Vtwin rod bearings with synthetic oil

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Ive heard from a couple big wig utv/atv builders that syns spin rod bearings in v twins. Well, I just checked mine today. I've got 18,000 miles on my engine, and it's had a diet of synthetic oil for probably 16,500 of those miles, and my bearings have zero play. They feel brand new.
Guess what I'm putting in the engine when I get it reassembled......
thumbsup2.gif
 
My dad has ran synthetic in his Kohler v twin lawn tractor for like 15 years now and also in his Harley for the past 8 or something. No issues at all. I've never heard of that one before.
 
Some riders like to lug the engine and set the idle too low because they like the sound. I was told by a rep for S&S once that idle should be 1000 minimum and you should avoid full throttle below about 2K rpm for best life. Below 1000 RPM idle is associated with rod bearing problems.
Rod
 
My Moto Guzzi Convert is a V twin ,and when you mention V twin it is assumed its a Harley.

Ducati , Moto Guzzi , and numerous Japanese bikes also have V twins air and water cooled.

In my case ive used Mobil 1 15-50 synthetic in all the Guzzi's that i ridden ---equals well over 500,000 miles

NO ISSUES.

Of course the Guzzi has flat bearings on the big end of the con rods and runs up to 60 lbs. Of oil pressure.

If the bearings are turning its because of being to tight or little to no oil . If that's the case you have other problems to worry about.

TOMB
 
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Quote
Old Wives Tale.

Started by Harley because they didn't have a synthetic oil with THEIR
name on the bottle. Losing sales to other oil blenders.
Once they found a blender that slapped the Harley name on,
it suddenly OK to run THEIR synthetic oil on a V twin.


My 2¢
 
Originally Posted by dwendt44
Quote
Old Wives Tale.

Started by Harley because they didn't have a synthetic oil with THEIR
name on the bottle. Losing sales to other oil blenders.
Once they found a blender that slapped the Harley name on,
it suddenly OK to run THEIR synthetic oil on a V twin.


My 2¢

Pretty much correct. It was stated that a synthetic was "too slippery" and would cause the roller bearings to "skate" and not roll during operation. Of course, once the MoCo came out with their own synthetic, they magically fixed the "bearing skate" problem right before!
 
Originally Posted by Linctex
Originally Posted by kawie_guy
a couple big wig utv/atv builders


What proof do they offer up?


Not much. One of the gurus claims that he sees spun rod bearings several times a month, and 90% of the time, the owner of the machine said they were running synthetic.
He invites people to swing by his shop if you're ever on the interstate running through Pennsylvania, and he will show you his collection of spun bearings. This is a guy who's world famous for building some of the fastest Kawasaki and Can Am engines on the planet, and he's got a very loyal following.

I may not be a an engine building guru, but I know the chemistry and physics of oil, and what these guys say makes no sense.
 
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Originally Posted by Convert
My Moto Guzzi Convert is a V twin ,and when you mention V twin it is assumed its a Harley.


This is a Kawasaki atv. Its a water cooled, 732cc engine.
 
I will be running full synthetic in my Honda CX 500 when I get it fixed up one day. I run synthetic in everything including my 5hp Briggs and Stratton.
 
Originally Posted by kawie_guy

This is a Kawasaki atv. Its a water cooled, 732cc engine.


What sort of bigend bearings ? The Old Wives Tale is about roller skid on roller bigends. Nothing is going to happen with a plain bearing...or a roller bearing.
 
Originally Posted by kawie_guy


Not much. One of the gurus claims that he sees spun rod bearings several times a month, and 90% of the time, the owner of the machine said they were running synthetic.
He invites people to swing by his shop if you're ever on the interstate running through Pennsylvania, and he will show you his collection of spun bearings. This is a guy who's world famous for building some of the fastest Kawasaki and Can Am engines on the planet, and he's got a very loyal following.

I may not be a an engine building guru, but I know the chemistry and physics of oil, and what these guys say makes no sense.


That proves nothing unless you know what percentage of total customers use synthetic oil.

I'd guess a large portion of Harley owners use synthetic. It's not like most of those bikes are bought/used as cheap transportation, they're toys that their owners paid a lot for and take pride in. They probably aren't going to cheap out on oil for them.
 
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