Final Drive cracked case

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existent80
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Final Drive cracked case

Post by existent80 » Sun Jul 14, 2019 10:42 pm

Hiya,

Today was going to be a big trip report... but instead I’m posting here. :cry:

2013 Ural Tourist (1wd)
Big trip, about 100mi up, only 20min at 60mph, mostly 40-50mph. 100mi back down the same. Start feeling thrumming / pulsing at rear drive, like I wasn’t getting a consistent power to rear wheel. Then clunk sound like I dumped into gear (but didn’t). Pulling over to inspect , more clunks, I stop and see the attached - big chunk outta the drive case. :o

What happened, how can I start diagnosing, and how effed am I for repair?Image
8A4B022A-4B59-434A-BF36-ED13197EE4FE.jpeg
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Re: Final Drive cracked case

Post by Msblu79 » Mon Jul 15, 2019 8:37 am

Ring gear bolts are most likely failing. Take it apart and see how much damage was done. Case will have to be welded or replaced. Use 12.9 grade bolts for the ring gear and red loctite and torque them to 25lb/ft. If the gears are OK then rebuild using new gaskets to set gear clearance. Myural or Gobium vids will help show the way.
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Re: Final Drive cracked case

Post by existent80 » Mon Jul 15, 2019 8:55 am

Thanks for the reply. Of course I have to take it all apart and inspect, hopefully not too much got trashed inside. I'm seeing other threads after searching; a bit disappointing this happened <5,000km.

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Re: Final Drive cracked case

Post by wildhair523 » Mon Jul 15, 2019 11:18 am

Same bike, same year, 14K km - mine spit 2 bolts thru the FD case - all 8 were sheared off the ring gear when I took it apart. I got a new one from St. Croix and will have the old one rebuilt (I think) by Terry Crawford. Ural of NE has a couple of FD's in stock when I called a couple weeks ago. Good luck to you.
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Re: Final Drive cracked case

Post by Lokiboy » Mon Jul 15, 2019 11:23 am

Just my thought. The nuts came lose and allowed the FD case to move and put the bolts under stress. A out of alignment FD could cause internal trouble. Regardless, check the nuts holding the FD bolts at least every 2,500kms.

Good luck.
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Re: Final Drive cracked case

Post by existent80 » Sat Aug 10, 2019 1:53 pm

Apologies for the late update. Was on vacation for a bit.

Looks like I'm buying a new final drive.

Whatever happened, lost a tooth on the gear and way too much damage to the casing. And yes, as RC20 said, totally blown thru not just cracked.
IMG_20190810_122541.jpg
IMG_20190810_122817__01.jpg
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Re: Final Drive cracked case

Post by Desantnik-VDV » Sat Aug 10, 2019 2:10 pm

"Start feeling thrumming / pulsing at rear drive" - already sounds like missing/broken tooth...
Good lock replacing your FD and happy miles.
Alex
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The rest is just a History:
2014 Ural M70
1998 Honda f6 GL 1500 Valkyrie Tourer /Champion Escort sidecar
1999 Ural Deco Classic/BMW R100 engine
1980 BMW R100RT (2nd Heart Donor for 1999 Deco for more HP)
1983 BMW R80/7 (1st Heart Donor for 1999 Deco)
2002 Ural Barberian Classic
2003 Honda Shadow ACE
1999 Ural BC (went to US circus in Tokyo to adapt a bear driver)

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Re: Final Drive cracked case

Post by RC20 » Sat Aug 10, 2019 11:15 pm

Looks more like a hole blown through it not cracked.

Good luck may be one of those better to replace the whole thing.
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Re: Final Drive cracked case

Post by existent80 » Tue Aug 20, 2019 6:04 pm

Got a new final drive from Ural NE sent overnight. Replacement as about as easy as could be - except for muscling the axle back in - quite a struggle and had to call in a second pair of hands.

Was able to get a late start up to Cooperstown for the Glimmerglass Opera festival. A lovely ride through the Catskills and in to the Leatherstocking region of NY. Always a favorite destination, and it's a real treat camping with the Ural.
ural glimmerglass2.png
Question: It was pointed out to me by a moto-savvy friend that the propeller shaft slaps around a bit - possible that the pinion and final gear aren't meshing properly? I'm terrified I'll see another failure of this $$$ magnitude.

Thanks all for reading, appreciate the advice here.
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Re: Final Drive cracked case

Post by URAL CT » Tue Aug 20, 2019 6:16 pm

Hope you "phased" the driveshaft when you installed the FD. Enjoy ur trip !!!
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Re: Final Drive cracked case

Post by sKiZo » Tue Aug 20, 2019 9:01 pm

Thought that phasing thing was only with the 2WD machines?

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Re: Final Drive cracked case

Post by stagewex » Tue Aug 20, 2019 9:19 pm

Glimmerglass Opera, Cool.

No, 1 or 2 wheel drive... phasing is important. I had thought you meant a second pair of hands to help with the phasing.
Get it done or do it as soon as you can before heading back down to the city. Not hard but certainly can be a PITA.
Check your u-joints while you are at it too.
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Re: Final Drive cracked case

Post by Mr Wazzock » Wed Aug 21, 2019 1:49 pm

existent80 wrote:
Tue Aug 20, 2019 6:04 pm
Got a new final drive from Ural NE sent overnight. Replacement as about as easy as could be - except for muscling the axle back in - quite a struggle and had to call in a second pair of hands.
If like mine (and not exactly, 'cause you've got the 2WD FD), I discovered you need to put the spindle thru before tightening the FD fixing bolts / nuts. This is to line up the FD hole with the swingarm hole. First time we had the wheel off at the dealer was to replace the speedo drive gears. This meant FD and shaft off and swingarm loosened to get donut off and gearbox output yoke. He put it back on tightening the (only 2 on a CT) FD fixing nuts before putting wheel back on. Why wouldn't you. Because (it turned out), spjndle holes don't quite line up hence needed walloping the spindle with BIG hammer to make it go thru. Later I figured what was going on, so I loosened everything then did up the spindle first, then the FD nuts. Last time we had the wheel out for a new tire was so much easier, spindle came out and back in much more like you would expect. As a footnote, the driveshaft rubber boot was leaving a pronounced rub mark on the sidewall since the first time, thus indicating to me summat's not right, i.e. wheel is slightly skewed. Which it was, due to the spindle being slightly at an angle due to the misaligned holes. Incredible but true. Something to double-check. :thumbsup:
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Re: Final Drive cracked case

Post by Msblu79 » Wed Aug 21, 2019 2:30 pm

I noticed in the picture of the broken gear that the splines that drive the rear wheel are bone dry & fretting, the teeth will last longer if you apply some grease to them before installing the wheel on the new FD. Go easy on the clutch and drivetrain, shockloads & hard shifting/clutching will wear out the donut & break the gear teeth, smoothness and easy on the throttle are the keys to long life and fewer problems. This is not a modern durability tested design and is being asked to do alot more than originally intended (1938 with 26HP). It doesn't take much abuse to start breaking stuff. :)
2010 Black Patrol 92,000km's
Modtop airbox, 2013 branch pipes, Perch rings, Yamaha petcock, Drilled slides, Gossie needles, 145 mains, 45 pilots, insulated manifolds, Modtop pushrods, Dual FMF exhaust, PA Multi-spark system w/ VOES, Spin on filter conversion, 33mpg, Royal Purple fluids.

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Re: Final Drive cracked case

Post by Desantnik-VDV » Wed Aug 21, 2019 4:59 pm

Yeah, that Brocken tooth got between the case and the gear, and caused the scrape, crack.
Alex
2007 GearUp NOS

The rest is just a History:
2014 Ural M70
1998 Honda f6 GL 1500 Valkyrie Tourer /Champion Escort sidecar
1999 Ural Deco Classic/BMW R100 engine
1980 BMW R100RT (2nd Heart Donor for 1999 Deco for more HP)
1983 BMW R80/7 (1st Heart Donor for 1999 Deco)
2002 Ural Barberian Classic
2003 Honda Shadow ACE
1999 Ural BC (went to US circus in Tokyo to adapt a bear driver)

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