ES2 transmission judder

Previously wrote:

Hi Albert . I had a very similar problem with a Norton 99 many years ago. It was worse when the engine had got very hot. It was a sort of judder and screech and it was very annoying. I also suspected the clutch at first, butI alsosuspected it might well be the drive side bearing outer race spinning in the crankcases. Like your problem it only occured when pulling away in first gear, I cannot remember if I ever fixed it, (40 years ago). Also, just like yours, the noise was always accompanied by the drive grabbing quite fiercely which made town riding in heavy traffic nearly impossible. As I go through the memories now, it does seem that it has to be the clutch plates going into a fierce chatter and grabbing, but I distinctly remember suspecting the main bearing spinning in it's housingtoo at the time.

I know you have checked the clutch, but it could just be the steel plates are buckled very very slightly and when they heat up the deformation increases, so when they come together they cause a severe vibration as they pass over the other plates friction inserts just before they actually close up together, but having just said that, the screechwas very sharp and quite metallic that's why I considered the bearing outer was spinning in the case.

Anyway, I would check the clutch steel plates on a surface plate (granite kitchen cutting plate) perhaps using some engineers blue to witness the contact. You could use a straight edge but I think a surface plate would be better with this circular item. You could alsouse wet and dry abrasive paper to clean up the surfaces of the friction plates before reassembly too, but pre oil them first. If it isn't the clutch maybeI was rightabout the bearing. I'd be interested to hear what was wrong when you solve it.

Les

Many thanks Les for your reply.

I will check the plates for warpage. I was wondering if play in the silentbloc bushes in the swinging arm would also give rise to such a judder/snatch symptom ?

a

Previously wrote:

I don't think that would be the case Albert. I know my Featherbed bushes were ok, but swing arm bush wear can cause a vibrationand usually this if felt when one locks up the rear wheel in a skid and you get a strong noisy vibration run through the frame.

Thinking back, the memories of problem become clearer, and I can now hear and "feel" them as if it was riding the bike yesterday, more so than any other physical memory, including the handling, it was such an odd effect. Releasing the clutch slowly produceda strong simultaneous metallic screech and an uncontrollable lurch as if I had dumped the clutch, plus avibration felt right through the bike, but only when the bike was getting hot and bothered in traffic.

The reason I suspected the main bearing problem has also become clearer too. I'm pretty sure at the time I thought the clutch wascausing the grab and vibration (which must be obvious) but I was convinced that the sudden primary chain load, caused by itdoing so, was side loading the main bearing with such an extra forceas to cause it to slip round in the case and it was this that was creating the screetch. I think this may well have been proved correct with a later engine strip down but cannot remember for sure.

Les

PS Of course, I am assuming your symptoms are the same as my ones, they do soundvery similar but the reality could be that theyarequite different.

There are very strong similarities Les except for the screaching sound, but I cannot bring myself to accept that the problem goes beyond the clutch and final drive. The bike does lurch forward but it does so all the time, fresh out of the garage or have been on the road for a while. I will try the bike out without the primary chaincase on, in the hope of noticing something happening as i take up the drive.

a

Previously wrote:

Hi Albert. With the extra info of your last postit does seemsomewhat different to what was happening to my bike especially that my fault only occured when the engine and transmission had become very hot and there is no screetching either.Your last post also says it is there all the time whether cold or hot.

Someone has emailed me to suggest it is the the nut on the top gearbox bolt that is loose, allowing the gearbox to move. As this is easy to check, perhaps you should do this first. It could be this and if so, make sure you go right through the primary chain adjustment routine (slacken the primary chain with the adjuster and thenpull back with the adjuster to the correct primary tension and tighten large nut.)

Les

Hmm could well be Les, but I wont be able to check it before next Wednesday as I am going away for a few days. Will let you know what I find though when I do. I thank you for all you help and guidance.

Best wishes,

Albert

Previously wrote:

Albert:

When you "checked the clutch" did you fully disassemble it?

I would think that the slots in the clutch basket have gotten indentations in them. As you go to release the clutch the drive plates are hanging up on the indentations.

Anyway, just my thought. If you are going to disassemble the clutch to check the steel plates, take a look at the clutch basket slots.

Mike

Hi Mike,Many thanks for your email.Yes I did check for that sort of problem but I found none. In fact both basket and plates are new. I have discussed the problem with other fellow vintage motorcyclist and it seems that the problem could be due to the fact that I am running the clutch dry (ferrodo linings). The reason for this is that I cannot find a replacement rubber gasket of the right width and thickness to make the chaincase oil tight.I have been advised to pour an eggcup full of ATF over the plates, apparently this does the trick.Will try anything at this point.Regards,Albert