Surface rust on bearing cage

[fischer550]

Hi all, I took apart my motor Dasa 1100 with 10mm crank due to a very slight front crank seal leak. While apart, I noticed what appears to be some light surface rust on the rear ball bearing cage.

It looks worse in the picture due to the flash, as you can see if you zoom in the balls have zero rust, and the rust on the cage is merely discoloration at this point.

Is this ok to run or a definite no go?

 

[fischer550]

Also to add, ski was running great and the rest of the crank appears spotless.

 

[john zigler]

I would NOT run that. Time for a crank rebuild

 

[DylanS]

if inside the race and the balls are clean and it spins smooth i would find a way to clean her up a little and run it.
I actually have a stock stroke crank with a similar issue I was going to vapor hone and try out. Obviously slightly different though.
If anything you could see if someone will just do the outer bearing if you’re looking to save money but most will want to replace the rods and all which may be the way to go if it’s a high hour crank.

 

[Jr.]

I would not run it either. Buy a new OEM Yamaha bearing and change it out.
too expensive a motor to play russian roulette with.

 

[Jhucke]

This is slightly on topic, but does anyone reading this rebuild their own cranks? It seems like there are fewer and fewer good options to have them rebuilt. I understand the process compared to other types of engines is fairly painstaking, requires expensive or custom tools, tribal knowledge, etc. How difficult is it for a DIY-er to replace one bearing on the end and test to be within spec?

 

[WFO Speedracer]

This is slightly on topic, but does anyone reading this rebuild their own cranks? It seems like there are fewer and fewer good options to have them rebuilt. I understand the process compared to other types of engines is fairly painstaking, requires expensive or custom tools, tribal knowledge, etc. How difficult is it for a DIY-er to replace one bearing on the end and test to be within spec?

There isn't any black magic to it , you need more knowledge than special tools , you do need a bearing Seperator set at least a 30 ton press and some dial indicators, feeler gauges and a fairly large brass hammer though.

I used to rebuild Seadoo cranks all the time till the rebuilt cranks got to a point pricewise that it wasn't worth doing anymore, it is a fairly time consuming process.

 

[Myself]

Clean it with brake parts cleaner and THEN spin it by hand, turn it back and forth. Small pitting can be hard to feel on an oily bearing, it needs to be clean and dry. Otherwise, just order that one bearing and change it out, all you need is a bearing splitter to remove, and a heat gun to or hot plate to reinstall.

 

[WFO Speedracer]

Here is the thing, this is a listing for a WSM crankshaft rebuild kit for a 650-760 Yamaha , I doubt you will find anything much cheaper than that so $417.72 plus tax , plus shipping , the price on an SBT rebuild which is what Jetmaniac uses in their engine builds is $285.00 plus shipping and you have to send them a core.

WSM - Your Hard Parts Source

WSM - Motor Parts for recreational vehicles

www.wsmparts.com

Basically in the end you will end up with the same quality of crankshaft except the pins won't be welded and it will cost you more time, money and aggravation .

Competitive crankshafts is probably your best bet , hard to find pricing on them so best to give them a call but last I heard was around $400.00 .

 

[Jr.]

Here is the thing, this is a listing for a WSM crankshaft rebuild kit for a 650-760 Yamaha , I doubt you will find anything much cheaper than that so $417.72 plus tax , plus shipping , the price on an SBT rebuild which is what Jetmaniac uses in their engine builds is $285.00 plus shipping and you have to send them a core.

WSM - Your Hard Parts Source

WSM - Motor Parts for recreational vehicles

www.wsmparts.com

Basically in the end you will end up with the same quality of crankshaft except the pins won't be welded and it will cost you more time, money and aggravation .

Competitive crankshafts is probably your best bet , hard to find pricing on them so best to give them a call but last I heard was around $400.00 .

SBT cranks is a Crap Shoot at Best! some have good luck, I just dont like to gamble with someone else's performance motor
fYI, the OP Crank is a +10. Not going to use anything but quality parts on it.

P

 

[Myself]

I believe that's a 6307nr bearing. Skf f.a.g, koyo, nachi......take your pick $30-50 just about anywhere. Probably cost you another $30-50 to get a machine shop to swap it out.

 

[MTRHEAD]

What oil did you burn with that crank?

 

[fischer550]

What oil did you burn with that crank?

Klotz SkiCraft, VP110 race fuel

 

[WFO Speedracer]

, SBT cranks is a Crap Shoot at Best! some have good luck, I just dont like to gamble with someone else's performance motor
fYI, the OP Crank is a +10. Not going to use anything but quality parts on it.

P

My response was to jhuckie's post , he didn't specify a stroke on his crank question so I assume stock stroke and my comments were geared to that assumption , I do agree with your analysis of SBT cranks however , I personally never had great sucess with them and that is on stock couch engines, I am no longer an SBT dealer and if I had to choose between WSM and SBT I would go with WSM all day long.

 

[Jr.]

I believe that's a 6307nr bearing. Skf f.a.g, koyo, nachi......take your pick $30-50 just about anywhere. Probably cost you another $30-50 to get a machine shop to swap it out.

Wish it was that easy. Yamaha uses that bearing size and then machines it to accept a snap ring , ring is used to control thrust.
changing bearings to the ones your suggesting, without the snap-ring will cause crankcase damage, maybe more.
the yamaha bearing list price is $75. Cheaper options avail from WSM.

 

[Myself]

Yes, it's that easy. Yamaha just puts somebody elses bearing in their own box.When it's only a bad outer bearing I replace them myself with a simple bearing splitter.

Ball Bearing SKF 6307NR C3 NEW Open With Snap Ring 307KG 307SG 43307 6307-NR | eBay

SAME DAY SHIPPING - ORDERS BY 4 PM - SAME DAY SHIPPING - ORDERS BY 4 PM [Visit our Ebay store] (https://www.ebay.com/str/rodavictoriausa) Description: This 6307NR SKF bearing is a Open Type Deep Groove Radial Ball Bearing with a snap ring groove in the outer ring and an appropriate snap ring...

www.ebay.com

 

[MTRHEAD]

Klotz SkiCraft, VP110 race fuel

Ok. That oil (Ski Craft) contains rust inhibitors. I’ve ran 927 and Benol and had rust later because the esters in those oils are hydroscopic.

 

[JC-SuperJet]

Wouldn't that Bearing Face be coated, protected and lubricated more by the required Grease Packing of the Crank Seal?

Seems like it would be difficult for the Oil Mixture to reach that Bearing Face.

Maybe the Grease was not packed generously or the Seal was leaking grease and later Air?

What brand and type of Grease was used to pack the Seals?

 

[fischer550]

Wouldn't that Bearing Face be coated, protected and lubricated more by the required Grease Packing of the Crank Seal?

Seems like it would be difficult for the Oil Mixture to reach that Bearing Face.

Maybe the Grease was not packed generously or the Seal was leaking grease and later Air?

What brand and type of Grease was used to pack the Seals?

Couldn't tell you what kind of grease, I purchased the motor pre-assembled. I will say when I removed the old seals, there wasn't a ton of grease in between the 2 rear seals.

 

[Jhucke]

Wouldn't that Bearing Face be coated, protected and lubricated more by the required Grease Packing of the Crank Seal?

Seems like it would be difficult for the Oil Mixture to reach that Bearing Face.

Maybe the Grease was not packed generously or the Seal was leaking grease and later Air?

What brand and type of Grease was used to pack the Seals?

Someone correct me if I am wrong but every instructional I have seen, grease application has been described as spreading a thin layer on, rather than packing anything. What is the best practice on this?