[bill440cars]

While browsing 350 stuff on Ebay, I noticed a pair of 350 Honda sleeves and I remembered the 350 Powroll kits for the 305 Super Hawks. My question is, would it be possible to have a CB77 cylinder bored out to accept a set of 350 sleeves and would you be able to use the 350 pistons without having a problem as far as valve clearance and such? I'm probably just wasting time, but you never know. I DID see, over on the 305.com forums where there was discussion about building a 500cc engine out of the 305, that involved using the 450DOHC head and cylinder, but I don't have a clue what all is involved in doing that. Sure would like to see some deatails and photos on that!

 

[66Sprint]

Can't help you on this one Bill, but I can't see why it would not be do-able....Maybe you should just go for the 450 top end on the 305.....The posted pic looks awesome!....AND, it combines two of your favorite bikes!...... (mine too).... Steve

 

[MNellis]

My question is, would it be possible to have a CB77 cylinder bored out to accept a set of 350 sleeves and would you be able to use the 350 pistons without having a problem as far as valve clearance and such? I'm probably just wasting time, but you never know.

Many years ago I had to do something similar situitation when I needed to bore out an old Kawasaki 750 Z2. In the end, I used Suzuki GS1000 pistons but the problem became one of wrist pin to piston height. In this case, the distance between the centerline of the piston pin to the deck of the piston was less than the Kawasaki part so I had to shave the top of the cylinder to get the compression back..

I think you'd have to take some measurements of the piston pin to piston deck on both pistons to answer the question. The next question would be are the piston pins the same diameter. If not then it wouldn't work without boring/sleeving the small end of the rod to match the 350 piston.

 

[tbpmusic]

Bill -

Comparing specs on the two bikes, the 305 is listed as 60mm bore, 54 mm stroke.
The 350 is listed at 64mm bore, 50.6 mm stroke.

So it sort of feels like a bit af machine work might be required to allow the fatter sleeves to fit in to the lower crankcase. As I recall the old 350 overbore to the 305 was about 3mm or so, and didn't leave a lot of meat left.
But the stroke isn't all that much different - you might need to cut a bit off the bottom of the 350 sleeves so the 305 crank doen't whack them, but there's probably plenty of cylinder there to make up for the slightly (3.4mm) longer stroke.
Plus all the stuff that Mike mentioned......
I guess it depends on how bad you want to do it.

bill

 

[bill440cars]

Can't help you on this one Bill, but I can't see why it would not be do-able....Maybe you should just go for the 450 top end on the 305.....The posted pic looks awesome!....AND, it combines two of your favorite bikes!...... (mine too).... Steve

Well Steve, Since I DO have the major parts of both the 350 AND the 450, I'll be looking into seeing just what the specific measurements are. Like YOU, I really think that the 305 with the 450 top end, looks pretty decent at that. Which ever way I go, if I decide to go in either direction, will depend on the complication of doing the task. I am aware of the fact that there will have to be SOME machine work. I would lke to get some details of the 305/450 engine that HAS been done, but I understand that they are pretty tight lipped about the details of THAT one. :| With a little bit of Luck, THIS just might turn out to be quite a little "Hybrid"!

Thanks, and take care, Bill

 

[bill440cars]

Funny, while I've been talking about the feasibility of getting a set of 350 cylinder sleeves into a set of 305 cylinders, over on the 305 forums, they're talking about building a "FIVE HUNDRED CC"Super Hawk! :shock: and talk of one that's been done, with one of those Nova 6sp trans! :roll:

Man, sure like to check THAT one out!! Here's the setup that was used (and I don't mean that this is the EXACT one, but of the same setup.)