305 Type I CL77 engine top end rebuild questions

Snakeoil · Post by **Snakeoil** » Sat Apr 06, 2013 10:51 am

Gents,

Since it looks like my top end will need rebuilding, probably next winter, I have a few questions I'd like to ask up from regarding past experience with these engines.

Bike as 16K miles on it.

-Are valve guides known to wear on these engines?

-How do the cam chains hold up and should I plan on replacing mine?

-With one cylinder smoking, I assume I'll have to do a rebore and go with oversize pistons and rings. But still would like to know if past experience has revealed ring wear but no serious bore wear and a slight hone and re-ring is all that is required.

-Is there a list of typical wear parts, other than gaskets that are required for a top end rebuild on these?

-Finally, any top end rebuild tips while I'm in there? Mods or upgrades that would be recommended?

I'm asking in advance since I'll have to start locating the necessary parts to do the work.

Thanks,
Rob

davomoto · Post by **davomoto** » Mon Apr 08, 2013 7:30 pm

Rob,

Valve guides are usually good to go. I always replce the cam chain and cam bearings with c3 spec bearings, cheap on ebay. Take the cylinder and pistons to a machine shop, and they can mic them for you and tell you if you need to rebore. Post pics of parts when disassembled if you have questions as to if they are worn or not.

Davo

Snakeoil · Post by **Snakeoil** » Mon Apr 08, 2013 9:11 pm

Thanks, Davo. I was hoping guides were robust in these engines. Cylinder wear and such is no problem to check/measure. Plus I have a top notch machine shop within spitting distance. Was just looking for any unique parts I might need.

Another thing I was thinking about was going with an EI and that means disabling the mechanical advance. Is there a preferred method to do this?

Regards,
Rob

davomoto · Post by **davomoto** » Tue Apr 09, 2013 10:13 am

As in a crank mounted EI ? Other wise advance unit remains in play. Remove the springs and weld the arms to the body of the advance unit. Also check for loose rivets, or just weld the sprocket to the assembly.

Cam chain tensioner wheel is often worn as well.

Davo

Snakeoil · Post by **Snakeoil** » Tue Apr 09, 2013 12:18 pm

Cam mounted EI. Idea is to disable the mechanical advance and use a totally electronic igntion, including advance curve.

Yeah, I've read the threads in the past about the tensioner wheel and not being able to find them. Mine looked pretty good and I have a spare from a spare engine I was given. I also have the capability to machine my own wheel, so not overly worried about that one... yet.

Charlie's has igntions and I have to find out what the details are as I did not see any on site. They look like Dynas. But his site says they are made in house.

regards,
Rob

davomoto · Post by **davomoto** » Tue Apr 09, 2013 1:35 pm

Designed in house is more like it. I beleive they rely on the stock advance unit, but not sure on that. Let us know what you ind out. Most of the cam mounted EIs retain the stock advance unit.

Davo

Bob750 · Post by **Bob750** » Fri Apr 12, 2013 11:58 am

I've been looking into Charlie's EI, too, for our CA77. Of course, that would be after I get the Regulator/Rectifier and Halogen headlight setup... :-/

Anyone running all three who can report on them?

Bob