Hi , my old 56k miles gs 500 reads about 95 on according to a cheapy compression tester .. both sides are similar not to matter . Runs ok, plugs are just a little sooty , nothing terrible - but burns oil . Is it time to think about a replacement . Hope not i like the bike. I tried putting a little oil in the pots and it lept to 200 plus psi which makes no sense so the gauge may be bowlocks or it got somehow blocked with the oil from the pot ... a mystery ... could out of spec valves effects this .... thats another job ... trying to discover if rings or valves are causing the burning oil , its not terrible but i want to solve if i can ... all help appreciated... should i get this tested at a garage where the gauges will be a known quantity ?
Maybe i should add that the bike does 90mph with little bother and cruises at 85 or so which is why i am bemused by the low compression , it seems to have a reasonable amout of go in it , it accelerates well enough as well ...
It sounds to me like the rings are shot. With 95 PSI dry and 200 wet, and the fact that it's burning oil. If it's valves you get little to no difference between wet and dry measurements. So then the question becomes, how much do you care? If you're looking for a winter project, you've got one! :)
you may be right but I just examined the gauge and oil dripped out so it has been blown in under pressure which makes the higher readings meaningless.... it went up to 275 once oil added which just doesnt add up .... I`ll get it checked in a local garage and decide what to do from there ... if its effectively worn out I guess just keep riding and sell it cheap in the spring to someone who wants a prject and upgrade .... shame , ive spent time on this and its close to how i want it .....
I tookthe bike to a local garage and it was tested when warm . The compression went to120 on one sideand 115 on the other - still kinda low but i hope good enough ... what do you think ?
Gauges are great at telling you what the problem is. But if it's running as well as you describe, I wouldn't call it a problem. Something to keep an eye on maybe a couple times a year, but not obsess over. Ride on!
Thats the conclusion I have arrived at as well ... Going to check the valve clearances and keep an eye on it and ride for the time being , iff/when i start getting meaninful symptoms I will replace the motor , rebuild or sell the whole thing as a project and move on to something else ... Thanks for your advice . After replaceing the carb main needles and tubes it runs better than ever , smooth linear power- i hope i can keep it going for a long time ...