Cush Drive too rigid

b'knighted

Well Known and Active Forum User
VOC Member
If you have the high first gear the bike is capable of 70MPH in first gear. As I understand it all postwar twins, maybe with the exception of very low geared outfits, will happily pull 70MPH in second.
Rather than trying to improve the low speed, high gear, pull away of a 60 year old bike, wouldn't it be kinder to change down.
I run an original clutch with the Australian extra multispring ESA set up from Neal Videan which I am assured is too heavy for solo use, without problems. If the ESA was intended to constantly run in and out, rather than just react to clumsy clutch take ups, would we not have seen that many had needed replacement over the years due to a level of wear similar to that of cams and followers?
My bike will, if I'm desperate, pull away from a standstill in third gear (on the flat) but, in general use, I change down to accelerate. It may be less economical in terms of fuel consumption, but I'm sure that using more revs to reduce shock loading will prove more economical in the long run. If you want to chunter around at 40MPH in top, why have a Vincent?
 

van drenth

Well Known and Active Forum User
VOC Member
I got the same problem and it endedup that the drive schaft was slipping in the flywheel of the crankshaft.
Regards, van Drenth JC
 

timetraveller

Well Known and Active Forum User
VOC Member
Just a thought here. It is being assumed that the ESA is too rigid but is it? John Emmanuel built a jig which allowed him to run the engine with the primary cover off to use a stroboscope to see what happened to the standard ESA. He discovered that it is really like a switch. Once load is taken up it immediately goes to the maximum position in one direction and on the over run goes all the way to the maximum direction in the other. That is, the standard B/C set up is not rigid enough. Possibly why the 'D's had extra springs? I was just wondering if your problem was that the springs are too week and essentially the ESA is locked one way or the other once it is under load. Just a thought.
 

tjcassar

Well Known and Active Forum User
Non-VOC Member
Ian,
I like to know that I have a well sorted Rapide. That is the reason why I like the flexible engine. Yes, changing down to third gear when just under 50MPH does give a better feeling in the engine. But being in Europe and in the South where the roads are not that straight and fast does make one potter around in top gear at between 30 and 60MPH. I am trying to achieve that objective and have the set up flexible enough to give me this possibility.
I have the first long gear that gives me about 50MPH if I have to, obviously I do not go that route.
Thank you all the same for your input.
Tony
 

tjcassar

Well Known and Active Forum User
Non-VOC Member
I did not go as far as opening up the cases but my shafts seem fine. Thanks all the same.
Tony
 

tjcassar

Well Known and Active Forum User
Non-VOC Member
Certainly not week springs. They are all new and very very rigid. So my problem might be elsewhere. I am suspecting being slightly too advanced. I will check this first and see what the ignition timing looks like.
Thank you all the same for your contribution
 

Tom Gaynor

Well Known and Active Forum User
VOC Member
Tony:

I actually said "pull away at 40 RPM...

I guess this is one of Francois's spruiters, which do NOT act like a switch. (Actually nor do new Lucas or new Roy Price, but new Lucas aren't available.)

It seems to be widely accepted that the D ESA is much better than the B and C, which are not quite in the bete noir category, but just aren't very good. Since my C ESA was worn enough to need new parts (at 45,000 miles), I bought the new parts to converrt it to D spec, and thus upgraded. Until today, now 62,000 miles, I've never thought about it. It just works.

I'm running my standard Shadow, 7.3:1, Gary Robinson 105 Mk II cams, at 34 degrees advance. I suspect that it might go better with a degree or two more, but since it has perfect "city" manners and will haul itself up to 100 mph with no trouble, I've left it alone.

I don't know why, but it does look as though the new springs (perhaps combined with worn parts?) are the culprit

Hi Tom,
I guesss not enough information was given in my short message. My Rapide is set with coil ignition. Its one of those with the bobweights inside the unit rather than the original ones. I have fitted two new Concentrics 928's. And, I have the long first gear!! however, prior to changing the cush drive springs, this did not bother me. I have also fitted the original clutch which works well and does not snap ( This was completly rebuilt so it is as it should be. Yes, I do try to pull off on top gear say from 40MPH, is this not correct?? If I do so, I get plenty of thumping felt on the foot pegs. This also happens on first gear when moving from stand still. I find that I have to rev up and slip the clutch rather than open the trottle slowly and pull up without jerks. It could be that I am slightly more advanced then I should. I will have a look at that now if you tell me thet the cush drive is not the culprit. I do not know these motorcycles enough to have experienced their habits. Is the cush drive one of their bete noir ???
Thank you for your input.
Tony
 
Last edited by a moderator:

Hugo Myatt

Well Known and Active Forum User
VOC Member
Anyone considering updating their Comet to a 'D' ESA it does not fit in the chaincase, at least not in mine. This is with new components from the VOC Spares Co. I wonder what the D Comet & Victor used?
 

tjcassar

Well Known and Active Forum User
Non-VOC Member
Thank you Tom,
I will take your advise and get a D ESA fitted first opportunity. Although, I must say, Once I tightened both chains, it made a huge difference. Still not perfect though. Any idea which parts need changing? Do I need to change the lot??
Tony
 

Tug Wilson

Well Known and Active Forum User
Non-VOC Member
Cush drive.

I have assembled my Comet c/drive with "original" springs after 30 year lay up (basket case) and noted that there is very little movement if pressure is applied to the spring plate. Engine not running yet so cannot test but there is certainly less ramp movement than other British bikes I have owned/repaired. Is this normal?
 
Top