no balance

Hi, unlike Bultaco I can't find any books on Ossa's, I'm mainly looking for info on the Mar range, so if you know of anything (in or out of print) I would be greatful if you could let me know the title or ISBN number. Cheers in anticipation ! NB.

I think the main difference is trials bars are straighter. You do see mx type bars on trials bike and to me they look a bit odd, but I suppose it's personal preference.

Hi, sorry for the slow responce guys, haven't looked on TC for a long time. Truth is I never did get the electronic ignition to work, I sent it back to be checked for a fault but was told it was fine and the most likley cause was the crank case oil seals or a carb issue. I did get it to run again using the old Motaplat electronic ignition by fitting another HT coil. I also replaced the new Mikuni carb because of over fuelling issues, no amount of jet changing etc made any difference, so I fitted a old 70's Mikuni (the bolt on flange type) that I removed from a 250 Bultaco Sherpa years ago and it's run spot on ever since, and it's now my bike of choice. Plug colour is good and it starts cold or hot really well, it pulls from nothing so well, cutting down the use of the clutch in sections. I still don't know if the new electronic ignition will now work on the bike because I haven't tried it, I did try to fit it to my other Mar but when I pulled the fly wheel it was the wrong type, sods law!!

Been looking at the ignition again tonight and I think I've sorted it, after returning the stator plate back to the position it was supplied in, I noticed it had another set of threaded holes next to the one's being used, so I moved the fixing bolts into the other holes and moved the stator plate as far to the left as it would go, refitted the flywheel and cover and started it, the differance was huge and it was back to how it was before the old one packed up. I'm hoping all I need to do now is strobe time it to get it spot on. I'm only used to timing bikes with points and can't find any marks on the flywheel or case to use for strobing it and the flywheel doesn't have a hole for a timimg pin/tool. So if I use my DTI gauge and set the piston at 2.5mm btdc and put my own marks on and strobe it with the engine reving fast to get full advance, would I be doing it by the correct method?

Thanks for your reply, but his ignition comes pre-set and the fitting instructions say not to move it from that setting!! it can be advanced and retarded and doing this has made no difference. As for timing marks for strob use, I will have to check that out. Cheers.

Hi, last time out on the Ossa Mar it decided to pack up, after stopping, I tried to restart it but it would only kind of four stroke with the throttle wide open. Back home and the bike cooled down, it would start and run ok for a few seconds and then start four stroking and cut out. I changed the coil with a good spare one I had but still the same, when checking the spark it was very weak. So I ordered a new electronic ignition to replace the notoriously troublesome Motaplat electronic system, with the new ignition fitted the bike started first kick, the problem I have now is the bike lacks throttle responce to the point that it would be useless, on the old system it was quite lively for a Mar and equally as good as my Bultaco M91, any suggestion as to why it's not what it was would be most welcome. Cheers.

Hi Andy, in your first post to this topic you said you can get two trials bikes in your Caddy, have you got the Maxi or the standard size?

Hello, you could try Rex Caunt Racing 01455 848 287, they sell an alloy cylinder kit which I think is ported for trials but you would need to check that with them, not cheep though £420.20. They also do other stuff for trials Bantams and are very helpful. Cheers NB.

Hi, I think you will find that models 242 304 307 308 309 and 311 use the M39 engine so this should increase your chance of find the part you need, have you tried Ella Stone Off Road ? Cheers NB.

It depends on how much money you want to throw at it, personaly I wouldn't spend out for full electronic on a three speed engine, as we all know the most competative Bantams have four speed boxes with second and third gear swopped around, so yes would have to agree that a Electrex World full electronic ignition would be the way to go on a four speeder. Cheers Nb.

Hi Tony, Simple answer is yes you can run with the other coils removed. The timing is 1.5mm btdc (best done with the head removed) or 2.5mm btdc if using a Todd high comp head etc. You could also look at fitting a Rooster Booster Junior type module, so you can do away with the condenser. I have one fitted on my bike and it works very well. These modules can be found cheeper at places like Garden Machinery Repair places or Ebay, I have seen them as cheep as £12.50. Cheers, No balance.

Many thanks for the input Guy's, and I do have to agree with Charlie regarding building a bike that is British, I was thinking that doing it my way was going to be the cheapest option, but by the sounds of it maybe not. When the actual build gets underway I will try to post some photo's of the frame and engine mods etc. Many thanks, NB.

Yes, I know what your saying Woody but I was thinking about 32mm jap ones, with a strongly fabricated fork brace to take the flex out. In My opinion the larger diameter front forks can look it bit out of proportion on a little Bantam, as long as the compression and rebound works well I would be quite happy with the 32mm size, unless there's a good reason not to ? NB.

Hello, just in the process of gathering parts to build another Bantam trials. I have found a set of BSA C15 forks and was wondering if these are any good for tricking up with internals from say a jap bike ? if so, any suggestions for what to look out for, advice or info much appreciated. Many thanks, NB.

Thank you for the recommendations/advice, OTF is correct and after speaking to the Mot tester yesterday I will be taking his advice, which is to have the following:- Speedo, any type. Horn, any type, bikes after 73 (I think) have to have a continuous sound. Brake light. Number plate, it should be full size but that just would't be practical ( would it officer !!) I plan to make all of the following items as quick detachable as possible.