Author Topic: Yamaha outboard 2stroke rod bearing (Read 2610 times)

2wheels · « **on:** January 22, 2018, 06:03:52 PM »

I had no idea they made split bearings for 2 stroke engines. Like car rod bearings sort of. Is this common?

strynboen · « **Reply #1 on:** January 23, 2018, 03:34:04 AM »

yes i meed one in a evenrude...had to look carfull to be shure it vas fabric cracked in 2 pieces.....but the crank vas massive..so no vay it can be mounted in one piece

dave500 · « **Reply #2 on:** January 23, 2018, 03:59:38 AM »

unless its a pressed together crank,you wont get those at your local bearing supply store.

simon#42 · « **Reply #3 on:** January 23, 2018, 10:14:38 AM »

yamaha tz500 mains are like that and im buggered if i can find any .

2wheels · « **Reply #4 on:** January 23, 2018, 12:11:49 PM »

Quote from: simon#42 on January 23, 2018, 10:14:38 AM

yamaha tz500 mains are like that and im buggered if i can find any .

When I seen these in a 2 stroke I just wondered why everyone does not use them. It makes crank shaft rebuild so much easier.
Then I started wondering how the bearings work, I still don't really get it as it appears the rollers cannot roll.
Then I looked at the replacement price. WOW. And as you said , if you can find the bearings.

333 · « **Reply #5 on:** January 24, 2018, 06:31:46 AM »

Quote from: simon#42 on January 23, 2018, 10:14:38 AM

yamaha tz500 mains are like that and im buggered if i can find any .

And that, my friends, is why we choose Honda. When I worked a parts counter, I had a guy looking for rings and pistons for a 7 year old Virago. Of the standard and 3 sizes over, Yamaha had one or the other, but not both rings and pistons in any one size. And not out of stock, but discontinued.

simon#42 · « **Reply #6 on:** January 24, 2018, 10:07:07 AM »

the tz is a racing bike and yamaha are pretty good with spares , if you need parts for 80's or 90's honda race bikes you have no chance .

333 · « **Reply #7 on:** January 24, 2018, 08:54:00 PM »

But how many race bikes vs other bikes are there? I'm still getting some parts for my '73 Honda.

dave500 · « **Reply #8 on:** January 25, 2018, 01:35:17 AM »

theres a couple of special NLA bearings in 500/550 transmissions.

2wheels · « **Reply #9 on:** January 25, 2018, 05:32:59 AM »

I feel like a 10 watt light bulb (not to bright)
Wondering what NLA is.
After a little searching. it is NO LONGER AVAILABLE

Still, no one is telling me how these fancy split needle bearings work. ( i'm wondering if this is another -10 watt light bulb- moment for me. I mean, is it obvious, or maybe no one knows?

333 · « **Reply #10 on:** January 25, 2018, 06:14:04 AM »

They work just like roller bearings, except they're thinner, to fit in the rod ends, and are split so you can get them on the crankshaft. Oil will enter easier than a solid bearing, which is important for a 2 stroke, because it isn't submerged in oil like in a 4 stroke.

Truthfully, I've never rebuilt a 2 stroke before, but it seems to me a solid bearing wouldn't lubricate very well.

2wheels · « **Reply #11 on:** January 25, 2018, 06:55:09 AM »

Quote from: 333 on January 25, 2018, 06:14:04 AM

They work just like roller bearings, except they're thinner, to fit in the rod ends, and are split so you can get them on the crankshaft. Oil will enter easier than a solid bearing, which is important for a 2 stroke, because it isn't submerged in oil like in a 4 stroke.

Truthfully, I've never rebuilt a 2 stroke before, but it seems to me a solid bearing wouldn't lubricate very well.

I guess i really need to see the bearing installed and moving. It seems to me keeping the cage locked in place ( at least i think it is) would be a problem.

strynboen · « **Reply #12 on:** January 25, 2018, 08:52:04 AM »

seargh for " evenrude2 stroke autboard- rod/crank- split- bearing"....and you vill end up right here.....
http://www.go2marine.com/product/82281F/rod-crank-end-bearing.html

but you miss the auter part..to get it working..this auter ring is cracked in two pieces..and pressed in the engine case vill hold it as a solid piece..it run vith 2 crac in the roller bearing...i vas skeptic first i sav one

simon#42 · « **Reply #13 on:** January 25, 2018, 10:42:36 AM »

most two strokes dont use these bearings in the rod as the crank normally presses apart and you can use normal needle roller bearings
some low performance engines use a one piece crank and split rods , then you use this type of bearing . they work very well . once on the crank the rod stops them moving around and
they are just like a normal bearing
race bikes use them as main bearings and they are very popular in gearboxes .

jgger · « **Reply #14 on:** January 25, 2018, 06:48:59 PM »

My 79 Toyota 4WD 5 speed transmission had them in there.

strynboen · « **Reply #15 on:** January 26, 2018, 02:31:16 AM »

oh nooo.... somday i vill meet them Again...

think the evenrude had 3 main bearings..and the mittel one vas the "crack type one"..so you can thange thange mains vitaut split the crank..or it vas the rods vho had them..its 25 years ago...cant have it all in my brain anymore..proierty must go on..learning use my" cat" telefone is the NeXT big steap a head

2wheels · « **Reply #16 on:** January 26, 2018, 05:29:03 AM »

The yamaha outboard i am working on is 90 HP. 3 cylinders. probably about 25 years old. very similar to a similar evenrude.
Has these bearings on the connecting rod. I am praying they are still good.

crazypj · « **Reply #17 on:** January 26, 2018, 06:05:05 AM »

Quote from: dave500 on January 25, 2018, 01:35:17 AM

theres a couple of special NLA bearings in 500/550 transmissions.

Really?
Is the 'oil pump bearing' (right side output shaft) still available or is that the discontinued one? I don't think te 500f had it though?

dave500 · « **Reply #18 on:** January 26, 2018, 01:34:05 PM »

yeah that was 550 only,also those needle bearings in cups are nla,you could probably find needles but those cups are special as is the dual row output shaft bearing.

simon#42 · « **Reply #19 on:** January 27, 2018, 03:32:38 AM »

Quote from: 2wheels on January 26, 2018, 05:29:03 AM

The yamaha outboard i am working on is 90 HP. 3 cylinders. probably about 25 years old. very similar to a similar evenrude.
Has these bearings on the connecting rod. I am praying they are still good.

Good engine you have there , as long as it's had a decent two stroke oil in it it should be fine

2wheels · « **Reply #20 on:** January 27, 2018, 10:12:50 AM »

Quote

Good engine you have there , as long as it's had a decent two stroke oil in it it should be fine

Compression measured 120. 115 (middle) and 120. Engine cold and been sitting a few months, no oil added. We took the head off and cylinders are good, pistons appear good, not sloppy at all. The marina that investigated running problems, lack of power said a complete rebuild was required. Im not sure i agree from what we have seen so far.

crazypj · « **Reply #21 on:** February 02, 2018, 05:02:04 PM »

Quote from: 333 on January 25, 2018, 06:14:04 AM

They work just like roller bearings, except they're thinner, to fit in the rod ends, and are split so you can get them on the crankshaft. Oil will enter easier than a solid bearing, which is important for a 2 stroke, because it isn't submerged in oil like in a 4 stroke.

Truthfully, I've never rebuilt a 2 stroke before, but it seems to me a solid bearing wouldn't lubricate very well.

Another reason they work well in a two-stroke is the 'cushioning' effect of combustion every time piston gets to TDC. On a four-stroke, over revving or wrong ignition timing can destroy needle roller bearing real quick
Honda did a fantastic job with their roller bearing cranks, almost impossible to destroy the 50/70/90/125 crank but as piston weight goes up the inertia loading can get out of control.

Yamahawk · « **Reply #22 on:** February 03, 2018, 04:09:19 AM »

Quote from: 333 on January 24, 2018, 06:31:46 AM

Quote from: simon#42 on January 23, 2018, 10:14:38 AM
yamaha tz500 mains are like that and im buggered if i can find any .

And that, my friends, is why we choose Honda. When I worked a parts counter, I had a guy looking for rings and pistons for a 7 year old Virago. Of the standard and 3 sizes over, Yamaha had one or the other, but not both rings and pistons in any one size. And not out of stock, but discontinued.

My old 1981 XV920RH can be rebuilt using connecting rods and pistons... out of a chevy 350 lol... bore it 3mm oversize, I believe, and they work well. Nice MegeCycle cam, and 105rwhp out of the old girl. I talked to a couple of flat track racers who used to run one, and they said some shop teacher rebuilt theirs like that, and it kicked butt on all the other racers out there. They were disappointed that they couldn't run it in the 750 class... until I told them a set of XV750 cylinders and pistons would bot right up on their crankcases... although I don't believe they could run the chevy rods with that setup.
Charlie

vfourfreak · « **Reply #23 on:** February 03, 2018, 09:47:34 AM »

Quote from: 2wheels on January 27, 2018, 10:12:50 AM

Quote

Good engine you have there , as long as it's had a decent two stroke oil in it it should be fine

Compression measured 120. 115 (middle) and 120. Engine cold and been sitting a few months, no oil added. We took the head off and cylinders are good, pistons appear good, not sloppy at all. The marina that investigated running problems, lack of power said a complete rebuild was required. Im not sure i agree from what we have seen so far.

As I was getting into my stride here in France about 9 years ago and had found the time to start my own business, I was getting set up to be a repairer of marine engines. Europe's largest pleasure port is only 10Km from me so I started to do some market research amongst the boatyards there to see if they might pass some work my way. The two things I discovered were that while they might be good at defouling a hull, they knew jack #$%* about engines and that their workshops for motor repair were a disgrace. I am certain many a customer got a false estimate / assesment for an overhaul (possibly in part due to the assumption that boat owners there MUST be rich foreigners (or Parisiens - same thing really) and can afford to be ripped off) or at best a totally bodged repair given the conditions under which the work was to be undertaken. Frankly, amongst the many businesses there, I thought they were all crooks.

Kev

crazypj · « **Reply #24 on:** February 03, 2018, 12:50:43 PM »

Quote from: simon#42 on January 27, 2018, 03:32:38 AM

Quote from: 2wheels on January 26, 2018, 05:29:03 AM
The yamaha outboard i am working on is 90 HP. 3 cylinders. probably about 25 years old. very similar to a similar evenrude.
Has these bearings on the connecting rod. I am praying they are still good.
Quote from: 2wheels on January 26, 2018, 05:29:03 AM
The yamaha outboard i am working on is 90 HP. 3 cylinders. probably about 25 years old. very similar to a similar evenrude.
Has these bearings on the connecting rod. I am praying they are still good.

Long time ago, (around 1980) I changed piston on my DT400MX.
Piston came in Yamaha Marine box and was for outboard. Sucked as in Britain all 'boat' parts are classed as 'luxury items' and have a higher sales tax rate

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Author Topic: Yamaha outboard 2stroke rod bearing (Read 2610 times)