As David said in the post before this you use a tester as described. You must have all of the plugs out (with the wires off), or the engine will start. You will notice a drop in speed of the engine turning as the cylinder you are checking hits its compression stroke. I usually count 8 revolutions and read the gage. A compression tester is around $20.00. Like I said: it is very unusual for only one cylinder to read low if it's rings. Also, if the engine emits smoke while running, one can ascertain that it is usually valve stem seals/guides if it smokes after idling,like at a stop sign, or rings if it smokes during hard acceleration. The valve guides are suspect also if it emits a plume of smoke when starting that disappears quickly and there is no more upon hard acceleration. If there is still smoke out the exhaust after several times hard acceleration, rings are suspect as well. None of this info will help - meaning the smoke - if there is only a valve seating issue causing #3 to be low and everything else is kosher (no smoke at all). One more thing: valve stems worn or seals not sealing will usually consume oil without the telltale smoke like with rings, except after idling and taking off. Someone's shop did a valve regrind on this particular engine and left the valve stem seals off. It really consumed the oil. Be that as it may,not all engines use them...
Sent via DroidX2 on Verizon Wireless™ -----Original message----- From: Dave <[email protected]> To: [email protected] Sent: Mon, Mar 5, 2012 15:16:03 GMT+00:00 Subject: Re: [Nighthawk Lovers] Nighthawk with disappearing oil I've been reading your posts and a couple ideas have come to mind... if the bike was full of oil last time you checked it, and it ran a bit, and if the piston rings are bad, its possible that your burning oil, which could be why the mechanic said it was 'out' of oil. A compression check "kit" is basically a fitting that screws into where your spark plug normally goes attached to a vacuum line w/ a pressure gauge (preferably the kind that have a reading that sticks) on the other end. To get the gauge to read compression you have to crank over (not start) the motor. this can be done w/ the starter or by turning the crank if you have access.. hope that helps a bit. The mechanic saying that the there is low compression on #3 might be an indication of bad rings? I'm no mechanic, but I have had some experience.. my next mechanical project is a complete rebuild of a small block international v8... I'm projecting a couple of weeks for that project... hopefully if you have to rebuild the engine in your bike it doesn't take near as long! On Sunday, March 4, 2012 9:41:15 PM UTC-5, stefano wrote: > > Tinkrmann, > Thank you for the information. > What is the best way to do a compression check? Is there a kit that you > can buy somewhere? Also, are valves generally hard to replace? > > Stefano > -- You received this message because you are subscribed to the Google Groups "Nighthawk Motorcycle Lovers!" group. To view this discussion on the web visit https://groups.google. -- You received this message because you are subscribed to the Google Groups "Nighthawk Motorcycle Lovers!" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/nighthawk_lovers?hl=en.
