Page 1 of 1

750 crankshaft installation

Posted: Fri Mar 27, 2020 10:58 pm
by Toyman57
I'm finally ready to install the new crankshaft in my 2012 Patrol.

My bike only had 40k miles on it when the front rod started knocking. The other is still very tight.

My thoughts are the crank was damaged when it was installed.

I'm having some difficulty finding the proper procedure for this.

I've watched one guy pull his crank into a 650 with special tools but these engines are capturing the bearing in the front.

It looks to me like the bearing must be installed on the crank then pull the assembly in while holding it true in alignment from the rear with the rear bearing in the carrier with long bolts.

I hope someone chimes in here that is knowledgeable on this subject.

I'm really wanting to get this put back together in the morning.

Re: 750 crankshaft installation

Posted: Sat Mar 28, 2020 12:50 am
by jaybird

Re: 750 crankshaft installation

Posted: Sat Mar 28, 2020 7:00 am
by Tomcatfixer
Have you visited MyUral.com yet?

http://myural.com/installing_crankshaft.htm

Re: 750 crankshaft installation

Posted: Sat Mar 28, 2020 8:55 am
by Toyman57
There appears to be a lot of debate on the proper way to perform this procedure.
Having one rod fail on my last crank leads me to believe this was done wrong the last time.

I will try MyUral's procedure.

Re: 750 crankshaft installation

Posted: Sat Mar 28, 2020 9:50 am
by jaybird
Not saying your rod bearing failure isn’t from improper installation, but most times it’s only a single bearing failure and I think most often the left side.

Happy trails,
Jaybird

Re: 750 crankshaft installation

Posted: Sat Mar 28, 2020 10:26 am
by eastbloc
Tomcatfixer wrote:
Sat Mar 28, 2020 7:00 am
Have you visited MyUral.com yet?

http://myural.com/installing_crankshaft.htm
Haven't we determined that the procedure on MyUral is based on the 650 motor which captures the bearing differently, and therefore dangerously incorrect?

viewtopic.php?f=5&t=56392

That's certainly how I have come to interpret the above thread, after watching Van's video of Sergei's work.

Re: 750 crankshaft installation

Posted: Sat Mar 28, 2020 11:16 am
by Tomcatfixer
Ah, you're probably right.

Re: 750 crankshaft installation

Posted: Sat Mar 28, 2020 12:41 pm
by Lokiboy
eastbloc wrote:
Sat Mar 28, 2020 10:26 am
Tomcatfixer wrote:
Sat Mar 28, 2020 7:00 am
Have you visited MyUral.com yet?

http://myural.com/installing_crankshaft.htm
Haven't we determined that the procedure on MyUral is based on the 650 motor which captures the bearing differently, and therefore dangerously incorrect?

viewtopic.php?f=5&t=56392

That's certainly how I have come to interpret the above thread, after watching Van's video of Sergei's work.
Van said MyUral is not a correct/optimum procedure. Something to consider, My Ural is for do-it-yourself with few special tools and before Van pointed our a better way, for over a decade, folks used the MyUral procedure. So, bottom line, it seemed to work

MyUral rig was. 750cc 2002/2003

Re: 750 crankshaft installation

Posted: Sat Mar 28, 2020 12:56 pm
by rougaroo
Here's Van's video on crank installation:



The basic principles to keep in mind is not stressing the bearing by applying pressure to the wrong race. If you pound on the crank from the back, you're applying force to the inner race of the front bearing. What you want to do is hold the inner bearing stable and pull the crank through it.

Mounting the bearing on the crank first does essentially the same thing, since you aren't supporting the inner race. Doing it that way, the drag is on the outer race and you're forcing the inner race to pull the outer race forward.

The ball bearings are in a cage with races on the inner and outer faces. You should make every effort to keep the races stabilized, with no "sideways" force to the cage that might distort it. When Van's saying "tweak" in the video, I think he means "twist".

Rougaroo

Re: 750 crankshaft installation

Posted: Sat Mar 28, 2020 1:17 pm
by Snakeoil
We just had this discussion a few weeks ago and the issued was batted back and forth and the OP found all the videos and took all the informed opinions and came up with a way for him to do it. Do a search if the links that were provided here are not that very discussion. If I remember correctly, Claus shared his procedure and you can pretty much taking any guidance from Claus to the bank.

My two cents is inspect that new crank thoroughly. I would suggest you flush it out with new mineral spirits. And I mean flush it out. My NOS crank was filthy, with machining chips caught in one of the slingers. Granted, my 650 crank was from an earlier time at IMZ, but it costs nothing to clean the crank thoroughly. I suggest a white plastic w@$# basin for the cleaning process. Easy to see any debris that washes out. Clean the basin and run those min spirits thru a filter if you are cost conscious, or use new min spirits and then flush the crank again. Keep doing that until there is nothing in the basin. Then, when you are SURE it is squeaky clean, lube it well with fresh motor oil, injecting oil into the galleries and pouring it over the big end areas before installing. A new plastic w@$# basin and a couple of bucks worth of min spirits and motor oil is a very sound investment IMHO.

Re: 750 crankshaft installation

Posted: Sat Mar 28, 2020 5:49 pm
by BillyG
And just for the record...that “hammered” engine still runs like a top 😉

Re: 750 crankshaft installation

Posted: Sat Mar 28, 2020 6:36 pm
by eastbloc
BillyG wrote:
Sat Mar 28, 2020 5:49 pm
And just for the record...that “hammered” engine still runs like a top 😉
For what it's worth, I haven't installed a front bearing, but your instructions did not work for me installing the rear bearing carrier plate on my '02.

Hammering it in drives the whole crank forward and the front bearing out of position. It's impossible to get the bearing plate to fully seat this way.

And if you make the mistake of doing that with the cylinders on, you'll be hammering against your connecting rods -- a potentially very expensive mistake.

Instead, I'll be making a tool like Sergei uses in Van's video that immobilizes the crank and presses the bearing carrier against it.

Re: 750 crankshaft installation

Posted: Sun Mar 29, 2020 6:59 am
by rougaroo
This is from the National Bearing company: https://www.nationalprecision.com/libra ... .php#mount
How to Mount Bearings

When bearings are mounted incorrectly the balls will cause brinelling on the raceway and undermine bearing performance and life. Brinelling (dents) as small as 0.1micron in depth will have an adverse effect on acoustic noise levels as well as causing increased torque.

Several general rules apply to mounting bearings. When assembling a bearing on its shaft or in a housing, it is critical that no force be applied to the balls. When mounting a bearing to a shaft always press the inner ring. When mounting into a housing press the outer ring. Never apply force to the outer ring when mounting to a shaft or to the inner ring when mounting into a housing. Never apply a shock load in either case.

1. When manually fitting a shaft into a bearing through its bore do not force the shaft because it may cause brinelling to the bearing.

2. After gluing a bearing to a housing using a guide through the bearing bore take the guide out very carefully or it may cause brinelling to the bearing.

3. When motors are being assembled bearings may be attracted by the magnet and hit something causing brinelling. To avoid this, hold the motor shaft in your palm and cautiously insert the rotor. For automated assembly, use an air cylinder and steadily operate the assembly. Bearings are easily affected by shock forces. In the case of NMB P/N L-940ZZ, for example, brinelling would begin when a 100 gram weight was dropped 4mm away from the bearing.

4. Brinelling would also occur when bearings are automatically press-fitted to a rotor shaft if the shaft and bearing bore are not kept accurately in line through their bore.
Not saying BillyG's method doesn't work, particularly if you cool the crank first, but if your goal is to maximize the probability you won't have trouble down the road, do it like the manufacturer says. Good sense for all the other bearings, too.

Rougaroo

Re: 750 crankshaft installation

Posted: Sat May 16, 2020 3:06 pm
by petermertos
There is a video with English subtitles. Used k-tools from www.ural.ca and hydraulic shop press.


Re: 750 crankshaft installation

Posted: Sat May 16, 2020 10:39 pm
by RC20
Rougaroo and the NBC info is 100% accurate.

Removing a bearing you no longer care, installing one you do.