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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Atabeach on October 26, 2025, 09:41:58 PM

Title: Grub screw , now Transmission woes…
Post by: Atabeach on October 26, 2025, 09:41:58 PM
Fellas…I think I’m in trouble. Took apart the tranny, tightened the grub screw…when putting the cover back on I was careful to pull that arm back with drift pin and release it “ clunk” ….all good! The shaft spun   smoothly in neutral and grabs the drive spline shaft in gear…Put the whole bike together ….The bike has a  Rap, Rap, Rap! When started….in neutral. Tried pulling the clutch in....no change. The clutch pack was not touched and the alignment tool spins freely....WTF?
Title: Re: Grub screw , now Transmission woes…
Post by: daveson on October 27, 2025, 12:49:15 PM
Tried pulling the clutch in....no change. ...WTF?

Repeat the test, pull the clutch in, then click it in gear, with the clutch still in ... does the rapping disappear?

Rapping could be from a large number of causes. Can the location of the rapping be pinpointed? For example, do you have a loose registration number plate?
Title: Re: Grub screw , now Transmission woes…
Post by: Atabeach on October 27, 2025, 09:21:54 PM
Thanks for the reply Daveson I will re test shortly and take video. I really think it is in that transmission.
When opening the case one of the shift forks ,see photo, stuck to the lid and came out from the bottom plate ever so slightly .lThis is “ fork “ is in two pieces. I was able to carefully get both shift forks and their rollers back into the corresponding grooves of the shift drum…. The fork did not rotate at all and went back nicely. On the bench she runs through all the gears nice and smooth. 
Title: Re: Grub screw , now Transmission woes…
Post by: Atabeach on October 29, 2025, 06:21:59 PM
Ok sooo  problem solved! Not exactly sure what I did wrong …but one thing I discovered I never tightened the neutral detent ball bolt. The spring and ball may have been the cause of the noise. Shout out to Laitch and The Mighty Gryphon for private message help…now to the 85 Barn find!
Title: Re: Grub screw , now Transmission woes…
Post by: daveson on November 01, 2025, 04:13:34 AM
Goodo. Did you end up doing the click it into gear test? The point I was trying to make was that the gearbox input shaft might have been turning slowly in sympathy with the crankshaft. When clicked in gear, the input shaft and output shaft would be connected, so you could be sure that the input shaft isn't turning, since as a result the rear wheel wouldn't be turning.
Title: Re: Grub screw , now Transmission woes…
Post by: Atabeach on November 01, 2025, 06:08:15 AM
Yes…did exactly what you suggested. Worked perfectly! Thankfully I took your advice ( I was going to open the case again ) 😳😳😳…I used gasket material to seal it. In the future…be sure to snug down that detent ball bolt! PS ….keep an eye out on my ‘85 Barn find post. 13K, untouched.