Topic: 1978 Honda CB 550 Four AC generator hot.

[briancairns]

Hi,
I live in Ireland and have an American import 1978 Honda CB 550 Four.
Bike fully serviced , carbs refurbished and  balanced . Electronic ignition fitted. All fully serviced by experienced motorcycle mechanic.
However the AC generator stator coil burned out and got it re-wired as a new one is extremely expensive.
Bike starts ok but idle will not go below 2000 rpm when warm no matter what the mechanic does.
Also can't get bike to go above 60 mph however the engine seems smooth.  When running can't get the bike above 5000 rpm but in neutral it revs to whatever I want it to.
Also after a 60 mile run today , I touched the casing of the AC generator and it was red hot! ( burned my hand).
My mechanic is now totally baffled but admits he is not experienced with this bike.
Can anyone advise?

Thanks in advance

Brian

[newday777]

Welcome aboard Brian from across the pond north of Boston in New Hampshire.
How long did it set while you had the stator rewired? I ask as it sounds like you have clogged carbs. It only takes a few weeks setting with gas in the carbs to start hardening the gas left in the tank and carbs today with ethanol gas.
Have you cleaned the tank of rust? Even surface rust will put off tiny particles into the carbs. Pull the bowls and inspect for junk.
It sounds like the re-wiring wasn't done correctly causingtheoverheating. I'm not up on the 550 so I'll defer to others that will come along.

[bryanj]

Isit a K or an F model, K was fitted with pd cbs and they are notorious for cloggingand those symptoms.
As to generator all the 500/550 coils are the same but check the charging voltage as it may be fully charging all the time

[briancairns]

Ok thanks Newday and Bryan, will check the carbs again. What would cause continuous charging?
Cheers
Brian

[briancairns]

Sorry it’s a K model

[69cb750]

Ok thanks Newday and Bryan, will check the carbs again. What would cause continuous charging?

Regulator failed.

[briancairns]

Thanks.
Would this cause the stator coil to burn out? The AC generator casing was red hot to touch and have already burned out a stator coil or would the regulator have a bad earth ?

Cheers
Brian

[dave500]

the generator cover will be as hot as the engine,that is itll be untouchable when hot.

[briancairns]

Thanks Dave…that would then be normal?

Thanks

Brian

[newday777]

Thanks Dave…that would then be normal?

Thanks

Brian

You should buy or borrow a non contact Infrared Thermometer Gun to test the temperature differences of the alternator cover and the other parts of the motor

[briancairns]

Ok thanks. I actually have one !

Brian

[bryanj]

As to carbs, have seen them needin ultrasonic 3 or more times plus the press in pilot jets need to come out

[briancairns]

Ok thanks

Cheers
Brian

[grcamna2]

Those PD carbs on your model 550:do they also have an accelerator pump ?

[bryanj]

Only 650 and 750 have the pumps 550 no

[MauiK3]

Check battery voltage when running, see if it’s over about 13.5 or so.
Check for leaks around the carbs, air leaks will raise the idle.

[briancairns]

Thanks all,

Bike booked with mechanic but will be doing some basic tests myself tonight.

Thanks all


Brian