tmihaylov
12/22/2007 1:33:33 PM
Ok so my values are Cyl 1 - 165 PSI, Cyl 2 - 150 PSI, Cyl 3 - 165 PSI, Cyl 4 - 155 PSI. Book states that it should be 185 +/- 25 PSI and how am i suppose to look at that? What would contribute to lower psi besides worn piston rings.
michigan_313
12/22/2007 8:20:58 PM
worn valve seats. worn head gasket.
Gogar
12/22/2007 8:58:27 PM
How did you test it? The temp of the engine will make a diff. Warmer will cause the metals to expand and pressure will be higher. As long as they're within 5-10% of each other, you shouldn't worry much.
Gearloose
12/22/2007 9:50:05 PM
Did you have to use an adapter between the compression tester one-way valve and the cylinder? If so, the extra volume in the adapter increases the static volume, reduces the compression ratio, and presto! lower reading across all cylinders.
tmihaylov
12/23/2007 2:32:12 AM
well the tool came with the adaptor for the 12mm motorcycle thread so it was like a 3" adaptor plus the almost 20" hose for the gauge itself so it may have played a factor but im thinking its just either a blown gasket or either valve guides or piston rings are leaking. As for my other post about engine troubles and smoke, i spoke to a friend who worked as a bike mechanic for a long time and he said (for future reference for anybody with smoke problems) If the bike has been sitting for a long time and it smokes when it idles or accelerates you should do this. Take it on an express way or highway to a high speed and high RPM and after a while the smoke should disappear since the temperature inside the cylinders would reach high enough that they will burn off anything that's been sitting in there for a while. If it doesnt then your piston rings are gone and need replacement. Anybody know where i could buy piston rings? I can't find them on bikebandit or service honda.
Gearloose
12/23/2007 11:42:56 AM
Regarding the compression tester, there should be a 1-way valve at the engine end of the hose, so the hose length itself shouldn't make any difference to the final reading, just to the amount of time to pump up the gauge. The volume of the passage inside the adaptor will add to the static volume, so (say) a 3cc adaptor volume will reduce the compression reading by 20% so the 185psi becomes 150psi. IMHO you should check whether you have an accurate reading before deciding whether to carry out a high-speed remedy.
Sources of piston rings: try crotchrocket.com, Ron Ayers etc.
