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I found a 84 JS440 with a 550 swapped in for a pretty good price. Looks and runs good. Are the JS440 the same as the JS550, just different motors? Should I be cautious of anything in particular on this ski?
 

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Probly too late for this but if it runs good and looks good get it. The 440 has a smaller pump but it accually helps with control and off the line speed. Its a good thing. 440 550 swaps are the way to go imo
 

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yeah, +1 on 550subman's comment!

440 pumps are definitely better. I have a 440 that I dropped a 550 into myself. As far as I know the pump is the only difference between the two.
 

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If you end up putting more hp into the engine (porting) you will need a bulkhead support. The 440 pumps will stress crack the hull when they are hopped up. The 550 pumps are bolted to the frame of the hull, the 440 are not.
 

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The nice thing about those old JSs is there seems to be an endless supply of new and used parts! We have an 85 JS500 and it's bullet proof! Get it and have fun!
 

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Js 440 / 550

Im new here and have a few questions i have just go a js440 for £50 quid and the engine is knackered will a 550 fit and run off the same ignition system any help would be great...
 

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..will a 550 fit and run off the same ignition system...
absolutely. They are the same part as far as i know. I used the 440 ignition components when i did my 440-to-550 swap.
 

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Any other things i should be aware off as im compleatly new to this. should i stick with the original carb for a 550 or is there a better one i should look out for and the 550 motor i have my eye on is the old one with no reeds as there is nothing else around
 

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Oh the other thing is are the bottom ends the same as the 440 i have has a good bottom end. So is it possible to fit a 550 barrel on it and head to match or even a 550 barrel the one with reeds. if i use the one with reeds do i need a different intake manifold as its at a slant cheers nigel. sorry for all the questions
 

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should i stick with the original carb for a 550 or is there a better one i should look out for and the 550 motor i have my eye on is the old one with no reeds as there is nothing else around
If your 550 comes with a carb use it unless its hosed. The 1986 and later 550s (the ones with JetPower exhaust) use a larger carb than the older ones. I have a pre-1986 550 and am using a 440 carburetor on it and it works just fine.
 

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Oh the other thing is are the bottom ends the same as the 440 i have has a good bottom end. So is it possible to fit a 550 barrel on it and head to match or even a 550 barrel the one with reeds. if i use the one with reeds do i need a different intake manifold as its at a slant cheers nigel. sorry for all the questions
The bottom ends for the piston port motor are the same, but the reed 550 motors have different stud spacing so they are not the same. You can put the top of a 550 on a 440 as long as it is a piston port (pp) Hope this helps.

Mike
 

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I did in the end got a sbn44 and slowly still coming together just in the process of re spraying it at the mo. done the bottom just need to do the hood and top half. ski pole already done and put a new bush in new pump this morning and put in new cooling lines threw the hull. used some 10mm plastic micro bore that they use in underfloor heating as its rigid and dosent colapse
 
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