wiseco pistons

[Whale]

Just installing new wiseco pistons and i noticed that the new pistons didnt come with spacers/washers that go either side of the top end bearing, as they did with my stock pistons?

Should i have them in the kit?

Should i put the stock ones in?

What i got in the box's was pistons ,wrist pins, circlips and rings.
Thanks for any help:smile:

 

[Mike W]

When I rebuilt my top end last year mine didnt come with them either. I just installed the old ones and with a gazillion hours on my ski last year I had no issues. Im sure someone will tell you not to for whatever reason but I really dont see where reusing those will hurt anything. Unless they are worn or damaged.

 

[WFO Speedracer]

As long as they will fit no problem you can use the old one or just leave them out.Yamaha is the only one that uses those and they don't really do anything.

 

[Water Worx]

Leave them out & they dont come in aftermarket piston kits.

 

[63chevyll]

the spacers keep thr rod from moving side to side too much. put the old ones in

 

[Maico]

Rupp L/C sleds were the same way....

The old Rupp L/C snowmobile motors were the same way. The cranks did not use thrust washers on the big end. The pistons used thrust washers to align the rod on the crank. Better leave 'em in.

 

[WFO Speedracer]

I have built them either way and no engines have come back with problems so I am assuming it dosen't matter,its just something else to argue over like abs vs pvc vs aluminum pipe.

 

[robertg]

I thought you had to use wider bearings from a Kawasaki when you left out the spacers.

 

[norcal ex]

I thought you had to use wider bearings from a Kawasaki when you left out the spacers.

yep, thats what i understood also.... different bearings use different spacers.

 

[WFO Speedracer]

Let me ask you this ,where exactly is it that the bearings are going to go?

 

[hooka-2]

I left mine out and haven't had any problem ..........yet

 

[WFO Speedracer]

Pistons,aluminum or pvc,please stay tuned for the answer.

 

[SUPERTUNE]

Ding, Ding, :arms: robertg and norcal Both Win! :cheer: In the oem yamaha part # is U2 in it for using the thrust washers, and if you omit the thrust washers, you need to use the yamaha oem part # thats says U3 instead of U2. I just use the Pro-x or Wiseco's pin bearings for the 20mm (small pin) Kaw 750 motor as they are the U3 bearings. (something like .8 mm longer than the stock pin bearing that used the thrust washers). So if you want to build it right, use the right bearing depending if you use the thrust washers!

 

[WFO Speedracer]

I use the bearings that come in the wsm kits and they are the correct length so I don't have this particular issue to deal with.

 

[SUPERJET-113]

From what I remember, the 650 SJ came with the wider wrist pin bearing and the 701 SJ's came with the shorter wrist pin bearing and the thrust washers. That's right isnt it? Why did Yamaha switch? Just curious.

 

[matty180]

Yeah, if you use the 650 bearings you do not have to run the thrust washers. They are wider. This is what group K reccomends. This is what I run on all my motors.

 

[Kohldanielzimmer]

Ding, Ding, :arms: robertg and norcal Both Win! :cheer: In the oem yamaha part # is U2 in it for using the thrust washers, and if you omit the thrust washers, you need to use the yamaha oem part # thats says U3 instead of U2. I just use the Pro-x or Wiseco's pin bearings for the 20mm (small pin) Kaw 750 motor as they are the U3 bearings. (something like .8 mm longer than the stock pin bearing that used the thrust washers). So if you want to build it right, use the right bearing depending if you use the thrust washers!

Going to win oldest thread bumping award here. I was curious about this today and I was able to find this explanation.