Not surprising the compression is low. Get it running and it will probably come up to normal.Thank you for your input Gentlemen! The bike has been sitting for five years. I have not had it running and the test was done cold with the intake runners unbolted and shimmed up away from the head. The odometer shows 49,500 miles. The spark plug threads on cylinder number three are in need of repair.
How much repair is required for the spark plug threads? Can you just run a thread chaser through the hole or is it too stripped? If it needs a major repair use an insert and not a Helicoil. Helicoils do not work well in that application.Thanks for all your help Gentlemen. Yes, the valves were checked and adjusted before the test. Now to address the spark plug threads.
Could also get another head.How much repair is required for the spark plug threads? Can you just run a thread chaser through the hole or is it too stripped? If it needs a major repair use an insert and not a Helicoil. Helicoils do not work well in that application.
If you go to an automotive shop and leave a deposit they would have the tools and insert required, Otherwise traileer the bike to them and they might do the job right on the trailer. It is best to have the intake valve open and blow air in the cylinder while you do the drill and tapping. The air blowing out the spark plug hole will keep the metal out of the cylinder that way.
Many cars, trucks and bikes with aluminum heads have that issue. Most any shop should have no trouble doing the rather simple process. It just requires drilling, tapping, screwing in the new insert and stake it in place. 15 minute job. You can remove the head for the repair but it really is not necessary.My plan is to remove the head and deliver it to a reputable, local, automotive machine shop to do the thread repair on it. The number three spark plug threads are seriously in need of repair. Does anybody have a recommendation for a machinist to do the repair, local to 29720?