Richard Hobbs

Right, regarding the cracked piston, it’s bad news so far unfortunately…

To start with, I’ll actually show you the problem…

As you can see, on the top edge of the piston there is a crack running vertically from the top of the piston edge, down through the top two ridges. This is what makes this piston unfortunately useless.

So anyway… the brand new piston that was kindly posted to me from the chap in Derbyshire was sadly the wrong diameter – I need a 72mm diam. piston, and this was 74mm. That piston was therefore sadly posted back.

I then started making phone calls again and found that there a 72mm piston at AMC Classic Spares. I drove over there Saturday morning to compare the piston with my original one, and to hopefully make a purchase.

When I arrived, the piston was the correct diameter (72mm), it had the correct gudgeon pin diameter and distance from the crown, and everything about it was correct apart from the grooves cut out of the crown for the valves to drop into as they open.

Nevertheless, I purchased the piston and set about assembling the bike carefully, minus the gaskets, to see if the engine would turn over, and sadly it doesn’t. The inlet valve touches the top of the piston, meaning I would have to have the piston milled out to the correct size. The problem with this approach, however, is that there doesn’t seem to be enough metal on the underside of the piston to mill into and the strengthening ridges on the underside of the old piston to account for the deeper grooves don’t exist on the new piston so unfortunately, I’m back to square one again!

Just in case there are any fellow motorcyclists reading this blog, please get in touch if you think you can help! You can contact me through my 1966 Matchless G3 site!

Also, here are a few pics of the original piston so you know what i’m after…

1966 Matchless G3 "short-stroke" piston - 72mm, 85.5 stroke

Top of the old piston

The inlet valve groove is much larger than the the exhaust groove, as you can see. In the above photo, the inlet groove it at the bottom of the photo.

So… there we go - I still have a cracked piston, I still don’t have a replacement, but I’m ever hopeful that I might stumble across one soon enough. Let’s hope so, anyway!

Before I get onto the situation with the Matchless, I’ll start with Fallout 3 (mentioned in my previous post) and my Xbox’s new blog!

First of all, Fallout 3… I’ve finished it!

In the end, it took just over 75 hours from start to finish and I’m glad to say I kept “good karma” throughout the game and instead of making my companion enter the highly radiated room in the last moments in order to activate the purifier, I went in myself, thereby paying the ultimate price for the greater good.

This is, of course, still a game, so no price was paid at all. I even borrowed the game from a friend, so literally no price has been paid at all!

I also stick with my previous statement that this is a game I strongly suggest you get hold of if you have the equipment necessary to play it!

So… onto the Xbox’s blog!

There is a site called 360voice.com which acts as a way for your Xbox 360 games console to write it’s own blog posts every day about your gaming habits, achievements gained and other aspects of gameplay.

In actual fact, the games console itself has nothing to do with writing the blog posts (as you may have worked out already!). 360voice.com simply looks at your stats each night and generates a blog post based on that information, which looks suspiciously like it was written by the Xbox itself. It’s kinda funny, and a novelty to have, so here’s a link if you want to have a read: http://360voice.gamerdna.com/tag/fishsponge

Right… now it’s time to talk about the Matchless…

After yesterday’s post, you will know that the piston rings were worn out on the motorbike and needed to be replaced, so this morning I took all the parts to Bill’s house where, after cleaning the valves, re-grinding the valve seats, putting the cylinder head back together, finding and manufacturing an alternative solution to the broken sleeve nut, removing the old piston rings and cleaning out the grooves we went to put in the new piston rings!

Upon putting in both parts of the oil control ring, we discovered it wasn’t rotating as freely as we’d like, so Bill took the ring off and we went to examine the groove a little closer.

It was at this point Bill informed me that the piston appeared to be cracked.

Upon hearing this news, I realised that this was something of a disaster. It’s good that we found it because a cracked piston could disintegrate in the cylinder, destroying large chunks of the engine in the process, but it’s bad that it was cracked because original pistons for a 1966 Matchless G3 350cc short stroke are phenominally hard to find.

I coincidentally inquired at the Spares Scheme while I was there the other day to see if they had any, and the answer was, not surprisingly, “no”!

So anyway, Bill phoned a friend of his to see if he could give any leads as to where to obtain one, and believe it or not, he had a brand new one, in a box, never used, with all the rings, the gudgeon pin a the various other bits you need to install a new piston!

This was unbelievable!

So… this kind chap is going to post the piston to me, I’ll post a cheque to him and hopefully, with a bit of luck, I’ll be up and running soon!

The one thing to note, however, is that with a brand new piston etc… it has to be run in, which involves riding 500 miles no faster than 35mph. Given that the first motorbike run of the season is at the end of March, that gives me around 4 weeks to achieve 500 miles at 35mph or slower if i’m going to make that first run!

Providing the weather holds out, the evenings aren’t too dark, and the bike goes back together as well as I hope it does, that is just achievable in my opinion. A relatively tall order, but just about achievable.

I’ll keep you updated!

I have been playing games on my Xbox 360 a lot since Christmas, mainly because it’s winter and there’s not a lot else to do indoors that’s quite as much fun!

Other than Forza Motorsport 2, Pure and A Kingdom for Keflings I’ve been playing a lot of Fallout 3. I’m over 60 hours into the game now and estimate that I have somewhere between 5 and 10 hours remaining before I reach the end.

For those who don’t know, Fallout 3 is an action role-playing game which takes place in the year 2277, 200 years after the nuclear war that devastated the game’s world in an alternate post-WW2 timeline. It’s not a particularly cheerful theme, but it works really well as an action RPG.

The trailer for Fallout 3 is below.

I can’t get rid of the advert that appears after 12 seconds, I’m afraid, but if you click the small grey “x” on the right hand side of the advert when it appears, it should disappear

NOTE: If you can’t see the video above, click here

So anyway, this is a truly excellent game in my opinion and I strongly suggest that if you have the equipment to be able to play such games (a half-decent PC, Xbox 360 or Playstation 3) you get hold of this one!

So anyway, onto the Matchless…

Although I have been riding the motorbike throughout winter (on dry days, after the salt has been washed off the road) ever since last summer the piston rings have been worn out.

More specifically, the bike was burning oil, and both valves were perfectly OK (as per the post “It does appear to be working, but now there’s rain!“), so that leaves only the piston rings!

On Monday this week, I started to take the top of the engine off again, on Tuesday the local expert and friend of mine, Bill, came over to lend a hand and to examine the piston rings, the piston itself and the cylinder and we determined that the piston rings certainly needed replacing. In fact, the scraper ring (which is supposed to keep the oil below the piston) looked like it wasn’t doing anything at all, so there was certainly a problem.

So, off to Kettering I went, on Tuesday afternoon, to speak to John about a sleeve nut (which I’ll come to in a minute), Rick about a new set of piston rings and Jim about a gasket set, which I’ll need to put the bike back together, of course!

Well… I got the gasket set, there’s no such sleeve nut as the one I need, and Rick was at home!

Not to worry though… John phoned Rick, who happened to have the piston rings I needed at home (thanks, Rick!) and was willing to have me pop over on my way home to pick them up!

Rick Edwards, by the way, aka “Piston Ring King” has his own blog here if you are interested, and his knowledge and piston ring collection are like none other, so get in touch if you need anything!

Anyway, regarding the sleeve nut, there is a bracket on top of the engine that secures the top of the engine to the frame, and this bracket is held on with 2 nuts that go on the tops of the double-ended bolts that go into the top of the rocker box, and another nut and bolt that goes through the frame itself.

However, the rear nut was stuck fast when I came to remove it, and was already rounded off due to many years of attempted removal in the past, and to cut a long story short(ish), I had to take a drill to it in order to remove it.

This, unfortunately, left the sleeve nut ruined:

You can’t really tell from this angle, but the washer is stuck fast to the underside of the head, and the head is completely trashed, so basically, I need a new one.

The trouble is, the combination of parts that this sleeve nut is part of seem to be non-standard and therefore impossible to replace, so an alternative solution is required (which Bill and I will hopefully figure out tomorrow)!

So there we go… that’s about all I have to write about at the moment, so I’ll leave you to go and read and bookmark Rick’s blog!

I shall post another update once the bike is back together again.