QuestionI have an '89 Hawk. It has over 70K on the odomoter and an unknown past. It was running well until it backfired at slow speed in town. It then continued to backfire at low idle and had about 1/4 power as the throttle was opened. There is an oil leak from the forward cylinder head (of the v-twin). I know only enough to realize there could be a bunch of things wrong. My questions are:
-can I / should I drive it to a mechanic?
-will it be cheaper/better to swap out the motor than to investigate and fix this one?
-at this mileage is the bike worth repairing or should i salvage and buy another in better condition / lower mileage?
Many thanks (even if the answer is depends).
Mark
AnswerHi Mark,
I suspect a defective ignition system to be the cause of the problem. Electrical diagnosis would verify the cause of the backfiring. Could be a fouled spark plug from the leaky front cylinder.
Remove the spark plugs and examine them. Visit NGK's website: "www.ngk.com/sparkplug411.asp" and compare the plugs with those imaged on the website under "Plug Problems." Clean or replace the plugs accordingly.
Measure cylinder compression. If necessary, perform a leak-down test. These tests will verify the condition of the engine (sealing properties of each combustion chamber) and locate the source of any leaks.
Q: can I / should I drive it to a mechanic?
A: If the above tests check ok, drive it to a mechanic, otherwise I recommend trailoring the MC to avoid further damages and for everyone's safety.
Q: will it be cheaper/better to swap out the motor than to investigate and fix this one?
A: Dunno at this point. Learn what the cause is first and then decide.
Q: at this mileage is the bike worth repairing or should i salvage and buy another in better condition / lower mileage?
A: That's very high mileage. Again, learn the cause and costs of repairs and then decide.
Respectfully,
Mark Sihvely
