Suzuki GN250 1992. possible compression issues

[ksmx]

I was hoping someone might be able to point us in the right direction.

We purchased a non running GN250. After first inspection we noticed that an exhaust valve had blown and had damaged the piston. So we replaced both parts and hoped that this was the solution to the non running engine.

It wasn't!

It has spark, it has fuel, we have also used easy start and it has caught fire but no explosion for piston to start (newbie description), we did use gasket sealant and now are thinking it must be compression issues. When the engine is built and a finger is placed over the spark plug hole there is a slight amount of pressure but not enough to blow the finger off.

Our thinking is to replace all the valves as some look burnt and possibly not creating an effective seal and replace all gaskets.

Next move? Any advice appreciated!?

[Tango]

Yeah....The compression should be able to blow your finger off the plug hole.

Check valve clearances, valve seats, head gasket, piston rings, etc........no compression will definitely be why the bike don't run......

[eastanglianbiker]

first thing is..............did you use a new head gasket........2nd thing did you grind the valve in to make sure the seat was cut in correctly if you skipped either of these 2 steps then it is very possible cause to very low compression,if you did replace head gasket with new one then like tango says check valve clearances as fitting a new valve it will almost certainly be a very slightly different length hence needing gap resetting