snorkel if it protrudes from the air box. You can rivet the mesh or use hot glue or high temp gasket sealer around the edges and around the holes you make.

If you do either of these mods, the first being a permanent type mod whereas the second you can always reattach the snorkel, you can then put the mesh on permanently over the holes with either mod after you test them out.

The flat spot John is talking about can be taken care of by having the throttle bodies readjusted, if you like the mod. Talk to your service mechanic and ask if he/she would recommend or can a remapping of the ECU be performed as well. Also, if you go with permanently removing the snorkel, I would suggest a quarter size hole on the opposite wall of the box for flow through. With the snorkel mod the box will only ram so much air before a type of back pressure emerges. Cutting a hole behind the snorkel relieves that pressure while still getting a ram-air effect. If you do either of these mods, try a K&N filter set-up, or if Honda has a high performance air filter you can go with that too.

I suggest you try the snorkel off first. easiest mod and reversible. If you like that, then add the performance filter and try that along with and see if you like that. Never mind any flat spot in the power band. That can be adjusted with the tweak of the TBs as mentioned above. If you want to keep the snorkel attached then do the air box holes and finish it off with the mesh, then get the TBs resunc and a possible remapped ECU. The best way to make sure you get the most out of the mod is to have it Dyno tested. Most places don't charge much for that and a good mechanic can fine tune your engine in with a few Dyno runs.

If you don't want to cut into your air box, or are afraid to, I would suggest buying another one as a replacement, or practice dummy, so you have a back up stock air box. You spent so much on the cans already that an air box is not a major item.

With your flow through pipes on already, be set for a fairly loud bike!

Stan

 

On some models of after market exhausts you have to specify that you want the baffled version. Most allow you to take the baffles out by yourself later if desired. I think Two Brothers comes with the baffles.

 

My understanding is the VFR's TB's are factory set and not meant to be adjusted, the Starter Valves can be adjusted and balanced, my motorcycle Tuner checks them for me as part of every Service although my understanding is SV's mostly impact Idle smoothness and throttle crispness from Idle when moving off.

A PC3, Dyno and good tuner may be able to smooth out Flat spots but due to high cost not an option available to me, besides my VFR Standard with aftermarket Can has enough Power to keep me happy and keep my friends litre Superbikes honest through the tight twisties. :biggrin:

 

I think Maybe a different airfilter like the K& N as suggestred , might be the nextmove .

Truthfully though , I am content for now as to what I have done .
Lord knows I have to justify The amount spent as it is !!
Thankfully the mods spoken of Now amount to little more than a bit of time and skill , nothing else ...

 

John...

For the most part you should be able to set the throttle bodies and leave them alone. From the factory they come tuned to factory stock settings. But when you mod a bike it's a good idea to have them fine-tuned to the new characteristics of the bike, then leave them alone. TBs can go out of sync, but it's not very common. They're pretty rock solid. And yes, you can do some fine tuning with the TPS (throttle position sensor) and even the throttle cable tension at the grip.

A dyno is too expensive? Hell... here at my friend's shop they had a weekend where they did it for free as a promotion! They normally charge about $50 to Dyno tune a bike.

Stan

 

Looks like you've worked with Fuel injection before and agree a tuning specialist with the right equipment could probably do anything.

My caution comes from having read before the VFR800's TB's should never be touched, doing a search found below as quoted on the UK VFR sites Technical Section posted by "greenVFR" who looks to be the UK Guru on things VFR.

"Caution: The throttle body assembly must be treated as a sealed unit. NEVER loosen any of the white-painted bolts/screws on the assembly as these are pre-set at the factory to ensure correct synchronisation of the throttle valves and idle circuit. The only components on the assembly which are serviceable are the "starter valves" and the various vacuum hoses."

 

John...

Yes, the key words being preset at the factory. That means for the factory stock set-up.

All throttle bodies are adjustable, as are carburetors, but ask even a seasoned mechanic if they enjoy tinkering with them and they'll tell you it's a bitch to do it on some bikes. Even when a mechanic re-jets a carburetted bike it takes them a few hours to dial it in the way it should so it yields the most fuel efficiency, best torque curve, and best power curve and smoothest throttle response (hence the suggested use of a Dyno).

If you go with a full after market exhaust and air filter and new ECU it's imperative to retune/resync your TBs. Most after market exhaust systems come with their own ECU and CD for re-mapping, and yes, they usually don't tell you to meddle with the TBs, but if you honestly want to see the real performance come out of your purchase, then you need a mechanic to adjust the TBs.

I am unsure whether the quote from that 'guru' is his, or if it is a straight out warning in the owner's manual. Most companies put that kind of warning in the owner's manual so you don't tamper with that stuff yourself.

If you are not a Honda tech you would probably void the warranty on the engine when you do an adjustment like that yourself and later have to bring it in and have it re-adjusted. If they marked certain screws with paint it's to show if someone has tampered with them. If Honda does not show in their service records that it was them, then guess what? Bye-bye warranty should something go terribly wrong with your engine.

I read many threads in different sites on different makes and models of bikes dealing with this lean running Euro 3 emission standard type oxygen sensor set-up. Most dealership mechanics will tell you that your TBs are only so adjustable. They can only lean out or enrichen the fuel mix to a slight degree, because of the non-programmability of the factory ECUs.
Stan

 

Stan (Wabbitt1961) did you make the trade for vfr yet? if you have or did a test ride how dose the ride compare with your st3.
Jeff

 

chomper -

Hoping to do the trade-in this Saturday. I'll let you know if I get it at the price I want or not. If not, I'll wait till they scream for me to take it off their hands, as they have three '07s on their floor, and more than likely a few 2008s banging at their back door. I don't think I'll have a problem getting it at my price, so I hope I can tell you about my first ride Saturday!

I did test ride a 2006 once before, but I prefer to pass judgment on the bike after I've had it at least a week. From what I remember, the bike was a bit heavier in feel. The weight is a bit more forward because the ride position is more forward than my ST3. The legs are a bit higher, and I am hoping not too high as to be a problem on long rides, as I am 6'2-3". It doesn't have the pick-up that the ST3 has, but that allowable since it's over 200cc smaller (781 vs 992). I'm really not into it for it being faster or slower. Comfort and reliability are paramount to me. I think I'm probably compromising a bit on the first, but hoping not too much.

 

Well picked up, he was quoting it from a VFR workshop manual as a warning to only adjust the SV's which are meant to be Sync'd as and when required.

Still if I had fuelling issues with mine would probably bite my lip and purchase a PC2 for my Gen 5.

 

John, that's what they all want you to do. Leave them alone cause they know it's a headache and go spend your money on a PC or a new exhaust and ECU.

I battled with Ducati for 3 months and got the Ducati North America rep involved before they finally took me serious and fixed the problem. The shop kept telling me that that's how they run, you're just feeling the pulsing of the engine through the chain, you're imagining it, blah blah blah... when they KNEW all along that there were issues of this nature with the bike because of the closed loop system.

I am willing to bet that if you pressed the issue with Honda they would simply do that PAIR valve block, re-tune it a bit, and tell you they solved the problem! I found out my Ducati mechanic took off the hose when I pulled off the fairing about a couple weeks later to change the oil and saw the hose just sitting loose by the battery.

I do plan to ride the new Honda a week or so before I pass judgment on it, and and see if it does the same thing as my Ducati did. Maybe they'll already do the PAIR block on it when they tune it up and deliver it to me, knowing I would come back otherwise.

Never know these days. Shops are tricky. I trust my regular mechanic with my servicing.I don't plan to go to Honda for it at all. He's Honda certified anyway, and his labor charges are more than a third less than a factory tech. He rebuilt my 1982 Yamaha Turbo from the frame up, charged me $1,200.00 total, and the bike ran like brand new. He worked on my Concours and brought it to life. He also worked on my FZ1 and VStrom. I never had issues with any bikes he worked on for me. They deserve my business and my trust to be straight forward with me. In fact, I told him my plans to trade in the Ducati on the Interceptor and asked his opinion. He said he rarely sees them come to the shop, but that they're easy to work on. High praise for the Interceptor in my opinion.

 

Truth be known I don't have fueling problems. The throttle is beautiful from idle to Redline, then again mine is a Gen5 Mk 1 which doesn't have cat, O2 sensor's or closed Loop system. The bloke I take it to for service is a fully trained ex Honda mechanic with his own race tune business and best of all a fellow VFR Gen 5 owner & VFR enthusiast. :smile:

Having said that have just performed the PAIR Valve blockoff anyway. One of mine gummed slightly open last year with a confusing drop in mid range power and fuel economy, both retuned to normal post clean but 11 months on couldn't be bothered cleaning them if it gummed again. If nothing else one positive byproduct of the Pair Valve blockoff is the exhaust seems to sound crisper throughout the Rev range. :biggrin:

 

A guy named Dan on the other VFR site makes a PAIR valve block off kit that he sells for $45 delivered. I just got one from him and the work is first class. Includes hardware and some very detailed instructions for installation.

 

Recieved mine from Toro1 ( Dan ) from vfrdiscussion shipped out a few weeks ago, now if I can just find time time to install them.

 

There be a link?

 

Dan be the man:

Hi Pete,

The total comes to $45. As soon as I receive the money order, I'll ship the plates out via Priority Mail.

My address is:

Dan Antonelli
4835 Cheshire Rd.
Doylestown, PA 18902

Send him a money order for $45 and your address info, and a week later the mail man will hand you a box with his PAIR block off kit in it. Plates, stainless steel hardware, and very detailed instructions. First class stuff.

 

In for a penny, in for a pound. Has anyone ever thought (or tried) just cutting the entire top of the air box off and just installing the bottom lip and about a half inch of the air box top - just enough to hold the filter in place. I haven't owned a motorcycle yet (carbed or fuel injected) that didn't have a positive response to getting more air to breath. Seriously, look at how little area the snorkle(s) have and all of the air has to come through those two little openings.

I am very tempted to try it. If it doesn't work, I buy me a new air box top. If it does, I'm ahead of the game. Obviously, I would take the bike to a good Dyno Jet tuner with a dyno and get a new map made up.

 

Ok, my update...

I've had the bike about 4 months now and put about 5,000 miles on it in stock configuration. It's my daily ride, day in, day out, rain or shine. I don't think I would have done that many miles on it if I had any issue with a surging problem. To me it's minimal at best. You shoulda rode my Ducati ST3 in stock form! Its surging was dangerous, and throttle response was either none or too much, which forced me to keep it in a lower gear at higher revs for better throttle control. No thank you.

My 2006 Interceptor is fine, as-is. Yeah, I notice the surging a tad, but nothing that effects its rideability as far as I am concerned. When holding a steady speed at say 4krpm and applying light throttle to accelerate say another 5 mph, there is a major flat spot, but the bike's telling you to shit or get off the pot. In other words, downshift or accelerate a tad harder. I find this acceptable behaviour. I am averaging 43mpg in city driving, ranging from 35-60mph. I get 220 on a tank. The low fuel flashes at about 180-185 miles. I find this also acceptable. I could probably even have it leaned out a bit for higher mileage without affecting the performance of the bike.

As for the airbox... Many people drill quarter-size holes in the lid or the entire airbox. K&N also sells lid and filter kits for most bikes (basically a set of clips and the K&N air filter... no lid at all actually... the clips hold the filter to the box's top.) so you don't have to cut up your stock airbox. Do NOT do this mod if the bike stays outside daily or you will get water down the box and into your intake when it rains. If you do keep it outdoors, as I do, buy a cover!

This mod works, but be prepared to retune the throttle bodies for better response. When aerating the box, the onboard computer will read the bike as running lean and enrichen the mix, constantly, so at idle and low rpm it will waste gas. It will also be LOUDER when you aerate the airbox. Whenever you feed the bike more air with this type of mod you'll have to lean out the throttle bodies a bit.

Been riding for 30+ years, so take what I say with whatever creedence you like. Been there, done that. I like the bike the way it is. I have nothing bad to say about this bike, which is RARE for me since I usually pick them apart with a magnifying glass and complain about one thing or another. This bike's a winner.

IF I was going to mod the bike I would buy a Power Commander and leave the hoses alone. That would undoubtedly smooth out the rough edges on this bike, in my opinion.