Fuses under tank one on left blown one on right welded in, just had new piston small end bearing,koso temp guage, rev counter with lythium battery so no power from that thou

This should be for 2 cycle oil injection , find a owners manual online for proper oil ...

Check the fuse panel under the dash and the power distribution panel under the hood for any blown out fuses.

Sounds like you are running lean at the top end. Unless you are a moto-psychic, proper tuning gear is important to prevent holing a piston or overheating. But a few things can be tried before dropping by your local Yama shop:



1. New parts may combine with a less than spotless work area to cause problems. Start with clean hands and work space!! If you are running the engine for more than a 30-60 seconds at a time, get out a good fan and keep things cool. It\'s cheap insurance. Now, since you posted in November and are likely north of the equator, I\'m assuming you have fresh, winter blend gas in the tank....



2. See if the engine revs differently with petcock set for run or reserve. If so, it\'s the petcock or tank filter that need attention.



3. Check the tank vent tube for blockage and sufficient flow. A vacuum will occur in the tank if it\'s wrong and counter fuel flow.



4. Check that spark timing or quality haven\'t been accidentally whacked. That will affect top end. Check all connections and wires.



5. Drop the float bowl and see if fuel flows well (note you may need to apply vacuum to the "automatic" fuel cock, if you have one, to get fuel to flow). Check fuel tank filter, fuel petcock, fuel line and carb needle and seat for blockages. You can use a paper coffee filter under the fuel drop area to see specifically if anything is there (and catch loose parts).



6. That done, get the carb manual or PDF to know what you are getting into. Carefully clean the fuel passages in the carb body. Maybe there\'s a bit of manufacturing grit or casting flash in the system. Carb spray may not do it. I\'ve found steel guitar strings and welding tip cleaner rods are the trick here. These are small holes. Be careful and don\'t force anything!!!



7. Lastly, that new carb may mean you need to increase carb jet size or adjust the metering needle to get enough fuel at high revs. This is especially important if you are above 5000 feet and the carb is jetted for less. The shop is best for this BUT, if you must DIY, get the carb manual or PDF to know what you are getting into. Jets: go rich one size at a time. Metering rod: move up/down one place at a time.



Hope that gets you down the road!!

Is the machine a two stroke? Because if it is a blocked exhaust (full of carbon deposits) will cause exactly this symptom. The best way to clean it is to stand it on its end and fill it with oven cleaner and leave it for a day. In the old days it was just a case of heating the exhaust with a blow lamp and tapping the pipe gently to loosen the deposits

There should be a fuse under the dash for the instrument cluster...you may need to refer to the owner manual to get the printout of the fuse block

I had the same problem with my 636. It turned out to be just a cable problem. Try to see if all the electric cables work correctly and connected.

Good Luck,
Elad.

The piston seize destroys the piston, rings and cylinder wall. Bad enough, and repeated seizing, can get metal bits into the crank rod bearing and crank end bearings and seals. This is serious stuff. Sorry to be the bearer of bad news.

Seizing is caused by friction. Not enough lubrication means friction that creates heat. The heat builds and the piston and rings "weld" to the cylinder. A faulty cooling system can also cause heat. Any oil will break down and loose it's lubrication ability when the heat gets too high. A water pump malfunction or plugged coolant lines, leaking coolant hoses, plugged radiator and bad gaskets can create heat.

Other sources are > timing is off, air leak causing the fuel to be too lean, incorrect spark plug heat range, carbon buildup on piston and head causing detonation, motor oil used in gas instead of 2 stroke engine oil and over revs on the engine. I have probably left a few things out but these are the usual causes. Be aware that combinations of small problems can add up to a seize.

The engine needs to be rebuilt. Normally I would just rebuild the top end but since you have had multiple seizes the bottom end is probably contaminated. New crank bearings and seals should be installed. If the cylinder can't be bored then you will need a new cylinder. New piston and rings are also required. Bear in mind, you must find the cause or causes of the heat and fix those problems also. If you don't, the new piston will quickly seize up.

Top rating for this answer! Thanks Kev...

pull the instrument cluster out and check the printed circuit and connector to it from harness, plug it in and out three or four times, this may cure the problem.

There is a fuse box underhood and one under the rear seat next to the battery. I would definitely check for a blown fuse first.