Any reason an owner would intentionally do this?

[Dartman]

thanks for all the input,

lets remember, this engine needs alot of lean way, since its crazy and im inexperienced.

Im liking Dartmans observations. Dartman, any reason restosud would recommend stock settings?



PS. just bought Braided ignition leads, nom nom nom, cant wait to crimp......... .... ? ...... ?? :0

Can't speak for him...I'm just stating my experience with 550 cast iron cylinders in hi performance applications like racing and using dual cooling.
Took me a long time to figure this out. I learned that when I leaned out the mixture screws to run really good on the top end it would seize.
Basically it was seizing from the piston to wall clearance being too small, not from being too lean.
Think of it this way, make more power...by product is more piston crown heat. So the pistons expand more.
Now the jet pump makes more thrust, so does the cooling line pressure and even more water volume when adding a 2nd line.
This extra cooling to the cast iron cylinder keeps the cylinder from expanding as much, thus creates smaller running piston to wall clearance.
This is where the problem I had with leaning out the mixture screws to run good.
When I got the piston to wall clearance increased, it quit seizing and ran really fast on the top end.

 

[550surf]

okay, thanks for teaching me this. I will need all the help i can get with this ski.
Dartman, can i ask what your carby settings were for your ski with similar set up?

 

[550surf]

should i go any more over .010 clearance aswell????
Id like to make the setup the safest and most reliable.

What can i do to the setup of my machine to extract such attributes???


thanks dman

 

[restosud]

the crank case cleanup referred to by wiseco is a boring cut of the top 1/2 case for the piston skirts to clear when at bottom dead center. it has nothing to do with the crankshaft.
550 cranks and seals are not bulletproof .the front bearing takes a beating so at least replace it along with seal if in doubt.check the snout taper for runout also.
since you're in there,replacing all outer bearings is no panacea but won't hurt anything
the later model iron cylinders were troublesome when ported heavily.the reed mod allowed for a smoother power band without chopping it too much.the cylinders distorts unevenly with heat and running extra clearance is a patch that brings it's own problems.

 

[Quinc]

I would try and find a builder that has experience with high performance 550's and see what they recommend. I also sent you a pm.

 

[550surf]

cheers restosud, given my setup, what clearance exactly would you personally run?
keep in mind, i wana reliablility/saftey then ill chase max rpm.


Quinc, theres no builders in oz, thats why i came to Xh2o and PWCtoday. Xh2o is my fav tho lol
ill read the pm now, thanks mate


just finnished laying down all the Fiberglass and thickened epoxy resin today, whole new ski it is, every nok and cranny, fiilld.
will post some pictures after the sand tmorrow.

 

[550surf]

Hey,

when i was first asking about my ski, some DK told me it was using 650 sx reeds so i bought some, i know now tho its not an goki adaptor but reeds cut into the side of the crank, Can i use the 650SX /X2 reeds?

Looking now on ebay at 550 reeds i feel so stupid not comparing it but i just took his word for it
now im stuck with these reeds, FKKKD and i dont think i can send it back.

Can i use them or will it not work ( dumb question /10 ) ????

will i have to buy the 550 sx reeds? looking at the pictures on ebay ( there appears to be 3 DIFFERENT reeds all labelled the same.......im so confused
i think i need the middle ones since use a metal plate and the middle ones have a metal plate tho, wouldt they all have a plate to hold them in

WTF