Frame Tuning

[davidd]

I thought that this was interesting in terms of technique and tools. It is an involved process so there are two videos. If you want to follow the computer screen shots, full screen is best.

https://www.youtube.com/watch?v=hmyR9_VeKQE

https://www.youtube.com/watch?v=Tp3GPHSLXKM

David

 

[vibrac]

thats a lot of technology and equipment to accurately get to measurements that I guess must have been obtained by 'seat of pants' somewhere.

For the seat of Pants method, You cant beat Mervin Stratford who has developed his pre war 250 Rudge over 50 years (he used to overtake me on my Norman B3 twin on the way to work in 1961 on one of the Rudges he still races) I saw him beat a field of yamaha two strokes at Pembrey one day - magic stuff.
I said to him one day in the paddock "that frame looks a bit bent to me the rear wheel is not in line with the front its at an angle."
"I know" said Merve "Its supposed to be, thats my Cadwell short circuit frame I dont use it at some circuits".....

 

[craig]

Hi David, In this digital age, is there a standard tool to set up a Vincent UFM and/or RFM to check and correct alignment ? This video was very inspiring! Thank you
Craig

 

[timetraveller]

Just to give you some idea of what can be done without special tools but with lots of care. One of our local members, who earned a living from rebuilding classic racing cars and old motorcycles, bought an ex-Argentinian twin and set about checking it out. Using only straight edges, set squares, clamps and the kind of measuring equipment we almost all have, he found that the inner faces of the rear frame lugs, which take the rear wheel spindle, were not parallel when clamped up to the correct width. Frankly I have never even thought to check that measurement. Fortunately he had the skills and equipment to mill the two inner faces back to parallel. Ingenuity and care can replace a lot of high tech. The device shown in David’s video is a treat to watch but my guess is that it cost a fortune and requires a lot of training and practice to make best use of it.

 

[davidd]

I have spent a lot of time aligning transmissions (on singles) and rear wheels, but I have never done the "GMD" digital alignment. I have found that the rear wheel on the racer is perfectly aligned with the front wheel and transmission when it is cocked 1/8" to one side of the RFM. As a result, I do think it is worth checking.

David

 

[clevtrev]

I have spent a lot of time aligning transmissions (on singles) and rear wheels, but I have never done the "GMD" digital alignment. I have found that the rear wheel on the racer is perfectly aligned with the front wheel and transmission when it is cocked 1/8" to one side of the RFM. As a result, I do think it is worth checking.

David

So what happened to your chainline, after you cocked it up ?

 

[Kansas Bad Man]

Just to give you some idea of what can be done without special tools but with lots of care. One of our local members, who earned a living from rebuilding classic racing cars and old motorcycles, bought an ex-Argentinian twin and set about checking it out. Using only straight edges, set squares, clamps and the kind of measuring equipment we almost all have, he found that the inner faces of the rear frame lugs, which take the rear wheel spindle, were not parallel when clamped up to the correct width. Frankly I have never even thought to check that measurement. Fortunately he had the skills and equipment to mill the two inner faces back to parallel. Ingenuity and care can replace a lot of high tech. The device shown in David’s video is a treat to watch but my guess is that it cost a fortune and requires a lot of training and practice to make best use of it.

Five years ago vincent.com ask me to write an article on this very subject. It is written in 5 parts and is titled (FIRST THINGS FIRST) go there lots of info gained from restoring lots of Vincent's , written not to sell but to share. ENJOY ITS FREE!

MAX

From the plains of Kansas.

 

[bmetcalf]

Can you share the URL page address? I looked for it and couldn't find it.

 

[roy the mechanic]

A very impressive set-up. I bet the "magic" set ups are not on his computer for our old clunkers. Many years ago I had a "big one" on my racer. Took it all to bits, went to the local motoliner fellow, he made a good job of aligning the headstock to the swingarm pivot, what he neglected to do was check from the rear spindle (axle) location to the headstock. Put it all back together, it handled like a pig with a wooden leg ,the swingarm was twisted! Now i do it myself with bits of string and spirit levels and set squares. The way the guy in the video was working from his special swingarm pivot reminded me of this aggravation.

 

[TouringComet]

Can you share the URL page address? I looked for it and couldn't find it.

I think this is what Max is referring to, scroll down a ways

Max Restoration Notes