feetupfun

He was 9 when he started riding the GasGas, and we changed because the OSET was very difficult to ride in sand and water-worn stone creek beds, a function of the small diameter wheels and very short travel suspension on the 2007 model OSET 16. He was quite small for a 9 year old and could still fit the OSET OK as far as size goes when he was 9. He is 12 now and about the size of an average 9 year old and the GG50 is perfect for him. Yes the GG50 has a lot more power than the 24V OSET and it has very good suspension. The only riding drawback I found with the GG50 is that they come fitted with tyres that are not really trials tyres. They are commonly replaced with Cheng Shin tyres. As far as clutches go, the GG50 has a clutch that can be made to work as a centrifugal clutch and/or as a manual clutch. As they come standard they are auto clutch with manual override, and if you take the springs off the centrifugal weights, it becomes a manual-only clutch. For those people saying how good TY80s are, I agree.My son also rides a TY80. If we are going on a trail ride, or competing in a classic trial, he chooses the TY80 and when he is competing in a modern trial he usually chooses the GasGas 50

Your brain and body will adapt to any clutch in time. Also bear in mind that a 2002 Sherco 290 is great for blasting up things but not the easiest motor to manage in technical riding. If you are OK with your clutch control in technical stuff when fresh but have problems later on in a riding session, then your clutch pull muscles need more conditioning You can also test other people's clutch pull to judge if yours is unusually heavy Unless you have unusually small hands or very thick fingers, then standard levers will be fine

my son went from an OSET 16 to a 2010 model GG50 (in 2010). There have been a few minor problems with the GG but it is a strong performer with great suspension and brakes. We live and ride in a hot place. A friend's child rode a Beta 50 auto for a few years and the way the motor used to overheat and carry on did not impress me. We chose the GG because it is water-cooled with a thermo fan and copes very well with our climate. I can list the little problems we have had with the GG50 if you want

near the bottom on this page http://tyoffroad.weebly.com/restoration.html

I rode with a Leonelli lanyard for my last four or so trials in 2013, to get ready for the 2014 season (they are now compulsory for all trials riders at Motorcycling Australia events). In 40 years riding trials, it was the first time I had ever used one. I had no problems with accidental activation or missing lanyard. Holding it under your thumb as Paul suggested is a good idea. I did try and move my left hand off the bars a few times to do something while stopped, but the strong magnet in the Leonelli lanyard meant that I felt resistance to lifting my hand so didn't pull the magnet off. I have had many crashes in trials where a lanyard would have made for a better outcome. I reckon the benefits of a good quality lanyard switch outweigh the risk of negative outcomes by a huge margin.

Its the rings and bore surface that need running in - not the piston. A lot of heat is generated by the friction of rings on a fresh bore so the main thing is to only run the motor until the cylinder gets hot, then let it cool down. If you get it too hot, the rings and bore can be damaged. On the first run it might only take 1 minute to get hot. With each successive run, the time it takes to get hot will be longer. I judge that the cylinder is hot when I wipe a wet finger on a fin and the water/saliva sizzles. If you have an infra red thermometer, 110 degrees C is about right. Use a fuel mix that has a lot of oil in it to reduce the risk of damaging the rings or bore. I use 20:1 semi-synthetic for the initial runs. If you use full synthetic oil it will take more running time to bed the rings in. After the first few runs, the heatup rate will be slow enough that you can ride it gently for a short while before it gets to water sizzle temperature. When you notice that it is taking a normal time duration to warm up the motor, the rings will have been run in. I find that new rings on a fresh bore usually takes 5 to 8 runs to bed in.

A useful tip for setting the clutch spring preload: Fit the plates and pressure plate with a coating of oil on them Set the free play for the push rod Set the clutch spring preload so that there is just enough drive through the clutch that you can kick it over compression with the kickstart without the clutch slipping That will get it very close to perfect before you take it for a cover-less test ride. The last two bikes I did, did not require any further adjustment after using the kickstart test method to set the spring preload (M49 Sherpa T with Barnett plates and M138 (350) Alpina with Bultaco plates)

As well as fixing the hub and basket, I would be fitting a set of Barnett plates. They are flat and because they use friction material, you can run with less clutch spring preload without slipping. You would have noticed that even the flattest standard plates have high and low spots. If you compare the Bultaco plates with the steel plates in many other bike clutches, you will see that the Bultaco contact pattern is on the inferior end of the quality scale. I have seen standard Bultaco plates ground flat on a surface grinder, which improves the contact area, but reduces the thickness of each plate so makes them even more likely to put grooves in the basket fingers and the hub splines.

a word of warning about flexible sealant liners - if you use one of these liners then suffer structural damage to the tank, the liner makes it much harder to repair the tank (fibreglass, steel or aluminium tanks). In the case of metal tanks, you can't use any process that involves heating for the repair. In the case of damaged fibreglass, the repair will be complicated by having the internal flexible coating. For fibreglass tanks like yours I recommend lining with either petrol-resistant polyester resin, or with epoxy resin. They are available in a viscosity grade suitable for lining our tanks using gravity to spread a thin layer over the internal surface. I've successfully lined many 1960s and 1970s Spanish fuel tanks with epoxy. I originally started lining them because the fibreglass was in poor condition internally and I was worried about possible petrol leakage damaging the paint scheme I was about to apply. That was quite a while ago now. The new components in our petrol are now another good reason for lining them with epoxy. I use this stuff bought from our local boat shop http://www.westsystem.com/ss/

The pressure plate travel is not much on a Bultaco clutch, so the flatness of the plates is very important for having it release fully.

I suspect that this might be a Barnett clutch kit http://www.inmotiontrials.com/product/clutch-plate-set-all-models/

what bike are we talking about here?

Also you may not have enough clearance in the backing plate axle hole to allow the shoes to be centered in the drum

Teikei Y26P as fitted to the first model TY250 (now known as TY250A) main No 112 Needle Jet S-85 Jet needle 5C9Z Clip position 3 cutaway No 3 Pilot jet No 50 Air jet 2.5 Starter jet No 90 Air screw 1.5 turns Float level 21 +/- 1 mm

If that is a TK carby (that came on the 1973/74 TY250) that you have, I can give you the jetting specs, but they will probably not be right for the 320 motor

Cable and mechanism both need free play

Yes you should check the adjustment. If that is OK it probably needs new springs and/or plates. New oil does not usually make any difference to a clutch that has sagged springs or worn plates.

There are clear period photos of Bultaco Wasps in "20 years of twinshock trials" volumes 2 and 3

if you have a leaking crank seal on the drive end of the crankshaft, you can test for it by measuring the quantity of oil that comes out when you change the oil. The discolouring of the oil with use you describe sounds pretty normal to me. If the oil is doing its job, it holds the fine wear particles from the clutch plates, bearings and gears in suspension and these fine particles change the appearance of the oil. Also if you are looking at the oil soon after riding the bike, the oil will be full of microscopic air bubbles, which also change the appearance of the oil. As far as change frequency goes, base it on the number of times you have to refuel the bike, or number of riding sessions, rather than in elapsed time. However if you don't ride much, the 6 months oil change is a good idea because oil absorbs water from the atmosphere whether you ride the bike or not. If you ride in water, check for contamination of the oil after each ride and change it if there is any water contamination. Trying to answer your question about a possible link between the condition of the gearbox oil and a smoking exhaust - no, old oil will not leak more easily through the crank seal than new oil. Maybe you are worried that crankcase fumes are leaking past the crank seal and discolouring the gearbox oil? If this is a problem you could test for it by extending the gearbox breather tube and putting the end of it in some water with the motor running and see if bubbles come out. Another thing you can do to put your mind at rest is to take note of when the pipe smokes. As has been mentioned earlier, oil condenses inside the exhaust when you ride as if you are competing in a trial, and it revolatises when the exhaust gets hot (when you ride up a long hill, or ride along a road at speed). You should see more smoke when the pipe is hot, compared with when you are puttering around gently. It is good to give the bike a hard run and heat things up, because apart from cleaning out the exhaust, the piston rings may otherwise become gummed into their grooves.

maybe because the TY fork tubes were bent in a frontal impact????

Standard TY250 twinshock frames have straight front downtubes. That one has either had an accident, or someone has deliberately bent those tubes to change the steering head angle. Have a look with the tank off and see if the top tube is bent too. I've seen a few with the top tube bent from a frontal impact

125mm from the top with forks fully compressed and springs removed works very well. If you don't care how well the level is set up, the A model has a different volume to the BCDE models and my specs sheet for the C model says 162 ml/leg of 10, 20 or 30 wt oil. Unless you are pretty heavy, 10 WT works well. If you are heavy then go for the 15 WT. Gearbox is 1000ml and any lightweight gearbox oil is OK. I use Castrol VMX 80 or Castrol MTX and they both work fine. Book says 10W-30 motor oil but remember the book was written in 1976 and things have moved on a bit with oils.

I agree with Jon about the financial benefits of the old bikes not depreciating. Trouble is I tend to spend any savings on restoring multiple old bikes

It looks like it was set up for a small rider with the fork tubes slid through the clamps like that. Unless they have limited the fork travel, the mudguard will smack into the lower triple clamp. That might be why they don't move far Standard wheels on Cota 200 are 21 inch and 18 inch. That front hub is a Honda design that was introduced to Montesa trials bikes in the early 1980s, and may be from a later model Montesa 242 or 349. Those front hubs are notorious for the spoke flanges breaking

I generally practice ride after it cools off a bit in the evenings just before dark I wear a thin T shirt and long cotton work pants in summer. If you think you might crash though you should wear your elbow and knee guards. I don't do huge obstacles or take chances in my summer trials clothing, its really just for fitness and to maintain riding skills. Chilled water in the camelback helps if you are riding for an extended period The creek cool-off technique works well too Another thing to do is to go out straight after a storm while it is still coolish Mix up the trials practice with a bit of trail riding to get your body temp back down