stork955

Gday, it would fire every revolution. Its called "wasted spark" and its very common. The only way to have it only fire once per cycle is to use a sensor on the cam as it rotates only once per cycle. Often tacho's will ignore the second spark because its voltage is very low while there is no "load" on the spark plug from compression. The injector pulses on and off continually, its the length of the pulse that determines how much fuel is injected. Each pulse lasts for a few milliseconds according to demand. ("on" Longer for more fuel, "off" longer for less fuel etc.)The system on these bikes is not overly sophisticated as far as EFI goes. Cheers, Stork

Gday, if the plug is a good colour and you can find no electrical issues (most likely plug cap etc as mentioned above) have a good look in the exhaust. A buildup of carbon inside can cause some issues, and all 2 strokes need a clean every so often. Cheers, Stork.

Gday, it still sounds rich. If you have to start it with some throttle, this is a clue. The spark plug is probably partially fouled at this stage, so it may pay to slip in a new one unless you can clean it properly (so the porcelain is white again). Something in the back of my mind says there is a weird thing you can do to those Keihins which makes them run like this... I'll have to think on it today and get back to you there. Cheers, Stork

Gday, you are on the right track. If fuel is running from the breathers its a float/needle issue. You can check that the float is OK by putting it in a jar of fuel and seeing that it floats "high". If it is puntured it will float low (under the surface) or sink. Its unlikely since the bike is relatively new but something I would check since you have already looked elsewhere. Double check the float level as well - you must do this by tilting the carb on its side to a point that the float just closes, not all the way upside down. This loads the spring in the needle and will give you an inaccurate level setting. Hope this makes sense, Cheers, Stork

Gday, I second what one old banjo said. However, you can get proper rubber grease for brake rubber components. Use that instead of brake fluid. If any components have been in contact with any petroleum product you will need to replace them. The pistons must be totally frre of marks and corrosion (otherwise they will leak). Good luck. Cheers, Stork

Gday, hard to say without hearing it, but I would say maybe main bearings (on the crankshaft) and the tapping noise is probably piston related. My old 99 Techno had a top end noise that never altered, even after a rebuild. Certainly a strip and some mains cant hurt, measure up the rest while its open.I dont think you will need a rod. Cheers, Stork.

Gday, It's a NH 350. I think also that the T suffix means trials. It certainly is a comp model with the high exhaust. The muffler is not standard. I should know this stuff better - I have some Ariels... Its around '54, If you dont want it, just send it to me and it will have a good home! Cheers, Stork

Gday, this is correct, the bigend comes as a kit with the rod. This may not need replacement but the only wat to know is checking after stripping down. Can you tell us more about the noise in the engine? Cheers, Stork

Gday, if there are scores in the cylinder it is definately a new one. Search for the massive amount of rear brake posts in this forum for more on bleeding. Good luck. Cheers, Stork

Gday, after the above work, if it still no good, you can strip the cylinder and clean it. It is not unheard of to have some rubbish blocking the transfer port. dont use any solvents, only warm soapy water and a nylon brush (old toothbrush maybe). Blow it out with compressed air. The transfer port is the smaller of the two holes above the piston, about halfway down the cylinder. Double check it is clear. Flush the thing with hot water and dry it out with air. Lube the piston and seals with brake fluid and reassemble. Check for clearance at the end of the piston and bleed from there. Good Luck. Stork

Clean the exhaust. It will need it by now. See how it goes after. Cheers, Stork.

Good find. Now measure that conrod side clearance! It may save you doing this job again soon when the bigend fails... Also - lubricate those crank seals with grease on reassembly. Cheers, Stork

Gday, when your crank is out have a feel of the bigend as several folks have said.Any roughness and its a new one. If that is OK, get a set of feeler gauges and measure between the rod and the crankshaft. There are no actual specs that I know of for the Beta but any more than around 25 thou is geeting too big. Again a new bigend is in order. If it is less, good news! Good luck with it and remember to clean all your gasket surfaces perfectly. Scotch pads work best for this job. Clean everything thouroughly with a solvent just before reassembly. Cheers, Stork.

Gday, Main bearings most likely. Big end possible. Measure side clearance on the rod. Eithewr way, engine split and crank out is coming up. Cheers, Stork

Gday, check all your engine mount bolts. Some loose ones could cause vibration. Cheers, Stork

Gday, what colour is the spek plug? Check this first. It may save a lot of time. Cheers, Stork

Gday, Further to Jon's post, you might clean the exhaust front to rear, especially if the bike has had a few years service, and that may well be all you need do to get it running well. A quick check will show if there is a build up of carbon in the header pipe, this is normal for all 2-strokes, and will effect performance greatly. There are many threads on exhaust cleaning for you to peruse if this is the case. Cheers, Stork

Gday, a black dry plug is fuel over-rich. This can cause oil consumption over a long time as it causes "bore wash". (Probably worn needle/needle jet). The fuel actually washes away the oil film on the bore and makes the rings wear prematurely. Iron rings are fine, the secret as you say is in the run-in. The first 10 minutes are the most crucial for any engine, it must be loaded to seat the rings properly. Engines running light loads also can do a similar thing like the generator above. Check your plug fouling issue first, it will be pointless doing any repair until this is OK. Cheers, Stork

Gday, further to the above, get it wrong and melt your piston in about 5 seconds. My advice is leave it be and get a larger bike if that is possible. Cheers, Stork

Gday, no. Synthetic oil wont cause glazing on its own. What sort of bike are we talking about? Cheers, Stork

Gday Marty, let that lever go! Check first that you have some clearance between the lever and piston. Then with the bleeder closed, gently and slowly just crack the lever -you move it around 10mm at the end and repeat endlessly. After a bit you should see some bubbles emerging from the ports in the m/cyl. Keep going until thesee bubbles stop. You might have to roll the cylinder around the bars a bit to get all the trapped air out that you can. It also helps to tap the line and fittings with a screwdriver handle to help the bubbles move up and out. When this is done you can finish off normally. Be patient, it takes a while. Cheers, Stork.

Gday, You have a high tension insulation issue. Cracks in the coil/plug lead/cap are all a source for this. A new coil or at least plug wire and cap will sort it. Cheers, Stork

The Lighting coil also powers the fan. You have one, its not working by the sounds of things. A rewind or replacement is your only option. Check for silly issues first though -examine the wiring all the way to the stator. Cheers, Stork

Gday, how is the cam chain? You shouldnt be able to lift it off the sprocket. Also, that motor in the CRF does have gudgeon issues. They are meant to be replaced every 15 hours or something like that if I remember correctly. Have a look into these areas. Cheers, Stork.

Gday Ross, heat is the go, and plenty of WD40 or equivalent. Cover the mouth of the crankcase up with a rag to stop the rubbish dropping into the case area. Give the ends of the studs a tap with the nuts on to protect the threads as well, this might help to shock the rust free. Good luck. Cheers, Stork