Honda305.com Forum

Your pistons are 1st oversize and a stock/standard size head gasket will work. .........

I'd say the head gasket had been leaking for quite some time.<br />That one side was running and the other really wasn't .<br />When these engines run for any extensive length of time on one piston that piston will HOLE because it is carring the total load and will eventually overheat and hole itsel...

The vents between the carbs (CA/CB/CL72/77 HONDAS) were ment to remove any moisture at the intake valve guides. The tubes went to a plastic "Y" and then to the front of the right side air cleaner. Nothing to do with engine tuning. They were so important and useful that HONDA discontinued t...

If the gasket is made by Honda and is the standard size it will work for any of the 5 piston sizes made by Honda for your 305. eBay is a good place to find ring sets. I have all sizes but as you may imagine they are not cheap. .......................

My best guess is that the kick shaft is warn at the 21 tooth counter shaft where the 12 small roller bearings are. If the shaft is warn all the gears on it will not align correctly to the gears on the main shaft. ...........................

I've been involved with the the 305 bikes since 1963 and have never heard of a 6 SPEED gear set for them. Honda and a company in England made the 5 SPEED sets for a while but they are scarce. I have a OLD 1961 CB72 frame that was a GP racer many years back and to my surprise when I got it the gears ...

As I rebuild about 10 of the 305 (Dream and CB72/77) engines a year I was curious why the Dream has less compression than the CB/CL77 engines. I had a Dream and a CB77 piston on the work bench side by side and the Dream one looked as though it should actually give more compression than the CB/CL77 o...