Hap Jones Pistons for CB72

[LOUD MOUSE]

Ya have a 1964 issue.
Were it a 1961 the numbers would be CB77-11XXXX. ...........lm

The numbers are a bit mangled, but the frame number looks like 100020, and the engine number is 100023 (from memory, the bike is at home). I do remember reading somewhere that some '64 models started with 1 before they went to the longer numbers which all started with 1, so it probably is a '64. A few people have looked at it and said it'a a '61, so I didn't argue, even though I had my doubts.

With regards to machining the head and barrels, what do you guys do about getting the cam timing correct again? It looks very difficult to index the cam sprocket.....

[wombat200]

I have a few of these Hap jones +3mm sets for the CB72, I was planning on using a set in my CA72.... I wonder if they'll drop the compression too low?

Guys, I'm also in Melbourne (Aust) and have lots of pistons, barrels, engine cases, etc, for both 250's & 305's. Get in touch if you're looking for stuff.

Regards,

Rob.

[davebern]

I have assembled the bike and taken it for a ride. It seems OK, although I didn't push it. Because the barrels had been machined so the pistons stood proud of the deck, I machined the proud areas of the piston head down, which gave me about 8.5:1 compression.
The wife and 4 kids gives me little time to play with bikes, so I don't know when the next test run will be. I'll keep you posted on progress.

P.S. Rob, are you a member of the VJMC?

[wombat200]

Dave, yes, currently a VJMC member, although may not stay that way. I've got lots of these Dreams, including a dry-sump bike, always happy to swap ideas, parts, etc.

You can get me on wombat200@hotmail.com.

Regards,

Rob.

[teazer]

Dave,

Did I understand that post to mean that you machined some or all of the "lump" off the top of the piston so it's flush with the top of the barrels or did I misread the post?

Or did it mean that the squish band was above the barrels and you had that part machined down?

[ColC]

Hi all
My name is Colin Campbell new 305 forum member, Im also in Sydney Australia, not far from Dave I live in Epping. Have a couple of cb72/77 classic race bikes. I hear Loudmouse is coming over here to watch the Australian historic motorcycle championships, if so I hope to meet you as I will be at Phillip Island as well. looking forward to being part of the forum, cheers Col

[LOUD MOUSE]

Welcome Col.
I will be with Jerry Kooistra most of the time (camera in hand) and for sure look forward to shaking hands when we meet. ............lm

Hi all
My name is Colin Campbell new 305 forum member, Im also in Sydney Australia, not far from Dave I live in Epping. Have a couple of cb72/77 classic race bikes. I hear Loudmouse is coming over here to watch the Australian historic motorcycle championships, if so I hope to meet you as I will be at Phillip Island as well. looking forward to being part of the forum, cheers Col