peterb

Hi Tombo, That's a really smart looking Gasser. Well done. It'll stand out at a trial. Remember to run it in for 8 hrs, change the gearbox oil too. Bye, PeterB.

Hi there, The problem is most likely the radiator cap. As these get old, the seal deteriorates and so the coolant is not allowed to get up to pressure. try a new cap. Next thing to look for would be if the head O ring seals were passing, then the coolant would be over pressured, you may see this as white smoke from the exhaust system. I don't think there are any manuals for these bikes, quite a straight forward motor to work on, just need to ask on here if you need help. Bye, PeterB.

Hi Olly, Just a small point, what year is your 200? From 2005 onwards, the PRO uses mineral oil in the clutch actuation system, not hydraulic oil (DOT 5 for example) - just so you didn't add to your current problem, which I still think is related to the clutch pack height, as advised by Jon. When looking down into the clutch, the lever fingers should angle upwards/outwards more so than resting in the horizontal plane. They act like a kids see-saw except the pivot point is a central ring. If the levers are showing to be angled outward, then they have a good mechanical advantage and will provide an easy to use clutch actuation. Bye, PeterB.

Hi Goreboy, You can do both seals from the outside, look at the previous posting for the clutch side. Best to have someone help you if you haven't done this before. To replace the mag side, you need a flywheel puller that fits your particular bike - not the same puller as a PRO motor. If the mag side seal had gone, there would be an oil mist around the seal and symptoms of running lean. Very carefully prise out the old seals without damaging the housing and the crankshaft. Get the proper seals, hi temp viton. Bye, PeterB.

Hi GJ, It's summer here, bit warmer than up your way. We've had a bril summer, been well over 20C for the past 8 weeks or so, in fact, too hot for riding. Started to cool a little now which is a good thing as we are trying to get one of our lads (ex Cumbria rider) ready for the Scottish - a proper trial! Practising every weekend and into the gym most nights, wet rocks, dry rocks and more rocks, all sections uphill. Ta ta, PeterB.

Hi GJ, Thanks for putting the link in, all filled out for 50:1 and super petrol. Years ago, some well informed guy out this way advised he had seen research on 2T fuel/oil mix and concluded that the max ratio was approx 63:1 for efficient lubrication on a 2T motor. Anything less could lead to trouble. I'm a bit old fashioned in this respect and I like to be sure I have plenty of lube for my motor, at 50:1 there hasn't been any plug fouling problem over the last 25 years or so. I'd tend to stay with more, rather than less oil in the fuel. Bye, Peter.

Hi Jay, Welcome back to trial riding. The PRO model was released for 2002, is your bike an Edition model? The motor would then have a separate round clutch cover approx 160mm diameter. Riders use pre-mix anywhere from 50:1 to 80:1, I've always gone with 50:1 without any problems. Tyre pressures, 3.5 psi rear, 5 psi front, cold pressures. Fork oil 5 weight, approx 280ml per leg, there is a height measurement, have a look on the Gas Gas USA website, stacks of bril info. Sag settings - well on the rear shock I usually have approx 15mm sag. Bye, PeterB.

Hi Goreboy, Was there a lot of oil coming out of the crank drain plug? - are you sure it was the crank plug, the one closest to the front wheel, don't mean to sound condescending or whatever the word is, but better to check this out first than to get deeper involved with a stripdown. I've never seen lots of g'box oil exit from the crank, if it is so, then at the minimum you'd need to replace the clutch side crank seal. You can get there by removing the clutch, if you have an air drive unit or impact driver, you can remove/replace the clutch centre nut easily. Do not wedge the clutch centre with a screwdriver or pair of pliers! those clutch spring posts break off quite easily. You can also get the centre nut off (it has a tab washer) by removing the pressure plate, then using a small G Clamp, clamp the plates together. Very very carefully, trap the clutch basket to remove the nut, or try leaving the bike in first gear. The crank gear is fairly tight, needs a 30mm socket. All threads are RH. Do not lose the ball bearing from between the clutch pushrod and the mushroomed rod follower. Be very careful when re-fitting the outer housing to ensure the white plastic gear is properly engaged before firmly pressing down the cover. Unless the bottom end is grumbly, I'd leave the mains alone at this stage, sorry Craig! Big ends are very sturdy and not known for premature failure on these bikes, only need replacing if the motor has been drowned and not had the water drained. Only problem with the clutch on these bikes is if the fibre plate material has started to lift of the metal backing - have a good look. Good luck, PeterB.

Hello Olly, Usually, a heavy clutch on a PRO motor is indicative of the plates swelling - usually by contamination with water or incorrect gearbox oil. If the clutch pack height is correct, and more importantly, the clutch basket lever height is within tolerance then this department is ok. Only other problem I have found is the clutch hose being nipped causing a restriction in the ID of the hose. Have a look under the tank around the headstock area. Bye, PeterB.

Hi there Sheffieldtrials, There are two bushes that run inside the 2 pairs of needle rollers, these are the spacers that you refer to. These two bushes are inserted into the inside of the swinging arm such that the larger diameter faces up to the gearbox mounting area of the crankcase, they don't fit the other way round. There are no more spacers in this area. I liked the GT32, my first Gasser. Had stacks of bottom end go but didn't rev out too high. Was a bit rich on the main jet. Bye, PeterB.

Hi cymroboi, My sister has recently just moved out of Wales and into Oswestry somewhere, nothing to do with setting the timimg though! On the PRO motor, there is an ignition sensor mounted external to the flywheel. It is mounted on a bracket, you can slot the bracket holes and rotate the sensor anti-clockwise to retard the timimg, (Or advance the other way if you need more) it doesn't take much. I really like the motor with a Hebo flywheel weight fitted, it's an extra 750 gms, easy to fit, just need an M8 x 1.25 tap and 6.8mm tapping drill. Instructions are in the box, complete with plastic cover spacer and all mounting screws. Best to set the gap between the sensor and the flywheel to approx 8 thou. You can file the holes in-situ with a rag over the important bits of the motor, doesn't take long at all. The standard throttle is a white tube, is that what you call a fast one? Ta ta, PeterB.

Hi Trialstime, I haven't owned a Scorpa SY250 but rode one in a 5 day trial in France (bit like the SSDT but far, far warmer and also with the most fantastic scenery) and have been working on a friends bike for some time now. The French bike was a standard 2007 model, I thought it worked well but was a heavy bike to change direction in dry, rocky sections and I didn't like the rear suspension action. The motor worked well but had too much flywheel weight, standard is approx 3,000 gms, my friends bike is down to 2,650 gms and this feels good. You can turn a step down on the OD of the ignition flywheel to reduce the weight. Gearing is fine. We fully advanced my friend's SY ignition by rotating the backplate though I feel this is too much, the motor is a lot more peppy but a little jerky now at the bottom end. There is a very good Scorpa site in Australia, might be called hellbikes or similar, there is a good section on tuning. Haven't heard of the centre box rubbing. The rear silencer (muffler) tends to burn your leg on road sections, good to fit a carbon fibre protector there. Also worth getting a protector for the exhaust pipe. Bye, PeterB.

Hi Angus, Fuel/oil at 50:1 is fine, I've used the same mix for over 20 years and never been a problem. It's just that with puttering around doing trials sections the exhaust doesn't get a good cleaning out and as Slapshot said, it builds up in the silencer. Bye, PeterB.

Hi montaco, Can you confirm the place, is it Reporoa? if so this is near Rotorua and fine for Tauranga trials. If it is Raparoa then I don't know it. There is a farming family at Reporoa who are trials riders and this would be a good contact, if it is the right place! Let me know and I can either give Tim the details or direct to you. butt mooar - There used to be a very small following of sidecar trials around the Wellington region, check out their local website - Ixion motorcycle club, best to google it. In the South Island, there was another following - I think in the Christchurch area, try looking for the Pioneer Motorcycle club web site for this area. Bye, PeterB.

When I lived in the UK during the 70's, Brian was in Stokesly - not sure if he is still there. I was in the East Yorks team with Brian (and Peter Cartwright, Jack Galloway and Rob Edwards) in 77 I think for the Inter Centre Team Trial, Yorkshire won as usual but we came second, was a good trial. Brian was riding the then new Suzuki RL250, I had one for a while but after 6 months got back on my beloved Bultaco again. Can't go wrong there. Glad to hear he is still out and about. Cynical, if you are from the area as Hutchy I may know you too! I'll PM you to see who you are! Ta ta, PeterB.

Hi Ed, My 348 is over in the school workshop, I have an original rear guard with it and will photo that area for you, then ask Tim to show me how to post the photo on here, thanks Tim. Bye, PeterB.

Hi egsmyth, Best mod I found for the Sherpa forks was to make up a spring spacer that recess's nicely into the fork cap and spigots into the spring, about 25mm long, nylon or aluminium as the forks tend to sag a bit. I use 10 weight oil. 20 is thicker and may give you too much damping action. Some lads tried fork tops with air valves back in the 70's but never to any brilliant effect. The 348's have them as standard I believe. The air pressure supplements the spring action, usually about 10 to 15 psig. Bye, PeterB.

Brilliant photos, you certainly are a well travelled, and fortunate trials rider. Can't be many riders who have ridden around zebras and giraffes, I guess t'other shot is a springbok - is it Tim? Bye, PeterB.

Hi DabDab, That great guitarist is Andres Segovia, born in 1893 down south in Linares, Jaen in Andalucia. A maestro in the true sense of the word. Segovia the city was once the base for Ferdinand and Isabella, the King and Queen of Spain in the late 1400's, "Los Reys Catolicos" (The catholic kings) who were famous for pushing out the Moors from Spain and supporting Columbus on his travels to the New World. That 349 is a stunning looking bike. I had a 348 in the 70's and always thought the footrests were too high, even after lowering them I couldn't get on with the bike and after 3 weeks traded it in on a new 325 Bultaco that I kept for the next 10 years. Bye, PeterB.

Thanks Ed, There is no rush, you could PM me the photos when you have time. I am flat out getting my latest project ready for a practice this weekend! Thanks again, PeterB.

I think it's earlier than that Scorpa3, looks very much like a 1993 250 Gas Gas with USD forks, we can rebuild it! The fire has charred the rims looking like a black anodized finish. A friend was burned back in the UK when working on his Ossa, wasn't too bad though and he recovered well. It's the fumes that are highly volatile, still there aren't many smokers who ride trials these days, are there? Another friend here in NZ had a garage full of bikes that mysteriously all went up in flames, there was little left of his PRO as he had oxy acetylene bottles in the place that went up too. There was only the frame left, forks and swinging arm melted, and most of the internals of motor where intact. Bye, PeterB.

Hi Ed, thats very nice of you to go to the trouble to photograph the rear hub, thanks. Not quite what I was looking for though, I was trying to find out what the set up was inside the rear hub, on the brake side, to see how that side wheel bearing is housed. Mine has a bad fitting steel sleeve fitted into the aluminium casting, doesn't look original. If you have the time, could you photo the inside of the hub please. Bye, PeterB.

Hi spud plark, Thanks for posting the photos and the Bultaco link. I had a look for a photo of the mag side of the 4T Bult but nothing there, wanted to see how the drive was accommodated for the camshaft. I'll try the guy who posted the original info. Bye, PeterB.

From the initial symptoms, it sounds to me like the mag side crankshaft seal has failed, letting air into the crankcase and providing the lean mixture syndrome. Have a look under the flywheel and see if there is a little oil mist around the seal. Doesn't take long to replace. Other problem may be a split in the rubber inlet manifold. Bye, PeterB.

I've never seen the Portus Montesa before, nor even heard of the Rotax Bultaco - which does look a little large in the stretched out frame. Excellent postings. I saw the 4T Bultaco aslo in Todotrial, it looked like a Honda TLR250 top end on a Bultaco M199 bottom end, got me thinking for my next project! I always fancied building up a 4T with a spare Bult bottom end, I wonder where the oil pump would be driven off and how to get the oil onto the camshaft. Bye, PeterB.