4 speed tranny rebuild question

[bobdo]

All,
I have a recommended shop willing to Line Lap the Race. Its close enough to drop it off,
I just have to find the time during the week.
Thanks again for all the help & info.
-Bob

[tomcat1]

any updates

[bobdo]

Hello Tomcat1,
Ya, but I was hoping to wait until I had good news. I'm still having the same problem after Line Lapping the bearing race.
The Main Gear still won't free spin on the mainshaft when the sprocket nut is tightened down. The mainshaft assembly
spins, but fourth gear won't spin. I've studied this hard & I thought the Line Lapping would solve the problem. The only thing
I can figure is the Andrews Main Gear is faulty. I ordered another one to see. If that's not it, I dunno.
I'll definitely post any results.
I see you have a 47 EL, that's what I'm building. This tranny is the last puzzle piece.
-Bob

[67sidecar]

Have you tried another gear yet? I've done a number of these trannys and have had this problem only once. If I understend the issue when the main drive gear, spacer, sprocket & nut are assembled you are running out of end play. My guess is a slightly thinner thrust washer will put it to bed. The factory didn't offer different size thrust washers but the aftermarket does. If you tighten the sprocket nut in steps while checking you should see your end play shrinking till it binds. Good luck.
Bill

[bobdo]

Bill,
No, that's not the problem. I have .007" end play & I'm using a thicker .070" thrust washer. The main drive gear will spin with end play. Everything is new high quality & assembled correctly. The gear will also spin independantly on the Mainshaft until I tighten the sprocket nut. Then the Main Gear is locked onto the shaft, only spinning with the shaft. The first thing I did was find a reputable machine shop to have the bearing race Line Lapped. That didn't solve the problem. So, after scratching my head I bought another Andrews Main Gear to see if that was a faulty gear. That didn't solve the problem. Today, I'm taking it back to the machine shop to take a little more out. I honestly don't know if that will do it either. It looked like they had done a fine job the first time. The problem has to be the gear race binding on the Mainshaft due to misalignment of the bearings The mainshaft assembly spins nicely with end play.
If anyone has any thoughts or solutions, I'd appreciate hearing them. Thanks, Bob

[Jerry Wieland]

You can guess all day and not come up with the problem. Assemble it with machinists bluing applied in the critical places and then see where the scuffing is and you will have found your problem. Without seeing it in person that is as best as I can do.

Jerry

[67sidecar]

Bob,
Sorry for my misunderstanding! When you had the shop line lap the race did the conition improve ANY? You state everything is new. Does that inclued the mainshaft? Before I took any more out of the case race, I'd want the mainshaft diameter checked ( diameter, roundness, taper ) along with the bushing. Is there any side to side movement with the gear, spacer, & sprocket tightened, WITHOUT the mainshaft installed? All new parts with std rollers correctly fitted will have a slight movement. When you spin the tightened assembly WITHOUT the mainshaft installed does it "walk" in or out when rotated in a given direction. I love a puzzle!

[bobdo]

Jerry,
Your right. I decided the thing to do is take it back to the machine shop to have him look at it again. He thinks he knows where he went wrong & won't charge me to Line Lap again.
67sidecar,
Everything was replaced with Andrews products or NOS. The case itself is in great condition, I ran it earlier. The Andrews Main gear spins freely on the Andrews Mainshaft. The Main Gear spins well in the case with .007" endplay & slight movement. The Main Gear also spins while on the Mainshaft in the case, but when the sprocket nut is tightened it is put in a bind & won't spin. It did not improve at all with the other Main Gear purchase or the Line Lap. The Main Gear I just bought was from a second lot #. I ruled that out as the possible problem. The only thing that it could be is alignment. I appreciate the honesty of the machinist who did the Line Lapping, he said it was the only time he didn't use the locking ring to pull the Bearing Housing tight against the case while lapping. He thinks thats the problem & is giving it another try. That's hard for me to understand, the wall of the case is pretty thick & should align when the Bearing Housing shoulder is seated.
I understand that it doesn't take much to misalign, but....damn that can't be much. When the gear is in a bind it is absolutely solid to the shaft.
I'm dropping off my Bearing Plate after work today for him to use, we'll see how it goes.
Thanks for the interest. It is a puzzle alright. -Bob

[bobdo]

PROBLEM SOLVED_
Apparently the problem was in the Andrews Main gear, actually both of them. The gears even have different batch #'s.
The bushing extends slightly past the steel, at that point the bronze has a slightly smaller ID. After running a 1" reamer through
the Main Drive Gear bushing, it shaved a small amount only at that location. After it was installed, no problem.
Now all I need is some time to assemble. Thanks for all the help. -Bob

[67sidecar]

Bob,
Congratulations! Thanks for sharing all the trials & tribulations of putting the puzzle together. Never would have thought two different gear from two lots would have the same problem. Just think how many other bad gears are out there waiting to mess with one of us. Again, great thread everyone!

[bobdo]

All,
Andrews makes great product. The reaming took out very little. Maybe it wouldn't have been
a problem in someone elses tranny. If anyone has a similar problem, this thread might give them
something to consider. Also, the Andrews Mainshaft is slightly larger in diameter. I hope this helps
someone in the future trying to figure a tranny out for the first time, like me. I learned a lot.
-Bob

[bobdo]

All,
I finally completed the bike, now I'm in the breakin process. The tranny & clutch are working fine. Setting the carb has been my latest dilema.
Its running too rich & fouling plugs. I've only got 9 miles on it, grinning the whole way.
Thanks for all your help. Bob

[kg993]

I just ran into the same issue but maybe a different reason for the lock up with the spkt. torqued. I remembered following this thread and kept looking back to find it.
I pulled down a 58 fl trans to replace an elect. start mainshaft with the correct one. It had been rebuilt and stored un-used long enough for the bearing grease to turn to a hard yellow wax like substance. Since I had to drive the needle rollers out with a small drift I assumed that was why it was hard to turn over. Cleaned and assembled with the correct shaft and gaskets & seals. All was great till I put on the sprocket.
Pulled it back down and started measuring. The 4th. gear bearing surface is .010" shorter than another that I had under the bench. It had a .0585" spacer on the gear and the gear looks to be from an oriental source. I'll slip an old oem gear in and lock the nut down first on Monday and see if that frees it up.

[kg993]

Well the .010" more end play helped but wasn't the problem. Turns out the race is cocked in the case enough to make the kicker side of the main shaft about .018" off center. The under side of the left main area on the case has been welded and looks to go all the way to the hole for the race. I haven't pressed out the race to see but I bet they filed or used a sanding drum to do their machine work. I'm not going to touch it until the owner see's what I've found.