Yamaha sj650 into a 550sx????

[motoxracer1551]

Don't want to start another thread on arguing why and which is better. its a 550 so this is an upgrade. i don't have a k650 to put in. im upgrading to a 701 so i will have this perfect motor as an extra.

So how much work would it be to put the motor in my ski in the sig. 550 is running like and i don't want to deal with it. should be a FUN ski with y650 in it.

 

[motoxracer1551]

just saw the thread with the 701 and 650 pump. so would a 650 be too much for the stock 550sx pump?

 

[tnj4life]

Im in the process of putting a yamaha motor in my js550. Its not cut and dry. Im using my stock js550 pump and driveshaft for now. It will be alot like a fx1, you will have cavitiation with a small pump. Heres the issues with the swap.

1. couplers and motor hitting battery box
2. motor bedplate
3. ebox mounting
4. Exhaust

Foximus covers alot of this in his 550 build. This is not near as easy as the kawi motor conversion. Im having to get a js550 coupler tapped out to fit the yamaha motor because the tigershark and yamaha coupler combo wont reach due to the battery box and the tigershark coupler not having a long enough neck. But yours might work cause your using the 550sx driveline, the js550 driveline uses couplers that have the longer neck where your coupler on the driveshaft is flat on the back. I will most likely have to shim my driveshaft coupler a few washers to reach as well. Keep in mind that foximus grafted his pump section in and was able to set his up however he wanted to.

Blowsion sells kawi couplers for yamahas, but I dont wanna spend $100 for just needing one coupler.

 

[FX-Rex]

some kawi shafts will accept a yamaha coupler. Alleast the zxi900 shaft will.

 

[tnj4life]

The js550 couplers are 18mm and the yamahas couplers are 24mm. Im pretty sure the 550sx couplers are 18mm, foximus used a tigershark coupler on his 550sx driveshaft and they are 18mm.