norvin

[Howard]

Jim,
In the absence of a reply from John (I'm sure he'll get back to you) - The CB750 seems to have come in 2 lengths, there is a fairly short one, and one that apparently comes from a sport model about 1974 which is longer. Mine is the longer version and reaches the bottom of the back inspection cap, where John's reaches the top. If you're cutting and joining two together I can't see it matters which you go for. The Honda spline is smaller, so it leaves just enough room to cut a Vin one. You may need some fancy work on footrests and gearlever to avoid the kickstart, because it starts from above them, not below like the standard Vin one.
I haven't managed to fit mine yet due time constraints and commitments so I can't post a photo.

H

 

[jim burgess]

Thank you Howard,
when you say "room to cut a vin one" for the splines do you mean that you hand cut a new spline? Err. How? Files? I have never tried and thinking about it, it seems a very difficult proposition...
cherrs
jim

 

[Howard]

No, I had it wire eroded.

I meant the Honda one was small enough to allow it to be cut out, and a Vin spline to be cut in its place.

 

[John Jones]

Hi,
I'm sorry you didn't get a reply. I did leave one yesterday but I am using a new Mac and it seems to have got lost in the inter web. I'll try again.

 

[John Jones]

This was the 2nd posting that has not appeared.

The CB750 F has a kickstart that sticks out a little at the gearbox end as on my photo.
This means it throws the lever further away from the casing and is better than the earlier CB lever.
A 6" splice was cut on each lever to give a long weld joint.
The finished length is only about 1.5" longer than the Honda lever and about 1" shorter than the Vinnie.
The shaft hole had to have the splines recut by a local engineer who made a jig and used some kind of milling machine.
I'm not an engineer but do know that the spline arrangement is the same as a Burman box.

 

[John Jones]

 

[Little Honda]

Hi, John,
can you give the figures of your front forks springs? Mine are original Atlas 99, which are too soft, visible by a shorter visible chrome blend. Are you using the
standard Norton rear brake? I disliked its very poor braking performance plus the disadvantage of having all foot mechanics on the right engine side. Better to
have the rear brake anchor plate on the same side where the pedal is - less friction, easier ops.
To my taste, yours is the most beautiful version, I have seen so far...

 

[Little Honda]

Well done, John! I had the same problem on my Atlas99-frame and had to scrap my first main stand, when I changed my rear wheel to lhs- brake anchor plate,
which caused a new main stand, made from a MotoGuzzi1000 - main stand. It needed new lugs to be welded under the beginning of the lower rear frame bends. I was surprised to find out, that the frame bends had got different wall strengths by bending at the works, causing some excitement during welding!
I solved the spring problem by 2 non-contenting spring-solutions by using rubber! This sort of rubber ring, truckers are fitting their trailor-cover with to the frame.
If PIPER use rubber bands to support their undercarriage of PA18s, it cannot be the wrong material for a main stand!

 

[John Jones]

Hi Little Honda.
​

The forks are manx but to increase the strength and take the extra weight of the Vincent engine, we put in both internal and external springs.
​

Then Dave the guy who did the work for me pushed the forks up and down and we shortened the inner springs until it felt just right.
​

When first riding on the road the forks would occasionally top out if I went over a hole or the front went light so we took another 10mm off the inner spring length and now it is perfect.
​

You can also make the internal springs shorter and then turn packers to fit under the fork top nuts pressing on the springs. These can then be adjusted in length to get your preload just right.
​

The rear hub is manx magnesium from the 1950s . I wanted to use a rod instead of a cable so Dave concocted a neat crossover mechanism through the rear engine swingarm mount (which had not been cut off).
​

​

 

[John Jones]

I mentioned earlier in this thread that on fitting the Quaife box I had experienced a slipping clutch, then when shimming out behind the gearbox plate to push the mains haft to the drive side and pull the clutch centre in towards the drive side the gear change became stiff.
Well now I think we have solved the problem.
The splines on the Quaife mainshaft are so tight into the V3 clutch centre that it was not going fully on by about 2-3mm.
This caused the clutch to slip badly.
By shimming the mainshaft we solved the slipping but made the gearbox tight.
By stoning the splines for an hour we have managed to get the centre fully home making the clutch tight and the gearbox loose.
Final testing tomorrow.

Another issue with the V3 clutch graunching occasionally.
When you pulled in the clutch lever the pressure plate would not lift evenly. The obvious thing to do is to shim the springs even though it should not be needed on a new Kawasaki clutch.
What I noticed was that when I rotated the clutch the unevenness of lift would change position randomly. So however you shimmed the springs you could never get the pressure plate to lift evenly as it rotated.
The problem is the pushrod being loose in the mainshaft and not being supported at its end.
The solution (I hope) is a phosphor bronze bush and a neat little ball bearing in the pressure plate.
Roll on the Manx.