Cogs needed - WTB for Josef's rebuild

[Steverat]

The gearbox has had a hard time and I need to replace 3 cogs:
67-3196 17 teeth
67-3199 27 teeth
67-3191 16 teeth

Thanks for looking!
Steve

[Greybeard]

The gearbox has had a hard time and I need to replace 3 cogs:
67-3196 17 teeth
67-3199 27 teeth
67-3191 16 teeth

Thanks for looking!
Steve

I still have the bits that were taken out of my gearbox during a refurb. They may be better than nothing. I'll have a look later when I'm dressed.

[duTch]

 Steve, where did you garner that info...? The only gear listed on 'The Chart' is your 'G' gear 67-3191, so I have to ask what year is the box? From memory I'm thinking '51, which is close to the end of the early boxes (as far as I can gather),....if so, it and the other two gears may may have different selection dogs, that may or may not be compatible.....but you could have a look on;
 http://auto-cycle.co.uk/parts.htm , or give 'em a holla

[Steverat]

DuTch, thanks for the info. My box is on a '51 plunger machine; your table is for S/A machines. That probably explains the inconsistency.

[Steverat]

The gearbox has had a hard time and I need to replace 3 cogs:
67-3196 17 teeth
67-3199 27 teeth
67-3191 16 teeth

Thanks for looking!
Steve

I still have the bits that were taken out of my gearbox during a refurb. They may be better than nothing. I'll have a look later when I'm dressed.

Thanks for the offer, I'm most grateful! Incidentally I note you are in Leamington which was my home town. I wonder if we are acquainted already?

Steve

[berger]

I went to the pub steverat 67-3199  and 67 -3191 are same as swing arm 67- 3196 is the odd ball- errr gear that one is 42-3020 in a swing arm box..  edit confused now 67-3199 gear H -27t in both my books--- 1954 to 1957 and 1960 to 63   for swing arm and plungy its the same but on that chart its 42-3097 so i'me going back to the pub!

[Swarfcut]

Steve,  The layshaft and mainshaft fixed pinion gears are pressed onto the shafts and locate against wire circlips. They require a fair amount of force to remove or replace.  The position of the circlip groove on replacement pinions may differ if you use pinions from a later S/A box. This is because the circlip grooves are in a slightly different position on a S/A layshaft and mainshaft. Using the later gears and matching layshaft from a S/A box is theoretically possible.  Also the design of the drive dogs changed slightly in profile, so be careful with your final cog selection. We all assume the gearbox is as original, but experience shows that after all this time and several well meaning owners, you may already have a mongrel assortment in there. Large  drive dogs can be square profile or slightly rounded, the smaller dogs can be arrow profile or square ended, all depending on  the year. All need to match type with the adjacent gear. So although the number of teeth may be the same as required, the gears themselves have several variants. They carry no part numbers with the exception (sometimes) of the big first gear, so sorting it out can be a bit of a struggle. There should be a hardened steel washer between the 1st and 2nd layshaft gears. The thickness of this washer controls the layshaft end float, which may change if you remove or replace the fixed layshaft pinion and/or the large first gear cog.

  Good luck with it.

  Swarfy.

[JulianS]

The plunger layshaft fixed gear 67 3196 shown left in photo and the swing arm fixed gear 42 3020 on the right. You can see the different dog form and circlip position.They dont interchange. The adjacent layshaft pinion also different.

[Swarfcut]

Julian... Thanks for the pictures, they show what I was trying to explain, the different profile of the dogs and circlip position do mean they are not a direct like for like substitute as single gears. Hence the need to be careful sourcing replacements.
 Swarfy

[Steverat]

Julian and Swarfy, thanks very much. I confim the dogs are the square profile type so it looks like I still need the same part numbers as originally mentioned. Yes I had noticed those two cogs are a bit tight on the splines. Should I press them on to the point where the outside flank of the cog is dead level with the splines on the shaft, or just keep pushing until the circlip stops me?

I have a variety of thrust washers in my box of bits, some 1/16" and some 3/32" thick. Is the idea just to take up as much endfloat as possible? Perhaps I need some thinner ones for more precise adjustment? Or is endfloat up to 1/16" okay? Should they be on both shafts?

Thanks
Steve

[duTch]

 

......I have a variety of thrust washers in my box of bits, some 1/16" and some 3/32" thick. Is the idea just to take up as much endfloat as possible? Perhaps I need some thinner ones for more precise adjustment? Or is endfloat up to 1/16" okay? Should they be on both shafts?

 Fairly much No,No,No, and No.....the only Thrust washer you should need is the one on the layshaft between 'F' & 'H' gears, from memory it's either 0.090" or a bit more and imperative that the internal chamfer goes toward the 'D' gear- if it's not there, the thing might go *BANG*

[Swarfcut]

Steve..The gear usually bottoms on the circlip and ends up slightly proud of the end of the shaft splines to give a larger bearing surface against the face of the bush. Ideally you will end up with both the face of the gear and the end of the splines dead level to give the maximum bearing surface to the bush. Mainshaft endfloat is controlled by the ball race in the inner cover, so should be none existant, only the lateral slack in the bearing.
  As duTch says the thrust washer goes with the internal chamfer towards the clutch. Look closely at the layshaft, there is a nice smooth transition in diameter, the chamfer clears this.  Aim for the smallest possibe endfloat, even grinding down the thrust washer thickness to achieve the best result.

  Layshafts usually end up with scoring and damage to the blind bush contact area, so the usual fix is a new, expensive layshaft, a better used one, or get the damage ground off and obtain a custom bush with a smaller ID to fit. If you are lucky and the shaft is reasonable, a new bush may be all you need. Unsupported at the timing side end, there will always be little waggle to the layshaft. It is the excessive running clearance that causes the problems of noise and vibration.

  The bush is best removed by heating up the case, oven, camping stove etc and knocking it into the case with a flat bottomed bar drift . Freeze the new bush to aid installation into the hot case. Make sure the oil hole lines up.  The bushes tend to close up once installed, so now the layshaft will not fit. You may be better off getting a package deal from you local machinist, reaming a blind bush at the end of the case is a pain. Otherwise the emery cloth on a round dowel trick as extolled by duTch.  ( A very clever fella if I may say so).

   Swarfy

[berger]

wow cheers you lot you could make very good school teachers, after seeing the picture I will have to get in the box of gear coggy things and see what I've got . you never know I might have a cog or two to fit a plungy box, i did find a plungy mainshaft the last time i was ratting about. first job though is heater plug relay cutting out too soon on van ---- maybe a bit of arcing i will investigate that first

[Steverat]

Found a 67-3196 plus a newish (well much newer-looking anyway) layshaft on Ebay. So I suppose its my lucky day.
Thank you for all your help (again)
Steve

[muskrat]

G'day fellas.
I just put a plunger layshaft into my s/a box, all working good so far. May not work the other way around. The dogs on the s/a layshaft gear look to be a stronger design due to the position of the circlip.
Cheers