It has been some time since I was here, on the forum, due to a huge workload and business travels.
It is so nice to see all of the old names on the forum, active as always... (-:)
So, it was a while since I rode my bikes and I want to start ride it again.
In one of them, a bike I rebuilt the motor and gearbox with mostly NOS parts,
I have an intersecting issue, which I thought to ask about, before start to dig into it:
I always ride with my left fingers resting on the clutch lever. not pressing, just resting.
-An old habit from when I was riding high-rev 2 strokes which seized at times.. (-:
So what I have on the M20, (WARTIME GEARBOX CASE) is that the clutch tension on the lever is normal, and then, when just cruising in whatever gear i'm in,
I feel that the lever loses tension of about 1/4-1/3 of it's travel.
If I keep riding, it usually pops back after few minutes, and then goes down again after a while...
I can not put more tension on the cable when it is slacked, because after a while it starts to slip on me, upon return of tension,
And on the other hand, it is hard to put into gear and drive at the times when there is a slack.
I can understand the cable tension can be lost, but how can it regain tension after a while, just riding along?...
If it helps, the issue started when I was riding a "longish" ride of about 60Km.
I did think about it, but then,
There are 2 rods with a bearing ball in the middle.
I cannot see a reason why there will be a slack, and then things would be normal,
In a loop every few minutes, but it is easy enough to check it, and I will give it a try.
Just a thought (I’m no BSA M20 expert), could it be that the clutch is slipping and causing it to generate heat, which is in turn causing the clutch plates to warp? This could effect the feel of the clutch, and then return to normal when it cools down. Do you have sufficient free play at the clutch operating arm?
Good luck solving the problem. In my experience the difficult problems are often a result of two contributory factors, showing as a single symptom.
Regarding the slipping- no, all clutch plates are new, both metal and friction plates,
And I can kick it over without any issue. (712cc with one of Ian's pistons) even if I do not press the Ex' valve lifter.
Also, the change is quite sudden- you can feel the lever drop under your fingers,
And after a while you can feel it rising back again, with no RPM change.
Too much end float on the mainshaft is something I did not check.
If I will not find another solution, I will remove the clutch and check all I can.
When rebuilt, I put in a NOS mainshaft with new gears and new bearings.
Al was well at the first 500km, and then it started. very add!
Noam I've seen a bent push rod give similar symptoms. But your ball bearing in the middle should help eliminate that problem. But worth checking. A blob of grease on the end of the push rod to grab the ball and some ingenuity to retrieve the other half without stripping the clutch. Ron
Hi Noam.Ive known ball bearings between clutch push rods to give trouble . I find its much safer to use a 1/4 clutch roller instead.It provides a solid face for the rods to bear against with less chance of the ends flaring and binding within the mainshaft.
So I will will first start with the push rods and the ball, then.
When I inserted the rod, I remember making sure it is straight and has no friction or drag when moving,
But who knows, and anyway, it is the easiest place to start, so fingers crossed the culpable is there.
