Old Yank outboard racer and 2-stroke fan (seattle smitty)

[seattle smitty]

Raced 250cc alky-burning Konigs and other oddities (Quincy, Anzani, Yamato) on hydroplanes and racing runabouts in the mid-60's thru mid-'70s. Still have some old gear, hope to get back on a racecourse and impede everyone else's progress sometime before I croak. My interest here is in 2-stroke engine tech.

Since few if any of y'all are boat guys, let me tell you a little about this. Over the decades, outboards have usually been one or two generations behind the current 2-stroke design and practices in motorcycling, esp GP racing in Europe. The outboard racing I'm talking about is jocularly referred to as "PRO," i.e., Professional Outboard Racing as practiced by the APBA (American Power Boat Assn.) or the USTS (United States Title Series), a tiny, amateur, in-crowd hobby-sport. This sort of outboard racing is not to be confused with Formula One tunnel-boats powered by big V-6 factory production racemotors, usually built by Mercury or OMC complete with starters and full cowlings, burning gasoline and often racing for actual money. By contrast, the PRO category of racing that I'm talking about uses motorcycle-sized engines (125, 175, 250, 350, 500, 700, and 1100cc displacement) completely stripped down, with unmuffled pipes and burning real racing fuels, powering hydroplanes and racing runabouts. I should say that some of the best of this sort of racing is done in Europe, up to 500cc, and in fact all of the most up-to-date racemotors we use now are coming out of Europe, mainly Italy.

My tentative understanding, based on very sketchy input, is that nothing resembling our PRO racing is being done in NZ or Oz, though there apparently was some stock outboard racing done many decades ago, and some tunnel-boat racing. That's too bad for those of you who are real far-gone 2-stroke lovers. Like you, the 2-stroke crowd in North America grieves for the loss of 2-stroke GP motorcycle racing (and the bikes didn't even get to burn fancy fuels). There's something of a 2-stroke comeback in motocross, so I hear, yet even with sleds (snowmobiles) the 4-strokes are always preferred by and often favored by the authorities-in-charge. PRO outboard racing is nearly the last arena for the most fanatical 2-stroke tuners and modifiers. The only real limits, within a given displacement, is no bottled fuels or oxidizers (nitrous is out), and no supercharging (other than that done via expansion chambers or intake tract tuning). The advantages of PRO outboard racing for our kind is that first, the 4-strokes are always going to be too heavy and especially too top-heavy to work well, and second, the 4-strokes wouldn't get any kind of traction advantage as they can on a motorcycle roadrace course. A modern racing propeller (generally 3 or 4, sometimes 5-blade) is not only quite efficient, but it HOOKS UP to the water all of the power you can find in the engine.

(Hope this will get a few of you old 2-stroke bike racers excited).

--Smitty

[unstuck]

Hamilton jet.

[ellipsis]

Welcome...there are certainly some very serious 2T people on this site...maybe some of the more serious I have ever come across...you wont have to go past the bucket section here to find out...I got to check out a bit of classic boat racing over your way...my bro in law, southern californian, was very much a nautical man...yachts and power boats...a friend of his reconditioned older outboards, but to a point where some people would display them on a pedestal...I have an old anzani around here that will be pulled out for fixing someday...

[Grumph]

As Ellipsis said, look in the bucket section here. The ESE engineering thread has contributions from some of the world's top 2 stroke engineers - and a few of us amateurs too, LOL....
It was one of i believe 3 sites where the Aprilia 125 information was made public - and you literally can't get better than that.

The bucket foundry thread is good reading too.

[Mental Trousers]

Gidday.

http://www.kiwibiker.co.nz/forums/sh...s-engine-tuner

Hope you find that useful and hope you can contribute to it as well.

[Motu]

Over the decades, outboards have usually been one or two generations behind the current 2-stroke design and practices in motorcycling,

I remember pulling apart Evinrudes, Johnsons and Mercurys and finding deflector pistons - WTF???? '70's outboards with pre WWII technology.

[seattle smitty]

When I started racing Stock Outboards forty-five years ago, the engines for all of those classes (250/322/500/700cc) were Mercury factory racemotors, meaning production engine powerheads on short towerhousings with small, low-drag, direct-drive lower units and light flywheels. No modifications allowed. I believe that these small stock Mercury engines were what got raced Down Under, long ago. Most outboard racers here start out in the stockers, learn to read the water, to make starts against a clock, and to race. The competition is close and the speeds are not insane, and many race drivers (as opposed to tuners, men with shop skills, and 2-stroke tech enthusiasts) prefer to stay with the Stocks. Some of the old crossflow Mercurys of the '50s and early '60s still are enthusiastically raced, no longer in the Stock or PRO categories, but in a semi-modified category, burning gasoline and running open megaphones. Moreover, there have been a runabout and a hydro class for old twin-opposed cast-iron block motors first raced in the 1930s. These Antique C (500cc) classes burn methanol and nitro, are run by themselves at PRO races, and limited to the original open-exhaust configuration of eighty years ago. Old alky racers who keep at it often end up in the Antique C boats because they aren't too fast, make good sounds, and are raced by men who have been pals for life.

Crossflow 2-strokes actually were a pretty good design for small, low revving outboards. I have a 1956 5 1/2hp Johnson that is as smooth a motor for trolling hour after hour for salmon as anything built today.

(EDIT) ellipsis, when you get around to doing something with that Anzani, if you're interested I can impart a ton of obscure and otherwise useless info on that engine.

[seattle smitty]

Somebody please clue me in on a couple of terms (hey, I'm old, I don't even know the current slang HERE, let alone any regionalisms!). A "bucket" is a 2-stroke? Where did that come from? And "2T" and "4T" refer to 2- and 4-strokes, right? Finally, would somebody give me a clear definition of a "motard"? I asked that of a dealership salesman at a motorcycle show last year, and still have no clear concept

[Mental Trousers]

Somebody please clue me in on a couple of terms (hey, I'm old, I don't even know the current slang HERE, let alone any regionalisms!). A "bucket" is a 2-stroke? Where did that come from? And "2T" and "4T" refer to 2- and 4-strokes, right? Finally, would somebody give me a clear definition of a "motard"? I asked that of a dealership salesman at a motorcycle show last year, and still have no clear concept

Certainly.

Bucket - short for bikes made from a Bucket of Bits
2T - 2 stroke
4T - 4 stroke
Motard - dirt bike with road wheels, usually 17" so they can use common road/race tyres

[Grumph]

Smitty - i'm one of the oldest here and have a little hydro time so i'll try to answer some questions....

There was i believe some interest in the small outboard hydros in the late 50's early 60's here. Personally i never saw one racing and have only seen them as static exhibits now. My own hydro involvement was crewing for 100CI and 150CI inboard hydros in the very early 70's.
These are now also a thing of the past sadly. The only Hydros being raced here now as far as i know are the 7 liter GP class. Several venues have been lost due to noise regs too...

Buckets are a bike race class. based on road bikes, 100cc 2 stroke water cooled, 125 air cooled with carb restrictions. 150cc four stroke. "bucket" comes from the colloquial "bucket of shit...." Gone upmarket now, LOL, formula 4 and F5 (50cc)

Motards are a bastard thing (literally) semi motocross with touches of roadracing bike. Used on circuits which are part sealed surface, part dirt. made for TV....Origins were the US "superbikers" TV specials featuring Lawson,Spencer etc.

Hope this helps. Set aside a week or so to read the ESE engineering thread - and take notes.

[ellipsis]

...it can be a bit of a struggle for outsiders to keep up with our slang and colloquialisms...coupled with the dramatically altered grammar of some, and some posters who seem to have their own form of language, you may struggle for a while...

...I saw the Anzani at the back of one of my sheds recently...it doesn't need a lot to make it go...I have enough unfinished projects going as it is, so it will stay there a while longer...

[seattle smitty]

Thanks all for getting me into the 21st century (well, I guess; so far I think that overall the late-'50s/early-'60s were the best of times, at least in this part of this country).

I've been slowly working through the ten thousand pages of those threads, bliss for 2-stroke lovers. Looks like a couple of posters were near or right at the top of 2-stroke GP racing in its heyday (is "kel" who I think he might be??). Any possibility one of them would lower himself enough to take PM questions from an outboard racer on applying modern tech to our lower-tech engines?

Again, I think fellows like them, or any far-gone 2-stroker who lives to carve on ports and roll cones for pipes would have a blast working on engines with almost no limits to modifications or fuel. Actually, two such men, both Italians, have got into outboards, and are manufacturing the first up-to-date racemotors our little sport has seen in a long time. Giuseppe Rossi, a many-times European champion outboard racer, builds the GRM 125/175/250/350/500cc engines which are winning most of the races in those classes here and in Europe. Carlo Verona, who I understand has done contract work for some of the motorcycle factory teams, makes the VRP engines that are fully competitive with the GRMs. A slightly sad consequence of the competition between these two well-informed men is that their engines are so good out-of-the-box that ordinary outboard racers know they aren't knowledgeable enough to improve on them, which used to be half the fun of PRO outboard racing. However, there are still possibilities for getting an edge . . . heh, heh, heh.

[Grumph]

Smitty - just go ahead and ask your questions on the ESE thread. Wouldn't surprise me if Frits Overmars knows the guys you mention - 2 stroke design is a very small world...he's proving to be a very forthcoming source of info.

[seattle smitty]

Very slowly plodding through it due to time constraints.

Need another term, what is a "spigot"? Is that the intake tract from the carb, or is it the venturi in the carb, or what?

I'm not far into the thing, still reading 5 year old posts, but wondering how "TZ350" made out with his experiments on cylinder cooling. I've always thought that the front wheel of any motorcycle is a terrible obstruction to engine cooling, and that big ugly air ducts would be the solution (for air-cooled barrels anyway). I Also think you can help the situation a bit by welding some cooling fins to the first several inches of the exhaust header-pipe, right after the monting flange. As we all know, the megaphone section of the expansion chamber draws some fresh air/fuel charge some distance into it, and this is then crammed back into the cylinder at exhaust-closing by the positive return wave from the baffle cone (in Seattle, in the first days of expansion chambers, we boatracers called them "bounce-pipes.). This column of air/fuel picks up heat while it is in the exhaust tract; I'm guessing it would pick up less of this heat if the header-pipe had cooling fins.

I did this, welded some cooling fins to the header pipes, on my '76 Yamah RD400C when I made a new exhaust system. But I did no before-and-after testing of that feature in isolation. I don't race it, and ride it like an old lady (I'm old, I never raced bikes, only boats, and I don't mind a splash but don't want to crash), so can't tell you anything about the practical effect of the fins, sorry.

Actually, there is some evidence seemingly supporting my idea, from the sled (snowmobile) racers (who have some interesting 2-stroke tech, if you want to check that out). When the pipes on a sled get hit by a big load of snow, they cool off, the wave-speed slows, and they go out-of-tune until the snow melts off. Same thing can happen with racing outboards. The sled guys sought to prevent this by wrapping their pipes with thermal-insulating wraps. They soon found that it was best to leave the first several inches of the header-pipe uncovered, no thermo-tape, because of what I'm talking about, an over-heated slug of air-fuel getting shoved back into the cylinder.

[avgas]

I have always wanted to take the old mans 25hp Yamaha and put that in an old Deltabox frame. I loved the sound of that motor as a kid - don't care if its not fast. Will sound and look great.

I suspect it will be my retirement plan - or when I get enough money to buy the old man a new boat.