FH - more polishing

 A bit of a workshop tidy this afternoon left me with the opportunity to move the primary side on a little. I can't fix anything until the secondary chain and gearbox sprocket is fitted, but we'll get there.

Here's a few pictures:

FH - fitting stuff and testing the dynamo

 A few minutes in the workshop yesterday allowed a bit more progress on the Huntmaster. The headlamp is now fitted, with the grommet at the top. This seems to be the only way I can fit it and still allow access to the rim clamp:

Next, the tank badges. All this needed was to clear the paint out of the threads with a 3BA tap and fit the badges with some short countersunk stainless screws from stock:

Finally, I've refitted the toolbox knob using a plain washer on the outside, Thackeray washer on the inside, another plain washer and two nuts - curiously the knob appears to have a BSF thread?

Last thing for today, and this is a bit lazy, is to look at the dynamo. I've cleaned it, motored it and fitted it - it motors ok and in the right direction so it is working and polarised correctly:

It's smooth and quiet, so maybe I won't overhaul it just yet. The cork washer is missing though, so I will need to make one:

One thing I forgot - I've fitted the oil line unions to the engine, with new washers from the gasket set. The bottom one is the feed, the top is the return:

FH - assembling the inner timing case

 Lots of work faces now, but an interim look at the cylinder head reveals that the valves and guides are beyond use - there is a couple of millimetres of rock at the edge of the valve head, with the valve half out of the guide. 

So, while I wait for a new set of guides, valves and springs let's start on the timing gear. Fitting the pinions is straightforward once I have deburred the Woodruff keys. The timing is set to the marks:

I've cleaned the dynamo straps since you have to have the inner timing case off to fit them. I'll plate these at some stage if I'm not too busy riding the bike:

The oil pressure release valve has been through the ultrasonic bath and has a new 5/16" ball. The old one was grooved and rusty:

Next, for the record, the pump drive washer is fitted:

I've made a small spacer from gasket paper for the end of the pump. Each of the stud threads has been cleaned up and fitted with blue Loctite thread lock:

I've used the original deep nuts - I've flattened these and recut the threads, adding a chamfer:

If you read my last post, you'll know that there is supposed to be a thrust washer in the nose of the pump, under the circlip. It needs to be 14.5 mm OD x 2 mm thick.

I had a bit of 3/4" EN11 in the lathe to make a late-pattern QD hub nut spanner, so I've used a bit to make the thrust washer:

I've left the pip in it to make it easier to get out. Next, the pump drive lock washer - the inner tang fits in a groove (like a keyway only less deep) in the end of the crankshaft. The tang on the new one is much wider than the remains of the one on the old washer  - time to get the needle files out:

With that in place, we can knock the tab washer down. On the crankshaft, I have bent the washer over both the lock nut and the pump drive sleeve:

For the record, the cam drive tab washer is knocked down too:

I've also finished polishing the timing cases:

I had to clean a lot of carbon off the timed breather sleeve before it would fit, and relieve a pip on the outside. It's fitted with the thickest cork washer available (5/32") and the gasket is coated with Wellseal. I've only done the inner face for the moment as I will want to take it off again.

Test fit:

That's it for now. Next I will probably fit the dynamo drive sprocket and it's seal, but then to do any more in here I need the dynamo and the Automatic Timing Device. Both of these bits need rebuilding.

FH - oil pump

Over three years ago now I pulled this sludgy oil pump out of the timing case, planning to look at it and consider it for further use. It would barely turn.

Since then, much has come and gone (some of it twice) but I have stripped the pump and freed the high spots in the drive that caused the seizure. With these Mazak/Zamak castings, impurities in the alloy corrode and cause the casting to swell and crack, in this case causing high spots in the drive gear bore and damage to the circlip recess - though fortunately nothing irreparable. 

The body casting had a bit of carbon in the smaller bores:

The ultrasonic bath fixed that, and revealed some scoring. If this leads to excessive wet-sumping we will have to replace the pump.

With it all back together and working, I realised there was a thrust washer missing, which is supposed to fit under the circlip. I'll have to make one.

FH - polishing

Strangely enough I enjoy this job. It’s methodical, I have six mops with their associated compounds and if you have the time it’s quite fulfilling to see a mirror shine appearing before your eyes.

These are the two halves of the timing cover, currently going through the process with 300 grit on a stitched mop.

RE Interceptor - chain & sprockets

 A nice little jaunt this evening to see the grandchildren and to help son Thomas replace the chain and sprockets on his 2019 RE Interceptor, supplemented by spaghetti & meatballs to keep us going.

The gearbox sprocket is easily accessible under an alloy cover retained by three screws and the gearchange lever:

The bike has done about 9,000 miles on the original parts and it's high time they were replaced. The tab washer and nut were removed with a socket and breaker bar before we removed the chain. We slackened off the rear sprocket bolts as well. The chain is endless, so we get the Dremel out to slice through a side plate and grind back a rivet:

The rear sprocket is retained by six M10 screws and nuts. This is the new one, bought from Hitchcocks:

You can see the wear on the gearbox sprocket:

All done and back together in a couple of hours. Next stop, tappets and an oil change.

FH - carburetter

 If any of you recall this post from last year, you'll know that the Huntmaster kit arrived with an Amal 928 Concentric carburetter:

Now that we are getting around to fitting the cylinder head, we'll need to sort out the jetting for this carburetter. A plea to the AOMCC forum revealed that revered Huntmaster rider Steve's FH is fitted with a 626 Concentric with a 200 main jet and a 3 1/2 slide with the needle clip in the middle position.

The difference between a 928 and a 626 is the body size - the 900 series is the larger. The 600 Series comes in 22mm, 24mm, 26mm and 27mm bore sizes and the 900 Series in 28mm, 30mm, and 32mm bore sizes. Presumably a 626 has a 26 mm throat and a 928 has a 28 mm throat; for the record, 28 mm is just over 1 3/32".

As you'll know from this post, this FH is built to Cyclone spec, more or less equivalent to a Road Rocket. Later Road Rockets use a 1 1/8" Monobloc; earlier ones use a 1 1/16" 10TT9 with a 340 main jet, so this 928 should be there or thereabouts but jetting it might be fun. We learned from the forum that Concentrics run about 10% richer than Monoblocs, so we should fit 10% smaller jets and a slide one size smaller.

Standard fitting for the 1958 FH is a 376/12 Monobloc, which is 1 1/16" throat diameter. Jetting is as follows:

• Size: 1 1/16"
• Main Jet: 240
• Pilot Jet: 25
• Needle Jet: 106
• Needle Position: 3
• Slide: 3 1/2
• The carb parts list indicates it uses ferrule 6/132A, which means it doesn't have cable adjusters.

Standard fitting for the 1958 Road Rocket is a 376/36 Monobloc, which is 1 1/8" throat diameter. Jetting is as follows:

• Size: 1 1/8"
• Main Jet: 290
• Pilot Jet: 35
• Needle Jet: 106
• Needle Position: 3
• Slide: 3 1/2

The kit 928 R300 is set up like this:

• Size: 28 mm or 1 3/32"
• Main Jet: 210 (I've got a 260 to replace this)
• Pilot Jet: None, drilling only; apparently 0.0016 (equivalent to size 20) but I understand these can be drilled out and a jet fitted
• Needle Jet: 106
• Needle Position: 3
• Slide: 3 1/2
• It hasn't got any cable adjusters.

Apparently you can fit a pilot jet in the threaded port shown here, on the right & under the bell mouth:

There's an excellent page on the Amal website that tells you all you need to know. It's here, and it revealed that the needle I have is the correct one for a 4 stroke 600/900 series carburetter:

Workshop - Switzer Bike Lift

First published 12th March 2023

Legend has it that the bike lift is, or at least becomes (with advancing years) one of the most useful tools in the workshop. Some while back I spent a few hours faffing about with drawings, replanning the workshop in an attempt to fit one in. 

Thoughts turned to this again recently and looking around I discovered this Switzer lift, marketed by KMS, which is shorter and less wide than most. 

I posted a question on the AOMCC FB page and got a host of encouragement from the members, including one who had exactly the same lift and was happy to take some measurements that were not available on the KMS website. Using these measurements, I modelled the space the lift would take up on the garage floor with some timber and paint pots, and lived with it for a week. 

And I'm glad I did! The model didn't get in the way unduly and I took the plunge. Actually, when the lift is in place, particularly in the raised position, it seems to liberate space - it effectively gives you another bench and more foot room than having the bike on the floor. 

The bike is so much easier to get to now. That ramp lifts off, and I've laid it on the floor under the lift and there is a removable panel to allow you to drop the back wheel.

At the front, there's a bump bar and a wheel clamp.

The lift arrived in a plywood box - 10 m thick, poor quality ply but I'll use it for something.

The ram is going to spend most of it's life extended - I've coated it with ACF50 to try and inhibit corrosion. The lifting pedal you see here is removable.

At the front end, there are two jacks that stabilise the lift and a stout bar that holds the lift in two positions should the hydraulics leak down.

I'm really pleased with it.

Almost a year later, after the lift had been in constant use I added a new wheel clamp:

It's much more rigid than the original one.

FH - Lucas HF1441 horn

While waiting for bits for the QR50, I took the opportunity to refinish the horn for the Huntmaster. It tests OK in that it pulls a current and deflects the diaphragm, so some adjustment will have it working.

Lucas catalogues are very useful. This is catalogue 716A, section F - six pages of horns and horn pushes. The application page tells you which part number you should have:

In the case of my 1958 Huntmaster, it's a HF1441 model horn, part number 70048. The spares list tells us a bit about it:

It's black, and looks like this:

So, I had the correct horn (bought from eBay I think - it was missing from the kit) and all I needed to do was strip it and give it a coat of paint.

First up was the various bits of bracket:

It’s good to clean the points in these horns, but this nut is usually very tight and it retains the diaphragm to around the moving point. I had it soaking in Plus-Gas for a few days but I couldn't shift it:

Since the horn worked I gave up and cleaned the old paint off with emery tape. 

I painted it with the usual U-Pol etch primer and gloss black. I know the tone disc is supposed to be black, as is the nut, but it looks nice like this: