Got my hands on my first enduro, 1973 CT175. Trying to use it as a true dual purpose bike, riding from my house to all sort of local trails and mountains. What i have quickly learned is its almost a death wish to be outside neighborhood streets on this thing if there is a hill or head wind. Climbed 1,000' on pavement over about 5 miles yesterday and the bike would not pull 5th gear at all, I was down to 4th at 7k rpm to try to maintain 45mph (55mph road, single lane each direction). No idea how others ride these bikes, but is 7k for a few miles on end acceptable? I am much more familiar with 4stroke dirtbikes, not road sections or 2 strokes.
Compression test shows 100-110 hot, WOT, starts and runs good, just doesnt seem to have the power for 5th unless its flat or downhill (hit 60mph coming back down). Would a milled head be worth it to try to overcome the 5th gear bog? would the extra heat not be worth it? last thing i want is to be sitting on the side of the road blown up. Bike currently is mostly stock, stock pipe but missing the spark arrestor (id like to find one) and a slip on foam air filter. Considering richening the needle 1 notch to see if power on hills feels any different. just picked up 2 new plugs yesterday to try to get a fresh plug read as the other one has a lot of carbon buildup from the getting it running phase. 

Burning out the crap in the exhaust pipe might help. Also KDI has the spark arrestor.

On my CT3 I had the cylinder milled down about 30 or 35 thousands so the piston was at zero deck height at TDC. This did give my CT3 a boost . Also, I do agree with goatboy56. Pull the spark arrestor and make sure it is not clogged up, that will definately limit the power

Exhaust is important plus correct ignition timing as points tend to close down with fibre heal wear if not been check for years which retards the timing.
But bottom line--are you expecting too much from the old girl--just asking so as to compare with similar or same model that others are using in comparable conditions.

I might be expecting too much out of it, but its also hard to find much info on how others use similar bikes and given the bike was nearly 20yrs old already when I was born I have no first hand experience with seeing these things on trails/roads.
I am loving the bike, it just quickly became apparent that it is much happier on the trail or on small neighborhood streets not on wide open roads fighting Karen in her Subaru lol
With that said, how "OK" is it to run these things at 6500-7k rpm for 5 or so miles at a time? Many of my planned rides require short 2-10 mile road sections. a little more torque would definitely be beneficial!

I geared my 1975 DT 175B up one tooth on the front sprocket (from a 16 to a 17)and now for me 55 mph is 5500 rpm and 60 is 6000 rpm. I will run 55 t0 60 mph in a 55 zone for 5 to 10 miles and have had no issues now I did have enduronut port the cylinder(basically just smoothed/cleaned it up) and mine has no trouble getting to 7500 rpm and maintaining it on flat, slight hill or with some head wind.

Just pulled the side cover off mine, had never checked gearing and just assumed it was stock. I believe my factory gearing was 15/45, mine has 16/45. Cant go any bigger on the front.
i should also add im running a "huge" 130/80-18 rear tire that adds a few percent to my gearing/speed over stock. 

As mentioned by RT325 timing is important. The timing for the CT is 1.8mm BTDC, meaning that the points should open when the piston on the up stroke reaches 1.8mm before top dead center. Have you checked the timing?
Also, I have worked on many, many CT's and a correct running CT should easily run a 17/45 gear ratio (16/45/ is stock). On my CT3 I used a 4.10X18 Kenda K270 rear tire, also used a Kenda K270 on the front. The Kenda's ran GREAT on the road and in the dirt.

According to my research the 73 ct175 had a 15 tooth front sprocket. Looking at mine with the 16 I don’t see how a 17 could possibly fit and looking online I see 13-16 tooth available aftermarket but no 17 listed as available for my ct175.
I have not touched or checked timing. I’ll have to figure out the correct procedure to do so.


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84Prerunner-

Just as an FYI, DVM built the BEST running CT3 I've ever ridden.  And he rode the wheels off of it over many years on some very challenging trails.  He also was behind the "sleeper pipes" and part of a land speed record team that ran a CT at over 100 mph at El Mirage.  Speeds were certified by the SCTA (The same people that run Bonneville every year)

My point is that when he posts about a CT3, it reminds me of the old EF Hutton commercials....  

"When DVM speaks CT3, people listen."