Twinshock

I need some help here please. I have a 247 Cota around 74 75 vintage on standard bore (72.58) that has bad rattles in the top end. New rings, pin, bearing have not done much to stop the problem. I bought a new piston and rings advertised for a Cota 250 (72.75) (made in Italy) but have found that under the original packaging they are marked for a Bulty 250 Sherpa. That was crossed out and Cota written in texta. Both pistons are nearly identical. Original Cota has a port on the intake side with oval ends, the new one has a port with rectangular ends. High and low skirts appear to be the same. Ring pegs on the old one are at the front, the new one has them at the rear…

How long will it be before twinshocks are as modified as a pre 65 where the person with the deepest pockets wins. Some people are almost there

Hi all looking for the distance between holes on the front wheel stay, dont think mine is right as I went to fit a new cable today and it wouldnt fit think the hole centres on the bracket is wrong. thanks Could have things the wrong way around also, cable adjuster is on back of the fork leg, should it be on the front wheel stay on the front?

This is on a somewhat local listing for sale as a "UK" trials bike.Pretty sure it has a non stock seat,but don,t think I,ve ever seen one.Is it Chinese? A friend of mine is interested in it.

I'm sure this topic is similar to asking what type of oil you use, but I'll ask anyhow. I have a Penton/Wassell trials bike that I've been competing with regularly. Right now I have an old set of Betor shocks I took off my Ossa MAR. I want to replace these old Betors with a modern style shock, and would like some opinions from you folks as to what you would recommend. The only thing I do know is I've seen new Betors that didn't make it through a season (bent). And I've read about others leaking. Any advice will be appreciated.

Cant afford Maxton or Magicals. Rockshocks or Falcon alloy???? What do you think? anyone tried both types?

Hello, Does anybody know the weight of a TLR250. They look small and light but I rode one recently and it seemed just as heavy it's Spanish rivals. Thanks, NAT.

Had the hub welded twice. The first weld lasted good but the 2nd weld is disintergrating into thin air . It was painted immediately after welding. The weld took well and its only thin so preheating perhaps isnt really needed ?Ive read that preheating the mag to 200 degrees in only needed on thick material. Ive never seen anything like this before and the welder who didnt seem ti understand it either .The weld is magnesium as ive done the vinegar test. My guess is that perhaps the wrong mix of mag / alloy rod was used OR it been contaminated. I find the contamination theory strange as the hub was taken back to the brake liner , so all was there was the steel. I dont wa…

Hi all I am thinking about having the front wheel rebuilt on my Majesty, and was wondering if I fitted a conical hub could I still use the Yamaha rim which origionally had a full width hub or would I have to buy a new rim. Thanks. (please dont reply if you are going to say that this is against the spirit of twinshock trials, as I have numerous pictures of Mick Andrews and Shirty etc on bikes with conical hubs and leading axle forks back in the day. You know who you are)

I am looking for some photos of the works ossa monoshocks (Cheney frame) which were around in the mid seventies. Does any one have any images that show how the bikes were put together. I would also like to contact any of the riders or Roger Holden. Thanks for your help.

Hi everyone, I'm a new member so a quick hello. I'm sure this has probably been discussed before but I want to change bikes and would appreciate your opinions. The bikes I am interested in are a Yamaha ty250, Montesa cota349, or a bultaco250/325. Is any one of them better than the other handling, reliability wise etc? and are there any to avoid. I know there are othermakes of bikes out there but these are the ones I grew up with and have nostalgic appeal.I'm an avaerage clubman trials rider and would like a competative twinshock bike. Thanks in advance, Spawtydawg.

Well, against many peoples advise that I respect I bought the little TL-125 down the street. I just couldn't help it. This was more of an emotional purchase than a logical one...... I'll probably end up with a twin shock bike that will actually haul my weight at some point but this is fun for now!!! Anyway, I always wanted one of these as a kid and always loved the way they looked. The only problem is, just like everyone warned me, this thing has no power. I think an OSET has more power than this....... Soooooo, all you TL and twin shock experts......HELP!!!!! The good: 1. Frame intact and not too beat up looking. 2. Tank OK, I have a friend who can paint the tank …

noticed this was my 200'th post..and have been thinking of adding a 200 top end to my 123, I heard back in the day that you could put the 200 top end on a 123 bottom end and there was no difference in the 123 and 200 bottom ends, is this true? has anyone done this? my bike is a '82 model I think, (white tank, red frame) is the 200 actually a 173cc?

My Montesa Cota 348 (1978) has allways worked fine without any problems until yesterday but now there's something wrong with the intake. The carb is Amal 2627, and I haven't done any changes to the standard jets and settings. The engine works poorly with low rpm's and I can't find good idling with low enough rpm's. I can set the throttle top screw so that the engine revolution at idling is high but can't get my target speed for idling. The engine will stop when I lower the rpm's. Ofcourse I've tried to turn the air screw left and right but without succes. When I turn the throttle grip at no-load operation the engine revolution increases normally but when turning the gr…

Anyone bought? Is it worth buying?

Help! I have a fiberglass Bultaco 199A fuel tank that is leaking along the bottom edge seems. The tank was sealed at one point in its life with a "Kreem" type product. What is the best way to proceed in resealing the tank: a. Pour a new sealer over the existing one? b. Try and remove/disolve the old sealer? c. Apply resin to the drip edge seam and hope for the best? I poured and flushed the interior several times with Laquer Thinner, although this did a wonderful job of cleaning the tank it did not remove the sealent material. I have considered flushing with Acetone, however, I am concerned that this would eat in to the fibergla…

On my 349 I need to replace the gearbox bearings, two of which are in blind holes.... I have been told to support the case, behind the bearing, heat the case, and jam in the heads of a couple of large nails under the bearing to lever it out. Anyone got any further tips? Thanks Steve

Anyone on this site coming down south for the Exmoor 3 day?

Can anyone out there tell me what size bearings should be used in the rear wheel of a TLR200E? The complete NTN 6201 LU bearing on the drum brake side fell out when I took the brake drum off. The hub looks ok - there's no crack in it so I'm wondering if the bearing is the right one. TIA, Pete

I have the chance of purchasing an ossa, it has no documents but has been registered, and i can't remeber the number. However i wondered if any one new which model it is, Its all white in colour with a green stripe on the tank and airfilter cover, and the ossa emblem is written in gold, the bike hasn't run for about 10 years, and is in semi decent condition. Any one any ides Cheers