yamaha fourstroke crank bearings

[vroom ZOOM]

it looks as if you are going to have to use the ford part # on the OEM bearings to get the correct bearings .? what colour marking on them.
? has the crank been ground at some stage of its life. or was the crank possibly worn ( measure to see what spec it is)
the reason bearings come in 3 sizes from the factory is because these cranks vary in size ,PIA i know. also people clean up the journal's by nipping / linishing a few thou off.
this is why i posted , measure /compare the ACL race against the ones that come from the motor. its very easy to get it wrong as you have now found..

I wish it was that easy...

first of all, ford doesn't sell those bearings separate, they only sell short blocks. Second, the ford markings don't tell me anything, as they don't have colours. There are two size bearings that came out of the old motor, 2 03 R and 1 03 W. I am pretty sure the 2 03 R is the mid size bearing, and after measuring the 1 03 W is an oversize bearing. This would mean that yamaha "red" bearing would be = 2 03 R. Sounds good, but ford doesn't sell bearings. I go to mahle or something and they only have one size... Ugh!

 

[boscoe99]

All of the main bearings for the 63P model Yamaha F150's are available.

Why not get one of each colour and measure its thickness.

Then measure the diameter of each crank shaft main bearing journal and the block bearing bores to calculate what size bearing is needed to achieve the specified clearance?

Then use plastigage to either verify the clearance is correct or not.

 

[ct1762@gmail.com]

now wait im sure you had a typo there, but just to be clear 7 thousandths is written as .007'', not .7'' which is seven hundred-thousanths! Again im sure you meant .002''-.007'' just thought i'd make sure! But if that one bearing is .006'' you should be fine, no?

 

[boscoe99]

Hard to believe that these new 4 strokes are not well supported.----One stroke against Yamaha I guess.----Many folks will be disappointed by modern corporate policies !!

Bad information.

 

[boscoe99]

You get the idea that they don't want anyone rebuilding them, but shops that sell remans, must get those parts from somewhere!

Based on bad information, it might seem that way.

 

[boscoe99]

Well, I got a few updates for you all in case someone is in my situation.
The manual says 0.7 to 2 thou clearance on the mains. I figured if I would be around 1.5 that would be golden. I went ahead and made mistake #1, I ordered some ACL race bearings for a 2.3 Duratec/mazda cx-7 (the bearings that came out of block #1 were all good, and all had ford part numbers on them). Since yamaha uses different bearing colours, I needed to find a manufacturer that made that bearing in under/regular/over sizes in 1 thou increments. Only ones I could find was ACL. When the bearings came in they mic'd at about 8 thou clearance - WAY too much! Uhh that is when I found out that ACL race bearings come standard as 1 thou over, and I also bought the HX variant, which is another thou over!

But wait... that still brings me to 6 thou if I buy the regular variant - still too much! I am kinda just stuck at this stage thinking if I should try get the mahle standard size, or just say screw it and go visit the dealer (I got super lucky with my block/crank combo, all the bearings are the same size!)

 

[stresspoint]

I wish it was that easy...

first of all, ford doesn't sell those bearings separate, they only sell short blocks. Second, the ford markings don't tell me anything, as they don't have colours. There are two size bearings that came out of the old motor, 2 03 R and 1 03 W. I am pretty sure the 2 03 R is the mid size bearing, and after measuring the 1 03 W is an oversize bearing. This would mean that yamaha "red" bearing would be = 2 03 R. Sounds good, but ford doesn't sell bearings. I go to mahle or something and they only have one size... Ugh!.

that is a big problem , ? how bad are the bearings you removed .
if they are still in spec all over using a micrometre it is acceptable to put them back in.
have you looked at Mercury for bearing availability , they used that same motor in a 90 hp.

sorry mate i cant help anymore except to say it looks like you have to fet the crank ground and custom matched bearings fitted.

 

[boscoe99]

it looks as if you are going to have to use the ford part # on the OEM bearings to get the correct bearings .? what colour marking on them.
? has the crank been ground at some stage of its life. or was the crank possibly worn ( measure to see what spec it is)
the reason bearings come in 3 sizes from the factory is because these cranks vary in size ,PIA i know. also people clean up the journal's by nipping / linishing a few thou off.
this is why i posted , measure /compare the ACL race against the ones that come from the motor. its very easy to get it wrong as you have now found..

What parts don't vary in size?

 

[boscoe99]

that is a big problem , ? how bad are the bearings you removed .
if they are still in spec all over using a micrometre it is acceptable to put them back in.
have you looked at Mercury for bearing availability , they used that same motor in a 90 hp.

sorry mate i cant help anymore except to say it looks like you have to fet the crank ground and custom matched bearings fitted.

Have you a link to the Yamaha motor that Mercury used in a 90 HP version?

The Yamaha F90 and the Yamaha F150 are completely different animals.

 

[stresspoint]

What parts don't vary in size?

"probably "as you see the bearings the reason the are miss matched bearings in your motor.
the 90 horse yamamerk carbed version has the same powerhead, cant help with a link / model id as i dont have one here ATM ,but its around 2002 model.

 

[boscoe99]

Something is not adding up.

The carbureted Yamaha F90 was first offered in 2003. Identical to the Mercury 90 HP carburetted four stroke.

The fuel injected F150 was first offered in 2004. Not offered by Mercury.

Completely different motors. The F150 using a bigger block. Different crank shaft. Different bearings. Very little parts commonality.

 

[boscoe99]

 

[boscoe99]

This entire post started because of the OP's erroneous understanding that bearings are not available from Yamaha. Well they are.

All he has to do is to follow the service manual and install the bearings that are called for. Them double check them to be sure.

A tale told in error.
Full of sound and fury.
Signifying nothing.

 

[stresspoint]

Something is not adding up.

The carbureted Yamaha F90 was first offered in 2003. Identical to the Mercury 90 HP carburetted four stroke.

The fuel injected F150 was first offered in 2004. Not offered by Mercury.

Completely different motors. The F150 using a bigger block. Different crank shaft. Different bearings. Very little parts commonality.

sorry mate , my bad , i got the 2 motors mixed up on those last posts.

 

[carkivey3]

wondering if you found your solution. my f225 uses the same bearings. my crankshaft journal needs to be ground. based on your ford bearing numbers i was able to see they fit 2008 focus as well as others. then looking at parts pages i was able to find oversize bearings for less than $50 total. turning my crank beats buying $1500 new one plus 8 bearings at $30 ea. I have found oversize bearings for rod journals already. did you end up not grinding crank and using yamaha bearings. one other thing for me to consider is yamaha bearings match crank size plus engine block bore whereas ford bearings dont consider engine block

 

[vroom ZOOM]

wondering if you found your solution. my f225 uses the same bearings. my crankshaft journal needs to be ground. based on your ford bearing numbers i was able to see they fit 2008 focus as well as others. then looking at parts pages i was able to find oversize bearings for less than $50 total. turning my crank beats buying $1500 new one plus 8 bearings at $30 ea. I have found oversize bearings for rod journals already. did you end up not grinding crank and using yamaha bearings. one other thing for me to consider is yamaha bearings match crank size plus engine block bore whereas ford bearings dont consider engine block

Yes, I did. I talked to my machinist and basically he said the whole coloured bearings thing is a load of baloney upsell, the difference in sizes is so small it doesn't really matter. So I went ahead and got a set of king mb5442si bearings, and what do you know, the fit perfect. Clearance was around 1.8 thou on a 1.9 inch journal, pretty close to where I want it. I had the crank polished and bolted the sucker together. Ive built the bottom end but now the machinist looked at the head and said the deck surface needs welding, so he will grind out the corrosion and then I will take it to a friend with a tig machine for welding, then back to have the head decked and install a cometic head gasket.

 

[racerone]

The head is likely warped.------When you machine the head gasket surface , how does your friend deal with the cam bearing bores ???

 

[vroom ZOOM]

The head is likely warped.------When you machine the head gasket surface , how does your friend deal with the cam bearing bores ???

Why would it be warped? I checked with a straightedge and its fine. It needs to be decked after welding because the coolant passages in the head will be welded so the beads will need to be cut flush. Just to be clear, it is the water passages that are corroded around the cylinders and the concern is that the head gasket will not seal.

 

[carkivey3]

Yes, I did. I talked to my machinist and basically he said the whole coloured bearings thing is a load of baloney upsell, the difference in sizes is so small it doesn't really matter. So I went ahead and got a set of king mb5442si bearings, and what do you know, the fit perfect. Clearance was around 1.8 thou on a 1.9 inch journal, pretty close to where I want it. I had the crank polished and bolted the sucker together. Ive built the bottom end but now the machinist looked at the head and said the deck surface needs welding, so he will grind out the corrosion and then I will take it to a friend with a tig machine for welding, then back to have the head decked and install a cometic head gasket.

by looking at my service manual i saw there was only .0003 difference in bearing sizes. my thoughts were their ability to make cranks consistent were bad or their tolerance was mighty tight. this could be great info for those with damaged cranks that end up buying new cranks plus a complete set for under $50 vs individual $30 ea

 

[boscoe99]

The head is likely warped.------When you machine the head gasket surface , how does your friend deal with the cam bearing bores ???

What is there to deal with with respect to the cam shaft bearing bores?