trialsrfun

I think the piece you are interested in is here, http://www.tyoffroad.co.uk/store/c25/ENGINE.html

https://en.wikipedia.org/wiki/Johnny_Brittain John never found it a handful.

Hi Rhodri welcome to TC. If you do not mind travelling to derbyshire for a training day have a look on either the dales classic website or mansfield maun (the two clubs have merged) they have some very good trials tuition days in the peak district. In my opinion the Beta Rev is a good bike choice, which trials are you riding in?

A bit late to be of use to you but blocking the exhaust outlet builds back pressure and stops the engine running.

Deryk the bike Martin is riding in the picture you have posted is a Montesa not a Bultaco as you state.

A Beta 200 if you can find one would be the perfect bike.

Bike looks fantastic a great resrstoration job. I too think compression ratio was causing the problem, Greeves produced similar looking cylinder heads with very different combustion chamber shapes for all types of motorcycle sport.

I have a Sprite frame not a complete bike for hopefully a future project. I never have much success posting pictures here on tc but my frame is much the same as your one.

The purchase price may have been reasonable but on my frame the quality of the brazing is exceptionnaly good.

Some interesting Sprite info here http://www.bsaotter.com/1966_a_villi_good_year__.html

I have a similar Sprite frame, someone suggested it was possibly 1966/67 the last ones made 1968/9 did not have the tubes fron the swing arm pivot to the under seat tank area.

Must be a late MAR then which would have been silver.

As far as I know all MAR models had a silver frame, the first TR77 had a black frame which changed to green when the Verde (green) model was introduced. Are the upper shock mounts level with the lower side panel screws on your frame, on the TR77 they are near the top screw.

Should be eligible after all they are a reproduced 37a Villiers engine as will be fitted to many bikes ridden in the P65 as well as classic trials everywhere.

https://owdcodgersmcc.wordpress.com/ or www.­trickytrials.­co.­uk

Do not dismiss it, it looks to have a 4 speed gearbox, you should find a barrel, head and piston ok so it might yet come good. If you are not too far from Villiers Services take it to them they will tell you what you have.

A Greeves frame could be a good choice for your Villiers engine.

Thanks Woody, have you tried both OKO and Mikuni to get a comparison. I have had a look on the website you suggested is OKO K101 26mm the correct type?

Thanks Woody do they come jetted and set to suit the Bultaco

Where do you buy the OKO carbs from. I understand there are both genuine and copy ones out there, how do you know if you are getting the real thing?

The gearing on my 199a is the same as Woody is using, I also find the 11/39 too high for the events I ride in.

Interestingly the Puma and Vasquez built bikes I have seen are usually fitted with the fork type and sometimes a strip from the head to the frame down tube, anyone know why this is. Surely the triangular three point fix one would be better.

Large rockery!

My OSSA TR77 Verde

My 199a has the fork type head steady fitted, if I replace this with a triangular 199b type steady would this fit the rear bracket the same as now with only a front tab needed as on Bondy's bike which is pictured above.