Lambretta Boost Port & Cylinder Scavenging

[turbovan]

Tom the tuner is he a old man bloke met him sunday is he a tuner ?

[drunkmunkey6969]

Dan do you remember "Tom the tuner" who you met at Elvington.

He rubbishes the TS1 saying the boost port angle is wrong. He says that the Harry Barlow TS1 alike kit has the angle right and "works". He said this at Wicksteed last sunday whilst giving me one of his "lectures".

I suppose if he lectures enough people on as many topics as possible, its inevitable that he'll say something that makes sense sooner or later......

[tony]

Dan do you remember "Tom the tuner" who you met at Elvington.

He rubbishes the TS1 saying the boost port angle is wrong. He says that the Harry Barlow TS1 alike kit has the angle right and "works". He said this at Wicksteed last sunday whilst giving me one of his "lectures".

So when is tom's new kit coming ?
I do grin sometimes as so many people have the answer but how many actually go "there you are" here is a new kit.
As I said earlier... Terry Shepard would have looked at what was available pipe wise, what he was aiming at with the kit (by this I mean driveability with what pipe was available at the time) and decided that the old faithful back wall system was the way to go.
I read somewhere above about trans streams meeting the boost stream. I always felt that this wasnt how it was meant to be. I felt that if you look at the angles from a manufacturer you will see that in fact the boost doesnt clash with the mains. In fact in a modern motor the boost fires over the top of the mains and doesnt hit them at all. This would cause a mess tbh. If the old back wall method is being used I am sure the trans streams would hit the back wall and meet the tail end of the boost and therefore no restriction of flow would occurr. Or at least this is how it was meant to be. You do not want streams clashing in an obstructive way. If you use a too shallow boost angle and the port is opened at say the same time as the mains the 'clash' will happen. But if you start to angle up you lose area. Its all swings and roundabouts.
Modern stuff is using weird angles... 'cross trans porting' where the mains and secondaries meet in the middle at an angle and rise up into the head. Lambretta stud spacing kind of restricts this to a point.
Modern race vespa stuff from the likes of falc are even more 'out there' and well worth a look. Lauro is from a HRC background and his port angles reflect that. Its very different to say a ts1 or rb.

[tony]

There are a few professional tuners and kit makers on here. They would be the guys to give feedback on port angles and the effects of shallow or large angles?

[RICSPEED]

all i know regarding terry and the ts1 is he had to work within the constraints of what ray wanted .. eg .. to work with available pipes of the time (fresco ) had terry had his way the ts1 would have been lc .. i digress

[tony]

For sure Ric. And thats what I said. This takes us back to the pipe design. Thats the only thing has changed that will affect really... So... someone says "thats all wrong" well... they maybe right... today.... but when it was designed, maybe not at all.

[Special X]

Dan do you remember "Tom the tuner" who you met at Elvington.

He rubbishes the TS1 saying the boost port angle is wrong. He says that the Harry Barlow TS1 alike kit has the angle right and "works". He said this at Wicksteed last sunday whilst giving me one of his "lectures".

I suppose if he lectures enough people on as many topics as possible, its inevitable that he'll say something that makes sense sooner or later......

Very true . . If you see him ask him about the GT200 that he tuned in the 60's . . . . apparently it would cruise at around 90 mph with his wife on the back.

[drunkmunkey6969]

For sure Ric. And thats what I said. This takes us back to the pipe design. Thats the only thing has changed that will affect really... So... someone says "thats all wrong" well... they maybe right... today.... but when it was designed, maybe not at all.

Its not a case of who is 'right' and who is 'wrong'.....cylinder port scavenging techniques can be a very subjective item, which is what makes conversations like this so interesting. And its certainly not a case of saying TS didn't know what he was doing, not at all.... despite possible difficult instruction from his employers, or what he did/didnt have to work with at the time. The aim of the thread is to analyse where we are at today, because as we select pipes, pistons, porting techniques and so on, we are only concerned with what is available today and the power we are creating today.....and hopefully debates like this will tease out more and more collaborative opinions in order to help us to continue to achieve those goals. That is my goal, as its always been with Scooterotica....to share information, to analyse and discuss. Hopefully then, we all benefit.

Not like the days of yester-year..... cloak and dagger tuning techniques, grinding details of jets....the 'dark art' of tuning and jetting.......b@11@x to that bullshit i say! Which other site photographed dozens of tuned cylinders and supplied port maps, port widths, dyno charts and jetting examples? Complimented with a variety of information (ever growing) to help improve things even further. Most tuners wont even let you see inside a cylinder they have ported.....we photograph them and publish them! lol And if you request it, when i dyno scoots, i include the final jetting spec on the graph!

I think its a shame that most tuners who are actually good at what they do remain aloof and don't want to share. Its appears to be a terribly vain and self-serving way of trying to place themselves in some sort of higher-echelon (legends in their own minds) wanting to distance themselves from anyone who takes a practical interest in tuning as if they are beneath them. Happy to tell you what you DONT know, but not willing to discuss what they purport to know. But this backward view of not discussing anything publicly is usually more to do with fear of criticism......these people are often not willing to put their theory's up for debate, or share their working knowledge. Don't get me wrong, every year brings new development and new discoveries that keep the top people....at the top, and i'm certainly not suggestion anyone would discuss these finer details, not for one second. But there are generally speaking, very well known, understood and published tuning techniques....available to all and sundry in any tuning book, but most of the 'high end' tuners wont even chance a public discussion on these topics, or publish a picture of similar work they have done to explain the how/why.......shame really.

BUT WHY SHOULD THEY TELL US ANYTHING........ITS THEIR LIVING! I hear people hark at the back......yes, it maybe...but the majority of people who are interested in the tuning techniques to such a depth, already do their own tuning or have a relied-upon tuner that they use repeatedly to do it for them....so they lose no business, in fact the sharing of information generally results in MORE interest in tuning and MORE business for the tuner, not less. Just look at where we are now with Lambretta and Vespa tuning, we are in a golden age....new kits from Cam Lam/Charlie, Ron Moss, AF, GT, Falc, Quattrini, Polini.......websites like this publishing/sharing information. Home tuners modifying cylinders, tuning companies selling more 'tuning' goodies than ever, sprint meets, new people art BSSO race meets, faster laps times, more powerful machines each year......

Inspect, analyse, discuss, modify, analyse, share.....continue to improve.

But i digress...... ......in my experience the boost port on a TS1 is better employed at a steeper angle, combined with the use of a centre plug head. Thoughts?

[Rich_T]

Wow, your panties are in a bunch this morning, but generally I agree, I don't have any problem in sharing.
In the defence of other tuners and of the process in general. There is a lot to be said for "a little knowledge is a dangerous thing", that is a phase not a dig at someone in particular. Tuning has to be considered in the whole and the effects of a port angle or relative merits have to be considered within the entire system. Which is essentially, why this topic is going to bounce around for a good long time yet.

I would imagine the reason some tuners stay tight lipped (as well as the reasons you state to a degree) is that in discussing or expressing a specific opinion or point may inadvertently provide the oxygen to an argument about "he says/does...she says/does" sort of thing. Also, perhaps it might encourage an individual to make a modification only to report back that there was no change and therefore the idea/information or process was BS and by proxy the tuner concerned must also be BS. This is an understandable situation and probably justification enough to stay off a forum if only to reduce the stress of feeling obliged to strangle the living sh*t out of someone who, they might feel, desperately deserves it for having the impunity to ask.

Ultimately, those who are prepared to "walk the walk" do so and the results are either on the podium (this season or last), in the case of racing, or in satisfied customer and reliable engines in the case of touring. IMO, it isn't he who shouts the loudest who has the best advice or answers, if anything the inverse is true (empty vessels and all that). If someone has to re-iterate how esoterically influential they are then you really have to wonder if they have it at all.
From my point of view, I will always go for a 30 degree angle up the back face of the cylinder with boost and transfers opening at the same time. The reason for this is as much to do with production/manufacturing as it is for design.
The principle working along the lines that it takes time for the transfer charge to cross the piston face in the direction of the boost port. During that time duration the boost pot charge has already travelled someway up cylinder wall. By the time the transfer charge gets there it will be following in the low pressure immediately behind the boost charge, that’s the theory.

In production terms there is more flexibility in adopting a boost that opens at the same time as the transfers and at a shallow angle. Firstly, increasing the angle is “material off”, much easier than material on. Secondly, adjusting the port height down is achieved by increasing the bore and adjusting the port height up is achieved by “material off”. The way I see it, a large angle (as measured to the wall of the cylinder) does not have the “material off” advantages particularly if you are in a plated bore situation.

How everything else works together for one particular instance (timings, angles and inclinations etc) is a humungous topic. The fact that there is some much variation and conjecture, even in the big league Jap multinationals with massive R&D budgets, should be evidence enough that there will always be challenges to the status quo and that’s a good thing.

[Jazzy]

Reading rt,s last post regarding increase bore reducing port hieghts,
Wasn't the TS1 designed and first produced as a 200 and due to piston issues was then bored to 70mm.

If the barrells that dan measured are 70 mm then the hieghts may not be what Mr shepherd had intended.
It's quite a common comment that Ts 200 are much smoother than thier bigger brothers.