BCS-740 - Problem with gear shift

RussellRay · Jan 18, 2015

Dear all

For about a year I have owned a BCS-740 (European equivalent of 749 / 853)
powered by a Honda GX-390 petrol engine.
So far I have only used it in mower mode
(handlebars reversed, implements fitted to PTO at front, e.g. mower, shredder).
This was the position in which the tractor was delivered.
All controls (clutch, gear shift, PTO engage, brakes) worked fine.

I have now - for the first time and taking care to do this correctly
(i.e. gear and PTO rods detached, direction of turn, etc.) -
turned the handlebars round to normal mode
(implements fitted to PTO at back, rotavator, plough, etc.).

But I now have a problem with the gear shift rod.
Its movement is extremely loose and sloppy.
As soon as I try to move it into 1st (or any other) gear,
the joint marked in a circle in the attached picture
won't stay straight but keeps twisting and buckling to the left,
so that changing gear is not possible.

I can't see any way to tighten and straighten this joinnt.
It is held only by a pin, it seems.
(There is a nut at the very bottom of the gear rod
but I don't think this would make any difference.)

Is this joint damaged ?
Is there some way to fix this myself ?

Best regards
Ray

Jens767 · Jan 18, 2015

Hi Ray

You are absolutely right about the joint. It is held in place only by a little pin, and there are no way to tighten it. The nut at the lower end of the command lever is of no help to you. It only keeps the lever in place, and puts a little pressure on the spring. I am sorry to say, but to me it sounds as if you have broken it

But don't worry - I paid only 3,42 € for a new one, and it is very easy to replace yourself.

In this thread (page 6, at the bottom), you can see how it is supposed to be connected:

http://www.tractorbynet.com/forums/2-wheeled-tractors/231657-powersafe-clutch-bcs-6.html

If your tractor is only about a year old, you should easily be able to rotate between front-PTO (mowing) and rear-PTO (tilling) mode. On older tractors that have been used in the same mode for years, the PTO-lever - and sometimes also the column for the handlebar - can corrode and get stocked. This should not be the case with the command lever, as the rotation takes place at the top, plastic against metal. The two other ones rotate metal against metal, and if they are not properly oiled, they can "freeze" and you can easily break the plastic-joint at the top of the PTO-lever.

You should be able to rotate the gear- and PTO-pull rods with ease, so if you feel any resistance at all doing it, something is wrong!

I hope you will be up and running soon :thumbsup:

Best regards

Jens

P.S. Thank you for your nice comments on my English - like you, I try to do my best.

RussellRay · Jan 20, 2015

Hello Jens et alia

Thanks for your quick and informative reply.

I've removed the gear shift rod.
(I assume the only way is to withdraw the cotter pin at the joint.)

I can't see anything that might be broken.
So I'm just going to reassemble it and try again.

In the photo you posted it looks like your tractor is in front-PTO mode
with the gear shift rod inside and cotter pin outside.
So, in rear-PTO mode, the rod would be outside and the cotter pin inside.
Is that correct ?

Ray

RussellRay · Jan 20, 2015

Update

I'm beginning to think that the joint might be intact after all.

What makes the gear shft rod and the joint twist to the left is
that I am exerting pressure much more from the vertical than the horizontal.

If I withdraw the gear shift rod from the plastic clip and apply pressure from a lower angle
the rod and joint do not twist and the gear shift works OK.

But in rear-PTO mode, it seems, pressure will always be more from above.

Ray

Jens767 · Jan 23, 2015

Hi again Ray

I am not sure that I fully understand the "twist" that you have experienced, but I am glad nothing was broken!

When I got my BCS, I noticed that the joints for both the gear- and the PTO-rods are rather delicate. It has not been a problem though, and with normal gentle operation, they will probably last very long.

You are right about the clip. Just remove it, and the rod, the joint and the command lever can be separated.

You are also right about the clip when switching to rear-PTO mode; then the clip is on the inside, towards the tractor.

As you rightly point out, there is a difference in the angle between the gear rod and the command lever, depending on the selected mode (front-PTO or rear-PTO).

In 3rd gear, the command lever is almost vertical, leaning slightly away from the PTO-flange. When selecting 2nd or 1st, the command lever leans more and more towards the PTO-flange. With the handlebar swung to the front-PTO mode (last picture), the angle between the gear rod and the command bar is about 100 degrees with 1st gear selected. From a physical point of view, this is close to ideal (90 degrees is ideal), as you need to push with the lowest amount of force possible, to produce max torque on the gear lever. At the same time, it puts less stress on the joint. If you swing the handlebar to the rear-PTO mode (first picture), the angle has increased in all gears. In 1st gear it is worst, as the angle has increased to about 150 degrees. As you say, this means that you press more vertically. Due to the increased angle, you now have to push 97 % harder to get out of 1st gear than in the front PTO mode! Because you have to push almost twice as hard on the gear rod, you also put more stress on the joint of course, and perhaps that was what coursed the twist.

Sorry - this was a lot of reading for a minor issue perhaps, but the bonus was a little recap on force and torque

Best regards

Jens