JS440/650sx Conversion

[TomatCP87]

So its been a few years since I have been on here but I figure I'd update you guys on the new project.

My friend drowned his 1979 JS440 last summer and seized the engine, so hes giving it to me for free. I have a 1988 650sx that has a crap hull/prop/steering cable butt has a good engine. (It was sitting for 3 years but started up just fine the other day) So I'm thinking why not make a more fun ski since everyone seems to hate on the 650sx?

Well I bought the conversion plate and pulled both engines, so once I get back after work I'll take a few pictures if anyone is interested.

 

[yamijumpn]

i would be interested! I had one together back in 2008. Westcoast exhaust and MRD mechanical fuel injection. Went like hell when it ran good!

 

[Midlake Crisis]

Subscribed, might take the 650 skeleton off ya. . .

 

[TomatCP87]

So Ive been searching here and pwctoday.com and cant seem to find any info on this problem, has anyone ever experienced buying a conversion plate and not having it line up correctly?

With the plate between the 650 engine and the 440 engine cradle there is a gap of about 3/4 of an inch between the engine and driveshaft couplers, although the couplers line up vertically good enough.

I believe my only options are to extend one of the couplers to reach the other or cut and weld the engine cradle to move the mounting holes so the engine is back 3/4 inch. Anyone else ever have this problem or am I just missing something too easy?

P.S. I will definitely be getting rid of the 650sx hull, but not until this conversion is done.

Oh and pictures will come once some noticeable progress is accomplished

 

[TomatCP87]

PS its a Watcon conversion plate

 

[heynagel]

Is the plate on backwards? (Rotate 180). I know their is a front and back to those conversion plates.

 

[kswiatk]

So Ive been searching here and pwctoday.com and cant seem to find any info on this problem, has anyone ever experienced buying a conversion plate and not having it line up correctly?

With the plate between the 650 engine and the 440 engine cradle there is a gap of about 3/4 of an inch between the engine and driveshaft couplers, although the couplers line up vertically good enough.

I believe my only options are to extend one of the couplers to reach the other or cut and weld the engine cradle to move the mounting holes so the engine is back 3/4 inch. Anyone else ever have this problem or am I just missing something too easy?

P.S. I will definitely be getting rid of the 650sx hull, but not until this conversion is done.

Oh and pictures will come once some noticeable progress is accomplished

What coupler did you use? You have to use a 550 engine coupler, not a 650

 

[heynagel]

Ahh yes good call kswiatk, and from a JS not SX

 

[TomatCP87]

Damn, didn't realize I'd need a different coupler. Anyone know where I can get a js550 engine coupler?

 

[kswiatk]

Make a want to buy ad. Someone probably has one. Or contact John Zigler at www.watcon.com

 

[heynagel]

http://pages.ebay.com/link/?nav=item.view&alt=web&id=121608823802
Here's what you need. It's $5.00 on eBay. I copied this with my phone so hopefully the link works.

 

[TomatCP87]

Thanks for the help, I've got one on order so once I get it in and the engine mounted I'll take some pictures and show the progress

 

[mike b]

http://pages.ebay.com/link/?nav=item.view&alt=web&id=121608823802
Here's what you need. It's $5.00 on eBay. I copied this with my phone so hopefully the link works.

Are you sure that's for the engine side? It says engine-driveshaft. Or are they the same thread size

 

[kswiatk]

They are the same P/N so its all the same.

 

[Nolan_Glock]

Its a fun ski once you get it together. Let me know if you need the wiring diagram for the e-box. Are you going with the 650 rectifier in the 440 e-box?

 

[mike b]

Its a fun ski once you get it together. Let me know if you need the wiring diagram for the e-box. Are you going with the 650 rectifier in the 440 e-box?

I'm going to do this same swap and deciding to just mount the 650 box so I don't have to mess with electronics but could you post up the diagram or pm it to me incase I do change over to the 550 ebox

 

[TomatCP87]

Got the engine in and it lines up which is awesome. Tomorrow I plan on fitting the exhaust. I'm not sure on the wiring yet. The 550/650 conversion thread by laserman says you can just use the 650 stator and it all hooks up correct? If not I think I might need some help with the wiring....

 

[mike b]

Im doing this same swap. Im thinking making a bracket to mount my 650 electronics would be the easiest but the cleanest look is probably the 550 ebox. If you switch to the 550 box please have some detailed pictures of the swap in your thread. Ill be right behind you! lol

 

[TomatCP87]

Its a fun ski once you get it together. Let me know if you need the wiring diagram for the e-box. Are you going with the 650 rectifier in the 440 e-box?

Im under the impression I would use the diagram from lasermans 550/650 conversion thread. Would the wiring be different for my 440/650 conversion? If so a diagram would be immensely useful

 

[TomatCP87]

So here's another update...

I had to fab up a mount for the 650 electrical and a new mount for the battery as well. Also fabbed up a mount for the throttle cable but don't have a picture of that.

Anyways I got he running and took her out for a test today! It runs well and everything works although the idle is a bit high and the finger throttle needs to be angled down a bit.

The engine seems a bit weaker than when it was in the 650 hull is this normal? Also I need to check the compression since it was sitting for 4 years, but all in all she ran great and everything worked well so I'm happy.

If anyone has any advice it's always appreciated..