2005marke

thats is the same reason that I am considering having to do the same, in the event of a gearbox failure it seems easier to use the TY250 engine that I have already than finding another gearbox. But is it pemitted in the bigger twinshock trials ?

thanks for the replies, and I will try and keep both montesa's running, but to get back to my origional question. Will I be able to run a yamaha engine in the montesa chassis in twinshock trials ? I know it won't be a problem in my local club trials as I am normally the only entry on a twinshock anyway, but will it be allowed in the classic trials ?

I have stripped them both down and replaced bearings and seals because they have both been unused for many years, however attempts to find any source of pistons or even rings was unsucessfull. Fitted new mikuni carbs as I am not a fan of the mk2 amals and they run realy nice no rattles etc. My main corncern is the gearbox as one of them shows signs of wear. I have tried the usual suppliers, sandifords, mainly spanish, Bultaco uk, none could offer a piston or rings for the 242 so no chance of gearbox bits, it seems that 248 and 247 cotas are a bit easier to find parts for. Should I be looking abroad if so any contacts would be appreciated.

hello, I'm returniung to trials after retiring 20 years ago at the age of 18 !!. Having spent 20 years racing modern motorcross and enduros its time to return to trials. However the decision has been made to ride twinshocks as these were the bikes I remember, and I have recently switched to classic scrambling and just love the atmosphere that seems to revolve around the older bike fraternity. Having obtained a couple of Montesa 242's one has done next to nothing so will be kept for best, the other has done more work but still tidy. The opinion on these bikes by others seems to be that they are a bit fragile and spares are very hard to find. Having rode them a few times they seem to be nice bikes to ride, but as I plan to ride them most weekends in club trials as well as twinshock events I am worried about keeping them going. In the event of a major engine fault can I fit ty250 mono engine that I already have in the shed into the montesa frame and still be eligable for twinshock trials events. As far as I recall these were available at the time as twinshock montesas were still available new after the ty250 monos were launched. The aim of this mod is not to improve performance, its just to keep the bike competing. Will this be permitted?