Honda CB750 Sandcast
General Category => General Discussion => Topic started by: Joe K on September 09, 2010, 06:23:19 am
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Hello,
I was reading a recent thread from mrdeza and saw that 1941wld wrote that the rear sprocket shield did not start until serial # CB750-1026845. I never knew that. This is good info for me, because I have one that I was going to put on my sandcast. What is the rear sprocket shield used for?
Thank you,
Joe K.
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;) it was supposed too keep the chain running true if it had ever snapped and not jam up in the rear wheel, Honda also added a chain guide to the front sprocket to try and stop the chain bunching up and smashing the engine cases,not sure if it was added later than the sprocket carrier :-\
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Thank you for letting me know what the sprocket shield was used for.
Joe K.
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I was a Honda mechanic at Pasadena Honda when the Sandcasts were introduced and got to see all the recall mods as they were applied. I know, I'm old. The front sprocket guide was used in theory to prevent a "broken" chain from bunching up and going through the back of the cases. They were made available in 1970 along with the revised, shock reducing rear wheel dampers. Sometimes they worked and sometimes they did not. I have seen both the chain AND the guide go through the cases. The camshaft profile change and a few other minor engine mods in 1970 reduced horsepower enough that along with stronger, riveted master link drive chains, the problem was minimized.
As with all previous Honda models, the early Sandcast chains had a master link with a removeable clip so you could "open" the chain to remove the rear wheel. The removeable clip was supposed to be installed in one direction per chain rotation. The clip could be slung off if the chain side plates stretched longer than the clip could accomodate or if the removeable clip was installed backwards. Many of the "broken chains" were not actually broken but rather the master link would fall out.
The guide on the rear sprocket was implemented to accomodate removal of the rear wheel with the "riveted" and subsequent "endless" chains. Instructions were to loosen the axel, spin the chain tensioners down, push the rear wheel all the way forward, move the chain from the sprocket to the guide, and then pull the rear wheel out. The rear sprocket guide was used to hold the endless chain from getting in the way with enough slack in the chain to get the wheel out. Reverse the process to reinstall.
Keith
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I was a Honda mechanic at Pasadena Honda when the Sandcasts were introduced and got to see all the recall mods as they were applied. I know, I'm old. The front sprocket guide was used in theory to prevent a "broken" chain from bunching up and going through the back of the cases. They were made available in 1970 along with the revised, shock reducing rear wheel dampers. Sometimes they worked and sometimes they did not. I have seen both the chain AND the guide go through the cases. The camshaft profile change and a few other minor engine mods in 1970 reduced horsepower enough that along with stronger, riveted master link drive chains, the problem was minimized.
As with all previous Honda models, the early Sandcast chains had a master link with a removeable clip so you could "open" the chain to remove the rear wheel. The removeable clip was supposed to be installed in one direction per chain rotation. The clip could be slung off if the chain side plates stretched longer than the clip could accomodate or if the removeable clip was installed backwards. Many of the "broken chains" were not actually broken but rather the master link would fall out.
The guide on the rear sprocket was implemented to accomodate removal of the rear wheel with the "riveted" and subsequent "endless" chains. Instructions were to loosen the axel, spin the chain tensioners down, push the rear wheel all the way forward, move the chain from the sprocket to the guide, and then pull the rear wheel out. The rear sprocket guide was used to hold the endless chain from getting in the way with enough slack in the chain to get the wheel out. Reverse the process to reinstall.
Keith
That's a great bit of info Keith and I for one would love to hear more of your stories on the topics raised here. :o Old is only a number, it's how you feel and think is what's important. Cheers and thanks again ;) KP
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Keith,
Thank you for the information on the chain guard. I am not sure if you still live around Pasadena, but if you do maybe we can meet up sometime. I live in Hollywood. My e-mail is jkulick@yahoo.com.
Joe K.