trialsrfun

Thanks Woody for the TR77 info. Good luck Metisse with your MAR, I think it very satisfying to rebuild a bike to ride, much more so than just buying the latest model you can afford. Steve Sell @ Marlimar OSSA besides being the place to go for your OSSA bits sells a replacement ignition system if the Motoplat is up the creek. No point whatsoever in restoring a bike if the carb & ignition are past their best.

Thank you Woody for an interesting & informative feature on the MAR. I am currently restoring a TR77 Verde which I believe to be 1979 or 80, frame & engine no. begin with 700 which seems not to appear on any lists I have seen. The sump guard is made from pressed steel, looks like a No. 10 shovel & weighs a ton. Luckily I was able to source an alloy shield which will be used on the finished bike. Forks are Betor and longer than those on the earlier model, presumably the same as on the MK3. Rear shocks are moved rearward at the lower end & down to the upper side panel screw level at the top mount position when compared to a MAR, though not as far down as the MK3. When I got the bike it was semi dismantled so I have yet to see it on its wheels, with the forks dropped through the yokes a little is the overall height then similar to the MAR? I think there were some gearbox changes to the Verde model as well, do you or anyone here on TC know what the other differences were & how did the Verde bike ride when compared to the MK1 2 & 3 versions?

Tyres may not be made of soft rubber but they do not lack tread grip or depth. A great bike I think.

Was the MickMar & D18 Bantam one and same or two different prototype bike engines? As I understand it the MickMar engine used many Bultaco components including piston, & gears. I presume that BSA were developing the D18 to replace the D14/B175 Bantam and had they survived might the D18 have become their new competition engine, were they thinking of going 2 stroke following Dave Rowlands 2nd place Scottish finish. Would that then have developed into a two-stroke moto-crosser to compete against the CZ bikes that won everything until Suzuki chucked loads of cash at the sport.

30204 taper roller bearings are correct for your OSSA & a direct replacement for the angular contact type that may have been fitted when the bike was new. Have you removed the old bearing outer races yet? There is little or nothing much of a shoulder on the bearing outer ring to tap against using a hammer & punch. One way to remove the old outer rings that I am told works very well indeed is to run some arc weld onto the inner bearing face of the bearing outer, this shrinks the outer race causing it to almost fall out of the headstock.

Thank you Woody, my bike is a Verde model but until the frame goes off for powder coating I am unsure as to the final colour? Normally I like to stay true to the original colour but the all over Kermit look is a bit of an eyeful. The back box is an add on or aftermarket alloy straight through type, 24mm dia inner perforated tube and wool packed, middle box appears to have no packing at the moment and a rattley baffle tube so it needs some attention there.

Good job that Stu, nice looking bike. Hope to see you and your Dad at the Macc area trials.

Should the rear mudguard fitted to a OSSA TR77 be full length, as in down to the swinging arm or the shorter type. I am thinking the Gonelli type mudguards. Now to the middle exhaust box, should this be packed/repacked with exhaust wool or is it an empty expansion box with a baffle tube inside?

Thank you for the video, you have some great trial terrain there.

Am following this topic with interest as I am currently restoring a green TR77 250. How was the gearing on the one you rode Woody, does anyone know the best sprocket sizes to opt for?

REH, Robin Humphries went on to design, patent and build a prototype reciprocating engine which has no con rods, I think he calls it the Shane engine. http://www.volvoforu...hp/t-50440.html There used to be a lot of info on the web about this but it seems to have vanished for some reason?

I do not know which area you are from but Dynasurf @ Sandbach Cheshire http://www.dynasurf.co.uk/ is the place to go for fork rechroming.

I will ask my friend he may come on TC himself with the info, it is a very standard 1967/68ish Cheetah with the REH forks, yokes & REH cable disc brake. Cylinder & head are also REH made and are round with a centre exhaust port. This feature is very odd considering virtually all the bikes of the time had a single frame down tube which would be in front of the port. Sprite had twin tubes but these were closely spaced. The Cheetah frame is probably similar in dimension to the Greeves Anglian so not really a compact bike. One of the neatest frame kit bikes was possibly the Higham Firefly built by or for John Lee, I have only ever seen one of these when it was ridden in a local trial a year or so ago.

Hi, it is a Cheetah but obviously since it was built over 40 years ago time and various owners have made a few changes to it, it appears to have been adapted for road or green lane use but does look to be original in all main areas. The cylinder and head are Greeves Challenger type, they could have come from an Anglian trials model or a TFS but the porting was all similar anyway so it probably makes little difference. Wheel hubs are British Hub originals, front reasonably light, rear a bit heavy because of the cush drive but good brakes at each end. Original finish was nickel plate which can be redone. If you intend riding it consider fitting electronic ignition as well as a good Amal concentric carb. A friend has several Cheetah bikes including the ultra rare Villiers engine model with the disc front brake.

Any expert advise for Cub engine oil out there please?

Says it all above, what are you using & recommending?

Is the 199 more difficult to ride than the 250 198 due to bigger engine/more power or is it the handling that makes the difference?

Thank you for the info Guys. I need to make a similar plate for my Model 124 so the info is very useful to me. Have fun riding the bike.

An excellent job Guys, thank you for sharing the pictures here on TC. Do the countersunk M6??? bolts screw into captive nuts on the mesh guard or have you used ordinary nuts, just wondered if it is easy to get in there with a spanner if that is the case.

If I am reading their website correctly it comes ready mixed 2% 50 to 1 or 4 stroke to presumably mix your own fuel pre-mix. Looks to be a bit pricey though, £20 for 5 litres on the auction site.

Good one Woody it does sound like the black & white silent movie version of Dougie at Goodwood House!

The tank is a really good job, what thickness alloy is it. Did you also make the side panels?

Does anyone please know the bearing sizes or numbers for a 250cc OSSA TR77 so that I can have them to hand ready for the rebuild, Mains, bearings & seals, are both main bearings C3 type Gearbox bearings & seal Frame steering head Front & rear wheel bearings

I have just found this very interesting article, thank you Woody for the details. Have you changed the brake pedal or does it operate ok as it is with the new lower footrest position?

Looks a good event, enjoy your ride hope the bike goes well.