One of the most important things to do when rebuilding motors is to try and ensure all the mating surfaces are in good condition so when the standard gaskets are used, correct sealing is achieved without the need for any of the "gasket repair" products. Apart form using some Vaseline smeared on the case surfaces prior to assembly to encourage the gasket material to swell and seal better, no other sealer should be needed. The clutch covers on the Suzuki's are prone to corrosion pitting, warping and screw driver gouge damage so attention to correcting these defects before re-fitting is better in the long run than using a sealer especially if by some chance you need to remove and replace the cover in the pits to do running repairs.
Normally before I get anywhere near re-assembling a motor, I use a metal putty to repair any sealing face imperfections on all the engine case surfaces. This is then filed back and the cases rubbed on a surface plate (or a sheet of glass) with 800 wet and dry paper to achieve a true flat surface. A leaky clutch cover is relative easy to repair after a rebuild, but a bad sealing outcome between the centre cases is much more frustrating and regrettable for not paying more attention especially when gearbox oil starts to leak into the crankcase cavity or transfer compression is lost.
I also have a XL Honda where no gasket is used between the engine cases, then Theebond or similar is the recommended sealer.
