There's a nice article in Walneck's Classic Cycle Trader (Feb. 2009) about a 1967 SuperHawk pages 130-134. It's a reprint from Classic Bike, May 1994, and has lots of great things to say about the bike we know and love.
One of the things that is mentioned in the sidebar pertains to timing-side roller main bearings, and recommends replacement with 91002-259-020. Is this worthwhile doing?
Walneck's Feb. 2009....
Re: Walneck's Feb. 2009....Does the article state why the bearing should be replaced? Does it say what the difference of that one is to the original? It is a Ball Bearing! Does it say the cases must be split to replace it? Does it say what the symptoms are for replacement? 1985 I ask a racer from the period when these engines (250) were new and could run in the NOVICE flat track events why it is I could find many 305 engines and few 250's. His answer was that "We destroyed them racing Novice Flat Track". I ask what was the problem with that design and his answer was that "although the right side crank bearing would seem to get plenty of oil that when the bike was spending more time leaned to the left and little vertical that the bearing (pin bearing roller needles) would get hot and fail.
These engines if properly maintained (oil/timing) with clean oil and correct timing will run many,many miles and never need that bearing replaced. If however it wasn't maintained and the oil was allowed to get old or low that bearing could wear and ruin the bearing race on the end of the crankshaft. That is when the mentioned bearing is required as the crank bearing (end) can't be easily repaired or replaced. I've used apx. 4 over the years I've been rebuilding engines/bikes. That sidebar is like so many things published about these type engines over the years that may/but seldom happen to these engines. You are more likely to ruin the shift drum/fork/and clutch than that bearing. If you do run out of things to mess with on your bike you could always get your mechanics to tear your engine down and install one for you Vince. That is if they can find one. ..............lm
RIDE IT DON'T HIDE IT!
The article has a substantial sidebar regarding this person's (Bill Moore) bike, and his experience working on the bike he found. There's also a section on 'Keeping a CB77 on the Road', and it discusses the "timing-side alloy-caged roller main bearings" failing prematurely, and recommends that ball bearing part number to which I had earlier referred. No, I don't feel like messing with any more internal aspects of my particular bike, as I've already been through all that, but I was just curious to know if that was common knowledge in the CB77 community. The sidebar also refers to the rivets in the advance-retard unit, and that they could 'self-destruct' without warning, as well as other things to watch out for. Just an interesting article to read, that's all....
The cam sprocket rivets do loosen (self destruct?) at times but figuring the many engines issued it isn't a USUAL fault. The symptom is a ticking/clanking in the top end as you decelerate. Did he mention that? Can be repaired with welds or using a broad face punch and hammer two of the rivets to hold the sprocket. Did Bill mention the reasons that bearing fails? I'll find the article and read what I know I've read before to better know what is there. .............lm
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Yeah, the article doesn't really go into that kind of detail. Those technical suggestions in the sidebar are more like bullet points. I was just wondering what the significance of that particular part number was all about (not that I'm about to have it done!). All in all, the writer and the owner are completely smitten by the CB77 and its charms (extremely reliable, oil-tight, a giant-killer, great styling, etc etc etc).
You can pretty well find Walneck's in most 7-11's and grocery stores where the 'Trader' magazines are located.
Articles of this nature which all to often mention a part or adjustment problem and don't describe the symptoms and cure other than in this case a bearing number and nothing about symptom or the work required. Some technical items I've read over the years will say something about a part/problem and not explain the cure/symptoms or differences of the part/problem. Reminds me of some who hear and pass on myths they've seen/read and actually believe it without knowing what they say is fact. ............lm
RIDE IT DON'T HIDE IT!
Yes, you're probably right in that regard. I belong to a vintage camera discussion group, and the same thing will happen -- someone will bring up the topic of a certain rare German camera, like a twin lens Zeiss Contaflex from the 1930's, and others will say something along the lines of "oh I hear that they're really difficult to work with and not really worth using." But they've never owned the camera, let alone seen one in the flesh. So then you come to believe that particular vintage camera isn't really worth having because it's a bear to use. But if you actually took the time to understand it and try it out, you'd find that it's perfectly fine.
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