I have 17/48 sprockets and the rpms for local roads are 3500 - 4000, I like it.
What year? My 78K came stock 15-41 I just took the front one off and saw the PO had a 14-41 and I am going back to stock 15-41 can not remember what the larger front will do to my rpms or speedo. I lost all my Honda files from a virus.
Ken
It will cause you to tend to drop down one more gear, on average. I use the 17T/48T (530 chain size, yours is 630, so different tooth counts) in town so I can just 'touch' 4th gear at 40 MPH on a 110/90 rear tire size. If I use the OEM 18T front, the engine dislikes 4th gear until 45 MPH minimum. For your comparisons, just use the ratios: divide (REAR/FRONT-RATIO) and use the number to 3 decimal places so you have the same references.
All this aside: the beauty of the D8ES-L and the X24ES-U are that their tip stays hotter at a lower engine speed. This means the 750 is able to tolerate more of the 3000 RPM low end, and the post-1975 cams become smooth and torquey right about there, to redline. The earlier cams opened sooner, so the RPM need to stay higher, like 3500 RPM, before the smoothness and torque start. Their midrange torque arrives sooner, too (like 6000 RPM), so the original design was for 3500-6500 nominal running range, where the D8E plug "lived". When the gearing kept getting taller to reduce chain wear issues, the RPM tended to drop in use, so the hotter plugs had a new home. But, the D7E suffers the same 'turndown ratio' as the D8E, so if you run along at the 2500-5500 RPM range (i.e. 3000 RPM span) of that #7 plug, you find a hot exhaust guide at constant hiway speeds of 5500 RPM. The D8ES-L ("L" means "Longer tip") and the unique X24ES-U "womanly" design, as we called it back then (meaning: shapely!) produced the in-between temperature range that fits just right. (Why does this sound sultry?...).
I find it interesting that NGK was tapped in the early 2000 era to produce the DR8ES-L for the modern sportbikes with their CDI systems. I also find it interesting to see how many of those bikes are using the XR24ES-U instead, at least around here.
Hondaman, here in the Canada (the great white north), The Honda dealer still has D8ES-L's for $2.50..That plug works great in my 1976 CB750F.
That's cool! Around here we can only get the DR8ES-L version. It is only 2000 ohms, but it does raise an interesting point: the OEM Honda coils and plug caps are set for 7500 ohms between the coil and plug. The modern NGK plug caps are either 0 ohms (not good for these bikes), 5000 ohms (adequate, but not nominal), or 10,000 ohms (which proved to not last well on the post-1975 bikes). So, if you were to use the XR24ES-U or the DR8ES-L with the 5,000 ohm plug caps, this would be very close to the original spark setup, at 7000 ohms.
What this means in English is: since the Honda coils were meant to discharge into 7500 ohm resistors to obtain a 1.5mS duration spark, and since the 5,000 ohm plug caps are a little less than that, you get a slightly shorter spark of about 1.43mS (mathematically, anyway...and felt in the butt dyno). If you use both resistor plugs and 5,000 ohm caps, you can get the 1.5mS back. In the lean-burn post-1976 bikes with PD carbs, Honda 'stretched' the spark of the same coils to about 1.6mS with 10,000 ohm plug caps to help ignite the harder-to-start lean mixtures (for EPA reasons). The trouble was: the resistance is high enough that any slight crack or 'tracer' growth (from dirt or moisture), or even a cracked rubber boot, lets the spark jump to the engine and not the plug. So, the later spark caps "burned out" much faster than the earlier ones. Often, the rider would opt for the Dyna 3-ohm high-output coils to "fix" this, accidentally replacing the plug caps in the process, and receiving a temporary performance boost for his effort: hence the early-on perception that the high-output coils were an improvement, when replacing just the plug caps would have made a BETTER improvement, all else being equal...but, that's history now.
