The Honda Owners Club

Cx500 b
Started and ran ok for a few weeks. Backfired often, was lacking power at low revs now wont start at all. Turns over ok, getting a spark, getting fuel but wont fire up. Would welcome any tips or ideas.

Charlie

From what you say, it wasn't actually running OK, was it, if it backfired and lacked power?
How long have you had it? CXs are notoriously bad for starting if left for even a few days. You say it was lacking power at low revs, but what was it like at high revs (or did it never get there?) When did it backfire? They often pop and bang on the overrun (mine did it even from new).

Had it for about 4 weeks. After turning over a few times and not starting, it would then backfire, and next turn would start. Plenty of power at high revs.

As I said, they can be hard to start! If you keep trying to start it without success, then it does eventually fire, all that unburnt fuel in the system is going to ignite...........with a bang!
I don't use it much now, and I know what to expect, but I usually turn the petrol on, wait five minutes, and then try and start it. I've had it 28 years, so I know what it's like. Last time it started first press on the button, after a year's non-use!
I would have thought if anything, it would be OK at lower revs, and not running well at higher revs.

Only backfire I had on my old beast was where the Motad exhaust had small air leak. On slowing sometimes would fire exhaust gases.

Poor starting and lack of power suggests carbs/fuel mix wrong and/or timing a little out. Worth cleaning and checking adjustment anyway.

Dibble wrote:Only backfire I had on my old beast was where the Motad exhaust had small air leak. On slowing sometimes would fire exhaust gases.

Poor starting and lack of power suggests carbs/fuel mix wrong and/or timing a little out. Worth cleaning and checking adjustment anyway.

As I said, mine pops and bangs on the overrun, but has always done it, from new. CX500 starting problems are well known, and it's not very often due to carbs/fuel mix/timing, it's just that they seem to "dry out" and don't like getting "woken up" again! If mine was used every day, never a problem. Leave it for a week, and 'ere we go again.......... , but I've got to learn a technique, and have a bit of patience. (My VFR is a delight to start by comparison, even after "over-wintering" )

Sealed over where the electrics enter the crankcase, sorted a problem with one of the air intakes, tightened one of the HT leads, charged up the battery and away it went. Still backfiring but running a lot better. Will get it into the garage and have them check out the carb balance.

Thanks.

Charlie

I had one way back in 1987 on a W plate. Great bike...............when it decided to start. Exactly the same problems as described above. Had no choice but to sell it in the end. I see a post from south Glos, where about's as I'm near Stroud.

ronda the honda 66 wrote:I had one way back in 1987 on a W plate. Great bike...............when it decided to start. Exactly the same problems as described above. Had no choice but to sell it in the end. I see a post from south Glos, where about's as I'm near Stroud.

Thornbury.

You say you had a CX back in 1987, but elsewhere you said you've just bought your first Honda, at age 43! Slip of the memory, perhaps? My CX is a B model, on a W plate too. Prefer my VFR though.

Sounds like an air leak in the exhaust, like Dibble says.
My old CX used to run like a pig with the smallest of holes in the exhaust

There haven't been any posts on this topic for three month so I suppose it's resolved. Whatever. My diagnosis is a bad stator. If I'm right you'll have to pull the engine to fix it.