Why is it??

[Arch stanton]

After a day out on my CD175a sloper.
I was left wondering. Why is it. My 67 "get to work bike" is so much faster than my "sports" CB175k6 with its twin carbs etc.
The CB is in top condition. Whereas. The CD engine is getting ready for a refurb. There is almost 20 mph difference & the CD is quicker of the mark too. Don't get me wrong tho. I'm very happy with both bikes but. On paper the CB should be the quicker bike by far. But isn't! So I just wonder why.

[bobv7]

You say it's in top condition but it can't be if it's that slow. It may be called a sports bike but it is still only a 175 and the performance can be badly affected by wind conditions, rider weight, poor brake set up and even tyre pressures. Also you may be expecting too much; the difference in top speed of Triumph twins like the T120 and TR6 was marginal even though one had twin and the other a single carb. However it sounds like the carbs and air filters need checking out, and if you use 20W50 oil and not 10W40 that may also increase internal drag.

[Arch stanton]

I am fully aware of the things you point out.
But I am the same rider on both bikes. And the same weigh in each. As for the riding conditions. I have come to the conclusion that the Sloper is far quicker than the CB during the
25 years that I have owned the bikes . Over in America they race a lot of 175,s & the Sloper engine would appear to be preferable
Over the later vertical engine. They rev far more readily.

[bobv7]

The sloper is slightly heavier at 269 lb. and claims 17 bhp @10,500

The K6 a bit lighter 264 lb. and claims 20 bhp @ 10,000.

OK so these are only claimed figures and neither machines are in the first flush of youth by the best part of 40 odd years. However, being a touch lighter and with a bit more power theoretically the K6 should be the faster of the two. As always, it all depends on overall maintenance standards and condition of the cycle parts. Seat of the pants road tests must always be considered subjective and sometimes a bit of speedo tuning comes into play via tyre size. Maybe the US has a surplus of redundant and disposable parts so they're not too bothered or precious about blowing a few up?

[Arch stanton]

In the 60,s Honda knew how to make a bike thrive on revs.
Maybe a bit of GP know-how rubbed of on the humble sloper.
They are certainly more willing to rev that the vertical engines.
Even though it has 1 less carb & 1 less gear.
I'm not just going on Speedo readings I can see & feel the difference.

[hairygit]

If there is 20mph difference between them, there is something seriously wrong with the CB 175, worn cam or timing chain, damaged valves or broken rings, a CB in good order should easily do 80+mph, so if it can't, something is very wrong with it!

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[Arch stanton]

The engine is in fine fettle.
When just driving through the gears. The CB will bob along at 55/60. Thrash it through the gears it will go much faster.
But the cd  revs a lot more readily and rolls along at  faster pace.
Just to make it clear. I am not new to bikes.
I have not been without a bike for the last 45 years.
I currently own 10 bike properly restored by myself to a very high standard.

[bobv7]

Ah well............ But you did ask the question!

[hairygit]

Revving hard through the gears us what the CB was designed for, up to the red in all gears they fly along for what they are. The CD being a commuter bike produces it's torque lower down the range, thanks to the single carb, plus only having 4 gears as opposed to the CB's 5 speeds. All Honda's of that era thrived on revs, my CB175 used to outrun 250 Super Dreams to 75+. If as you say the CB is in fine fettle, once it's warm give it some stick and it's a great little bike, really wish I hadn't  sold mine a few years back as I miss that hard revving little motor.

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[Arch stanton]

Hello Hairy.
I too love my Cb175. It really is a little big bike. It is generally my go to bike. Great fun on the right road. I also have one in my living room. Unfortunately too good to use. But at least it fills the gap where the idiots lantern once stood. The sloper is a hoot to ride revs like mad handles like a tea trolley  & shakes like a shitting dog. But still great fun!