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Final drive gearing.

shaunbe

CB750 Enthusiast
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65
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Location
del rio
Hi all, I finally took my 76 out on the highway, but I hate that it runs at 5500 rpm at an I dictated 77ish mph, as far as I know it has stock front sprocket, the rear is a 48 so that should be stock size, I'm running a 130/90-16 tire on a henry abe wheel, what would be a good swap, put the front sprocket at a 19 and leave the rear at 48? Stock ratio would be 2.82 and a 19/48 would be 2.53. Would that be a good drop in rpm? I live in South Texas we have speed limits of 80 mph some places and I'd like to turn less than 5000 rpm at 75 mph, thinking anywhere between 4500 and 4800, I know these motors like to spin to make power so I don't want to take it completely out of the powerband but I also don't want it screaming it's lungs out just normal riding.
 
I run the DOHC at those rpms all day long, the engines like to spin more than they like to lug and easier to damage them doing so. The crap fuel used now can add to that.

You are out of the powerband below 5500 rpm. At least the DOHC is, with a header and in fine tune the engine just breaks into the harmonic howl a good header makes as the tuning all kicks in around 5400 rpm. Below that you still hear the individual firing impulses that signify out of power band. When the motor begins to put out that distinctive howl the cams are just coming into the beginning of the band.

Yours of course and do what you will..............it ain't no Harley.
 
I'm with you shaube. I hate for my bike to scream when I'm just cruising. Did you ever change your final drive gear ratio? I'm going to change mine before summer gets here that is for sure. I have read one more tooth up front is about the same as 4 less in the rear. I think I'll add one up front and take away one or two from the rear. Depends on if I can find what I'm looking for. I think the website I got some sprockets before for my little Suzuki GW250 was sprockets.com. Wish me luck. Docjones
 
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