BiKenG

As regards the widening of the pipe after it leaves the cylinder heard, have we not established that in top level racing this has been found to be very effective? Whatever the reasons, a header pipe that widens from the port diameter to a larger size is what seems to work best. Admittedly we're seeing here a series of different diameter pipes welded together, rather than a nice tapered pipe section, but that will mean a big cost difference and may not affect the efficiency of this design to any measurable degree. So I don't think the basic premise of this aspect of the design is a problem and neither do I think any fractions of a millimetre in diameter will have any significant impact by itself. However, the overall performance of this system, which is after all radically different from Honda's best design, can only be determined on the dyno and for that, we are all eagerly awaiting some real data.

That's what I thought initially, but in the picture the front pipes cross over, whereas the BW (and I think the Lextek but cannot now find the pictures) do not cross at the front. That's not to say though that these are not the actual manufacturers of said systems.

I have to say I can see both sides of this. On the one hand, we really don't want to piss off suppliers who are being helpful and offering a good deal, but it is also true that the customer deserves to know what they're buying and so far, we don't. Yes, Jeff is putting his on a dyno (he didn't have to buy a bike as he knew I was prepared to use mine so that's down to him, no actual brownie points gained) and we are (probably all) very keen to know the outcome of that. But so far we still have nothing, so I think it's not unrealistic of those waiting for this information to get impatient. However, when it comes to BW it's a slightly different story. They have a chequered history and although that may be behind them, we have long been assured they are working on the BEST system ever for the VFR yet it now very much looks like they are simply buying in and re-selling someone else's product. Not that there's anything necessarily wrong with that, just that it's not what they've been telling us for the last few months and now to cap it all, they seem reluctant to release any actual dyno results. Instead appearing to try and deflect such requests with very dubious claims that it's impossible to produce truly comparative data and we should simply look at figures from their different systems on different bikes as that should give us an idea. Sorry, this is disingenuous bunkum. I have no previous experience with BW, but right now I feel we've been somewhat led up the garden path. They can easily correct this situation by coming clean about the source of their product and doing some real tests and/or discussing it with us on here. No, we're not looking for race track performance, but right now we have NO idea whatsoever how this system even runs and I think (potential) customers deserve to know more than what we've been told so far which is quite frankly, not a lot. This is not having a dig at potential suppliers, just asking very reasonable questions, prior to stumping up any actual hard cash. How can they expect anything less?

Yes, as I think we can agree, the first VFR800 was a '98 year model, but first ones were sold at the end of '97. Still a '98 bike though. It's the Model Year that crucially defines the bike, not when it was first sold and/or registered.

Yup. That's what I said. And both at roughly the same price. It is kinda suspicious.

Well I don't think this has anything to do with Honda. They manufacture a certain design and spec of bike and it gets labelled as an 'J' or 'L' etc which is a simple code to denote its 'Model year'. When it actually gets sold and registered is largely nothing to do with them. It may creep in before the end of the previous year (during which it was actually introduced) or it may sit in a dealer's showroom for years so the date of first registration is not necessarily equivalent to the 'Model Year'. This is something a lot of people seem to find hard to understand, or use to deliberately misrepresent the age of a bike - even dealers sadly. But in reality it's not that complicated. The '98 model year was 'W' which to the best of my knowledge was applied to the very first VFR800. As far as I know there was NO VFR800FI-V. Ergo, the first VFR800 was a '98, even if sold at the back end of '97. I have to take issue with the statement that it was labelled as a '97 in the UK. So who labelled it? The press? Maybe and some dealers possibly and certainly Haynes, but the reality is it was never labelled by Honda as a '97 - anywhere. Not at the time, although younger employees with less concern for accuracy (as is the trend these days) may have subsequently implied otherwise. Back when I worked at Honda UK these actual age questions did not seem so important as it was all a lot newer and fresher in the mind. Now we're talking many, many years ago and memories fade and get distorted over time. But unless anyone can provide any evidence of there being a VFR800FI-V, we can all settle on the first VFR800 being '98-'99, then with added HISS (not USA) and Cat. '00-'01 and then V-Tec from '02. Please, don't get sidetracked by press and/or Haynes into believing anything different. There is one glaring anomaly to the above. The CBX1000. Back when it was introduced, Honda didn't have such a structured annual model naming system. 1980 was to introduce 'A' as the model year and although the CBX was actually introduced in '78, it carried the 'Z' designation which was used as a 'catch-up' to bring all models into line. So continuing with the 'Z' through '79 means 'Z' was actually used for 2 years. Once everything was in sync, they changed to 'A' for '80, 'B' in '81 etc and have carried that on until today, although running out of letters caused a swap to numeric code '1' in '01 which continues to this day. It's a bit like part numbers. Honda don't just throw out random numbers for all parts. There is a carefully structured system for naming of parts - even more important now than when first introduced with the number of parts growing year by year. Model Codes also follow a structured scheme. The RC46 is the 46th model of that type (road sports) in that capacity range (I forget the limits, something like 600 - 900cc). It is not some randomly cool code that the use of RC30 seemed to suggest. Likewise the model years. There is a system to all this that Honda do. They have to have a system or soon they wouldn't know what they were doing. Well they know in theory anyway. 😀

I cannot disagree with you but I think getting that info presents something of a problem. BW apparently refuse to provide any such thing which is disappointing and makes me think they're hiding something and although the Lextek is soon to be on the dyno, they do not have a catless header to compare. Indeed, when I spoke to Jeff (Lextek supplier) he tried to convince me that a one-off dyno run of his system was all that was required as dyno results are corrected for atmospheric conditions etc so can be compared with any other results from other bikes on other dynos. But although correction factors are applied, as we know results can vary significantly and the only way to get a true understanding of the effect of changing an exhaust is same bike, same dyno on same day and only the exhaust swapped. Sadly, I don't think we're going to get that with either of these systems. Having said that, an independent dyno run with just the exhaust change should give us some idea of how well they work or not and let's face it, we're not talking race track fine tuning here. I have to say though that I am still suspicious of how similar the 2 systems are. Same bore size change, done in the same way, same sensor positioning etc. and then there's the merge scheme. Previous (performance) systems have used the same scheme as Honda, now 2 systems appear that take a different approach and while that may indeed work ok for the road, it is surprising that 2 manufacturers simultaneously (and supposedly independently) both decide to go against accepted (and Honda's) wisdom and opt for this alternative merge scheme. Coincidence? As someone once said, "there's no such thing as coincidence". In any case, changing the merging from Honda;s original VFR800 scheme (Lefts and Rights) to the alternative Fronts and Rears is even more reason to want to see a dyno comparison of the new system against the Honda original. So we're back to that problem again. Still, I suppose this is a better problem to have than "who can we get to make a system". 😀

Well I remember first seeing the VFR800 as a new model at the UK Motorcycle Show that is traditionally held in Nov/Dec and that must have been '97. They usually show new models slated for release and availability the following year, but it is possible some bikes made it to the UK and were sold actually in '97. But they would have been '98 model bikes so despite some early sales, the VFR800 did really start from '98 year model. BTW, don't rely on Haynes for ANYTHING. 😁

Really, I must have missed that. In fact, I still cannot find any mention by the OP of that having been done.

I'd be interested to know what their current VFR750 system is like. Is it still the original SBS product with the rough/restrictive internals or a better made product altogether.

So just like buses, you wait forever for one, then 2 turn up. I've been studying the photos and there are minor differences, but the Lextek and the BW are uncannily similar. Interestingly, they both use the Fronts and Rears merge scheme, but is this simply for cost, or did they find that worked best on the dyno? In which case, what were they trying to achieve? We have established that Lefts and Rights each merging make best top end power whereas Fronts and Rears merging gives better mid range (according to the results of what Honda and others have used), so why have Lextek and BW ended up the same? Did they independently determine that better mid range was more desirable, or was some other factor (like cost) of greater significance? Whatever, we need to see dyno results for both of these systems. Something that is noticeably lacking from both suppliers at present. There are other questions though. As Seb said, we need to know the joints (merges in particular) are clean inside. From what we have seen the Lextek are good, but we need to confirm this for the BW. There is also the question of whether the Rears clear the V-Tec cam chain tensioner. I'm not sure if we confirmed that yet with the Lextek, but as yet we have no idea about the BW in this regard and do the flanges rotate to accommodate different head bolt orientation? Yes for Lextek, but also need to confirm that for BW. With both these 2 points confirmed, then to the best of my knowledge that would mean a system could be used on any 5th or 6th Gen or have I missed anything? I think we also established that the same system could be used on the 8th Gen with simply different (splayed) front downpipes to clear the rads and maybe a different outlet? I'm not 100% on this but if we can confirm it, then that's something else to discuss with both Lextek and BW. It has to be in their best interests to have a system that's applicable to the widest range of models. So a few questions to resolve and dyno results to be viewed and then looks like we'll have a choice of 2 systems. Could be worse. 😀

Yes, remarkably similar. Coincidence? 🤨 Interesting that they exclude the 6th and 8th Gen. Hmm, they claim suitable for both Carburettor and Injected models. That's a bit worrying.

Well I don't want to be a scaremonger, but "instantly" is exactly how it can fail and why Honda went to the trouble of the recall. Initially the Universal Joint is simply stiff due to the assembly process leaving the bearings too tight. So what you might then think is that it will simply wear out faster, but what Honda are concerned about is that the UJ will crack and break apart and that means instant and possibly catastrophic failure. They had I believe experienced 2 total failures like this prior to issuing the recall, although no injuries have been caused (to the best of my knowledge). Part of the process was to have each bike checked immediately to detect any imminent failures and if new parts were not immediately available, they would have to remain off-road until the part (shaft assembly) could be replaced. In fact I seem to recall in these cases a new 'old' type part (checked before fitment to ensure it was not too tight) would be installed to keep the bike going until the 'new' part was available and could be installed. Expensive for Honda, but when it comes to safety, they don't mess about. The above is not simply heresay. I have seen a drive shaft (my own, although not on my actual bike) where the UJ bearing mounts/retainers are badly cracked and likely to fail imminently if used. This was taken from a bike dismantled for entirely other reasons, not related to the shaft. I bought the back end and when the recall was announced some time later I had a look at my spare shaft and was horrified how bad it was. My actual bike was not that bad and the UJ simply stiff and 'notchy'. If I still had the 'old' part on the bike and there were no untoward symptoms, would I have continued to use the bike? Possibly, for a short while until the replacement part was available. But that would be my decision and in no way a recommendation for others to employ the same course of action. This is a potentially very serious problem and should be taken seriously. I don't think it is possible for Honda to deny supplying 'New' parts to any bike not yet fixed. That's part of what an official recall means. It is a legal as well as technical process. So there should be no issue getting parts. The replacement is a bit fiddly, but not hard and then you have a brand new drive shaft that should last the life of the bike.

Interesting reading for sure, but something is not adding up. I am not interested in max power figures, except for comparison purposes. In that Honda doc, they state the 5.2 makes 106 PS and the provided graph, while not including any figures shows the 5.2 making quite a bit more than the 5.1 they show for comparison. In fact from that Honda graph, a very rough estimate would put the 5.1 at no more than 100 PS. Yet figures I have for the 5.1 state 110 HP. Now I realise that PS are slightly bigger than traditional HP so the number would be slightly lower, but certainly not 10%. Those 5.1 figures are not from Honda literature, but from some press info. However, it is almost certainly simply copied from Honda's own literature at the time. So either I'm missing something here, or someone's being economical with the truth. BTW, Honda's figures for the Gen 6 are 107 PS max. So certainly same ballpark. The 8th Gen dropped to 104.

Pretty sure I see HISS there, so he will probably find an O2 sensor here as well... Yes I can see the HISS module as well. It's even advertised as a 2000, so that makes it a Gen 5.2 and the same as my bike. Oh well. I'm still available.😀

That's all good to know,. So I need a 5/6 Gen collector and rear downpipes, with 8th Gen fronts. Simples.

I am still trying to establish how Delkevic can use the same collector for 5 and 6 Gen systems. Is the outlet angle and position the same on these bikes with just a different link from there to the low can of the 5th Gen or the high level stuff under the seat of the 6th Gen? As I said, I'm needing the splayed front pipes of the 8th Gen with an outlet suitable for the 6th Gen's high level and although modification of the pipes to suit may be necessary, the less needed the better. So just trying to understand what might be required. Anyone know for sure about the outlets?

Well I am in the UK, but down south:-( However, I have a good trailer and a suitable bike and the time :-) Also, I'm very interested in this whole issue so would be prepared to truck the bike up there, especially if it got me a system to use. Then I just need to buy one more. I've started to make contact with Jeff to take this further. I'll update you all when I know more. Two more things. My bike is a Gen 5.2, i.e. with cat. So ideally need to source a regular system for comparison. Anyone got any Gen 5.1 headers kicking around we could borrow? If international shipping becomes an issue with this or anything else, I am prepared to accept items delivered here on behalf of members and ship them on to the final destination. I don't have any special deals with shipping companies and the original supplier may well be able to do it better and cheaper. But if for some reason they won't offer Int. shipping, I would help, obviously only at whatever cost the shipping company charges. You could even make your own arrangements and just have it collected from here. Anyway, just offering in case it helps anyone get hold of the VFR parts they want.

The Delkevic system is often dismissed for its poor collector joint internals, but has anyone actually tested on a dyno? Ideally a bike with standard system, then swapped for Delkevic to get a good comparison on same dyno, same day etc? It would be particularly interesting to see this for their 8th Gen system as they use the same L&R merging of earlier Gens rather than F&R as Honda use for that model.

I hadn't noticed that the 8th Gen uses a Fronts and Rears merge style, but it does indicate how the different merging affects power and torque. Personally I'd be more interested in healthier mid range torque than top end power and if that's the effect of a F&R merge on a 180 crank, then it shouldn't be dismissed out of hand. Although for those wanting the max. top end power, L&R merging remains the more desirable. So many options :) For mid range torque then, the Lextek may well be ok. Anyone want to try one and put it not the dyno so we can see the result?

The way exhaust pulses are combined can have a very significant effect on the power of the engine. For the 2000 FireBlade (CBR929RR) Honda used a (cast Titanium) combiner valve that joined 1+4 and 2+3, or 1+2 and 3+4 under different conditions specifically because to maximise power under all conditions required the different merge styles. It was their first exhaust 'power valve'. So the way the pulses are combined can make a big difference and the pulses from a 180° and a 360° V4 occur in a different pattern which Honda (and other exhaust engineers) have found require the different merging for each of the crank designs in order to maximise power. Let's face it, the way they merge Lefts and Rights on the 800 is much more complicated than Fronts and Rears, with more pipework required etc. They wouldn't do that if they didn't think it necessary. Using the wrong merge style isn't going to make the bike unrideable, or even be particularly noticeable to some riders, but on a dyno it would be very noticeable and with the main thrust of this topic being to source a good high quality, high power replacement to the TBR system, going the other way to something that makes less power than stock is probably not what people here want. This exhaust tuning should not be dismissed. When Honda were racing their multi cylinder 4 strokes back in the 60s, current thinking was that a separate pipe for each cylinder allowed freest gas flow and gave the most power. It has since been discovered that combining the pulses in the right way means one cylinder's pulse can help scavenge the exhaust of the other(s). This is one of the main reasons for the huge increase in specific power output of modern race engines. I cannot help but think that anyone who tries to tell you that a Fronts and Rears merged system works well on a 180° crank 90° V4 is trying to sell such a system that they made because it was the cheapest way to do it and I'd need to see dyno comparison charts to convince me otherwise.

Just had a chat to the seller of that Lextek system on eBay UK. I asked if the picture was of the actual correct system as the Fronts and Rears merging is really for a 360° crank motor and not the VFR800 which is 180°. To cut a long story short, he knows nothing about it and just sells them. Apparently Lextek say VFR800s run ok with it and it didn't need changing (from what though). Looks to me like they used an existing collector and bodged it to fit the VFR800 and as it does actually run (which it would of course) didn't look into it any further. While I think spending loads of cash to try to extract every last hp from a VFR is probably a mug's game, actually saddling it with a fundamentally badly designed pipe system is equally daft. Everyone can make their own choice of course, but IMO the Lextek system is to be avoided at all costs.

Thinking further on this merging issue, Honda merge the Lefts and Rights and then merges the resulting Left and Right (as does the TBR) on all bikes I've checked that use a 180° crank (VFR750 and VFR800), but on the bikes with 360° cranks (RC30, RC45, NC30, NC35) they merge Fronts and Rears and then Front and Rear. I think this gives a clear indication of what is the best for the bike under discussion here, i.e. the VFR800. Which rather leaves a question over the Lextek system. Unless the picture is actually of a 400 (or RC30/45) system. Again, do we have any idea about BW's intentions regarding this? As far as I'm concerned, the CSK system is way out of reach pricewise. It appears they do fantastic work, but even at the regular price indicated by Louis it's not appropriate for me and let's be honest, if you're that keen on spending money to get a fast V4, buy the Aprilia, or Ducati, or Norton. For my purposes the Lextek price makes more sense. That's not to denigrate CSK in any way. Fabulous looking work and Louis has jumped in here and been very accommodating, but it won't be for me.

I think this is something that needs to be settled. Honda pair the Lefts and the Rights as did TBR and Erion before that (same guy I think). Although the Tuono is Fronts and Rears paired, that may not be relevant to our requirement. The Aprilia has a different cylinder angle and I've no idea what the firing order, nor crank angle is. So what works best for Aprilia V4 power may not work for the VFR. So I would tend towards thinking the original Honda merge style would be best. Everyone holds up the TBR as the system to copy and that's what they use so does it not make sense to stick with that? Has this been discussed with BW? Any idea what their intentions are with regard to this aspect?

As far as I can make out, you +1'd JZH's comment about Black Widow, but then commented on the Delkevic which indeed seems to have their 8th Gen rear slip joints backwards. It does seem wrong to me, but in reality, does it actually make any difference. Not to the flow as there is the same small gap in the otherwise smooth internal bore. Where that gap then leads is surely incidental. Also, would it affect potential sealing of the joint? Since static pressure is going to be exerted in all directions equally, the only difference would be due to the movement of the gas and like the flow, I don't see how the direction the gap takes could make any difference. Indeed with a perfect seal, it could make no difference. As I said, it does seem wrong to me, but is that in fact just a misguided concern.