Here is one guy's answer to Yamaha not doing what they should have in the first place

[M61A1MECH]

Here is a post over on Delphi from a guy in London, England, that is building what Yamaha should have built the first time around with the Royal Stars.

If they had done this, we would probably still have new Ventures to buy.

 

http://forums.delphiforums.com/vrider/messages/?msg=16021.25

[WildBill1]

Great conversion and he was able to maintain the most important item in his build the "V Max Boost".

[cowpuc]

Wayyyy cool - guy did an excellent job on that sweetheart, THAT is for sure!! :clap2::clap2:

 

Hey Mech,, you by any chance happen to read the entirety of that thread over there on Delphi? VERY INTERESTING READ all about "Star" motorcycles being no more.. Sounds like its all going back to Yamaha.. Definitely a subject worthy of a discussion here on VR (IMHO).. Being your thread and a link you provided (THANK YOU MY FRIEND), would you mind starting another thread about that subject or are you good with us this one?

 

All in all Mechster,,, EXCELLENT post - THANK YOU!!

[M61A1MECH]

cowpuc,

Yes , I have been following that thread over on Delphi for a couple of days, I was thinking the subject was brought here on VR, but maybe not.

 

I am OK with hijacking this thread to talk about another Yamaha boondoggle.

[cowpuc]

cowpuc,

Yes , I have been following that thread over on Delphi for a couple of days, I was thinking the subject was brought here on VR, but maybe not.

 

I am OK with hijacking this thread to talk about another Yamaha boondoggle.

 

Thanks Mech! I had not heard anything about the push by Yamaha to drop the Star line,, gonna do some quick research here and see if I am missed another great conversation.. Cant help but wonder if reuniting the names back under one roof (back to Yamaha) has something to do with what is taking em so long to give us another Venture.. Maybe some kind of restructuring of something...

[Yammer Dan]

I have dreamed of a renegade V-Max ever since I started playing with these things. My pockets just ain't deep enough now that I have the time!! But I got Drool all over my keyboard!!!

[WildBill1]

I think it would be cool to put a V Max engine in a Harley Ultra frame and use a belt drive. Call it a Harley Ultra Max. Have the best of both worlds great handling and awesome power.

[Great White]

Kudos to the gent for giving it a go.

 

He's a little off on some stuff though IMHO.

 

Looking for 10,000 rpm will likely start to float the valves as the VMax is redlined at 9500. Valve float is a BAD thing....

 

Hoping for 150 HP is a little optimistic. VMax is only factory rated at 145 HP (crank) as delivered in the 'Max.

 

But he doesn't have the VMax airbox or Vmax exhaust which is part of the rating.

 

Those 4 individual pipes might make a nice sound and look cool, but cost power through loss of scavenging. They're built for style, not performance. On a small engine like a motorcycle, exhaust design makes for a significant chunk of the power. You need to take advantage of scavenging effect on a NA engine or you're leaving HP on the table. Same with intake tuning and for resonance.

 

You know he doesn't have a VMax airbox crammed in that tiny space. Smaller airbox costs HP also. You need volume to feed those hungry intake ports. Pods are an option, but ditching the box also messes with the Helmhotz effect. Needs some pretty involved carb work to get those CV's working with pods. Jet changes and needle work, but not just the mains: air jets, pilot jets, needle heights, profiles, etc.. I'd be thinking about a stage seven kit at that point, but then the VBoost manifold comes out in favor of open piping. not too great on a heavy low rpm street bike....

 

I'd estimate he's down about 20-ish hp on a standard VMax. Maybe more. So down to 120-125 hp right off the bat. I've got a couple tricks in mine and I'm only hoping for a high of 130, 100-110 at the rear wheel.

 

Just the math on the shaft drive 20%-ish (somewhere between 15-20% depending on bike) loss doesn't work: assume he gets a full 145 HP X (145 x 20%) = 116 RWHP. That's right around where a stock 'Max hits on the dyno (between 110-120 RWHP, IF you believe dynojet numbers ).

 

Now, that's not accounting for losses in the transmission, although those are considerably lower than what the two 90 degree shaft turns does to power transmission to the contact patch.

 

If you want to do it using my estimate of him getting 125 hp : 125X (125 X 20%) = 100 RWHP. Yeesh, that's even lower......but still a good bump up over a stock XVZ12/1300's 80-85-ish RWHP..

 

But unless he's got some work into that VMax engine that he doesn't talk about, he's a juuust a touch high on his expected 120 RWHP.

 

Even Sean Morely only squeezed 110-ish RWP out of his VMax/Venture hybrid (lacking Vmax exhaust and air box but he got all the rest in there). Sean essentially had a pair of "slip-ons" for exhaust (and from what I have heard on video it's LOUD).

 

It's all just number crunching and bench racing until the rubber hits the road, but S Morely had all the tools and talent at his disposal (and he dyno tuned it as well), so I'm inclined to believe that.

 

While it may have been the only way to get the clearance for the Vboost manifold, I'm not a fan of his "pop up" frame pieces. Looks kinda sketchy, to my eye. I would have suggested widening the double cradle "spine" and try to triangulate across them somehow to put rigidity back in. A little work on the tank would have let it sit down over it . May or may not make a diff in a cruiser application, but with about a 20% boost in HP, I wouldn't want to find out the hard way.

 

I actually wish Yamaha had applied the VMax modifications to the entire XVZ line as far back as 85/86 when the 'Max came out.

 

Had Yamaha done that, The Venture (full boat touring model) might have stood a chance at going the distance in the market to today like the 'Wing did and the cruiser variants would have been factory designed to hold the VBoost system in their frames.

 

Could have been killer. Ah, opportunities lost.

 

But I'm rambling now so I'll sign off with what I started with:

 

Kudos to the gent on the effort.

Edited February 22, 2016 by Great White

[cowpuc]

Kudos to the gent for giving it a go.

 

He's a little off on some stuff though IMHO.

 

Looking for 10,000 rpm will likely start to float the valves as the VMax is redlined at 9500. Valve float is a BAD thing....

 

Hoping for 150 HP is a little optimistic. VMax is only factory rated at 145 HP (crank) as delivered in the 'Max.

 

But he doesn't have the VMax airbox or Vmax exhaust which is part of the rating.

 

Those 4 individual pipes might make a nice sound and look cool, but cost power through loss of scavenging. They're built for style, not performance. On a small engine like a motorcycle, exhaust design makes for a significant chunk of the power. You need to take advantage of scavenging effect on a NA engine or you're leaving HP on the table. Same with intake tuning and for resonance.

 

You know he doesn't have a VMax airbox crammed in that tiny space. Smaller airbox costs HP also. You need volume to feed those hungry intake ports. Pods are an option, but ditching the box also messes with the Helmhotz effect. Needs some pretty involved carb work to get those CV's working with pods. Jet changes and needle work, but not just the mains: air jets, pilot jets, needle heights, profiles, etc.. I'd be thinking about a stage seven kit at that point, but then the VBoost manifold comes out in favor of open piping. not too great on a heavy low rpm street bike....

 

I'd estimate he's down about 20-ish hp on a standard VMax. Maybe more. So down to 120-125 hp right off the bat. I've got a couple tricks in mine and I'm only hoping for a high of 130, 100-110 at the rear wheel.

 

Just the math on the shaft drive 20%-ish (somewhere between 15-20% depending on bike) loss doesn't work: assume he gets a full 145 HP X (145 x 20%) = 116 RWHP. That's right around where a stock 'Max hits on the dyno (between 110-120 RWHP, IF you believe dynojet numbers ).

 

Now, that's not accounting for losses in the transmission, although those are considerably lower than what the two 90 degree shaft turns does to power transmission to the contact patch.

 

If you want to do it using my estimate of him getting 125 hp : 125X (125 X 20%) = 100 RWHP. Yeesh, that's even lower......but still a good bump up over a stock XVZ12/1300's 80-85-ish RWHP..

 

But unless he's got some work into that VMax engine that he doesn't talk about, he's a juuust a touch high on his expected 120 RWHP.

 

Even Sean Morely only squeezed 110-ish RWP out of his VMax/Venture hybrid (lacking Vmax exhaust and air box but he got all the rest in there). Sean essentially had a pair of "slip-ons" for exhaust (and from what I have heard on video it's LOUD).

 

It's all just number crunching and bench racing until the rubber hits the road, but S Morely had all the tools and talent at his disposal (and he dyno tuned it as well), so I'm inclined to believe that.

 

While it may have been the only way to get the clearance for the Vboost manifold, I'm not a fan of his "pop up" frame pieces. Looks kinda sketchy, to my eye. I would have suggested widening the double cradle "spine" and try to triangulate across them somehow to put rigidity back in. A little work on the tank would have let it sit down over it . May or may not make a diff in a cruiser application, but with about a 20% boost in HP, I wouldn't want to find out the hard way.

 

I actually wish Yamaha had applied the VMax modifications to the entire XVZ line as far back as 85/86 when the 'Max came out.

 

Had Yamaha done that, The Venture (full boat touring model) might have stood a chance at going the distance in the market to today like the 'Wing did and the cruiser variants would have been factory designed to hold the VBoost system in their frames.

 

Could have been killer. Ah, opportunities lost.

 

But I'm rambling now so I'll sign off with what I started with:

 

Kudos to the gent on the effort.

 

 

Hmmmmmmmm,,, ,,,,,,, I still think its gonna go like stink

 

Maybe one of the reason's Yamaha stayed away from using the V-Boost on the Ventures has to do with the increased lower R torque needs in a full blown touring scoot.. The V-Boost needs higher R's to be effective which (IMHO) does increase Horsepower but torque is another matter.. IMHO, another issue may have been fuel consumption,, I know when I run my ol V-Max up in the R's where he is really, happy fuel consumption gets pretty dicey - nothing like the 40+ MPG we expect out of our Venny's.. While I TOTALLY admire and appreciate the V-Boost concept and what it does to the performance on these V-4's, I still wish Yamaha would have hammered out a really good true turbo system, IMHO - had they of done that they could have had maintained the low R torque, good MPG AND easily seen the higher R HP numbers (probably even better) than the 1st Gen Max's have..

Concerning the scavenging effect and pipe thoughts.. I fooled around a little bit with Harley cam's and different varieties of cam grinds,, even hung a gear driven blower on an 01 Twin Cam that required some cam profile altering to pull right.. One of the things that I ran across while playing with Harley's thru the years is how little scavenging seemed to be going on unless I was dealing with a cam grind that had Valve overlap ground into it. Toss in a set of high compression pistons, flow the heads and increase the valve diameters, run an open air box or - better yet - velocity stacks and ya got one scavenging, lumpy running engine I tell ya.. Compression ratio's will fool ya (always did me) on a tester but when ya spin em up to the point that scavenging is taking place,, those ratio's REALLY begin to take affect..

[Freebird]

Here is the way the filters were done on the '89 SS that I had. Seemed to work very well.

 

http://www.venturerider.org/forum/showthread.php?35264-Bought-an-89-Venture-SS-FOR-SALE&p=337024#post337024

[Great White]

Hmmmmmmmm,,, ,,,,,,, I still think its gonna go like stink

 

Maybe one of the reason's Yamaha stayed away from using the V-Boost on the Ventures has to do with the increased lower R torque needs in a full blown touring scoot.. The V-Boost needs higher R's to be effective which (IMHO) does increase Horsepower but torque is another matter.. IMHO, another issue may have been fuel consumption,, I know when I run my ol V-Max up in the R's where he is really, happy fuel consumption gets pretty dicey - nothing like the 40+ MPG we expect out of our Venny's.. While I TOTALLY admire and appreciate the V-Boost concept and what it does to the performance on these V-4's, I still wish Yamaha would have hammered out a really good true turbo system, IMHO - had they of done that they could have had maintained the low R torque, good MPG AND easily seen the higher R HP numbers (probably even better) than the 1st Gen Max's have..

Concerning the scavenging effect and pipe thoughts.. I fooled around a little bit with Harley cam's and different varieties of cam grinds,, even hung a gear driven blower on an 01 Twin Cam that required some cam profile altering to pull right.. One of the things that I ran across while playing with Harley's thru the years is how little scavenging seemed to be going on unless I was dealing with a cam grind that had Valve overlap ground into it. Toss in a set of high compression pistons, flow the heads and increase the valve diameters, run an open air box or - better yet - velocity stacks and ya got one scavenging, lumpy running engine I tell ya.. Compression ratio's will fool ya (always did me) on a tester but when ya spin em up to the point that scavenging is taking place,, those ratio's REALLY begin to take affect..

 

Oh, I believe it will go, just not what the gent who builds it thinks it will. Numbers don't work. But with a 20% increase, I have little doubt his "butt dyno" will tell him its a 200 hp machine!

 

 

I enjoy a technical discussion now and then, so I’ll go a little deeper into it. I’m also stuck on the couch with a thrown back, so not much else to do anyways……

 

 

It’s a lot to discuss in one post and this is off the top of my head, so there’s going to be lots of holes and omitted details, but I’ll do the best I can to be comprehensive.

 

Scavenging is more a direct result of the exhaust design than the engine characteristics, although you also can’t have one without the other.

 

What you want in an exhaust design is velocity. Quite a few factors come into play in that, but the main one I’ll discuss in the exhaust pulse.

 

In order to gain the highest velocity (to help clear the spent exhaust gas out of the combustion chamber) a properly designed exhaust will use an exhaust pulse to create a negative pressure in the pipe that will be next subject to the exhaust valve opening event. Like so:

 

http://i1174.photobucket.com/albums/r618/justonepict/exhaust_zpscyiofdjk.jpg

 

I’ve just drawn a 2 cylinder system, but it just get expanded for triples, fours and sixes. Same principles. I won't go in to V4 exhaust designing, those rear cylinders make for a packaging nightmare to get equal length and maximizing scavenge effects. The moving exhaust gas past the non active pipe is what creates the negative pressure. If the pipes aren’t connected (has to be done right too, not just a balance pipe), there’s no scavenging effect and the engine has to rely on the piston movement to expel the exhaust from the combustion chamber. That, for the most part, makes for a "lazy" engine.

 

Now, duration and overlap come into play here, but the effects are mostly limited to how much time is allowed for the advancing piston and scavenging effect to do it’s work. Duration and overlap also help to pull in fresh charge in a NA engine (if the designer gets it right). NA engines can only ever achieve a theoretical 100% cylinder filling. But most only achieve around 80% (due to valve obstruction, port losses, etc) and that ‘s with scavenging working properly and doing it’s thing.

 

Increasing RPM gets you more velocity, which should get you more scavenging and more power. But then you have to take pipe diameters into account. Pipes aren’t variable, so the designer has to choose a diameter for an RPM range. Smart designers choose the torque peak and that’s why most engines get the best power/mpg when close to the engines torque peak. Get outside the pipe diameters effective range and scavenging becomes less effective. Get too far out and you can actually get into reversion, which costs HP.

 

Now if you want to throw in forced induction, things get weirder all over again. With FI, greater than 100% cylinder filling is possible. Scavenging also becomes less of a concern as the cylinder pressure is so much higher than the ambient in the exhaust. Scavenging gives you some gains in FI, but much less evident than NA. FI engine exhausts tend to be bigger all around due to the FI effects.

 

Comparing engines like Harley’s and Jap multi’s becomes even more confusing. Harley’s, comparatively, have slower moving exhaust due to their large (relatively) piston sizes and few (comparatively) exhaust pulses. In terms of exhaust velocity, multi’s have faster flow. They may have smaller pistons, but that just means less volume. But many small “bangs” make for a smoother and faster exhaust flow. This translates into more velocity, smoother exhaust flow and increased scavenging. That’s not to say Harley’s can’t take advantage of scavenging effects or be designed for good exhaust velocity, it just takes a different variation on the design principles.

 

All these principles are a lot of the reason people who use “slip ons” generally see little/no improvement in power. The “goodness” is mainly in the pipe design. The OEM mufflers are usually designed to work with that. Slip ons generally get the same HP (maybe less if they make the exhaust flow “lazy”) and the main gain is reduced weight. But more noise sure makes it feel like you're going faster!

 

Now, Mr Max uses scavenging in it’s exhaust design for the reasons above. If the gent has gone to 4 independent pipes, he’s leaving HP on the table.

 

VBoost is another subject all together. Low end torque and MPG is in the heads more than the fuel delivery. That’s ports design and cams. MR Max has bigger ports and “bigger” cams, so that is gonna cost MPG. It also moves the effective torque peak up the RPM range. In the case of the ‘Max vs the Venture, it’s approx 1000 rpm higher. The Venture has smaller ports and “smaller” cams which means increased intake velocities. Great for lower en torque production (increased cylinder filling/mixing at lower RPM) but costs you HP when you get into higher RPM. Basically, “choking” it.

 

Vboost comes in at 5500 RPM. Stay below that and your MPG isn’t going to be horrible, but (theoretically) it’s not going to be as good as the Venture due to the larger port sizes. Gents on the VMax boards can pull down close to 40 MPG in restrained riding. But that kind of defeats the purpose of Mr. Max!

 

 

If you’re enjoying a frequent run up to the VBoost “fun zone” MPG is gonna “suck”.

 

Just no way around that… But that’s more the operator than the machine...

 

Something that's interesting (and rather telling) is VMAx guys that drag seem to mostly report the same times with open manifolds or VBoost enabled. This indicates what I've long suspected with VBoost: it's a bit of a designers trick. Keeps fueling restrained below 5500 rpm and full on above. But no really significant increase in HP, just improved drive-ability and that 2 stroke "kick in the pants" that makes max "feel" faster than what it is. The clocks don't lie.

 

I more wish they had discovered the variable intake runner length principles (somewhat like the New R1 and VMAX) rather than the Vboost incarnation. Pretty much the same thing, just executed rather crudely.

 

 

Probably could have also compensated for low end losses in a VMax/Vboost equipped venture with a bit of their EXUP technology.

 

 

Oh well, if wishes and buts were candy and nuts we'd all have a merry christmas. Not to mention all that "cutting edge tech (for the time) would have driven a Ventures price sky high. Likely priced right out of the market. Sure woudl have been killer though....

 

 

Whew, that was a lot of typing....

Edited February 23, 2016 by Great White

[M61A1MECH]

Here is a video up date to this thread.

 

https://www.youtube.com/watch?v=kubMa4Q5Jjc&feature=youtu.be

 

I like it!

[Freebird]

Love it. Don't care for the seat but that's a minor thing.