General => Douglas Motorcycles - General Discussion => Topic started by: oily bloke on 07 Oct 2015 at 20:18

Title: EW Gearbox layshaft
Post by: oily bloke on 07 Oct 2015 at 20:18
Hi all,
Looking for a bit of advise regarding the layshaft and 2nd gear supplied by LDMCC.
I was having the usual problems with 2nd gear disengaging so I bought the new layshaft sold by LDMCC. When it arrived it seemed that the gear was tight on the shaft across the splines. I fitted it anyway and found 2nd was impossible to engage.
I relieved the splines in the gear and the shaft using fine paste diluted in oil until a smooth sliding fit was achieved. This improved things but still found changing down the box was either difficult or impossible.
I am told this is a known problem and that Quaife made the shaft and gear to modern tolerance. Is this so?
What should I do to resolve it as I don't want to over do the relief on the splines?
How much clearance should I have between the gears?
any advice would be gratefully received.
Title: Re: EW Gearbox layshaft
Post by: eddie on 08 Oct 2015 at 06:56
          Mr Douglas's design for the EW constant mesh gearbox relies on the second gear layshaft pinion being able to slide in and out of mesh with the splines on the layshaft. Now, if you have lapped in the gear to the shaft and obtained a smooth sliding fit, I think the problem lies elsewhere. With both chains removed, I would check that the 'box spins relatively freely - with no appreciable tightness. For instance, if the sleeve gear is tight on the mainshaft, the tendency will be for the sleeve gear and mainshaft to turn as a pair, thus causing the 2nd gear layshaft pinion to want to turn on the layshaft - making engagement with the splines difficult. The same applies with regard to the first gear pinion being free to turn on the mainshaft.
   Hope this helps,
Title: Re: EW Gearbox layshaft
Post by: oily bloke on 08 Oct 2015 at 07:12
Thanks Eddie,
Will have a look and report back.
Title: Re: EW Gearbox layshaft
Post by: tck on 09 Oct 2015 at 11:28
Had a lot of trouble with my new layshaft took it apart and back together many times just could not see what the problem was. In desperation took it to a well known expert in Cornwall and he knew a man who sorted it..... basically too much grease packed in! now running on Penright semi fluid grease very smooth.
Title: Re: EW Gearbox layshaft
Post by: oily bloke on 10 Oct 2015 at 15:31
Took the box apart today after rotating it with the chains off as suggested, it rotated clean and felt OK but the selector was still seized.
I pulled the shafts out and the 2nd gear was stuck on the layshaft splines. Light tapping freed it but it no longer passes over the splines easily.
Closer inspection showed that the castellation's inside the gear has very slightly burred due to the 'crash' nature of the box. Light dressing with a diamond file and lapping with fine paste restored the movement. The gear and shaft seem to be hardened appropriately.
I am concerned, however, that this will re-occur.
I am using Morris K400EP semi fluid grease and a couple of people have said they use the 250 non EP gearbox oil instead as it lubricates better.
Should I stick with the grease or switch to the oil?
Has anyone else had problems with the LDMCC shafts?
Am I not changing gear properly causing the burr?
Changing up I throttle down to slow the box and maintain the engine speed and I use the clutch. Changing down I throttle off and  change down.
The original gears and dogs are all good and has new bearings throughout.
Any further help and advice would be most gratefully received.
There is some end float on the mainshaft of about 1mm (40 thou) I think this may not be helping but I do not know what the parameters are.
The shim behind the sleeve gear bearing rollers is good and the bronze spacer is present between the sleeve gear and second on the mainshaft.
What amount of end float should I be working towards and where should I introduce any shims?
Title: Re: EW Gearbox layshaft
Post by: eddie on 10 Oct 2015 at 17:59
         I'm looking at an illustration of the shafts from a 3 speed box - it would seem that the layshaft is almost identical end for end, but the splines may be positioned a little off centre. Could you possibly have it assembled the wrong way round? From the illustration, it looks as if the longer end should go to the drive side of the box (leaving ample clearance for the selection of neutral).
Title: Re: EW Gearbox layshaft
Post by: oily bloke on 10 Oct 2015 at 21:40
Hi Eddie,
The layshaft was fitted the correct way round. It will not align with the mainshaft gears if you get it wrong.