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Member postings for Mick Bailey

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

Thread: Magneto coil conversion
08/07/2022 19:59:23

The bike doesn't have a generator - it has a modern 12v alternator fitted, SS rectifier/regulator and sealed battery Comments about easy starting with a good magneto are all accepted, but my feeling is that given the bike already has modern electrics for the rest of the system that a triggered coil would produce a far better spark at VERY low RPM than a magneto in good order.

08/07/2022 08:54:13

The bikes fitted with magnetos I've owned have been fine. I'm not sure though that even with a good magneto that starting a Venom is going to be easy - they're difficult at the best of times. I'm a good 20+ years younger than my friend and even when the bike ran well to was a real pig to start. Part of the problem is age and mobility, height (he's not so tall), the position of the kickstart, and the gearing ratio of the kickstarter. He could spend a fair sum on getting the magneto reconditioned only to find that he still had problems. Comparatively, fitting (say) a Thorspark would eliminate the need to achieve a decent rotational speed in order to start the bike effectively.

My thought on using the mag's existing points with a separate coil won't work - the K1F has a ring cam and the points rotate, making this mechanically complex to re-engineer.

07/07/2022 14:13:32

The setup is quite basic and I'm not aware of impulse coupling with the K1F, and my MAC 350 didn't have this. I have a couple of insulation testers and will check out the condenser out of interest in finding out what's actually wrong - a failed condenser is a common failure with this type of magneto. On first inspection the points, pickup and lead are all in good shape.

I saw a Venom the other week with a really frail chap struggling to get on the bike. I thought "he'll never get that started". A button push and it instantly sprung into life - I never heard it turn over a second time. The price is the killer (£2040), though this would be perfect.

My friend's Venom already has 12v electrics, a decent battery and an alternator conversion. This would make fitting either a Kettering setup or Thorspark simpler in that nothing else would need to be changed or uprated.

07/07/2022 08:36:40

My 84 year old friend has a Velocette Venom with starting problems and I called round to check things over and discovered that the K1F magneto has a very weak, intermittent spark. Even with the most vigorous kicking with the plug removed it produces a thin, barely visible whisker of a spark that will not jump more than 1/16".

The magneto is physically in good condition otherwise. Even if the unit was in good condition there's another complication in that my friend is barely able to kick the bike over, made worse by the low kickstart gearing. I'm thinking that a coil conversion would help him out, giving a fat spark regardless of rotation speed.

I can think of two possibilities - the Thoespark unit which replaces the magneto points, which is an attractive option. The second is if the points can be used (with an external condenser) to operate a coil - has anyone done this, or is there a reference? I recall seeing an article a while back but can't remember the specifics.

Thread: fixing loose valve guide
28/05/2022 15:36:20

I use a lever feed tailstock and it helps with anticipating if the drill or reamer is inclined to rub with aluminium bronze. I always either sharpen any drills, or use a new drill. I drill a pilot hole about 5/32" diameter then follow this with an intermediate sized drill, then something closer to the finished diameter. The drill always has to be cutting. Then bore the rest out to reaming size. Trefolex is my preferred lubricant. The reamer has to be new, or almost new and razor sharp. If it rubs it will need re-sharpening. For valve guides I've had a lot of success with good-quality expanding reamers.

The problem with ready-made guides is they're usually standard nominal bore sizes, which results in too much stem-to-guide clearance. You could go to the next size down and re-bore the guide, but if you're doing this you may as well do the whole thing from scratch. The exception is that there are some guide blanks that are made either in an alloy that's otherwise difficult to source, or cheaper than buying bar stock. The other issue I've found is that the OD of the blanks is often nor great enough for many motorcycle valves where there's a large diameter change between the main body of the valve and any flange (eg Honda CB450 DOHC guides) When re-using an old valve with a new guide its best to lap the stem using a split aluminium or copper lap to get it parallel and round, so its even more important to be able to size the guide to the valve.

27/05/2022 12:49:49

You could try using JB Weld, which has good high temperature properties. I used the regular stuff on a cast iron multi fuel stove after extensive bronze welding in order to level the surface after dressing back the welds. It's done three years at over 300 degrees centigrade towards the top, with no issues at all.

I consider anything other than fitting an oversize guide a short-term replacement. You may be fortunate in that an epoxy or retaining compound repair lasts, but it depends a lot on frequency of use and many other imponderable factors.

Many of the bronzes used for guides nowadays are difficult to obtain in the UK in small quantities. I've successfully used CA104 aluminium bronze to make guides for my Guzzi Spada and Lario (alloy heads) and these have stood up to high mileage. I would now perhaps favour Colisbro if I could get it at a decent price. Another alloy that I've found to be good for guides is PB104.

One consideration with an iron head is the difference in expansion of a bronze guide compared to an alloy head. With an alloy head the guide expands at a similar rate to the alloy, so the guide-to-stem clearance can be quite close. With an iron head the guide expands at a greater rate than the head, so if fitted with too tight a clearance can cause the guide to grip the valve stem when hot. The bore shrinks down and the guide extrudes due to the constraint of the iron.

Thread: Can't view sales and wants ads
26/05/2022 13:03:11

Ah!......Since you mentioned it, I just disabled ad blocking entirely and everything is now working. The odd thing is I was getting ads anyhow, as the site was allowed so never gave this a thought.

26/05/2022 12:56:05


I'm using Firefox 100.0.2 with Ubuntu 20.04.4. No cookies or history saved, and no logins or passwords remembered. Machine gets restarted at least 6 times a day because it boots so quickly, so no reason to leave it switched on when not in use. Everything is up-to-date, but I still can't view the ads. I've tried opening the links in a new window, but the same thing. Otherwise, the rest of the site is fine, but I will load up a Windows machine and see if the problem persists with different browsers.

This seems to be a recent thing.

25/05/2022 09:19:22

I can no longer view sales and wants ads - I get the listings and click on the links but just get the title and no content. It used to work fine. Do I need to do something different?

Thread: Pin-hole in oil pan - which product to patch it?
20/12/2021 10:39:18

Any disturbance of the pan could cause debris to circulate in the fluid. The slightest spec of anything can cause a valve sealing issue and mis-shifting or worse. Drilling or otherwise perforating the pan could result in a bigger problem than just a leak.

It would be a very unusual circumstance where just a single pinhole would form; usually the metal is so thin at that stage and corroded over a much wider area that it's not far off lacework.- I'm in agreement with Howard Lewis on this.

19/12/2021 12:22:34

It may be possible to use very thin silicone or oil-tolerant synthetic rubber and one or more suitably-sized N52 neodymium magnets used as a magnetic clamp. Or apply a thin film of silicone sealer or other product to the magnet (even blue Hylomar), allow it to almost fully go off and then attach it to the area. It all comes down to where the leak is from.

Thread: Thimble rotary steam engine
06/12/2021 17:49:32

I never knew there was so much information on rotary steam engines in one place. There's some hours of reading (and contemplation) in there.

06/12/2021 16:47:16

I've been looking for any reference to this engine. From what I remember it was a commercial design advertised in ME, perhaps in the 80s or early 90s. There was no detail, but I believe it was a simple design with few moving parts and the picture showed it without any flywheel, so maybe it didn't need one. Does anyone recall this, or have any further information?

Thread: Best way to make valve guides
23/11/2021 10:34:08

My preference where bronze guides were fitted originally is to use aluminium bronze, or cast iron where this was used. The nice thing about cast iron guides is they can be finish lapped before fitting and the bore doesn't shrink down and hour-glass like a bronze guide heat-shrunk into an alloy head, so no need to re-hone after fitting.

My local stockist has Colisbro but the size range starts at 1/2", so plenty of expensive swarf. I've also used PB104, but this can be difficult to get hold of. Last year I was looking around for some C63000 bronze, which is popular in the USA for making guides but isn't easily found over here in the UK. The same with some of the manganese bronzes that are suitable for making guides - special order only and in larger quantities than I could use. The cast iron bar in smaller diameters seems to have disappeared. I used to buy down to 3/8" but 3/4" or even 1" is getting more common as the smallest stocked size.

23/11/2021 08:52:09

Did the machine shop make the guides? No parts availability for my engine so everything needs to be made or adapted. I did think of getting spiral inserts fitted, though. Which machine shop did you use?

I reference the seat off the guide bore but like to achieve a concentric guide to minimise material removal from the seat. My valve refacer finishes the valve head to within 0.01mm concentricity to the stem and I like guides to have no more runout than this. This makes for a seat that only needs a light dressing to restore the angles and seat width and no need to grind in the valves.

My ML7 has a lever tailstock feed, which makes for rapid and frequent pecking to clear chips, but even with premium, new drills the hole will wander slightly with smaller holes. Last winter I checked my lathe alignment as I had a batch of guides to make in a larger size (6.98mm bore) and these turned out perfectly. I was able to use a solid carbide boring tool and then finish ream with a LH spiral carbide reamer and machine the outside and bore without removing the guide from the chuck for the main finishing. They only needed re-chucking to machine the oil seal register. I'll try different techniques and take a look at 'gun drilling' and D-bit finishing - I'd like to improve my methods of drilling deeper, small diameter holes accurately.

22/11/2021 18:07:22

This winter I intend to do a top-end rebuild on an old industrial petrol engine. The bronze valve guides are 4.45mm bore and 42m long overall. The problem I've previously had on small guides was getting the bore concentric. I've had to resort to finishing the bore but leaving the guide oversized, then mounting the guide between centres to finish turn.

I saw small guides being commercially CNC machined and the outside was finished first, then just drilled (using a solid carbide drill), reamed and parted off. I've been unable to drill through this length accurately enough, though I was using HSS drills. The drill always wanders and subsequent finishing follows the original bore

What's the best technique/procedure to use?

Thread: What is it
05/11/2021 10:30:40

I also maintain it's a valve guide tool for removing carbon without damaging the bore. No abrasives are used.

If you used this as a pilot whilst cutting a seat, the cutter would follow the seat and not be rigidly and accurately centred to the guide bore.

Thread: Synthetic paint thinners PT8 vs. white spirit
01/11/2021 15:20:23

I've been using Lidl (Powerfix) thinner over the past few years. It used to be labelled "Universal Cellulose Thinner" but lately the labelling has changed to "Universal Thinner", though it smells and behaves the same.

It mixes with the synthetics I've used just fine. I've tried white spirit but found the finish takes much longer to cure and doesn't go as hard as with either the manufacturer's recommended thinner or with the Lidl stuff. It's also good for spraying, as it evaporates much quicker and allows a more rapid build up of coats.

Thread: Calor 340
30/10/2021 10:03:34

When living in Australia we purchased the propane cylinder outright and filled them ourselves at the local garage at a self-service 'pump'. This was common practice where we lived in Adelaide. The cylinders had a screwdriver-operated vent valve in the side and the dispenser issued liquid propane. The vent allowed the liquid to flow in without resistance to back pressure (and vented to atmosphere!) I thought at the time this would never be allowed in the UK. I currently have a refillable Sievert cylinder that has a similar valve that's opened during filling.

Maybe safety was very lax over there in the 90s. Our brand-new kettle had an exposed wire-wound ceramic element and the mains plugs had push-on covers.

Thread: Microwave Oven
26/10/2021 09:53:47

There's usually some good high-temperature wiring with glass fibre/silicone insulation, as well as decent lengths of glass fibre screening. Also plenty of 6mm spade terminal insulation boots. I've used these for vehicle restoration projects where high temperature resistance is needed for wiring.

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