I have a question please regarding adding more oil to my gearbox. The bike is a 52 BSA B33 (older style gear box)The yellow arrow shown in the photo attached, if i add oil into this inspection clutch adjustment port will it migrate from between the outer and inner gear box cases into the gear box, I dont think so but not sure. This would be my preference if adding oil in this port if it will migrate into the gears and dogs. Another option is shown with the red arrow is my speedo drive port, this may also work but it may be slow to get the oil in there not sure best option. I had the gear box out of the bike last year for a rebuild but now its back on the bike its hard to get at the rectgangular shapped port on the top back of the box for adding more oil. Any tips much appreciated.......thanks wayne
Also of note - I am trying to add some thicker gear oil to the 50 weight motor oil I have in the gearbox at present as I want to try running a thicker lub, a few issues finding 3rd gear from time to time so experimenting a bit with different ideas to see if a thinker lub will help?
Hi Wayne
You add oil through the round cover that you identified in your attachment and yes, the oil will migrate to the inner area of the gearbox.
I use 20w50 oil in my gearbox (1949 B33). The trick is not to put in too much or it will just leak out. BSA manuals and Service Sheets for the B33 say to put 1 imperial pint or 570cc. Based on comparison with later gearboxes, I have determined that 400cc is sufficient. BSA recommended 400cc for my A7 gearbox for example. With 400cc in the gearbox, the oil level is about 1.0 to 1.1 inches below the main shaft centerline. I use a nylon tie wrap to measure this. Other people install sealed bearings on the output shaft to reduce oil leaking. There are previous posts on this subject.
I don't think thicker oil will help your shifting problem. I had a shifting problem going into 3rd and the cause was a worn shifter fork and a worn sliding dogged wheel. However, if your gearbox has just been rebuilt, it may only need adjustment of the arm connected to the shifter ratchet mechanism (if you are lucky). There are previous posts on this subject also.
Jim
Thanks Jim for the reply. Also I saw on the Brian Alfonso gear box rebuild when the drive spoket was spun I could see the gears moving inside the hole marked with the yelo arrow below so this confirms the oil should move as you say. :)
The reason i am thinking of trying a heavier oil is when the gearbox was on the bench at time of rebuild all the gears changes worked very predictably and well. But when on the bike and with the motor spinning not so great so. Under power and driving down the road when I pull the clutch lever in I sometimes wonder if all the gearbox assembly may still be spinning to fast for a clean engagement into third. I am thinking if a try perhaps a heavier oil it may restrict the spinning of the gears and dogs while I shift to third. Also on start up when first leaving the garage the bike almost always shifts into third no problem but after out on the road when things get warmed up I often stuggle for a clean shift to third.
Yes I have tinkered with rod adjustment length several times both shorter and longer and I feel I have it in the best setting now but still want a cleaner third gear selection kind of grasping at straws for some kind of improvement.
If you have recently rebuilt the gearbox did you get the positioning and end float of the shafts correct?
I recently worked on my B31 gearbox and thought I would be clever and reduce the endfloat as much as possible and ended up with none on the selector shaft. This resulted in my being able to engage all gears on the bench but not when the engine was running. Shifting to fourth required the mainshaft dog to move very slightly towards the 3rd gear before shifting to 4th and there was no play to allow for this. Another strip down and shimming later and it works again.
The recommended oil is SAE 50 (or 40) and fill to just below the round inspection cover.