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Rotax 503: is there still a market for it?

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Hephaestus

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Joined
Jun 25, 2014
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1,789
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YMM
The Chinese clones aren't terrible - if you rebuild them once you receive them. QA/QC is definitely lacking in the assembly department.

There's a LOT of 503 powered aircraft, all will need engines over time. Lots of them turn over on the classified sites too...

I picked up a 503 and a blue head last year for little more than core $.
 

Armilite

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Joined
Sep 5, 2011
Messages
3,362
Location
AMES, IA USA
I know of at least one 660 lb. kit plane that flies quite nicely on just 40 HP.

BJC
==========================

All you have to do is go back and look at some of these Older Planes that have been made for 30+ Years. My T-Bird I has had just about every Rotax UL Engine put on it, 277UL, 377UL, 447UL, 503UL, 462UL, 532UL, 582UL, 618UL, and two different Subaru's, two different Wankles, etc. The Lazair started out with (2) 5.5hp each Chainsaw Engines, then went to (2) Rotax 185's 9.4hp each, then went to (2) Solo 210 Engines 15hp each. There was even one Lazair that had (4) Rotax 185's put on one! The Rutan Quickie Q1 had an 18hp Onan Generator Engine, soon upgraded it to 22hp, and about every Rotax UL Engine has been put on one up to a Skidoo 583.
 

Armilite

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Joined
Sep 5, 2011
Messages
3,362
Location
AMES, IA USA
In it's day, the 503 was a great all round engine, the slightly more expensive Hirth had slightly better power, while everything else couldn't match the power to weight to cost.
That all said, the demise of the 503 (and it's ilk) is not just the worn out tooling problem in Austria, but also the fact the world is doing it's best to phase out two strokes because of the emission problems.
Most watercraft are now four stroke, garden implements are going four stroke or electric, and it's getting hard to find two stroke motor bikes these days.
I've got a brand new 503 still in it's box, and I'm hanging onto it for my final hurrah! ;)
=========================

The Newer Skidoo 2 Stroke eTec Engines have better Emissions than there Newer 4 Strokes. IF, you burn Hirths Blue Max Oil or Amsoil Saber Pro at 80-90-100:1 Ratio you will have less Emissions/Smoke also, and less Rings Sticking, less Decarbons to do.

For a Big Company like Rotax who many make there own Tooling & Molds, it's not that expensive. Like I was sitting in a Bar one day talking to a old high school friend who makes Molds for Plastic Injection. There was an Ash Tray sitting on the Bar and I asked him, what would a Mold for that Cost, he said $6000. I said No Way. He said think of it this way. There are about 20 cents of Plastic there. The Company that Pays me to make that $6000 Mold, then put's it in a Plastic Injection Mold machine that runs 24/7 making 100,000+ Ash Trays a day, who then Whole Sales them for $1.50 each, which then the Retailer sells them for $3 each. Everybody makes Money!

Now a guy in India on YouTube was Casting a Head very similar in Size to a Rotax 503 which Cost $450 each Retail, so $900 for a pair. I asked him how much it Cost him to Cast (1) Head and machine it, he said $6. A New Cast 582UL Head Cost $820, a New Billet Snowmobile/Jet Ski Head Cost $400 Avg. A Block of 6061 Aluminum off eBay to make (1) Head Avg $25-$35.

Billet Block of 6061 to make a Billet PTO Case I paid $29 for it off eBay.
 

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Armilite

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Sep 5, 2011
Messages
3,362
Location
AMES, IA USA
CORE PARTS:

All Stock Cylinders can be over Bored 2mm! Most can be Big Bored +4mm.


Skidoo 500F/503F was Built till I think 2003. The 380F & 440F till I think 2008, the 277 till 2008. You can still Buy some of the Core Parts.

1
Crankcase Ass'y Includes 1 - 7. 380F/440F. Has been discontinued! But many available on eBay.

Crankcase Ass'y Includes 1 - 6. 500F/503F. 420888493 $614.99
Will the provision 8 Holes need to be Tapped and Case Machined for Gear Drive, Yes. Cost about $150.

1
Crankshaft Ass'y Includes 1 - 7. 380F /440F. 420887249 421000154 $409.99

Crankshaft Ass'y 500F/503F. 420888391 421000155 $409.99

2 500F/503F Cylinder with Sleeve 420923417 421000500 $259.99 each.

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277F/300F Cylinder
28 Cylinder with Sleeve 420913219 420623180 $369.99.

There are many used Motors on Craigslist & Facebook Marketplace, and Heads, Cylinders, Cases Good on eBay, some have even been Machined. The Crank is the one item most People can't rebuild themselves.
 
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