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Member postings for Alan Donovan

Here is a list of all the postings Alan Donovan has made in our forums. Click on a thread name to jump to the thread.

Thread: new member
10/07/2022 07:18:10

Hi Graham.

‘Primary gear’ is not terminology we are used to with the ML10.

I recommend you take a photo or two of the gear and area in question, and post them in this thread, I am confident you have the answers you need within the hour.

Just be aware that to post photos, you have to place them in an album first to be able to then copy them into the thread.

lastly, welcome to the forum.

Best regards. Alan


Edited By Alan Donovan on 10/07/2022 07:21:13

Thread: Replacing a Neutral Switch.
01/07/2022 16:53:26

Hi all.

I believe I have a faulty Neutral switch on a Yamaha FZ 750. Replacement part plus new seal are now ready to be fitted, but its location on the bike is not obvious.

Close inspection of the bike and scouring thought the parts manual, I have come to the conclusion that it is located behind the drive sprocket cover. This cover also supports the hydraulic piston for the clutch (this appears to push on the end of a long rod that actuates the clutch) and also the gear change shaft passes through this cover.

I intend (hope) to remove the sprocket cover with the clutch piston assembly still attached ....... it seems possible. Before I go 'blundering on' I thought I would ask for a 'sanity check' and ask if there is anything I should be aware of, or take particular care about.

Please find below parts diagram for neutral switch (item 6) and a photo of the cover I intend to remove.



Many thanks in advance to all who respond.

Best regards. Alan.

Thread: De-snagging an SL125
12/06/2022 21:10:20

Hi All.

Well it has been a long time coming, but further to my original posting, I have had some success altering/reducing the noise emitted by the SL 125 silencer.

I tried a plain extension tube - no good. No room to put in a perforated baffle as per my original post - so no good

I then found a piece of copper pipe that was a 'snug fit' inside the outer pipe of the silencer outlet, if that makes sense. See sectional sketch of muffler outlet - above - for details.

I managed to make and insert three baffles into the copper pipe and the whole assembly was lightly hammered into the tailpipe. I had intended to put some wire wool into the inlet side of the muffler - but decided against that - it just didn't seem right in this case. The exhaust sound is now quieter and the harshness of the note has gone, so I am happy.

So this is what I ended with ..........


Copper tube hammered into place. The visible extension is about 2.5 inches long - 3.25 inches overall length.



View on end of extension pipe, with baffles inside.


I hope the final result is of interest to you.

Thanks again to everyone for their input - I am pleased with the result.

All the best.


Edited By Alan Donovan on 12/06/2022 21:11:35

Edited By Alan Donovan on 12/06/2022 21:12:07

Edited By Alan Donovan on 12/06/2022 21:14:19

Thread: Cast model locomotive wheels
05/06/2022 18:53:23

Hello John

Many thanks for your reply. This is very much appreciated.

All the best. Alan.

05/06/2022 10:41:07

Hello all.

I have been given some unmachined Cast Locomotive Wheels, and I am trying to identify which locomotive - or Locomotives these are from.

There are three differing sizes, the larger two wheels are intended as 'drivers'. The smaller wheel is a bogie wheel.

Here are the technical details followed by photos of the wheels. All dimensions are in mm and are 'as cast'.

Largest wheel - 43.2 tread diameter, 16 spoke, 6 off. Marked (stamped) 220.

Medium wheel - 36.1 tread diameter, 14 spoke, 12 off. Marked (cast) X222.

Small wheel - 23.2 tread diameter, 10 spoke, 4 off. No markings.

wheels front.jpg

wheels back.jpg

I have searched the website of a couple of wheel 'casters/suppliers' but have been unsuccessful in matching the reference numbers with their current offerings.

Any help would be greatly appreciated. Best wishes to all.


Thread: Myford ML4 cross slide
14/05/2022 07:21:53

NOS - New Old Stock.

It did take me a little while to work it out.


Thread: Code of Conduct
11/05/2022 18:22:40

Box, Muff

Rivet, Dick


Sorry - forgot the slang / swear equivalent.

Edited By Alan Donovan on 11/05/2022 18:46:07

Thread: Myford induction hardened beds
25/04/2022 15:55:49
Posted by SillyOldDuffer on 25/04/2022 08:03:02:

Does anyone know which parts Myford made themselves from scratch? .......................

Hello again,

With respect to the Myford lathes, it is true that some Myford (Beeston) components/assemblies were made by others, but they prided themselves in that wherever possible they would manufacture the component parts themselves.

They 'bought in' the obvious items like standard fasteners, standard bearings (ball & plain), electric motors, drive belts, paint. Castings were bought in from outside suppliers but machined by Myford. Fabrication work was undertaken externally by others, but any post fabrication machining was undertaken by Myford.

However, to pick-up on a previous post they rolled their own leadscrews (cannot remember if they rolled their own feedscrews), but they did cut all their own gears and manufactured their own ball handles. Some fasteners were made 'in house' where there was not a commercial alternative that suited the 'design intent', but these were rare. All machines were painted 'in house'.


24/04/2022 20:23:14
Posted by Chris Trice on 24/04/2022 12:51:54:

Am I right in saying the hardening only extends into the bed a few thou deep?


This is an opinion based on my observations of the induction hardening process while at Myford (Beeston). I am unable to back it up with any data.

The IH head moves along the bed and heats the top 15% of the bed shear depth immediately under the IH head. Once heated to the required temperature it is immediately quenched, thus hardening the material.

I would expect the upper surface of the shear to take on the full hardness from the process, and the material to be progressively softer as you go deeper into the material. There could (?) also be a tempering effect on the surface layers of the shears from the heat held deeper in the metal. The bed would then lose a little metal by the final bed grinding process.

So I would anticipate that that the FULL hardness depth to be only a few thou deep.


22/04/2022 14:10:53

Hi again. Further to my previous post on IHBs.

The castings for the IHBs were cast from a more 'exotic' grade of iron than the standard beds, that was more suitable for induction hardening. Production runs for the ML10 were much smaller than the 7 series machines so probably not high enough to offer the option of Induction Hardening on the ML10 beds.

At the time the 7 series lathes were designed, these were serious Industrial Standard machines. These were later followed by the MiniKop, 245 and 280 series lathes.

I may have inadvertently misled one of the previous posters - The machines whether they had hardened or none-hardened beds, were always painted the standard Myford grey (unless a special order), it was the trough between the bedway shears that was colour coded to identify whether it was an IHB or not.

I suspect that I had left for 'pastures new' when the IHB name plate was introduced, so I cannot comment if colour coding of the beds continued after that.


21/04/2022 08:20:56

As an ex Myford (Beeston - 60s/70s) employee, l can confirm Induction Hardened Beds we’re painted a different colour to the standard bed. But sorry I cannot remember what colour that was.

May I suggest you talk to the ‘new’ Myford about this for confirmation.

Regards. Alan.

Thread: Myford Super 7 gib screws
17/03/2022 12:06:39

Hi Ivy.

I have been following this post w.r.t. your gib screw problems on your Super 7.

Myford (the Beeston, Nottingham version) were not into making 'random' changes. I served my engineering apprenticeship there (68-74) and any changes to their products were very carefully controlled and recorded.

I feel that I can say with some certainty, that your counterbored holes are definitely non-standard, as to produce 4 counterbored holes are 4 extra machining operations, which is additional cost.

In addition to this, Myford policy was to use as many 'common' parts between all their machines as possible to benefit from the economies of mass production. So the ML7 and S7 saddles were probably the same part at that time your lathe was manufactured, so you probably have the correct gib screws as per original design intent.

With respect to your problem, it looks like it may be an owners modification. May I suggest that you undertake a detailed survey of your gib strip and the saddle holes. With this information you can design a set of bespoke gib screws to suit your saddle.

It seems as this may be the only way out for you.

I hope this helps



Edited By Alan Donovan on 17/03/2022 12:10:59

Thread: De-snagging an SL125
30/01/2022 19:37:52

Hi Rich.

The concept of a split cylinder head was totally new to me. A quick check on the internet and (I think) I understand what that concept is now. So to answer your question ...... No, it does not have a split cylinder head, it is a solid head. I have posted an extract from the Honda parts manual to show you the type of cylinder head it has. Just in case I have misunderstood this concept.


To answer your second question, ......

Sorry, I do not have any old ‘Motor cycle mechanics’ magazines from the 70’s. So cannot help with the advertisement or artwork.

I can only suggest that you start a new thread on this forum detailing what you are after. Someone may be able to help.

All the best.


Thread: Hello form Alton hampshire
12/12/2021 08:39:09

Welcome to the forum Ralph.

I agree with John Hinckley. Don’t be in a rush to regrind the lathe bed.

Depending on the level of rusting it could be easily recovered with a little TLC. Also, depending on what the damage to the bed consists of, it may be able to be ignored, or just a light touch with a hand scraper will correct the issue. MUCH cheaper than a bed regrind. As suggested, some clear photos of the affected areas would help.

There is a tremendous amount of guidance and experience on this forum (I have been helped on several occasions), so do not be afraid to ask.

best regards. Alan

Thread: Garmin sat nav
18/07/2021 06:32:27

Hello all.

Note to Clive Foster, You may be able to update your Nuvi with all of Europe again.

I suffered from being unable to update my Europe map on my Nuvi. The best I could achieve was the Benelux countries & France (without the UK). But my Nuvi is able to have additional memory installed (up to 32Mb on a micro SD card).  Memory was about £12 at our local supermarket. There is a memory slot at one end of the Nuvi body.

The memory was installed, the Garmin update programme recognised this, and now have Europe and the UK maps back on the device.

Hope this helps.


Edited By Alan Donovan on 18/07/2021 06:35:24

Thread: Shock at low pay for high skill
11/07/2021 21:52:04


I have been following most of this discussion, and Bazyle made a couple of interesting comments.

In my years as an Engineer, the ability to use higher mathematics (Algebra) was necessary. I cannot see how an engineering designer can design a piece of equipment if he cannot prove to himself and more importantly the client that it is 'fit for purpose'. There were times where an even 'higher' level of mathematical skill was required and we had a 'Stress Office' to provide guidance to the designer and/or fulfil that function.

The main problem I saw was not the ability to perform mathematics but the ability to actually understand how a component or structure is loaded when in use. Not all loadings are the 'text book' example we may think they are.

Degrees are regarded by industry as essential, but many of the degree qualified engineers are unprepared for industry. This is NOT a criticism of the graduate engineer, but a criticism of some (not all) employers who expect graduates to know ALL the answers. Some gentle mentoring of a new graduate by an experienced colleague(s) can make such a difference to the graduate AND the success of that company.

Do employers check that their employees have the qualifications (Degrees) they claim?

I would hope so and as part of the company's Quality Accreditation they are supposed to 'back check' with the issuing University (who should provide 'hard copy' evidence/proof). For large contracts, the CVs of those 'highlighted' to be working on the project are (usually) included in the bidding documents. Well ..... they were at one company I worked for.

I do however share Bazyle's concerns about whether employers make sufficient checks about a persons qualifications. But that is where the Auditors for the company's Quality Accreditation Organisation verify that the company is maintaining the necessary quality processes to retain their accreditation.


Thread: De-snagging an SL125
27/06/2021 15:43:03

Hi all.

Thank you so much for all your input. There are plenty of options for me to try. I have provided a sectional sketch of the outlet end of the muffler below.

I have found a piece of pipe in my 'it may come in useful one day' pile that is a snug fit on the exhaust (diameter A). So first off, I intend to start with just a short extension tube and see what effect that has. I could then try and add some sound insulation on the inside of that and see what effect that has if still noisy. - basically as per Phil P's suggestion.

I will probably try the diffuser style of modification as well just to see how that compares to 'tail pipe' mod.

To answer Emgee's question the diffuser would have a closed end according to the diagram, but my thoughs are to push the diffuser against against the baffle therefore effectively closing off the end.

I will try the easy solutions first before moving on to the more difficult stuff.


Best regards.


27/06/2021 08:59:09

Hello again

Thank you all for your comments so far.

The outlet on the aftermarket muffler is smaller than the inlet pipe. The actual exhaust pipe is the inner pipe in the photo below.



The inner pipe is welded into the muffler and has a baffle at the end of it. I think this is supposed to emulate the OEM diffuser, but as you comment the baffle does not appear to be doing much. There is a reasonable gap between the end of the inner pipe and the baffle, so I think it is worth making a diffuser to suit this. As mentioned earlier this pipe is smaller than the inlet end, so If this combined reduction in the 'gas flow area' is detrimental to the bikes performance, then that is the time to consider modify the outlet further.

P.S. Just a thought while writing this. The black box on the exhaust system is described as a 'muffler'. Is a muffler an alternative term for silencer or is a muffler technically different to a silencer?

Best regards to all.


Edited By Alan Donovan on 27/06/2021 09:01:39

26/06/2021 21:42:55

Hi John.

In answer to your question, I don't know.

My son and I bought this as five boxes of bits. Even the engine was down to its component parts. So we never heard it running.

It does seem to attract a lot of attention when I am riding it, and my neighbours say it is loud.

It is an all welded unit, and it doesn't feel (?) as though it has any packing inside - I may have to have a 'prod' inside to see its there is anything 'spongy' there.  

The muffler was bought new, by us, as the old one wasn't present when we bought the bike, but it is an aftermarket unit, which I am positive isn't built / manufactured to the same standard as the OEM equipment (for this particular item).


Edited By Alan Donovan on 26/06/2021 21:44:33

Edited By Alan Donovan on 26/06/2021 21:47:38

Edited By Alan Donovan on 26/06/2021 21:53:24

26/06/2021 21:21:03

Hello all.

For those of you that have been following the challenges of renovating a Honda SL125, it is now running, on the road, insured and officially an 'historic vehicle'. I am currently 'de-snagging' the vehicle.

A current 'snag' is that the exhaust is (very) loud.

It has an aftermarket muffler which isn't as well engineered (or expensive as an OEM unit - $2999.95 U.S.) but has the correct contours and is aesthetically correct. I propose to modify the aftermarket unit by putting a diffuser in the exhaust stream to hopefully deaden / reduce the sound. I propose that the diffuser will be similar to the OEM design - see item 6 on the sketch below.


This would require removing the existing outlet pipe and an internal baffle (Rotabroach cutter maybe) to provide room for the diffuser.

I am relatively confident I could make a diffuser to suit from steel, and that the primary design parameter is that the diffusers combined 'flow gas' area should be not less than the open cross sectional area of the current exhaust outlet.

So my queries are -

Is the above design parameter reasonable and do you think a quieter exhaust note would result?

Are there any other issues I should take into consideration?

Should I leave things as they are and claim ' historic vehicle / old technology' if challenged?

Lastly, and this is the most interesting bit,- have any of you any different solutions that could be applied to this to result in a quieter exhaust.

All the best, and thank you in advance for any input / comments


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