Model A - carburetter investigation

In a spare moment while waiting for parts I thought I would have a look at the carburettor provided with the Model A kit. I've not touched it since it arrived all those years ago:

In the last couple of days I have removed it and giving it a good clean so that I can discover what's missing and what's broken.

It's the original carburettor and is pretty worn but it cleans up well:

Standard fitting for the 1930 Model A is a 6/112 carburetter, now called a Pre-Monobloc, which is 1" throat diameter, and here is the evidence:

According to the Amal book, jetting is as follows:

• Size: 1"
• Main Jet: 4/042-160 (still available new)
• Pilot Jet: none
• Needle Jet: 4/061-106 (still available new)
• Needle Position: 6/065, position not recorded
• Slide: 6/0524
• Float chamber: 14/004

The slide is really bad - probably the worst wear I've ever seen. The grooves around the top of the needle are in pretty poor shape too - we should expect this and the needle jet to need replacement

The choke slide spring appears to have been cut short - fortunately I found a spare one in the carburettor bits box.

The float chamber appears to be correct - I didn't expect the bowl to be held by those two brass fittings at the bottom - there must have been a gasket in there

Initial observations:

• The main jet is missing
• The needle looks very tired 
• If the needle is tired the needle jet will need replacing 
• We probably need another cable adjuster 
• The slide is very bad which probably means we need a rebore from Joe the Carb.
• We need to understand how the float chamber fuel feed was sealed - possibly by some sealant in the thread

That's it for now - it's back on the bike and we can start some other jobs.

Model A - painting

 In my quest to put the primary side back together to clear the decks before starting to investigate forks, we come to a little painting job on the chain cover and clutch dome.

I've cleaned up the clutch dome with a 40 grit flap wheel, 60 grit paper, and degreaser.

This is the first coat of Tractol 816 grey primer supplied by Smith Allen to go under the Tekaloid 318 gloss black.

It goes on easily and dries very quickly but it does seem to hold brush marks and attract dust.

Twelve hours later, with a slightly larger brush I applied first top coat:

It goes on very nicely but I seem to have trapped quite a lot of bubbles. Perhaps I am over working the paint.

I put a second coat on the next day - after nearly 6 hours it was still slightly tacky. The second coat could be handled in 24 hours and these two parts are now hanging from the workshop ceiling to cure.

As everyone says, the depth of the gloss is amazing.

Model A - Primary chain

 Today I have fitted and tensioned a new 1/2" x 0.305" primary chain, which for the record has 80 pitches. If you recall, this bike has a new 23 tooth engine sprocket:

The 23 tooth sprocket I've fitted is the largest one Ariel offered in 1930:

This appears to correspond with an 80 pitch primary chain, though I'm sure 79 pitches would fit as the chain is nearing the end of the adjustment. Perhaps the 80 pitch chain is designed to suit the Burman clutch.

A 79 pitch chain would need a half-link which I believe are available from Simply Bearings. I might investigate that, but I don't fancy having two spring links in the chain.

W/NG - mileage

 It occurred to me recently that the mileages I record against each of the maintenance activities in my spreadsheets are inaccurate for bikes which have had their engines rebuilt since I've owned them. 

This issue is not really a problem for any of them except the W/NG which I rode for a while before I rebuilt the engine, so the engine related maintenance activities are not being held at the right mileage. 

This became a bit of an obsession for a few hours following my return from a two week trip to France for my daughter's wedding. After a bit of digging I found this receipt for the speedo rebuild:

Since I didn't have any records of any activities against maintenance activities, though I have hundreds of blog posts recording to work I have done, I went through all the pictures I had of the bike showing the speedo and recorded the dates and the mileages:

• September 2017 - first ride in my ownership
• February 2018 - 185 miles
• September 2018 - 383 miles
• October 2018 - 422 miles
• August 2019 - big service, documented in this post, probably about 600-650 miles.
• August 2020 - the engine rebuild, probably at around 1000 miles
• March 2022 - 1485 miles
• February 2023 - 2023 miles
• April 2023 - 2124 miles
• April 2023 - 2133 miles
• August 2023 - ridden to Tom's, and pictured in this post. It stayed there for two years.
• September 2025 - retrieved from Tom's as documented in this post.

As will be seen in this blog, various small jobs ensued and the W/NG is now the daily rider. Maintenance is now properly documented in it's own Excel spreadsheet - listed in this page.

Model A - kickstart spring cover: 3rd and final part!

 Honestly, this will be the last post about this kickstart - it's gone on far too long! To be fair though, making the shaft was probably the most complicated machining job I have ever done and I had no idea what the spring cover looked like - so forgive me three blog posts on this subject.

We are at the end though, the cover has been raised a little bit to reduce the clearance between the distance piece and the gearbox end cover and it's been cleaned up and painted.

Once I got a couple of coats on the spring cover I fitted the spring and gave it another blow over to cover over any damage.

And that's it, fitted and finished.

Apart from greasing it... might need another blog post?