stork955

Gday, something is weird if it wont flood using the tickler. Is the fuel supply to the carb flowing free? If that carb has the filter under the bowl on the inlet is it clear? Is the float level parallel to the top of the bowl? Cheers, Stork

Gday, it is too rich. I'd remove, clean and check the carb, particularly the float level. Check the air filter also -is it clean and re-oiled lightly? Cheers, Stork

Gday, does the black plug look dry or wet? Cheers, Stork

Gday, 250 or 270 in these. Mine is a 270. Mine has stickers on the swingarm (Its a 99) apart from that I would have to look at the engine to see if there are distinguishing features. Cheers, Stork

Gday, what do you mean by "heavy"? Are they too stiff? or do they seem to stick? This might help diagnose what is happening for you. Cheers, Stork

Gday, a 13mm Mastercylinder on the rear is probably a bit too big. Hydraulics work like gearing - a big "driver" (front sprocket, master cylinder) moves a lot of distance but doesn't produce much power. A smaller one gives power but not as much movement. I think most trials rear m/cyls are 10mm or less in diameter. Same at the other "driven" end - small pistons or rear sprocket gives lots of movement but not power and vice versa. If the pedal is firm (not spongy) there is no air present so this seems the logical cause to me. Cheers, Stork

Gday, If you can measure the ID and OD and width's I can cross reference them in my book and give you a number/s. Cheers, Stork

Most modern 4 stroke singles have this system. Have a listen to a BMW F650, KLR, XR, CRF, DR, YZF, WR, RMZ, etc. In fact every modern Dirt bike I can think of... Most of them have a slight "rattle" at idle which is the weight not quite "swinging" out after decompression for starting. Very common. Cheers, Stork

Gday, have a look at the engine pipe as well. Most people forget these... I have seen them so blocked you could barely get a garden hose through the pipe. there are many posts on cleaning these out, do a search and you will find what you need. Cheers, Stork

Gday, not really on a 4 stroke. What heat range plug are you using? What does the plug look like when it is fouled - is it wet looking? Or is it a dry soot? This makes a difference in diagnosis, wet is oil and dry is fuel. Cheers, Stork

Gday, yeah stick with the Mikuni. Any carb will leak when its upside-down. There is no horsepower to be gained by merely swapping carb brands and you have to go through the pain of getting it set up. If you are looking for performance clean the exhaust pipe out. Cheers, Stork

Gday, a fine bike you have there! Oil is 70:1. (1.5% synthetic) Use ATF Dexron 111 in the transmission. All the fluids are under the front cover behind the fuel filler cap. Pretty reliable old bike (mine anyway) with usual maintenance. If you want an owners manual send me a PM and I can email you one. Cheers, Stork.

Gday, grind it much as possible, crack it ( I use a chisel) and knock it off. Use the old race to drive the new one on carefully. Or press the shaft out of the clamp, and press the new one back together all at once if you have a press. Pack them with grease inside the cage before fitting - Just wiping grease on the outside is not enough. Cheers, Stork

Gday, the fan on my Techno is a generic Japanese one, I found a matching replacement off a 250 road bike of some description. It would be worth looking around a wreckers(breakers) too see if you can match it up. Cheers, Stork

Gday, The lights generally run direct off the lighting coil, but indicators and things use the battery as well, to maintain a consistent voltage when the bike idles. Check the battery out and make sure all your connections are clean and bright as mentioned above. Also check the correct voltage and wattage bulbs are fitted. That should sort it out. Cheers, Stork

Gday, Give it a good decoke (head off) and while you are at it, check your Carb as Jon said above, and clean the pipe from front to back. It should run like a beauty afterwards. It is a 2-stroke, burning all its oil after all. Cheers, Stork.

Gday, it also might pay to have a look and make sure the radiator is clean - no rubbish blocking the fins so Air can flow through. Cheers, Stork

Gday Wally, you can vary oil amount which will change "springing". More oil = less "springy", Less Oil = more spring. The Air space acts as a spring on its own, so if it feels too stiff, try adding a small amount more of oil. Careful you dont go too far as too much will cause hydraulic lock at a certain point, when there is no more space to use up for the oil. The best way to do it is to measure the height of the oil in the fork with the spring removed and the fork fully compressed. I assume the Aprilia has the Paoli's on it with the spring in one side and the damper in the other. Perhaps you would only need to adjust levels in the spring side, but it might be better to both the same just to be sure. I would think in an older bike that 5 weight would be as light as you would need, but I could be wrong... Cheers, Stork

Gday, look at the spring first! The spring does the work, and the damping slows it down. If your spring is too stiff no amount of fiddling with the damping (compression and rebound) will fix it. Get that right for your weight and riding style first, and then fine tune with damping. Also check there are no mechanical issues - bent fork tube etc. Cheers, Stork

Gday - a quick way to measure piston height is to make a tool from an old plug. Knock the porcelain out of the centre. Tap the remaining steel bit with a 10 mm tap and find a long bolt to fit in it. I grind the end of the bolt round so as to not damage anything. Then, you can screw it into the plug hole, GENTLY find TDC using the tool, and either measure or calculate 3mm in from there, set the piston to that and away you go. My tool uses 10 x 1.5 mm thread pitch so for me 3 mm equals 2 full turns in from TDC. I hope this makes sense. After you have found the correct spot once, put a mark on the flywheel to save time for next time. I just use pencil, it seems to stay there OK. Cheers, Stork

Gday, interesting subject and I'm no expert... They are actually a Helmholz resonator and the size of the bottle and pipe work (I think) makes a difference. The Wiki thing is basically correct as far as I know but the primary purpose of the bottle is to "smooth" out pressure fluctuations in the inlet tract so it could help Reed engines. IIRC the old IT and Earlier YZ yamaha's used them on some models, as well as a few other bikes. The size of the bottle would affect the engine speed that the bottle became effective at, so you could "tune" the bottles' operation. I have a very technical description of the systems operation if anyone wants to read it. PM me if interested. Cheers, Stork

Gday, keep in mind that air is less dense at altitude and that power loss is inevitable. Mixtures do need to be adjusted and engines actually mix air and fuel by weight, not by volume. Turbo or supercharging is the only answer. Not too practical on a trials bike! It makes sense that the O2 sensor and cat converter are for a road kit to meet exhaust emission requirements. Most jurasdictions would require this these days. Cheers, Stork

Gday, the O2 sensor basically acts as a final check for the ECU to see if it has the mixture correct. Removing it will make the system "Open Loop" in that there is no "final check off". The System will adjust for altitude and air temperature quickly. It may affect fuel consumption but not greatly so. It will increase exhaust emissions. HTH, Cheers, Stork

Gday Steve - good move there, thats the best way to go. Test stuff as you go too, the crank should spin nice and free and the tranny should shift through all gears. Keep in mind that you will need to rotate the shafts to get the box to change properly, this is normal. Good luck, Cheers, Stork

A few stiff drinks may help the girding of the loin move to the positive! ( And a night or two away from it...) Good luck, Stork :-)