The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: muskrat on 12.06. 2010 10:33

Title: Plunger layshaft end float
Post by: muskrat on 12.06. 2010 10:33

G'day all,
                finally got the '51 up on the bench to attack the 3rd gear selection problem. I had previously replaced a chipped claw but it didn't help with the problem. On strip down all looked ok except some wear on the cam plate lugs (the lugs the claw works on) so have put in a new cam plate. Inner cover back on and all gears work.
 Now my ? How much end float of the layshaft should there be ? I have 1.25mm and thought it a bit much. I forgot to measure the thrust washer but it's about 2mm.
Any thoughts ?
Cheers

Title: Re: Plunger layshaft end float
Post by: Brian on 12.06. 2010 23:19

1.25mm is a bit much, I would try to reduce that. I cant remember exactly how much mine have had but no where near that much. Bit of a mongrel to do as the only way is to remove the bushes and put spacers behind them or make new ones with thicker flanges. You would need to have a look and see if the cluster sits to one side or the other to work out wether you need spacers on one side or both. I usually aim for no more than .010", less if possible.

Those cam plates always wear, I have replaced every one I have had apart. You can buy them new or keep a look out for good used ones.

Title: Re: Plunger layshaft end float
Post by: muskrat on 12.06. 2010 23:59

Thanks Brian, I thought it would be you who answered first. Next in line with time zone (NSW - SA)
 The inner cover bush is flush with the mating surface of the cover, I would say this is correct. Which means the blind bush needs shimming, so motor out g/box off. BUGGA. I'll just try it with the new cam plate and claw and make a TEMPORARY shim to go on the out side of the blind bush. Suck and see. If it works I'll do it, at least I still have the cafe to play with.
Cheers
 

Title: Re: Plunger layshaft end float
Post by: muskrat on 14.06. 2010 09:33

No joy today. Put shims in front of blind bush. Assembled it felt better but once it was all back together primary and all, no 3rd gear. Gear lever goes all the way down to the stop without selecting a gear. Through the week I'll try the shims on the other end. I'm getting good at pulling the gear set now, must have done it 12 times over weekend.
Cheers