1993 virago 750 issues...see details?

Question

I've been having issues with my 93 virago 750. First the gas was getting into the crankcase, so I rebuilt and cleaned out the carbs. Found some nice junk behing both jets but everything else seems clean. Replaced all parts that came in the kits.No tears in diaphrams in carb,no external fuel leaking. Adjusted valves with feeler guage to spec, adjusted carb syncro s***w by ear to best of my ability, idles and starts great, loss of power and breaks up with load on it,(while riding). I can rev it up standing still and no indication of loss of power. Compression is even on both cylanders, about 150. Any ideas where I should go next? Note...I'm still testing and watching closley to see if fuel is still going into crank...I've had this issue for a while and continue to try different things and change the oil as I find it has fuel in it....please help!!!

Answer 1

Could have leaking valves.

After putting on some mileage, engines create carbon build-up between the valve face and valve seat.

Carbon build-up and metal ware cause the valves to eventually leak.

The cylinder's compression can still read good, but the engine's performance will be lowered.

Perform a cylinder leak down test.

If you don't have a gauge -

Remove the spark plugs.

Bring a piston to TDC of the compression stroke (both valves closed).

Using an air gun and compressor, blow into the spark plug hole.

Listen at the air box and muffler ends.

If you hear any hissing, that valve is leaking and the head will need a valve job.

Answer 2

the only way fuel can get in the oil is by the fuel inlet needle- if it (they) didnt come in the kit, get them- if they did, check the float level, also check for a sunken float- shake it and listen for fluid- also, shut the fuel off every time you shut off the bike- its breaking up under load because its running rich.