woody

I always used to run with just the original spring. What's probably happened is that as that has weakened over the years, people may have added helper springs as it wasn't possible to buy a new original type spring. They're available again now

I don't know what the original link was but this is the only picture I have of the bike

Absolutely beautiful restoration

i believe that John at the Twinshockshop in Devon can also confirm the ratios used in the Seeley

Willie REH, Ceriani and MP aren't considered Pre65. I'm pretty sure if I declared those components on an entry form I'd be declined. Yorkshire Classic also consider them Pre70, not Pre65. "There is a lot of people that put a huge amount of time and effort into the sport, all this is made more difficult, with the fact that unfortunately some people do take the p_ _s!!! trying to get away with fitting/using the wrong parts" It's not about trying to take the p*** or cheating. It's more likely about trying to save money as not everyone can afford the hundreds / thousands of pounds to build a compliant bike if they wish to be competitive. And that's what it is - a competition. And riders who have a chance of doing well want to give themselves the best chance of doing that with a competitive machine. A reasonably competitive and effective bike can be built for a fraction of the cost of a 'compliant' one using parts out of the shed. But it's not allowed. It's no more a cheat bike than the compliant one as neither will be anything like a true Pre65 spec or appearance. And after all, these ridiculous eligibility rules were originally brought in to keep the machines looking 'period'. 100% success in that respect then... A bit harsh also, suggesting that youngsters are shirking the rules out of ignorance. They usually ride a borrowed bike anyway. I've seen one bike compete that shouldn't have been allowed for reasons that are obvious and you could hardly describe the rider as a youngster.

Different issue altogether, they choose to ride that type of machine. This chap clearly wants to have forks that work efficiently on his Bantam, which rules out the standard Pre65 British items

Bultaco did it in 1974

Don't forget that those bikes had the pivot point moved forward so if anyone does come up with the length of the swingarm, you need to also know how far forward the pivot was moved. The same length swingarm on the standard pivot would probably be too long. Commerfords only did this conversion to the 340 models, but there was a 198b that was also done at the time by Reg. It was a special order by the customer that purchased the bike from them and was the only genuine conversion to a 250 model

But I imagine he at least wants to enjoy riding up the sections, not get bounced from rock to rock like a flea on speed if he uses genuine pre65 forks

Any 35mm forks can be used and turned down to slip inside the 3TA bottoms - Marzocchi, Ossa, Butaco etc. 35mm is max diameter allowed. For yokes, there are essentially two choices. Either period BSA yokes or the aftermarket billet yokes made by Alan Whitton and others. REH, Ceriani, Ossa, Bultaco etc aren't allowed. By 2015 though, the criteria may have changed again.

Good enough for the selector mechanism yes

You only need take the clutch cover off to check the selector mechanism and spring so start there, as it does sound like a broken or weakened spring. - assuming you haven't smacked the gear lever on something solid, which could present other problems

ok, I see, my knowledge of materials etc is pretty limited so not sure what the one I have is made from. Didn't realise they made them from two different materials, so I'm guessing mine isn't aluminium. They never mentioned materials when I tried to buy mine. Three times I've tried to buy a carburettor direct from Amal and three times they've told me I'd have to wait about 5 to 6 weeks as they didn't have any built up and the next production run wasn't due for another few weeks. I bought it from Surrey Cycles in the end, delivered next day.

ok, didn't realise they were different. New concentric - do you mean the Premier with side fixing pilot jet? I've got one on the BSA and the low down response is much better than the standard concentric I had before. It no longer has an erratic or unpredictable pick up off idle. Now pulls cleanly and smoothly from idle every time.

Thanks Mick, I did wonder initially if it was referring to monoblocs but as we were talking concentrics I assumed concentrics in the end. Can this trick be used on concentrics? I don't know what those bleed holes actually do. Someone did explain once but I've forgotten. As usual...

ok, understand that thanks. You could just try a 2 stroke jet then as they are the same but without the holes, saves the soldering.

Can't advise on the best option of 22 or 26mm for an Ariel, but if you're buying a new carb I'd consider the new Premier version with the pilot jet in the side. I've fitted a 22mm Premier to my BSA which is a long stroke C15 (337cc) and it's an improvement over the normal concentric. Much much smoother and predictable off tickover and seems stronger through mid range to top end. Main jet is 130 and needle is either 105 or 106, can't remember which. Pilot is a 17 (new numbering convention for these as they are completely different from the normal pilot jets)

I'm lost with this one ?? What hole, where? Needle or needle jet? The needle doesn't have a hole in it. The 4 stroke needle jet has two holes at the top, the 2 stroke needle jet doesn't have any.

They're gone as I machine them down to them. Never had a nut come undone so it's never been an issue, although it should be possible to drill new holes in what's left of the nuts, just in a different position

One thing to be careful of if backing off the spring tension is that the nuts will foul the inside of the clutch case and it's not pretty if you start the bike and that happens - trust me... They can't actually be backed off that far before they do foul as they are quite deep. What I've done is machine them to half their depth which allows them to be backed off as far as you want without them catching the case. With Barnett plates fitted, they require less tension, so a light pull can be achieved on the lever without the clutch slipping. The only pain with the Bultaco is that adjustment can only be done with the cover off, so if you back them off too much and then find it slips, the cover has to come off again. I generally set mine by riding it around the garden with the cover off before fitting it all together.

On thing to check is that the pins that the nuts screw onto aren't bent slightly. They're pretty weak and bend easily. If just one is off centre, the cup that the spring sits in can foul on the pin and stop the pressure plate coming off 'square' on that pin, the result being, the plate doesn't come off as squarely as you think it is. Take all the springs and cups out and eye up the pins in the holes of the pressure plate. They should be dead centre. If not, they're easily bent into the correct position with a screwdriver. From what you've said, your adjustment of the freeplay on the pushrod has been done correctly, so that brings you back to spring tension. Once you're satisfied the pins are true, reset the tension. They don't all necessarily need the same tension to get the pressure plate to come off square. I've had them where one is a full turn more / less that the one next to it. Is the clutch arm positioned correctly on the timing cover. If the angle is too far forward you may not be getting full travel on the rod. Correct number of plates fitted?

Glad you enjoyed it, thanks for the support. Not a bad entry for a boxing day trial. A bit wet... the weather over the last few days had rearranged some sections, blown markers out and the stream had risen and removed tape as well as markers. A bit of re-plotting needed this morning because of that, plus marking out 9 and 10 but the sections seemed to ride well enough on the whole, from speaking to a few riders during and after Results will go on front page when done, but probably not until tomorrow eve earliest at a guess

Yes, Speed and Sport was the dealer someone recommended previously

Yes, OTF, I had one on a Majesty 320. Reasons I did it were several The Majesty had been modified with a steeper head angle (and I wouldn't do that again either) and was fitted with mono forks. The result was a shorter wheelbase, even with the leading axle forks, so the swingarm needed to be lengthened. I had several choices, lengthen the standard swingarm, get another to lengthen or, I had a mono swingarm which I could modify to fit. I didn't want to ruin thae standard one, couldn't be bothered to wait for another t/s arm to come along to lengthen so I decided to use the mono item. Plus, the Majesty rear hub was broken all around the flange, so I could use the mono wheel with the swingarm (as I had a complete mono in the shed, fit for only breaking) And finally, it was an easier job for me, with limited welding / fabricating skills to make the mono fit. The mono arm is way too long in its standard length. I cut the front pivot mounts off, far benough back to give the length I wanted. Welded on a tube, same ID and OD as the original to utilise standard bushes / tube, spindle etc. Made up mounts for the shock mounts and in it went. Would I do it just for the sake of it? No. Basically, a swingarm is two sticks of metal attached to the frame one end and carrying a wheel and shock mounts at the other. There is no advantage at all in replacing the standard arm with one from the mono. I did it for a reason, as above, but it didn't work any better than a standard swingarm lengthened. It was still just two sticks of metal etc. Unless you've a specific reason for doing it, it really isn't worth the bother and will offer no advantage at all.

No, that's not Barnett. Just look on the Barnett website for part numbers http://www.barnettclutches.com/ossa.html If you search the Ossa forum for Barnett, one of the latest topics had the name of a dealer in the US that suppies them, can't remember it offhand. I got mine from Doug Elke ebay shop but that was a while back and he doesn't seem to be around anymore