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Steve, You have a 2003 250 Pro as I remember, it appears that somethings not right in the kickstart system, it should not act that way. You might want to take the sidecase off and take a look. Might be a tooth missing from the kickstart/idler gear (it usually will make noise, so this might be unlikely) but theres a U-tension spring in there that may be broken, only a guess, but worth a look. Jon

300-320cc's of 5-weight fork oil per leg. Jon

Hi Chris, and welcome from the "other side of the pond". Sounds like you have, with all those classic bikes, what we call, having all the bases covered. I think you'll find the Scorpa will not get you in trouble as fast as the RD. Cheers. Jon

Makes sense, thanks for your input. I posed the question to a retired Chemical Engineer friend of mine and I'll see what he comes back with. In other recent research, I came across a water-less coolant called "Evans NPG+" that's used in racing and other specialized engines: http://www.evanscooling.com/html/npgPls.htm . Boiling point of around 370 degrees F. as I remember, and designed to run without pressure (or little pressure) in the cooling system. When I go to pick up some race gas tomorrow, I'll see if I can get some info from one of the racing suppliers and maybe pick up a gallon and do some testing on it in some of the high-stressed four-stroke racing engines (MX & Quads, as you can't run it in the Roadracers) and maybe try some in my poor old 280 Pro test mule. I'm looking for better thermal stability in the four-strokes under racing conditions and since Trials is headed down the 4S path, it might solve some future problems should they arise. Jon

Many years ago, I had ocassion to talk with Jeff Smith about the Ti BSA frames and he said the Ti wasn't the problem, it was the welding techniques available. They would patch the failed welds in the field and they would just break faster. Not many high-level TIG systems to drag to the races in those days.... I know that Titanium is a highly reactive metal that forms compounds that can result in structure problems. When heated in the presence of air, the weld surface contains brittle carbides, nitrides, and oxides, each of which can reduce the fatigue resistance and notch toughness of the weld (Ti does not like to be scratched from what I'm told) and heat-affected zone (HAZ). You also need to flush the back of the weld of air (like stainless steel) to get a sound weld. I had one of my CAW (Certified Aircraft Welder) buddies tell me that Ti needs the "white glove treatment" as Chlorine from the perspiration on your hands can create spot corrosion and lint-free gloves are often used after final cleaning, before welding, to get a top quality weld. I think I'll stick with TIG and ChroMo steel, I don't think I ever owned a pair of white gloves.... Jon

No problem with any questions, ever. The "hot start button" is a device used mainly in four-stroke carbureted engines used for off-road. It is a special passageway that allows cooler ambient air into the manifold system to aid re-starting a hot engine after stalling (the four-strokes make and retain a high degree of "body temperature" compared to two-strokes). You have a two-stroke engine which does not incorporate a hot start device, so no need to worry. Jon

Peter, have you had any experience with a product called "Redline Water Wetter"? I've use it in my bikes since I had done some research with it in the roadrace bikes I built. I ran straight de-ionized water as they can't use ethylene and propylene glycol anti-freeze in their cooling systems (very nasty stuff when spilled on a racetrack) but with the Redline (used for it's anti-corrosion agents) the telltale temp tapes registered about a 15-20 degree drop in engine temperature and in a couple of the engines I could dial in a degree or two more static ignition advance for better drive out of the slow corners. It advertises that it " doubles the wetting ability of water", so I assume it affects the surface tension somehow. It also says that it "reduces cavitation corrosion" and I've often wondered exactly how it worked (technically speaking). Any ideas? Jon

Are they actual "shavings" or dark metallic powder-like particles? Either way it would be a good idea to pull them apart for a good inspection. The dark powdery particles (they usually collect in the bottom of the lower leg) are normal as they are deposits from the outsides of the springs that rub on the inside of the upper tube (a lot of riders mistake them for dirt, but a quick check with a magnet tells otherwise). If you look closely at the springs, you'll see how the outside of the coils, mainly in the center of the spring, take on a polished look. The stiction at the bottom of the stroke sounds like a bent upper tube and you'll also probably need to replace the bushings as a bent tube will damage the bushings if the forks have been used for a time with a misaligned tube. Jon

The one on your bike should work fine, especially if you are just starting out with one of the newer, lightweight bikes. The PWK is a good carb if you are looking for a little more performance and works very well at high-altitude for riders like the ones in Colorado here, but you will probably find the PHBL to your liking. Once set, it's pretty bulletproof and is easy to adjust for changing conditions. With my talent level, I'll probably need the extra power of a PWK28 on my bike as soon as I learn to walk on water without sinking..... You can swap out starter jets if you can get a larger one from your dealer but most of us drill the old ones out as they are just used for starting and do not need to be lathe drilled for precise accuracy. When you take the floatbowl off, you'll see the starter jet at the end of the brass tower with the black o-ring towards the end. Remember, the trick is to NOT open the throttle when starting cold (with the "choke" lever pulled up, of course). For some, as yet, unknown reason, I often find the Pros tend to act "cold blooded" and if my bike sits for any length of time, like when I'm walking a long section on a cold day, if it does not start first kick, I'll need the choke on (it's not actually a "choke", but an enrichening device and when you hold the throttle open, it will defeat it's operation) to get it to quickly fire up. Jon

Steve, your Fantic had a PHBH carb, also known as the "large body Dellorto" and the oval-slide "H" carbs were troublesome to tune, at best. The Dellorto you have now is the PHBL and is quite different. The oval-bore PHBH was used by GasGas on the 96' JTR370, which I had, and promptly chucked in favor of a modified KX80 carb (a PWK28 with the adjustment screws moved over to the other side). My friend with a Fantic was very happy to get an essentially new PHBH carb for free..... Peter's advice on the starter jet is sound. I also had a #60 (some come with a #70) and drilled mine out .031", roughly equal to a #80 and my Pro starts second kick every time. Just be sure to NOT open the throttle when kicking it over. It should start and immediately go to a slightly high idle to warm up and you can usually flip the "choke" lever down shortly after. It's normal for the Pro's to have a little clutch drag and it does make finding neutral difficult, if not impossible sometimes. It does, however, keep the driveline "loaded" and precise engagement in tight full-lock corners will be smoother than just about any other bike that totally releases. If you have problem stalling the engine at low RPMs in a section, adjust the idle speed with the bike in gear and the clutch pulled in where you normally would (usually with one finger and back against the knuckles), not in neutral. Jon

I agree with Peter. The "normal" 75W oil is too thick and will generally cause a lot of drag. I did test a "75W" trans oil, Maxima 75W "clutch saver" oil, but for the life of me I couldn't figure out how they got a 75 rating on such a light oil. It did work o.k., but still was a little too "thick" and caused some drag. The Dexron would be roughly equal to a 7.5 weight oil (also works great in forks in the Summer if you need a little more damping action). Make sure you have a little slack where the lever adjustment screw meets the master cylinder plunger that goes through the rubber boot. A lot of riders used to cables mistakenly think that screwing it in more will give more throw/travel to the piston but it will have the opposite effect. Jon

(I'm assuming the last sentence refers to the forks, not the shock) It sounds like the forks need to be dis-assembled and inspected, provided you tightened the fasteners in a way that kept the forks aligned correctly and the problem persists. Generally, the two things that contribute to fork stiction at this level are (1) worn bushings and (2) bent fork upper tubes. I have seen lower legs hit hard enough to dent them and cause internal binding but this is, luckily, rare and a problem with the cartridge internals could also cause stiction, but is also unusual. After the forks are completely apart, look carefully at the bushings (these are the internal "bearings" that allow the tubes to smoothly interact). There are two in each fork, one at the end of the upper tube and one inside the top of the lower leg. They usually are steel, with a copper coating the a coating of grey Teflon (the Teflon is on the outer part of the upper bushing and on the inside of the lower leg bushing). If the grey coating is worn through anywhere at all, they will need to be replaced. The upper tubes are checked with v-blocks at each end and a dial indicator probe at the center area. The tolerance is usually .003", which does not sound like much of a "tolerance", but a small deviation at the top end of a fork equates a large deviation at the other end and it does not take much to cause binding. I wouldn't try straightening them yourself without special tools, like a diameter specific pressure plate (it fits the exact diameter of the tube) and diameter specific support blocks that prevent distortion and flat spots. A good suspension or machine shop should be able to do the job relatively inexpensively. Jon

I'm guessing that the recommendation for de-ionized water is to address corrosion, not cavitation issues. I looked at the photo of the pump housing and based on the areas of damage I'd guess corrosion, not cavitation (the process of formation of vapor bubbles of a flowing liquid in a area where the pressure of the liquid falls below its vapor pressure, and the rapid collapse of the bubbles produces a minute, but locally strong shock wave that can produce pitting). I've seen cavitation damage to impellors (and sometimes at the end of the discharge tube) but usually only the metallic ones, not the plastic ones that are generally in use in Trials bikes now. Perhaps the seam from the o-ring to the inner housing chamber is a good place for metallic salts in the coolant to collect? Another area where cavitation is a problem on motorcycles is in shocks, which is, in part, why they are pressurized as high shaft speeds will cause cavitation at the piston face. Not such a problem with Trials shocks as the shaft speeds are usually lower (so pressurized to about 140-170 psi) but a real problem with roadracers that run much higher shaft speeds (and are usually charged to 200+ psi). So, my guess is corrosion due to contaminants in the water. Jon

That's a possibility but you should still get a spark, just at the wrong time. Like you, I'm also kinda suspicious about 10 sec at full chat frying any of the components. I'm also assuming that a new plug (BPR5ES or better at .024") was installed as that's a weak spot after a run-on. The readings do not seem to be too far off (I usually never get the exact numbers on my meters that are in the diagram spec.'s). I might want to check all connections and grounds just to be sure and inspect the air gap at the magnetic pick-up. Probably the best way to stop a screaming Trials two-stroke is to use a gloved hand to plug up the exhaust and then the killswitch will work when the rev's drop down. They tend to auto-ignite when WFO unloaded. Jon

That is one of the best basic guides to the PH series Dellorto I've seen. Heck, Copey, PM me with your address and although I don't have any TC stickers, I'll find something for you! Jon

Doogzie, You probably have the Ducati Analog CDI system in your bike (no points, it's electronic) and a copy of the system diagram is at: http://www.trialspartsusa.com/diagrams/Duc94to96.jpg if you want to test the system components with a meter. Sometimes, electrical components will test fine when cold, but will malfunction with heat. Since your bike has probably had 13 years of use, you might also want to check the stator plate area for corrosion. Make sure the fuel tank vent is working correctly and you have cleaned and re-tightened all the grounding wires and cleaned and re-connected all the electrical connections (pay attention to the kill switch and plug cap, sometimes taking off the cap, cutting about 10mm off the end and re-connecting it works). It also may be fuel related (hense checking the tank vent) so I'd see if the petcock is flowing fuel well when in the "on" position and make sure the carb floats are not snagged and the float valve is flowing fuel. Try these to start and I'm sure others will have some good suggestions also. Jon

No problem, your English is fine (and actually better than some people here in the Midwest...). What you are looking for is a special socket tool in the GasGas parts listing, "Vaso Con Esparrago Emb. R-7 E", and it's part #MT280350009. You can also probably find the same socket at any good tool store and it will also be known as a "12-point, 7 millimeter socket". Cheers. Jon

Yep.

Ask your dealer for a banjo bolt #MO106000, which has the bleeder nipple on it. Jon

We usually ran about 650-700cc's and Dexron ATF seemed to work well. Change it often to keep it fresh. Jon

This should help: 1998/99 TX270 2000/01/02/03 TXT280, TXT280, TXT321, TXT280

I think your bike has the radiator mount switch (#BT280437065) rather than the hose-T mount (#MO1020003) (I got two to compare). The rad switch looks like a grounding switch so you might check where the wire is grounded. They are pretty simple and my guess is a loose connection somewhere. If you have to replace it, you're probably lucky as the new type switch appears to be about 1/3rd the cost of the old style. I haven't had reason to check one of the newer type switches, but it looks like you can check the fan by grounding the wire that goes to the fan from the switch (notice the grounding connector on one of the wires). I'd check the coolant level and the head capscrews for tightness before you proceed (8 to 10 Ft Lbs or 11 to 14 Nm) just to be safe. Here's a photo of the old style switch (above) and the newer type (below).

Some of the newer engines do not use the T in the hose but the thermoswitch is mounted directly in the top of the radiator. I agree with Ishy, you may need to put some time and load on the engine to get the fan to come on, especially in this cold weather, that is, unless you live "down under" and get to ride around in t-shirt and shorts all the time like Mick Andrews, and not slog through the ice and snow like we are..... Jon

Braydon, Probably the easiest way is lay the bike on it's side, take the clutch sidecover off, and slowly pour the necessary volume of oil over the clutch. Make sure you use a new Allen wrench, or an old one with about 5mm cut off the tip to take off the small 3mm buttonhead socket screws and you will want, if possible, to use a hammer to rap the top of the t-handle to shock the screws loose, they are easily stripped. Jon