trialsrfun

Considering lowering the footrests on my OSSA MAR but what are the options for the brake pedal, has anyone any ideas please.

Cheers Woody you have been a great help

Thank you Woody for the info a couple more questions though if I may, should there be two engine to frame down tube bolts or one longer one with a spacer between, are the original bolts std metric thread or fine like on a Bultaco. The side panels are alloy but there is no spring or clip in the airbox to hold the foam between the two gauze panels what might be missing? Have yet to look in the hubs, do OSSA have steel brake liners or chrome on alloy surface again like Bultaco? Further checks have revealed, The ignition fitted is definitely electronic, no points. Looking through the crud inside the sump shield there is some light green paint so I would think this one was an all green model when new. Checked the Falcon site & shock length is 13.65" for all the OSSA trials models listed so 340mm length should suit. 340 millimetres = 13.3858268 inches.

Could you help identify which OSSA trials model this is please, frame number B-700~#~ engine number M-700~#~ I initially thought it to be a TR77 250cc but after a google search this model seems to start with a B-72 number designation. Also what is the correct colour, some TR77 models have a black frame & dark green tank, others an all over lighter green frame & tank. It has sloping down rear shocks, lower mounting at the rear end of the swing arm with the upper points a little way down the frame tubes. Full width hubs which as far as I know are the same as those on the MAR. Betor forks, gold anodised wheel rims, the exhaust pipe is longer than on a MAR, it goes down from the cylinder before turning back up and over the engine.Carb is Mikuni. Any other info would be useful such as shock length, ignition and carb settings etc.

Had me worried for a moment Woody, I thought you meant the hubs cracked in two...phew...so back to the tank. Yes I have considered having it welded together but as two pieces, servicing the air filter is a doddle & once drained the tank is simple to remove, it would be nice to have it as it original but we will see.

The 125 and 151 series were the only model range to have that rear hub as well. Woody I have a Model 124 with the same rear hub so did that part not appear on those models first? I understand that at that time the production runs were fairly short with the model numbers changing each time a few modifications appeared. The alloy tank seat is good really as it is ok with modern (poor) fuels, the one on my 124 though was sawn through by a previous owner so as to allow the seat unit or tank to be removed seperately. Was that a common thing which I suppose stopped the two cracking apart?

It looks to be all there so a good start and when complete another bike saved and back in use. Please keep us updated with the rebuild, good luck.

I have the Beta 250 my friend the 200. The 200 would be my bike of choice next time but I have lowered the 250 gearing on the rear sprocket to make it the same as the 200, a great improvement and really there is not much in it between the two bikes. The 250 has more low down power but the 200 is just as capable a bike, both have plenty of oomph for anything you will ride.

Just fit electronic ignition, a bike that does not start or run properly is not worth the hassle, replace any worn bits in the carb, check & replace cables as reqd, strip & reassemble the brakes to see if the linings are still good & secured to the shoes, replace tyres if they are old and had it then wipe over with an oily rag, job done.

I know of several Bantam & Cub trials bikes fitted with Electrex World ignitions & the owners have been very pleased with them. Why I wonder does the Bultaco UK ignition have a coil & black box while the Electrex ignition has only a coil? Electrex World also claim 'Electronic advance of 13 degrees is specifically developed to give the Sherpa smooth tractable power, ideal for trials' Is this something unique to their system or does the Bultaco UK one do this as well.

The reason Cub/Bantam rear hubs are often widened is that the rim needs the spokes altering to allow for sufficient chain clearance when using a 4.00/18 tyre, in other words the rim goes a little bit over to the right hand side of the bike. This means that the spokes on the sprocket side of the hub lean over a bit more but the right hand side spokes are near vertical loosing the triangular pattern between hub, spokes & rim which weakens the wheel structure. Widening the hub by increasing the width between the bearings regains the triangular shape which evens things up again, a side benefit is that the load on the wheel bearings is moved nearer to the fork ends of the swing arm so strengthening the whole thing.

When I built the bike the system came without a plug cap so I used a NGK hard plastic type without a resistor but I was now thinking of fitting a rubber type bit more P65ish so wondered if my earlier choice or no resistor was correct.

Is it better to have a plug cap with 5 ohm resistance or one without, bike is a Cub with PVL ignition.

Good idea that Stu, how have you secured the foam to the filter cage?

Thank you b40rt & totalshell for your replies, I have chain saw air filter oil in the workshop so I will give it a try.

Hi Totalshell, Its the rain that bothers me too, the (very nice) FB on your BlogSpot has a Villiers carb and Villiers air filter not Amal, am I looking at the right pictures?

Many British bikes fitted with the Amal carburettor use a round screw on air filter which usually has either a paper or gauze filter element. Which type is best though, some of the gauze ones look rather poor (you can see straight through them) the paper ones I suppose may get wet when it rains via the holes in the metal outer so which type is the better option?

Wonder why Vesty used a 175cc motor, I thought the 175 Sherpa engine unit was the same as that on the bigger Bultos or does it have a lighter weight crank assembly?

Thank you for the info.

Vestys X-Lite Bulto has a 175 bottom end and is a 272 engine capacity.It tips the scales at 81.06kg and he is working on shaving more weight. Which cylinder & piston were used to give 272cc ? Any other engine details in the article please.

Is it possible to buy a copy of the DVD at either the Pre65 at Kinlochleven or the west end car park on Sunday please?

This is the best way around Glasgow we tried it last time, thank you Andy.

What has he finally lost his voice???

Anyone know if Alan is organising anything for Sunday evening this year & if so where will it be held?

Do the Model's 124 & 125 have a bump stop for the sidestand when raised on the swinging arm ?