1929 Harley-Davidson Model J

2 hours ago

7 min read

My 1929 Harley-Davidson Model J belonged to my Grandad for over 30 years before he passed it onto me. For this reason alone, it holds a special status in my collection. In those 30 years he well and truly wore it out, so after recommissioning and repairing the bike, I now use it regularly for day runs and weekends away. Although it's perhaps not a bike I would have gone shopping for, I now understand why my Grandad loved it so much.

A Brief History of the Model J

Harley-Davidson introduced the 61cu (1000cc) Model J in 1915, and added the larger 74cu (1200cc) Model JD in 1921. Both had a 45-degree inlet over exhaust V-twin engine often known as an F-head motor. They received periodic updates until, by the time production ceased in 1929, a front brake, stronger front forks and pumped lubrication were standard.

For 1930 the side-valve VL models were introduced and Harley still use the 45-degree V-twin configuration today. My bike, from 1929, has twin headlights which were unique to the last year of Model J production.

My Harley

I have considerably more personal history with my Harley than any of my other bikes. My Grandad owned it for over 30 years before passing it on to me. He'd ridden tens of thousands of miles on it and taken it all over Europe, usually with my Gran on the back.

The two photos bellow show me sitting on it in the early '90's while my Gran looks on, and my Grandad with the bike in France in 1997.

My Grandad was riding the Harley until he was into his early eighties, but eventually it got too big and heavy for him. After eight years of it sitting in his garage, he has passed it on to me. I brought it home, put some fresh fuel in it, and had it running within about half an hour. After a once over I took it out for a ride and found a number of issues. It developed a misfire at about half revs, and kept jumping out of top gear. My Grandad had well and truly worn it out!

I managed to coax it round for a bit and ride it to visit him, first at home and later in his nursing home shortly before he passed away. It soon became clear that if I wanted to use it anything like he had, it needed some more serious work.

New Valves and Guides

There is a great Facebook page on Model J/JD Harley Davidsons so guided by lots of helpful suggestions on there we checked the valves and guides for wear. I remember Grandad having the exhaust guides remade a few years ago and he didn't do that many miles after that.

The inlet guide, however, is threaded and screws into the intake housing. These would have been more involved to make, so he left them alone... Wow… I think these were worn out a few thousand miles ago and I had no trouble seeing how these were causing the misfire!

Disassembled Harley-Davidson Model J valve parts, rockers, pushrods and springs arranged on a black background, with no text visible.

I had one big advantage over my Grandad here, I can use a computer and shop online. I soon found Antiquebike in Sweden, a fantastic website with a huge range of parts for the early Harleys. I bought inlet valves and guides from them, fitted the guides and finally cut the valve seats. I'll take this opportunity to say I have been very impressed with the quality of everything I have ordered from Antiquebike.

I also checked that the inlet manifold was airtight where it meets the cylinders and the carburettor - all seemed OK.

Clutch Inspection

I got the bike with a spare set of clutch plates so took a look at what was on the bike. The ones in it were like new so the clutch just needed a good clean up and went back together with no further attention needed.

Contact Breaker Points

These were badly worn so we stripped them down, gave them a good clean up and made some repairs. The biggest problem we found was the wear in the central bush. As you rotate the lever to advance or retard the ignition, the whole assembly rotates on a central bush, altering the points position relative to the cam. Simple, right? Well - on this bike the centre was so worn that the points plate flapped about all over the place, altering the points gap and, even with the twist grip pulling it against the stop, it was free to move about making the timing anything but consistent. It now rotates freely but has no side play.

After this I repaired some stripped threads in the base before reassembling and refitting the unit to the dynamo, the wires and connectors were looking a bit tired so I replaced all of these as well and added a dedicated earth wire. Once reassembled I checked the ignition timing which turned out to be as the book says it should be.

Gearbox Overhaul

This is where the most work was needed. All of the above work was done without really taking the bike off the road for more than a week or so at a time. I'd do a bit then try it. There was no doubt that the engine was going a lot better but this served to show how poor the gearbox was. It kept jumping out of top gear, whined like mad in second, and as fast as I poured oil in, it flowed out the other side. It was time to take it off the road and get this bike rideable.

I soon found the reason it was jumping out of top gear. The dogs were badly worn and were pushing the gears away from each other under drive. There is a gate mechanism on the outside of the gearbox to stop this from happening, but this was also badly worn. I had the dogs reground so they pull together instead of push apart under load, and made some repairs on the gate. I've never had a problem with top gear since.

The whining second gear proved to be a more involved fix. The bronze bush on the mainshaft was badly worn, allowing the two shafts to be pushed away from each other under load. From new, this bush was made in two parts, then soldered together on the shaft. 1929 was the last year they did this, for good reason. I will write a page on what was involved in replacing this bush, and why I couldn't simply buy a new one from Antiquebike (who do sell them). But for now, here are a couple of pictures of the bronze parts I made and the final assembly.

The gearbox had already been modified to take an oil seal, but it was rock hard and not really doing its job anymore. Unfortunately I couldn't get another one the same size, so I modified the modification to fit a readily available seal. This, combined with some careful reassembly has meant that the gearbox is now almost oil tight. It drops a bit and does need topping up from time to time, but I'm happy with the improvement on such an early bike.

Wheels and Tyres

I had no idea how old the tyres on it were when I got it, but I knew the bike had been off the road for eight years and, in truth, hadn't done many miles for several years before that. So although I used them for a few initial rides, I always planned to change them before I started covering any real distance on the bike.

I chose Mitas H-02 front and rear and am delighted with my choice. They are a similar pattern to the Continental tyres I was replacing and I'd already used one on the back of my CS1 as an alternative to a Dunlop K70. I went for the chunkier 4.00 × 19 on the Harley. They look good and I have been very impressed with how such a big heavy bike handles.

When I took the old Continental tyres off I found that the steel rims had not been painted on the inside and had gone rusty. How I hadn't got a puncture I'll never know! I cleaned the rims up with a wire brush in the electric drill and gave them a coat of paint to, hopefully, keep the rust at bay going forward. I fitted the tyres with new tubes and rim tapes as well to give me the best chance of avoiding punctures.

Saddle Repairs

I'm quite a lot heavier than my Grandad and soon found that any little bump I hit caused the seat to bottom out on the frame. When I took the seat tube out I found the springs were badly worn. Although there are sources for new springs, and one company even sells a 'heavyweight' set, I started by winding the preload up as far as I could and trying that. This made a huge improvement and I now only bottom them out on the big bumps (potholes) that I don't see coming. I plan to fit a heavier set of springs in due course but the bike is very comfortable now.

When I took the seat tube out I found it to be very worn and full of road dirt, mostly acting like grinding paste. I cleaned it up and made a new bush to go in the frame. I extended this bush by enough to fit an O-ring in the top and hopefully stop the dirt getting in and making things even worse.

Following the 2026 riding season, which was the first time I had used the bike in anger on several trips, the leather seat started coming apart. Fortunately I know a very skilled leather repair lady, and I have given her the saddle to repair over the winter. I'll add some pictures to this page when I get it back. I have also asked her to make me a set of leather panniers to match the saddle and fit the bike.

My Harley in Use

The Harley has been on and off the road since I got it in 2020 and it's been getting better all the time. 2026 saw the first summer of me truly feeling like I could jump on it and go for a ride whenever I wanted. I took it to France for a long weekend and used it on a couple of days in Wales.

It's taken some getting used to, with the foot clutch and hand change, but I'm pleased I persevered. It's not a bike I would have chosen to go out and buy, but being 'Grandad's bike' earns it special status in my eyes. Now that I have got used to it I can see what he loved about it. It isn't quite as comfortable or fast as my ES2, but it's over 20 years older. I don't think it will ever by my 'do-it-all' bike, there are some events and rides which I would find hard work on it. But for a long weekend plodding round northern France it is a joy to ride. Now it's sorted, I'll be using it a lot more for sure!