woody

If you have Akront rims on your bikes (like the SWM has) you'd be ok as at normal trials pressure the tubeless tyres sit ok on Akront tubed rims using a tube. No need to change to a tubeless rim to use the tyre. The DID and Takasago rims can be a problem though and I've never been able to run a tubeless tyre on them, they drop into the rim at anything less than 10psi Not sure about other makes as I've never had a bike with anything else.

It says you can't run it tubeless, you have to have a tube inside it. So you have to consider that if you're thinking of fitting a tubeless rear rim and are thinking of entering the trial. This presents a real problem if you have a puncture as you are going to have a real problem getting the tube out as you have to break the bead of a tubeless tyre to get at it. That is very very difficult to do without a bead breaker or something else to hand to do the job. Unlikely during a trial so it could end your day. It's one of the daftest and ill thought out rules - actually acheives nothing.

True, but I've had bikes fitted with a grease nipple there as well.

I'd imagine it only applies to insuring your own bike, in other words a bike that is registered to you, as this is generally a standard requirement to insure a vehicle For a definitive answer you need to speak to the insurers themselves as the answers you get on here will no doubt vary.

It's debatable whether they are any advantage these days - with modern soft linings which can be oversize, then machined down to fit the hub better, brakes are better than they were back in twinshock days I still had perfect working brakes on my Ossa yesterday at the end of the trial which included several sections in streams.

The gearbox and clutch share the same oil - 1 litre - I use Silkolene light. The gearbox drain plug under the engine is the only drain. The small screw towards the lower front of the clutch case is the level plug, not a drain. You put the oil in through the inspection cover by the kickstart

Even if you do, I don't see how it can grease the bushes. If one is fitted (there is a pre-drilled hole in the swingarm) and you pump grease in, as far as I can tell, all it will do is fill the cavity in the middle of the tube between the two bushes. How can it actually get into the bush itself? Don't you need to modify the spindle with holes / grooves so that the grease can actually get between the bush / spindle - using new bolts possibly, that are drilled and have a grease nipple in the end, the bolt also has holes drilled cross-sectionally, so that when you pump the grease in, it can escape through the holes in the bolt, through the holes in the spindle and sit in the grooves which will keep the bush face with the spindle lubricated? Or something like that anyway...

Personally, I favour the Castrol oil over Silkolene as Silkolene used to gum up the exhaust with its oily residue whereas the Castrol (now called Power 1 I think) is much cleaner. For the rings as well. I run at 50:1 but as said, it's personal choice and you'll get varied answers. I'd say anything between 40 and 60:1 is ok, most I know use 50.

I'd have thought any modern gearbox oil would do the job, such as Silkolene or other manufacturer's equivalent. 600cc As it is separate from the clutch you don't have to consider the affect of the oil on the clutch action, so whether you used say, Silkolene light, medium or heavy, I doubt there would be any difference I use Silkolebe light in mine with no issues If you still have a steel clutch, use ATF in the clutch. 300cc If you have fibre plates, you can still use ATF but not sure if light gearbox oil would be better. I still use ATF and I have Barnett plates.

No-one is going to worry about a TLS brake. There are no rules excluding them anyway, it's a drum brake and a period mod, available on a YZ from '81 I think. Nice bebuild to a nice looking bike - I sincerely hope that you're going to get it absolutely caked in crap at your Miller round. i had a ride recently on Ian Pederby's 200 Whitehawk, same model as yours I think and also has Yam mono forks. It's set up really, really well, as he's spent years sorting it. Rode superbly, a really nice bike.

Vazquez doesn't speak English The airbox is from the earlier 325 models from '76, '77. The works riders used to replace the airbox on the last red model and blue models with that airbox as they felt it provided a better airflow. I don't think they are available anywhere as a new item, you have to look for used.

Thanks Jim, there was no wear in it that I noticed. It's Philpotts that I'll be sending them to, so good news that I don't need to remove it.

The 175 came out in 1978 and is an early 1978 250 sleeved down. The early '78 250 is pretty much the same as a '76 and '77 250 and quite different from the Pre-76 250 that you had. So if you buy a 175, just boring it back out to 250 will give you a '76 - '78 spec 250 (which had a different frame from the '76 - '78 350) The 175 was done for the rental market which had a restriction on engine size in some countries. It was never really intended as a proper trials version. The 250 is much better.

Just removed the stanchions from the sliders of a black engine Beamish (last model) as they need re-chroming. I'm a bit confused at to what I've found, it's the first time I've worked on Suzuki forks. I removed the spring, tipped the stanchion up and out slid the damper rod assembly - surprisingly, there's no shuttle valve assembly like Betor or Marzocchi have, so I checked the manual on the owners club website and that's how they are. There's one thing I can't fathom though. In the bottom of the stanchion is what looks like a bush and it feels pretty solid, as though it is pressed in, picture below (not the best...) I've looked at the parts diagram again and I can't see this as an individual part. If it's part of the stanchion, that's fine, but I don't want to send them off for chroming and to then find that it is something I should have removed and is either missing or damaged. Anyone know?

It will be at Telford next week, so you can put any questions direct to Colin of TY Offroad

Make sure it is not just the weight that has worked loose, it's not uncommon. When it does and the engine is running it is a very noticeable rumble at low revs What can happen is that when the weight is fitted, the woodruff key gets pushed upwards at the back slightly which stops the weight from sliding fully home on the shaft. When the engine is run, the key may settle a bit after a while which allows the weight to move further up the shaft, enough that the nut is no longer securing it, so you get a slight rumble due to the weight moving on the shaft. Or, the nut just comes undone meaning the weight is loose. If you think it's not a loose weight, easiest way to check if it's the crank is remove the ignition flywheel and see if there is any movement on that side

85mm is the standard size for the 340 Sherpa so there are oversizes on top of that which means you have a few more rebores left in your liner yet. Contact Bultaco UK/In Motion for a piston

Solway - the parts you've listed, you're not really going to be able to get those from any specific source. More likely you're going to have to scour ebay and hope they come up from someone breaking a bike. There's no-one in particular specialising in breaking Ossas The cush drive nut isn't a normal nut, it's a top hat shape with an allen bolt head - just in case you didn't know and it's actually there in the parts you have without you realising. The brake pedal assembly is common to all MAR models, which offers a bit more hope when you see bikes being broken. The front exhaust could prove difficult. Try Wakefield Offroad as they have broken a few Ossas over the years. Steve Sell, as mentioned above runs his own engineering business, the Ossa stuff is a hobby/sideline. He's helpful and enthusiastic about Ossas but we have to understand it's not his main businees. He will be at Telford. As far as I know though, he doesn't buy up and break Ossas, so not sure what used parts he has.

You'll probably find it just strangles the motor and makes it run roughly - which bike are you trying to use it on? You'll also find it's probably noisier than a clubfoot as well, as there isn't the volume. I have a newly repacked original banana on my '72 325 and I altered its inlet and the outlet of the middle box to the same as the later bikes and, on the banana exit, cut off the end of the 'spout' which is tapered so that it wasn't restricted. It's now about 25mm instead of around 20mm (or less) Makes a decent pop pop noise at low speed but even though it's all repacked, it still isn't as quiet as a repacked clubfoot.

Weren't they made for the older bikes on which the inlet and outlets on the rear silencer and the outlet on the middle silencer were smaller than the later bikes, so you may not get it to even mate properly with the middle box if you're fitting it to a later bike. Were they to replace the clubfoot? I thought they were an alloy replacement for the banana silencer of the '73/74 bikes before the clubfoot was introduced

The book is a decent read but doesn't offer much to trials versions specifically I think to make the WD box fit you have to machine the inner casing on the distributor side to take different size bushes as the shafts are different diameters. There may be more to it than that though, I don't know. I don't know of anyone who has done it, so can't point you to anyone.

Yes, reduce it on primary to whatever it should be (I can't remember) and then fine tune with gearbox/rear sprocket combo. Again, can't remember but someone will have what the 'standard' set up is I ran mine on a normal road box and had no issues with the gearing / ratios for sections. I managed to get a proper trials box for mine eventually but I'm not sure it made a huge difference and I'm sure it felt slower on the road.

You don't mention whether it was bought as a runner or whether it has been laid up for some time. Does the carb flood as it should if you hold the tickler down? Essential for cold starting as that is effectively the choke and even after it fires you need to flood it a couple of times whilst running until it warms and runs on its own. From what you're describing, yes the pilot jet or pilot circuit itself could be blocked, especially if the bike has been lying unused for some time. Remove the jet and check if blocked. Even if it is, also remove the air screw and use aerosol brake/carb cleaner to flush through the pilot circuit, spraying it into the air screw housing, pilot jet housing and pilot intake in the rear of the carb. Once you're happy the circuit and jet are free from blockage, try the bike again.

My old C15 was on 250cc (I didn't notice any difference when the bigger Triumph piston was in to be honest) It was on standard road cam, head and valves, followers, low compression piston (ie: flat top piston for standard trials CR that is about 6.5:1) PVL ignition with a Rex Caunt CDI unit with a softer pick up - this was one I asked him to do for me before they came on the market a few years ago, not a current one. I think the one change I made that gave the biggest difference to pick up from idle, was spacing the carb back using two of the tufnel inlet spacers (forget how thick they are - 3/4"?) This made pick up off idle very smooth and predictable and virtually eliminated coughing/spitting back in all but the harshest of throttle opening. I used to run it with no tickover so that when I shut off it would come to a virtual stand-still with no clutch and it would pick up again off the throttle cleanly and with no hesitation. Carb was a 22mm Amal I'm not sure you can put a WD gearbox in a distributor engine as a straight fit as I think the shaft sizes differ.

Spud, you're missing the main point. There are trials that suit these bikes, country wide. The fact that they are a decreasing sight is because fewer people want to ride them, or feel safe to do so, no matter how easy the section. One cough stall and 350lbs of old iron is going to fall onto the rider who no longer has the strength to hold it up or speed and reflexes to get off it quick enough - it has little to do with the available classes, as people who just want to ride their bikes do so in a suitable event. See the Talmag. There are rigids in the Miller and PJ1 series - in the latter they have their own class. No-one modifies tele-rigids (the big 4-stroke variety) so I'm guessing they are pretty well period. Have a guess how many there are. I can't offer anything other than a logistical viewpoint on the problems of running classes for these bikes - as mentioned in my previous comment. I've no interest in riding one except for maybe a one-off bit of fun as I'm game to ride virtually anything on that basis. On a regular basis, no chance. My mate has an original '63 AJS and neither of us wants to ride it week in week out - him not at all after his one and only outing a few years ago. Locally, we have the BMCA who have been running Pre65 events for 30 years. The same riders are still turning out, some have fallen by the wayside, some no longer with us. A few new faces but not many. There were a good few on bigger bikes up until a few years ago. 30 years on, they can no longer handle them except for the odd one-off ride as most are in their late 60s minimum. Nothing to do with the sections, just the riders are 30 years older and they want to enjoy themselves without broken bones. Their focus is now lightweight Bantams, James, Cubs, C15 etc. Enjoyment on a more manageable scale. They aren't yet at the point where they want a section that is virtually a green lane so that they can ride the big 'un. Personally I don't think the support is there. Riders who would have enjpyed (!?) these bikes back in their day are now in the main too old. The number of 'new' riders that would be attracted to them is probably miniscule.