feetupfun

Yes the cylinder nuts are concealed by the head. I think as well as looking amazing, they handle wonderfully Some other character-building aspects are: 7mm threads on casing screws 7mm AF internal hex drive on cylinder nuts Square drives on both brake arms Unique tiny diameter brake shoe springs Plastic (anti) bottoming cones in forks that spread and swell and jam Triple clamps machined from alloy plate that eventually falls apart Bizarre gearbox vent system

The reason you could disengage the clutch in 6th gear but not the low gears is because 6th gear puts the highest torque on the clutch

There are different length pushers so you can adjust the position of the arm to suit your particular motor. If the arm is too far inwards when it starts to disengage the clutch, use a longer pusher.

349s have all steel clutch plates so are sensitive to the quality of the oil film between the plates as they come together. Lack of oil, oil of too low a viscosity, oil with water in it or the plates being too hot can all cause it to judder/shriek as it engages under load.

I sometimes pack out the shoes at the pivot ends when the linings wear down a bit. On some bikes, it is easier to do that than packing out the camshaft ends.

If the kickstart won't rotate the crankshaft when you pull the clutch in, then the clutch is disengaging. There will always be some clutch drag when it is disengaged and this drag will be most noticable with the motor stopped. Minimising clutch drag is a worthy goal, but don't expect a 349 clutch to be drag-free. A better test than putting the bike on a box is to put it on its wheels on a high friction surface like rough concrete, select 6th gear, sit on the seat, pull the clutch in and move the bike backwards.

Yes having a square drive for the arm is a bit of a weakness at times like that

One photo shows how the ends were machined down to 7/8". The other is the stamping that was between the mounting clamps, looking like an advertisement for Akront

My 1976 348 came with Akront 1" bars and they were great bars. They lasted until about 2014 before breaking which is quite a bit longer life than 1970s (unbraced) 7/8" Renthals

It isn't much of a problem though because it will prime itself again as soon as you start riding

Sounds odd. Maybe the oil is leaking down out of the inner tube when the shock is not moving. Does the free play go away after a few rapid strokes? (mounted on the bike so you can work it quickly)

I don't remember the amount now but I usually put in just enough so that they don't snore. You can test for this before screwing the top on. 5WT is better than 10WT for them

There is a bloke in the USA who makes new shaft seals for 1970s Betor shocks. I've bought and used some in the Betor shocks that came on Alpinas and OSSA explorer. I saw them listed on eBay by this person about a year ago. I looked for ages and have not seen them available from anywhere else. These might not be the right size for your Betors though because some 1970s trials Betors have a thinner shaft than the one I rebuilt You can always turn up a new seal retainer for your shocks and use whatever hydraulic seal is available locally to suit your shaft size

Brake cam to cam followers galling Brake shoe pivots galling Cable end galling in brake arm Cable end galling in lever One shoe contacting the drum before the other shoe Brake shoes being tilted due to worn/loose wheel bearings or angular axle misalignment Worn camshaft to backing plate fit causing camshaft to tilt What is really important is not that it makes a noise, but that whatever is making the noise may also be the source of the spongy feeling

I've just looked at you photo of the float bowl and can't even see an overflow standpipe

Is the (brass) overflow pipe secure in its hole in the bowl? If it can move in its hole from vibration, fuel can get to the overflow hose

It's a great mod for bum clearance but there is a trade-off. Frame strength is fine for riding, but if you crash it is much easier to bend the remaining frame stubs. Those afore-mentioned amazing legendary riders very rarely crash, but newcomers to trials do tend to crash a fair bit.

I usually hang OSSAs upside down so no rust particles fall into the crankcase as I take the cylinder off. That design is also a good reason to run a motor until it is warm after a wet ride or a wash

The only way to get the timing right is with practice

No point you copying the length of a standard stand because your bike is too high for that. Just fit blocks of wood under the stand until you get your bike to stand at the angle you want, then add the thickness of the blocks to the length of the stand

Here is a what a standard stand looks like on a standard swingarm. And thanks to whoever shared this lovely photo on the internet.

Maybe if you post a photo it would help work out what is going on

There are two different TY175 stands. One for the models that have the mount on the RH swingarm arm and the other for the models with the stand mount on on the LH footpeg mount. They are different lengths and are also opposite hand to each other. Another thing to consider is that almost no-one runs a TY175 nowadays with standard length shockies. Most common length shocks are 340mm which is about 20mm longer than original, and shockies longer than standard cause the standard stand to be too short. Some people run the fork tubes flush with the top triple clamp which also causes the standard stand to be too short. The other thing is that rear trials tyres are a lot deeper/higher than they were in 1975 so the lean angle depends a lot on how much weight is on the rear tyre when it is on the stand The usual solutions that I see are to extend the stand to the right length for your bike set-up, or leave it off the bike

Those nuts are specials with a reduced OD (smaller than the A/F dimension) on one end to locate inside the spring so if you use some other nuts you will need to machine the recess. I'll measure one up later and post the info up if no-one else does first

The 26mm OKO I bought for my 348 works a treat, came with a new rubber connector, fitted without modification and cost $200 australian dollars including freight