Spark plug hole too small

[Hfb1957]

I have a 1965 dream 305cc. It didn’t have any spark plugs in there t when I got it. I bought what the manual says would fit it but they are bigger than the hole. They are 12 mm DH8A. Any ideas on what it could be. Thanks in advance.

[DJM]

This one is easy, early C, CA and CB engines were fitted with 10mm plugs so that's what you need.

I'm pretty sure that the change to 12mm plugs was much earlier than 1965 (1962?) so your cylinder head either isn't original or the bike is much earlier than 1965, the engine and frame numbers will confirm this as pre '64 bikes carried a production year ID in the numbers.

According to the C72/77 Owner's handbook the correct plug is a C7HW 1mm x 1.25mm

[rrietman]

mid year 61 was the last year for the 10mm plugs. either your bike is much older than what you think or someone has been swapping heads. vin#'s?, what does the tank look like? breather tower on the crankcase above the output sprocket?
Good luck
Randy

[Hfb1957]

The numbers on the motor are CA77E-401086..on the frame I find CA78-401216. Maybe this will clear things up. Any help is greatly appreciated.

[G-Man]

Most likely your engine was rebuilt with an earlier cylinder head. It is a '64. I How many sets of points does it have?

G

The numbers on the motor are CA77E-401086..on the frame I find CA78-401216. Maybe this will clear things up. Any help is greatly appreciated.

[Hfb1957]

Thanks for the info. My bike only has one set of points. I found some plugs numbers c7hsa. I believe they will work. I am going to have to do some work on the threads in the plug holes though.

[G-Man]

Be careful with the plug holes. On early Dreams they were threaded directly into the aluminum cylinder head. They don't have the iron 'skulls' like the later bikes.

G

Thanks for the info. My bike only has one set of points. I found some plugs numbers c7hsa. I believe they will work. I am going to have to do some work on the threads in the plug holes though.