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**bh/** · 06-15-2013, 01:46 PM

An alky Crecent on display in NJ in 2005,
enroute to its new owner in Reg-5.
Note the Konig like O'Dea alky carbs.
Ignition is different, chain saw style,
clamps are Merc ,
Exhaust manifold looks stock.

In line 3cyl 2strokes are not unusual. Thor of WI sold a 3cyl fishing motor in the 30s, Konig sold a 3cyl 500cc race motor in the 50s, both deflectors,
OMC made 3cyl loopers common in the 70s,
Mercury laid an egg with a deflector triple in the 70s,
and so on to the current V6s.

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**johnsonm50** · 06-15-2013, 02:53 PM

Originally posted by bh/ View Post

An alky Crecent on display in NJ in 2005,
enroute to its new owner in Reg-5.
Note the Konig like O'Dea alky carbs.
Ignition is different, chain saw style,
clamps are Merc ,
Exhaust manifold looks stock.

In line 3cyl 2strokes are not unusual. Thor of WI sold a 3cyl fishing motor in the 30s, Konig sold a 3cyl 500cc race motor in the 50s, both deflectors,
OMC made 3cyl loopers common in the 70s,
Mercury laid an egg with a deflector triple in the 70s,
and so on to the current V6s.

I was lucky enough to be there, meet Brian & see it, any vid of them racing?..

**lcp8410** · 06-17-2013, 07:12 PM

crescent 500

holy...its goes 8k on ebay...does this piece of history really worth that much?.....cant believe it...

**lcp8410** · 06-17-2013, 07:30 PM

7,850.00 reserve not met....There will be no private sale after the auction closes.....seller happy to keep it if it does not meet reserve price...hahaha...mark his words....

**STEVE FRENCH** · 06-18-2013, 02:54 AM

Remember the "Never started"...In dealer counter display,.......... 10XS Merc a couple years ago?

Never sold.....But what an .......appraisal!!

**ZUL8TR** · 06-18-2013, 04:47 AM

Cresent 500

If somebody really wants one probably for a reasonable price I believe Marshall Eldridge Jr.still has the one he raced back in the 1970's. Give him a call 352-324-2867 he lives in Yalaha Fla.

**Danas66** · 06-24-2013, 01:23 AM

Hi
I am holding to put together a crescent cs500 I have used Yamato's lower unit. I'll test it this summer. /Daniel

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**Smitty** · 06-24-2013, 11:11 AM

Rumley asked about exhaust tuning. Inline triples are able to use an exhaust system called "pulse-tuned". Quiet, makes good power, not as much as the right expansion chambers but a lot less weight and inconvenience and noise. You can find articles on pulse-tuning 3-cyl 2-strokes via Google.

I had a quick look inside another guy's Crescent during the Super C days. Looked similar to some of the old A Konigs. The bore spacing was so close together that the transfer ports of adjacent cylinders had to be squashed down to a poor shape that limited flow. 2-stroke motorcycles of the day ('60s and '70s, were a couple of generations ahead of the best alky outboards, and remained that way until recently (or so I hear, because I haven't got to look at any of the new alky motors). The knowledgable bike engine tuners laughed when they were shown our motors. But an obsolete motor that's well developed and well-tuned will outrun an up-to-date motor that is not, and the factory Crescents came all dialed-in. Super Cs were fun to watch.

**BmJuby** · 06-24-2013, 07:04 PM

Wonder what reserve was...10k?

**lcp8410** · 06-30-2013, 11:21 PM

crescent 500

another crescent at ebay. 2.5k reserve not met. shipping is varies.

**STEVE FRENCH** · 07-01-2013, 02:59 AM

Originally posted by lcp8410 View Post

another crescent at ebay. 2.5k reserve not met. shipping is varies.

Link??....I'm lazy>> Like Cheney!!

**krazy karl** · 07-09-2013, 08:00 AM

I know a racer that had a foot for one of these that he used under a DMod Merc. It broke the prop shaft at the sheer pin hole. This was a few years ago. He may still have it. I can check if anyone is interested.
kk

**bh/** · 07-09-2013, 04:31 PM

Originally posted by amrkedede

It's good to hear that the port timing,and the piston allowed for the transfer of fuel from the crankcase to the combustion chamber. I am sure it will be best with performance. ....

Most reading this thread know all this, but all 2 strokes, save for Detroit Diesels, etc, control the flow of fuel mix into the cylinder, and out the exhaust ports, by opening & closing the ports with the rising and falling piston. What some find unusual with this 500cc Crescent,
is that it also uses the piston skirt to admit and control
the flow of fuel/air mixture into the crankcase.
It is nothing special, common in fact, and the cheapest way of doing it.
(save for a simple poppet valve)
What is remarkable is that the Crescent does it so well,
making the power it does, in spite of
'3rd port' timing, ie; piston skirt crankcase induction timing.

Most 2 stroke outboards 100 yrs ago used this simple and reliable system. Johnson's 1st factory race motor, the opposed twin PR40 of 1928 used one carb and to feed two cylinders via two passages to 3rd ports on each cylinder. By 1930, with the PR50, they switched to an external gear driven rotary valve to time the induction, and gain more power, at the expense of cost and reliability. Johnson service motors thru to the early '50s still employed a simple 3rd port system.
The very fine 2.5 & 5 hp alternate firing 2 cylinder Johnsons of the late '40s & '50s employed piston timed 3rd ports, and an internal
rotary valve. This not for speed, but starting and idling.
German Konigs in the '50s used 3rd ports, and his 1st 500cc 4 cylinder VC used 4 carbs and 3rd ports. It was cantankerous to say the least, and by 1967 the VC employed an external belt drive rotary valve and only 2 carbs, to time a very fast and successful race motor. So successful in fact, that it found its way into European GP winning motorcycles.
Reed valves, internal or external, are the other way to go.
Also cheap, and reliable.
So, what goes around comes around,
and nothing is ever really new

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