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I've been working on a new-to-me narrowcase 250 Monza that has aftermarket handlebar levers & perches. The clutch pull is very stiff. The perches' fulcrum distances (center of pivot to center of cable end) are about 1.5 inches or 38mm. I am accustomed to British bikes which tend to be either 7/8" or 1-1/16" (22 or 27mm). Can anybody tell me what this distance would have been on the original levers? And can I assume the brake and clutch distances should both be the same?
Thanks in advance!

450 Scrambler is 28 -29mm
Sorry I can't help with earlier models
Graeme

For the 350 scrambler it is 27 mm or less, depending on year i think.
38mm appears to me to be too much.

Are you using a nylon lined clutch cable?
Cheers George

I had the same issue with some cheap scrambles levers with 30 mm cc ,as an experiment i re drilled the pivot to give about 20 mm centers !. It worked well ,so its still in use . The clutch has the Lacey plates ( thicker and fewer than std ) and was carefully set up to spin without wobble when lifted springs slightly packed if needed. I am probably a bit too near to clutch drag although i have ridden it like this for many years including 50 days of holliday in the IOM . try 22mm

My NC 175 has Tomaselli levers which are 25mm as best as I can measure. It has the heaviest clutch action of my various bikes, and that's with one pair of plates removed so the springs are operating at a lower load. The same clutch is suitable for a 250 and I have never experienced any slip. With all of the plates in, my poor little hand could barely pull the lever.

I am told that some NC bikes have been modified to use the longer lever at the gearbox end of the clutch cable.

Hi,

Attached are a few pics

Various levers which i have aquired over the years in my quest to restore a Mach1, so its my assumption that these levers are for the 250 models.

The Mach 1 levers I removed from Mach 1 clip ons to take the pic.

Hope this helps

Bob

I'm so glad I found this group! From what I'm seeing here, 38mm is way too high. George, I had replaced the cable with a nylon-lined version and also tried re-routing it around the side of the cylinder as I've seen a number of people do. Bob, thanks for the photos! I will try a 22mm set and hope it pulls enough cable.

I can offer my own "solution", for what it's worth, on my 1974 350 Mk3...
It's got a standard and untouched factory clutch, but aftermarket Tommaselli levers on the (also aftermarket) Tommaselli-type adjustable clip-ons. The lever's centre-to-centre measurement is about 28mm.
At some point back in the early days of my ownership - I've had it since '77 - the cast cable-adjusting threaded outcrop on the crankcase snapped off, so I made up a steel bracket which I had seen on a race bike. Dead simple, but you do need a crankcase bolt that's a bit longer than standard. I did have a good reason to make the bracket for mounting on the left rather than the right, but I honestly can't remember what it was!
I was always slightly irritated by the cable run allowing it to billow out to the left of the cylinder (I just thought it looked untidy and not very well planned), so I had a go at giving it a curved tube to make things neater, and guarantee smooth movement of the cable.
As you can see from the photo, it's been there quite a long time, and the paint is wearing off the brass tube, but I'm pleased to say that with a lined cable it really is a two-finger clutch. Maybe three fingers at most.
Best of luck,
Pete.

I am going to say "almost snap!" on my 1974 350mk3 which also had a std clutch and the std clutch perch on the std clipon bars, for a number of years I employed a Honda nsr 250 clutch cable with bent guide tubes on each end of the outer sheath, this at a rough guess lightened the clutch lever action by about 30% and worked fine for maybe five years or so, this set up failed for a really odd reason (Documented in a previous post) unimportant to this thread. Certainly bent guide tubes and nylon lined cable plus perch ratio should get the best possible light lever action.
As an aside had anyone fitted an hydraulic actuated clutch on a single?
Cheers George