stork955

Gday all, As Copemech says, be careful opening up plug gaps in bikes, especially magneto ones like ours, they don't have great reserves of "grunt" like a battery/coil system does. Modern Battery/Coil ones like in your car can successfully hit 50K plus volts at a very high current (7 amps or more). This is to fire the very lean mixtures (15.1+) required by road cars. Most cars these days in fact use 1 coil per cylinder to help accommodate this.On the bikes however the system is limited in current and voltage by the source coil which makes relatively low output to drive all the ignition. Its like fitting a resistor plug cap to early systems, this can take the CDI out as a result of drawing more current than the system can safely handle. A wide plug gap has the same effect, the voltage required to ionise the gap and commence spark increases massively with wider gaps. Yes, its true that a wide gap can sometimes mask off a misfire or other symptom but this is temporary as you may well be driving your gear into extinction. Also, keep in mind that spark plugs rarely fail on their own (I know this as I have been fitting them for nearly 30 years now, for a living by the way) Problems are generally caused by some other issue like overly rich mixtures (Carb issues, air cleaner issues) and oil fouling (in 4 strokes mainly, poor oil control - rings, valve guides/stem seals) so if your plugs are failing on a daily basis, don't blame the plug, look for the actual cause! (Think about your car - do you change the plug every time you drive it? If you do you are looking for a problem somewhere as most modern cars and road bikes get 40 000km plus from a spark plug. Considerably more life than we expect from a relatively limited-use trials bike). All plugs are pretty much good these days, of course I have my favourites but that is based on 30 years worth of daily experience seeing what works well and what doesn't. Given that all else is OK with your engine any "correct" spark plug will do the trick for you. Hope that all makes sense, Cheers, Stork

Gday, If it was the wrong size ( I assume the wrong length ) I'd run it for a little while and have another look before changing anything else. Was it running OK? Cheers, Stork

3 years on the good 'ol BP8ES or whatever the Techno runs. Still showing no signs of wear on the electrode. Fouling is either an incorrect fuel mixture or the wrong plug! As Copemech says go with the manufacturer on resistor or non-resistor. If you want to spend more its up to you of course, but I don't see or have ever found a need to spend $$$ on spark plugs. Cheers, Stork.

Same for me in all my 2 strokes. Works well. Stork

Woodruff key sheared is most likely culprit. Pop the flywheel off and check it out. Use the proper tool - it will save building in any new problems! HTH Cheers, Stork

Pop the whole lot off, you need to replace the base gasket anyway if its disturbed. Have a look and get it measured properly (piston and barrel) This will remove any doubts. It does sound like the bottom end is OK. My Techno has a dull knock when hot under load, the piston is at its limit clearance wise and the ring grooves are about knackered, which I'll replace once I'm finished tinkering with my TY's. Probably a similar thing by the sounds of it. Cheers, Stork

What colour did the plugs have when they came out? If they are wet and black looking, there is a fouling issue which may be caused by Air filter or Carb. Always make sure you are using the correct plug, 2 strokes last seconds with the wrong one fitted! It is really important. Check it out and let us know. Cheers, Stork

Cool! I rode my 250A in its first Trial a couple of weeks ago too. If your forks are bottoming its the springs. Don't change the fluid, it only affects damping and not the ability to not bottom out. Go new springs or a spacer - don't go too big with the spacer as you may get it spring bound (the spring collapses fully onto itself and so becomes solid). I made an Alloy bash plate for mine which seems to work well, it didn't have the original anyway. It was dead fun to ride, makes you think but tractored around beautifully all day. My 175 is a week or so away from its maiden voyage next. Good luck with yours. Cheers, Stork

A quick answer - No. Spark plugs aren't magic, so spending heaps on them wont unlock horsepower. If there is an issue it isn't the plug, the plug will only be a symptom. Stick tp the recommended one and it's all good:-) HTH Cheers, Stork

That sounds like Hot Soak. Common problem. Try using just a small crack of throttle when hot starting - it leans it out slightly to compensate for rich fuel mist floating around in the inlet manifold. Costs nothing! HTH Cheers, Stork

Gday Neo, any discernable movement in the crank in any direction, and any "up and down" in the rod is no good. Also check rod side clearance - no more than around 25 thou between the rod and crank wheel means a rod kit is in order. Pretty easy to do, just use heat instead of large hammers! And for a rod, get your local bike shop to do the job, it takes the worry out of it. Cheers, Stork

Gday, sounds more like a trigger but it would be best to test them both to see which one is at fault. Use a standard multimeter set to AC volts, use a 10 volt scale for the trigger (pulser/pickup) and 100 volt scale for the stator. HTH, Stork

Ummm, ok - I havent seen one of these apart so I'll try and give you a generic guide. Normally I will mark the stator before removal and just line up the marks on reassembly but I have to assume you haven't done this. For basic fitting the stator will really fit only one way around - use the wiring loom as a guide to show the orientation. Fit the retaining screws/bolts/whatever. You may be able to "ballpark" it by lining up the existing bolt marks - do so if you can. Otherwise go midway in the slots. I think your bike is electronic so - refit the flywheel. Now you need a timing light. Get it started and check the marks for alignment on the flywheel and the case (at the top somewhere) at idle speed. If they line up -great. If not, stop it, remove the flywheel and move the plate a bit in the direction you need. Remember that to advance you go against direction of roataion i.e. anti-clockwise. Vice Versa to retard. Refit and repeat. Keep going till you get it and your done. Someone let me know if this bike is a points one and I'll give you the procedure for that. PS -sometimes (always actually) it helps to give a year model as there are differences sometimes that matter! HTH Cheers, Stork

Gday, and Yes, side clearance is vital. More than about 25 thou is too much. Specs say 0.6 mm which is 24 thou! ( Not a bad guess...)Keep sticking larger feeler gauges down the side of the rod till you can go no further. If you are replacing one bit you may as well do the lot as they all wear together and it must be dismantled completely anyway. Dont forget to check the small end also. This overhaul work is best done by someone who does this all the time, you need a bit of gear to press it apart and back together, and then true it all up. Yamaha will have all the bits you need. HTH, Cheers, Stork.

Gday, that sounds about right to me. Anyone got a better idea? I just spent $90 Australian for a set of rings for my TY175. Bike parts are not cheap considering I have bought 4 cyl car kits for not much more... Its a 10 year old bike so I dont see that as too bad either. You wont have any other real issues with it, apart from standard maintenance. Its a good opportunity to clean the exhaust, check the reeds and fit new ones if needed, and generally give the old girl a good going over so you will have peace of mind for riding. Cheers, Stork

Mine has a rattle under load when its hot. The piston to bore clearance is on its limit and I'll fit a new piston sometime soon. Its probably the same with yours. Cheers, Stork

Gday, you must use a gasket between the cases, it affects end float on the shafts inside the engine. Many bikes use gaskets (Suzuki) and many don't (Yamaha) so it is no real issue. Make sure the gasket surfaces are very clean before reassembly. A kitchen scouring pad (one of the scotchbrite type, not metallic) works really well for this. HTH, Cheers, Stork

Gday, sooty plugs indicate rich mixture. Dry and Black is fuel, wet-looking and black is oil. Which is yours? Cheers, Stork

Gday, that thing is a centrifugal filter, they work pretty well on the early hondas. Give it a good clean out while you're there, most people dont... You may need to use a screwdriver or similar to get the rubbish out from around the edge. The tools for them are quite cheap, from Bikebandit.com or Denniskirk.com etc. or other sellers of aftermarket parts and tools. Get a flywheel puller at the same time. Cheers, Stork.

Gday, have a look at the spark plug and see what colour it is around the tip. This might give a clue as to what's going on. Cheers, Stork.

Gday, they are the same thing. Coolant has Anti-freeze properties and Anti-freeze is coolant. Cheers, Stork

After you have have checked all above - Clean exhaust system? Cheers, Stork

Gday, have you checked your valve clearances? One tight one will do that. Cheers, Stork

Gday, first thing to do is make sure the air filter, exhaust and spark plug/ignition timing are all clean and correct for the bike. Doing this now will save hassle later... Next check that the carb slide is almost fully down - you need some freeplay in the cable and the slide should be set roughly 1-2 turns in from fully down - this will make sure that the bike is actually running on the idle circuit and not up on the needle. Then - if your airscrew is right in and it still runs you need a larger idle jet (the air screw actually restricts air on this carb) and it needs less air so this is the same as needing more fuel. The actual jet size you need will depend on many things but my suggestion is to go up 2 sizes from what you have now eg if you have a 35 go to a 45 and see what happens. Your airscrew should end up about 1.5 turns out from lightly seated when it is sized correctly. Then check for clean throttle response as you open the throttle. If it stumbles you can either play with the idle mixture or better still change slide cutaways. HTH, Cheers, Stork

Gday, If the plug is quite clean and white looking it is too lean. Try your needle back in the 3rd position (which is the usual rule of thumb spot) and reset your timing back to where it should be. Let us know how that goes. I dont have specs for needles on those, perhaps someone will chip in and say if its correct. It all sounds like needle to me. Cheers, Stork