trapezeartist

Obviously the "perfect" answer is to change sprockets and chain at the same time. The pragmatic answer is less clear. Using a worn chain means that the effective pitch has increased, so instead of distributing the load all around the sprockets all the load will fall on one or two teeth at the top. That is going to accelerate wear on the sprockets. Using a worn sprocket will eventually cause the chain to jump a tooth under load. (My first trials bike bought in 1969 did that when I first got it.) But generally you will change it before it gets that bad. Using a hooked sprocket will wear the chain and make it snatchy. My own conclusion would be that you should change the chain when it's stretch measures outside the acknowledged limits (which I've forgotten!). No need to change the sprockets as long as they look good. Change a sprocket if you can see the wear or hooking.

It's very confusing about which make and which year are the user-friendly engines and which are the fire-breathers. I'm starting to accumulate a few notes now whenever I find a comment. Trouble is, there is cinflicting information at times. I definitely take the point about the 200, and when you're dithering between a 125 or a 250, 200 seems a good compromise. I don't think I've seen even one advertised though, since I've been looking around.

Yes, "needing work" is a bit of an issue for me with a twinshock. It's not so much getting it into god mechanical condition, which is just a matter of time and money, but doing the tweaks to make it reasonably competitive in the modern environment. There's a lot for me to learn in that area and it would be so easy to buy something unsuitable.

Portishead, so I can easily get to the Cotswolds, Somerset or Exmoor. Thanks especially to oni nou and doc_d for allaying any fears about a 250 trying to kill me. I think that's the way I'll be going, especially as there are more 250s for sale so it makes it easier to find the right one. What year did Gas Gas start fitting the two-map ignition? That sounds very useful, but I have already logged the thought that I may just retard the static ignition a bit if I find things a bit fiery at first.

Thanks for all the replies. As expected, there are opinions going both ways but it's the reasons that help me sort out which way to go. It looks like it's going to be Modern. A further bonus that no-one mentioned is that all the training videos assume the use of a Modern. There seem to be clubs and events around my way that run a class for Over-50s or Over-60s on Moderns, so I won't have to compete with kids who can ride up cliffs and jump chasms.

Notwithstanding my other post that sort of assumes Modern, I'm still a bit split between Twinshock and Modern. When I sit here looking at photos and videos and whatever, the twinshocks seem to have the appeal. Then when I go to a trial, I come home fancying a modern bike. So come on experienced forumites: which way should I jump?

I'm coming back to trials after a short break (44 years), so I have to consider myself a total novice. One piece of advice I was given was to go for a 125 bike as it would be sufficient power but not enough to bite me. I have a little bit of a reservation about this. Is a 250 really going to be that unfriendly (I'm well aware of the need to avoid a 280/290/300)? I weigh about 80kg in riding gear, so rather more than the average youth rider that the 125s are aimed at, I would have thought. So as well as having to drag around a bit of extra weight, is a 125 going to be too lightly sprung for me?

And there was me thinking it had something to do with bacon, lettuce and tomato.

Thanks lowbrow. I managed to find a phone number on the AMCA website (eventually!) and confirmed that the trial is on.

Is there a trial at Breakheart this weekend? I've seen it on a fixture list but I can't find confirmation anywhere.

Nice one, Rabie. A voice of reason and clarity.

Back in the good-old bad-old days we used a rubber bulb blowing through a reed and a 6 inch metal cone. They were utterly pathetic and some didn't work at all. At machine examination, if one didn't work, every else in the queue blew theirs and the examiner would pass it.

Brilliant plan. He's a lucky Dad.

You've almost convinced me , but you've thrown a slight doubt onto something that I thought was a strength: the finish. A zinc-plate-and-passivate finish should be durable but I suppose if the passivation isn't done right then you've got plain zinc and that's quickly going to form a white powdery oxide. Is that what you're suggesting?

Getting back to first principles, motor insurance companies want to know about all your other motor claims because that may affect their assessment of the risk. That seems to me to be fair enough. If you fell off your Fireblade in the High Street, that may reflect on your level of risk when driving your car. HOWEVER, if you had your computer stolen from your house, that wouldn't affect your risk as a driver and there is no reason why you should declare that on a car proposal form. In my view, and I think this is what the OP is getting at, the second analogy is the one that is appropriate to having a trials bike stolen from a garage. With the benefit of hindsight, perhaps the bike should have been included on the house insurance as a high value item, rather like you might insure a pushbike or a piece of jewellery.

I'm thinking of coming back to trials after a very long sabbatical. Having looked around this forum and hoovered up as much information as possible from other places, it's clear that it's a very different world to the one I left. So while on the lookout for a bike I'm trying to understand the maintenance implications: What is the correct interval for changing gearbox oil? What is the best way to clean/lube a chain? What sort of life should I expect from tyres/chain/wheel bearings/head bearings/brake pads and any other consumables? I've seen a few people quoting life in hours. How do you measure "hours" on a trials bike? What other frequent (or infrequent) maintenance tasks have I missed? Please be gentle on me.

Dave Cooper (much-mentioned on this thread already) makes a collapsible trailer (I hope he means dismantleable trailer!) that is only about the same cost as his standard trailers. It's probably the way I am going to go, but I have a few reservations at the moment: It's not totally clear on his website how they dismantle (I think the single version is in three pieces and there are 2 bolts per joint) They look a little flimsy (Just two bits of tube; no triangulation) There is no front-wheel-stop On the other hand, I like the idea of zinc plating Can anyone confirm or allay my concerns? In the first place I came at this with a view to buying a rack because I think they look really neat and clever. But: My car has a max nose load of 75kg, which would be exceeded by even the lightest modern trials bike when you've added in the rack and lightboard. One slip while loading or unloading and there's a chance of a nasty bash on the back of the car. With the bike loaded, access to the boot is going to be difficult or impossible. So you have to change clothes and pack away tools, etc before loading a muddy bike back onto the car. Not ideal.

The oven should work fine. It's more controllable than the heat gun (you know exactly what temperature you're giving it) but inevitably the bearing will be as hot as the case. Do the same when you come to put the new bearing in, but then you have a hot case and cold bearing so it should go in easier. (These jobs are best done when the female of the family is not in the house. )

Better off? Falling off a boat can be a lot more serious than falling off a bike.

Portishead, near Bristol.

Thanks for all that advice. This is obviously a friendly forum. To be honest there is still a bit of conflict within: twinshock v modern. It's just that I'm leaning a bit more towards twinshock at the moment, but I think there's still time to change my mind when I've visited more trials and talked to more people. I fancy I'll have fewer excuses on a modern though.

Just 44 years after I last rode a trials bike, I'm thinking of having another go. Well, I'm more than thinking about it really, but SWMBO has declared "You've got to sell the boat first", which seems reasonable. Anyone want to buy a boat? My last bike was a 1966 4-speed Bultaco so for nostalgia reasons I'd like to get a Bultaco again. However I don't want something that won't be reasonably competitive, so I suspect I'll be more likely be looking for a Fantic or Yamaha TY (for Twinshock, obviously). No doubt I'll be dropping into the forum frequently, asking a zillion naive questions about bikes, clothing, trailers, techniques, clubs, practice grounds and who knows what else. Please be gentle on me.