Yamaha 50hp rebuild ?

[harpldpo6]

I'm rebuilding a 2002 Yamaha 50TLRA that had a bad upper crank bearing. I'm replaceing the bearing and new rings. My question is how to re-install pistons w/new rings in crankcase? My ring compressor is to big to fit, plus having to do all 3 pistons at same time. Do they make special ring compressor for outboard motors? Lots of answers will be what does your service manual say, the cheapest i can find online is $90, so i don" have one. Thanks Harold

 

[boscoe99]

I am not understanding your comment about having to do all three pistons at the same time.

 

[racerone]

???--Multi piece crankshaft.------Rods do not have caps.----Therefor the crank and pistons go in as an assembly.

 

[Mc Tool]

Yeah , but the 3 pistons are 120⁰ apart and the bottoms of the cylinders will have a taper/bevel ground into them to compress the rings as they go into the cylinder . Do one piston at a time ,either with an extra pair of hands or use small bits of wood to support the crank assy as you lower it .
Once you have the 1st piston in push it up the bore untill the 2nd piston is at the bottom of its bore then by either rotating the crank assy or just pushing it up the bore feed the rings into the bore ....do same for 3rd piston and your there.
Put oil on the rings 1st and you must make sure the rings are correctly positioned on the piston and you just sorta gently wriggle the piston and the rings will compress one at a time and go up the bore.
Have a look on you tube ,Im sure there will be vids showing how to do this .

 

[flyingscott]

Get tongue depressors or big popsicle sticks. Manually press the rings in 1 at a time. The Bevel will only work if the rings are perfectly That's why you need the popsicle sticks.

 

[99yam40]

I have used ty-raps before to get the rings orientated correctly and a little compressed and just cut the ty raps as the pistons go in

 

[harpldpo6]

I don't see any taper/bevel on the cylinders at all to help start the rings going in. On small motorcycle motors i have used hose clamps before but i don't think that will work with this block. I'm still wanting on the parts
Thanks everyone for the comments

 

[racerone]

Find a shop to install this assembly for you.

 

[99yam40]

I sent in my C40 crank to have it rebuilt some years ago.
they just sent me one that they put all new bearing into and seals, for around $400
me and a friend put it together in my den inside my house
ty raps work once you get the 1st piston into the block the ty raps slide off the piston and they are easy to cut and remove.
then you work on the next one