Morning all, I am having trouble fitting a new kick start return spring to my WM20-45458, in that the old spring, now u/s, fitted & operated OK but the new one is too deep.It appears to have an additional coil over the old one.
The WD spare parts books state the kick start return spring for the WM20 is 66-3058 however the springs advertised on line mention that the 66-3058, which they supply, is NOT suitable for the WD bikes.
With all you clever people out there who can help with this problem? Thanks in advance. Greg.

I can't comment on why the differences between the spring you have and the original spring, however, in my experience, if it will otherwise fit your box and you wish to use it, the additional coil can be heated to red hot and then unwound as needed, with the extra material at the coil end cut off and the new spring anchor end suitably reshaped to fit your application.

Be careful to only heat the portion of the spring you wish to reshape and be sure to use the anchoring end of the spring and not the k/starter end...

email (option): teladelujo@msn.com

Hello Greg,
You may have the spring for the newer gearbox model.
I can’t remember the difference right now, but I remember it’s not the same spring as the WM model.

Noam.

email (option): noam10@gmail.com

The WM springs are smaller in diameter .

John.

email (option): john.kater@chello.nl

WD M Series boxes and later M and B Series boxes which were a further developement of the WD types are listed as using the same kickstart spring..66-3058.
I have posted on this subject previously as I have come across variations, both in the number of coils and the relative position of the fixed and ratchet ends of the spring prior to fitting.
There is definitely more room in the later version of the box for the wide spring, which from memory has either 5 or 6 coils. Fitting this one into the WD box is a struggle as the spring is too wide. Also variations in the start and finish as previously noted mean the spring has to be 'wound up' to a different degree to pick up on the ratchet and the screw that holds the fixed end.
On a number of occassions I have come across springs in WD boxes with only 4 coils and these are a much easier fit.
I am convinced there are at least two patterns of spring for these boxes but as yet have not come up with any other part numbers to verify that.
To date it remains a puzzle that I have not been able to tie down but I am not currently convinced the wider spring is the right one...Ian

email (option): ian@wright52.plus.com

Mine broke over Christmas so i replaced it with a russel motor supplied spring which luckily fitted perfectly

Also changed the kick rubber at the same time which I bought from the nice m20 man from Bere Regis



JOb

email (option): jonnyob1@googlemail.com

Thank you all for the very valuable info. The spring which I am replacing is a 4 coil & this is where the problem of the 6 coil is arising. This 6 coil is the same as illustrated in the online ads. ie 66-3058.
I have a smaller spring being sent from Sydney so that may solve the problem otherwise I will take Johns advice & shorten the deeper one I have, thanks again, Greg

It would appear that over their long lifetime many WDM20s (and other models) have been repaired by having 1937-1938 outer covers and kickstart springs fitted.

I can only surmise that at some time there was a stock of the early spares and a shortage of the correct covers and or springs.

The earlier cover being perceived to be less prone to fracture near kickstart may have contributed.

The change to the 6 coil 66-3058 spring required the removal of metal supporting the K/S bush.

It would appear that someone insisted on a snappier return of kickstart lever, but ultimately this may have caused a lot of broken covers.

Having said that, it is my experience that cover breakage is usually the result of improper use of the valve lifter and excessive wear, particularly on the OD of the layshaft bush, which serves a secondary fuction of supporting the kickstart quadrant.

Regardless of the advice of modern salespeople, if correctly made, a 66-3058 will fit the cover for which it was intended, which is 1939 and later. If your bike has the wrong outer cover it is not the problem of the parts salesperson, or the spring.

Furthermore:

24-4300 kickstarter crank spring 1937-1938 M19 to M24 & G14 (0.140” Ø wire, approx four coils)

66-3058 kickstarter crank spring 1939 – 1960 all M models (0.140” Ø wire, approx six coils)

65-3135 kickstarter crank spring 1940 B29 & B30, 1948 B31 & B32 (0.125” Ø wire, approx four coils and has longer hook for quadrant, but hook fits heavyweight M quadrant ok)
65-3135 is from 350cc lightweight box, but appears to be a viable substitute for 24-4300.

For further information go to technical section, read my article on identification of M gearboxes and parts which Henk uploaded about a year ago.

I will ask Henk to include above data as an update.

"First, do no harm"

email (option): n.gentner@bigpond.com

Interesting info. which sheds some light on the subject. I went and took a look at what I have lying around after the initial postings. As well as the narrow springs I have a number of 6 coil springs..no doubt some original examples and some not.
One noticeable feature is the variation in the 'start and end' positions of the spring ends in relation to each other.
It is this feature, in fact, that makes the fitting of some springs nigh on impossible as the more the spring is wound up in an attempt to engage the ends the more distorted it becomes, to the extent it interferes with the casing etc. and in some cases will not operate correctly if it can be persuaded to fit..Most of the springs I have came with, or fitted to, either WD type or later boxes...Ian

email (option): ian@wright52.plus.com

I have just obtained & fitted a 65-3135 return spring which fitted perfectly. Greg.