Topic: Tranny Secrets Revealed! From: Rich Maund ( ) Date: Friday, May 05, 2000 02:09 PM Hi Folks
I'm at home and frustrated that fate has kept me from the Rally at Cheeks this weekend. Inspired by Chuck Sherman, I dove into the solo's tranny yesterday and this morning. Many of you may have read about Chuck's mods to make the gears engage better. Well here's some photos!
The first one (Mocked up Visual aid) shows how that large spring loaded ball in the front housing rides against the detents in the shifter mechanism. You can see the radius of the ball is far larger than the detent! (I mocked this up to show the size differences in mine. Yours may vary!) When you shift, that detent has to catch the ball. The pressure of the ball against the detent holds it in gear. If they don't fit well enough, it won't stay in gear.
Photo two shows a ball like the one in the forward tranny housing that I used to check the fit of the reshaped detents in the shifter mechanism. I radiused the detents to match the ball. Do not make them deeper! Just widen the radius to match the ball. Now they fit together well. I also smoothed the metal into a nice radius (About a 1/16" radius) where the detent comes up to the curved surface of the mechanism. This way when you press the shifter, the detent has a smooth curved ramp up to the surface to slide on down to the next detent. I lastly had to press the index ball deeper into the tranny housing so it would ride more firmly into the detents. 1/32" deeper worked well on mine. I recommend tapping it in very slightly and checking the "feel" of the shifter until it's right. Too deep, it binds. Too loose, it'll chatter.
Now when I shift the transmission, it drops into each gear with a nice positive thunk.
Now for the really tricky stuff! Don't try this at home unless you know what you're doing! (Or are willing to pay your Dealer to put it all back together!)
The third pic. shows the area where third gear engages it mate on the other shaft. Mine was fitted quite far aft. Only 70% of the gear teeth made contact. In this pic. they now line up well. As built, 3rd gear was too far aft. That would have effected gear service life. The last pic shows the area between 2nd and third where I inserted a monel shim (.060" thick.) to push third forward. This left the gear stack too long for the shaft. I had to grind material off of the hub of 4th gear where it meets the forward bearing (It was plenty wide!) to make it fit w/i the shaft limits. Then the washer and bearing were refitted. With the gear locations now in alignment, the shifter fork operation needed help. The fwd sliding collar wasn't getting slid far enough forward to engage 4th. And the peak on the shifter mech. that holds the shift dog in third needed some more clearance. Taking it apart again and flipping the fwd. shift collar over (It was slightly asymetrical) allowed the gears to engage properly. Removing a couple thou. from the peak on the shift mech. where it pushed the dog. let it shift smoothly into third. Now all 4 gears are in better alignment to each other and shift well.
One last bit of finessing was needed. After torquing the case shut, the shifter would bind slightly. It took me a while, but I finally realized that the forward shifter fork was now having to slide further forward during operation. It was binding against the forward tranny case. I removed it and ground off .030" of material from the slider. Now it's all back together. You can turn the output shaft and hand shift it with a satisfying "thunk" into each gear! (It only felt so-so as it was!)
The detent mod. was quite easy to do. No special tools required. Just a Dremel. Re-aligning the gears was really interesting. If you are satisfied with your tranny. It's probably fine. But if you're comfortable with gear boxes and want the best performance from it, improving the fit and clearances of the parts can help alot!
(Now watch Dealers go nuts a month from now correcting all the home-rebuilds that come from this!) ;-)
Thanks again Chuck! This was really fun!
Rich Maund
Rich's Cycle Upholstery
AMA, NARMA #9, USCA, MGNOC Life Member.
1997 Guzzi California with Ural sidecar
1995 Ural solo
Topic: Tranny Secrets Revealed! (2 of 4), Read 41 times From: Sam Baker () Date: Friday, May 05, 2000 02:33 PM Ok !!
I'm all set to make the modifications. Where is the gear box again???
Sam
sdbaker@gte.net
Flyin' My Ural Deco 2000
Flyin' My Hobie Cat H18
Topic: Tranny Secrets Revealed! (3 of 4), Read 40 times From: Robert Lewis () Date: Friday, May 05, 2000 02:44 PM Sam
The Transmission is that thing with that black/chrome air cleaner on top. I makes Klunkey noises when mash down on those squarish pads of steel with the checker board pattern on them.
Bob Lewis
Topic: Tranny Secrets Revealed! (4 of 4), Read 40 times From: Rich Maund ( ) Date: Friday, May 05, 2000 03:35 PM Folks
I was just hoping some of you would find that second part interesting. I cut that monel shim on my lathe. That, or hand sanding, is the only way to get the thickness needed. Those gears are tough! I had heard the Russian's don't harden their gears. These were almost not machineable. I had to use a carbide burr and grinding tools. I got the impression that after a good polishing during break-in, they'd last forever.
A P-grinder, surface grinder, bearing puller, drifts, and a number of other tools were needed to accomplish this. Not everyone has a machine shop in their garage like I do.
I wasn't trying to leave anyone in the dark here. Just shedding some light! Gear boxes aren't as mysterious as you may think!
Next week.... I blueprint the top end!
Rich Maund
Rich's Cycle Upholstery
AMA, NARMA #9, USCA, MGNOC Life Member.
1997 Guzzi California with Ural sidecar
1995 Ural solo
Foilisti!
I just had my most spectacular mechanical failure in 20 years. Remember my post about the tranny mods I did? If you're gonna re-shim the box as I did, look at it very carefully! It worked fine on the bench, but riding around this morning in first gear I could hear a faint "grr... grr" while putting along in first gear. I was just thinking to myself that perhaps the engagement collar for third was too close to the gear when "BANG!" third engaged, while I was in first gear. First gear lost the fight and I shredded teeth from the pinion on the clutch shaft and two teeth off of first gear. Third gear lost only one tooth.
Just got back from Bay Cycles. Gary, their fax order is waiting on you! I sure hope the parts are in stock. The weather is beautiful and I want to correct my mistake and get this bike back on the road! Please ship them ASAP! Thanks!
Chuck put it best; If you're going to do stuff to your bike, then the hot oily pieces are all yours! This was my fault. Looks like I'll need to settle for 80% engagement on third gear to allow clearance for the shifting collar to stay the heck out the way! The only other way to do it is to make a slightly different front shift fork. I'm not THAT motivated!
Some good has come of this. I may have spent $300, but I have learned alot! I can take the tranny outta the bike and disassemble it in 30 minutes! That's a skill! I could probably assemble a tranny main shaft blindfolded to impress my friends at picnics.
And I have some really well fractured gears to make an awesome "Hard Luck" plaque for the Narma Rally this year! (Jim, no fair if you enter the Ranger again this year! You entered it last year! ;-) ) The detent mod. really worked well. It did shift smoother and more positively. It's like one of my Chiefs once told me, "No matter how screwed up you are, you can always be a really good bad example!"
I'll get this right yet!
Rich "If you can't find 'em, grind 'em" Maund
Rich's Cycle Upholstery
AMA, NARMA #9, USCA, MGNOC Life Member.
1997 Guzzi California with Ural sidecar
1995 Ural solo
Topic: Humble Pie ain't cheap! (2 of 5), Read 33 times Conf: URAL Customer Service From: Vance Blosser ( ) Date: Friday, May 12, 2000 10:16 AM Rich;
We learn by doing; sometimes that incurs penalties. I'd be embarrassed to list all the stupid mistakes I have made with engines etc. over the years.
If the input shaft to the tranny is damaged, keep it - it is an EXCELLENT clutch alignment tool! (nothing like the real thing!).
The Original Hackers ride 3 wheels!
The intelligence of the world is constant - but the population is increasing!
Topic: Humble Pie ain't cheap! (3 of 5), Read 31 times Conf: URAL Customer Service From: Rich Maund ( ) Date: Friday, May 12, 2000 10:35 AM Vance
I already have a full set of factory engine tools. But I will keep the front of it for an alignment tool. Perhaps Sid could use it. I'll cut it off there and use the rest for a plaque!
6 years ago I had to rebuild a terribly worn out Guzzi 4 speed box. It took me 4 trys to get it just so. But it was worth it. One of the best shifting Guzzi's I have had when I was done. At least this one is far easier to pull out of the bike!
I am really upset with myself over this. Mostly embarrassed. I have learned many lessons over the years from mistakes. Mostly on engines. Since I have made almost every possible mistake on them, and learned from them, I can now do some very good engine rebuilds. But I haven't worked on as many transmissions as I have engines. I'm still finding mistakes to make there! ;-)
Rich Maund
Snatching defeat from the jaws of victory!
Rich's Cycle Upholstery
AMA, NARMA #9, USCA, MGNOC Life Member.
1997 Guzzi California with Ural sidecar
1995 Ural solo
Topic: Humble Pie ain't cheap! (4 of 5), Read 11 times Conf: URAL Customer Service From: Vance Blosser ( ) Date: Friday, May 12, 2000 11:59 AM Rich;
Your attitude will take you far. It's hard not to get discouraged after something goes wrong, more so if there was personal involvement with the part before it destructed. Without mistakes we never learn. As long as we remain sound of limb and mind then we can recover and go on...
The Original Hackers ride 3 wheels!
The intelligence of the world is constant - but the population is increasing!
Topic: Humble Pie ain't cheap! (5 of 5), Read 11 times Conf: URAL Customer Service From: Russ Noe ( ) Date: Friday, May 12, 2000 12:05 PM Well Gang. I've had my humbling fun too.
Perhaps the biggest error three of us made resulted in a broken 18" diameter piston and cylinder head.
It was on a steam engine (a V-2 Heisler geared locomotive), so we were able to block off steam to the damaged side and limp home on one cylinder. We steamed about 15 miles into Tacoma from the Mt. Rainier area. Did it at night. Less embarrassing.
So Rich: Your tranny bang is nicely small by comparison. At least you don't have to make patterns for the piston and cylinder head, have them cast, machine them and re-install the whole mess with a crane, because the pieces are so heavy!
Ride on! I love my IMZ-Ural!
Russ the Restorer
1998 BC-65 "Gort"
NARMA #25
Pacific NorthWet Pod
