Loop frame heim joint shift linkage slop?

[BrianK]

Greetings all.

Has anyone done this mod to a loop?  I'm referring to this:  https://www.thisoldtractor.com/moto_guzzi_loopframe_shift_linkage_-_footboards_and_a_5_speed_transmission.html

I followed Greg's instructions to the letter.  He reports of his mod, "the levers are completely without play now and give a really positive feel to the foot controls. It was terrible before, so I'm really happy with the modification."  Me, on the other hand, I've still got plenty of slop.  The heim joints permit an inch or two of play before they even begin to engage the gearbox splines.

Very frustrating.  The gearbox requires such long throws already, that adding additional throw to the linkage really makes shifting hit or miss.

I'm probably missing something basic.  Wouldn't be the first time.

Thanks - BrianK

[Tom H]

If you did like the pictures show, that removes all the slack from the pivot points where there was just a pin.

Are your levers loose on the splined shafts (pic 3)? For the shift, is the bushing set in the tube shot (again pic 3)?

I did this to both of my bikes and they are great now. I did need to replace the all the bushings in the pedals and the tube.

Tom

[BrianK]

Good suggestions Tom.  Gearshift pedal was loose on the splines, easily tightened.  Bushes seem okay.  I'm reinstalling in a few days with new heim joints; maybe the last ones wore (although I put them on, and I haven't put many miles on the bike since).  Here's hoping.

I will report back!

[Tom H]

I'm sure you know this. Everywhere the new joints are, you need to get the nuts and bolts tight otherwise they will just move around in the worn out holes.

Let us know how it works out!
Tom

[BrianK]

Everywhere the new joints are, you need to get the nuts and bolts tight otherwise they will just move around in the worn out holes.

Exactly the issue I'm running into now Tom - and I don't know how I solved it last time around (probably didn't, hence the current problem).  The non-splined end of the lever to which the top heim joint attaches fits nicely over the part of the heim joint that provides a couple flats you can get a wrench on.  But then I have no leverage to tighten the nuts on the other, outer end.  I could put a washer or nut on the inside but then the hole in the lever is so much bigger than the threaded shaft of the heim joint it doesn't seem right.  I guess if the nuts are tight enough it will work but seems like there should be a better way.  Too, doing that means the lever will be locked into position vis-a-vis the shaft of the heim joint and unable to rotate around it.  Maybe that's okay...?

Trying to see if I have anything to bush that hole with but haven't found anything yet (in my own parts bins).

PS - duh!  grip the end of the shaft with vice grips while tightening!  Problem solved.

[Tom H]

It reads like you solved your issue. The vice grip type pliers on the threaded end of the bolt/stud could be an issue down the road.

When I did my bikes, the Rod Ends that I used required a bolt and nut with washers. They did not have a "stud" fitted into them. The holes were rather worn where the rods attached to. Using a M6 bolt, flat washers and a nyloc nut solved my issues as well as new bushings as needed.

BTW: Guzzi bushings will not solve the slop of the brake and shift levers. Where the levers pivot on are worn as well. Guzzi stock will work as long as the pivot is not worn. Otherwise you need to find a bushing that fits the brake and shift lever hole, but ID too tight on their pivots and open up the hole to fit your pivot point.

Option: You could either dill out your brake/shift/levers and install a bushing/sleeve/tubing to make them M6. Or just drill them and use a Rod End like a M8. But then you would probably also have to make new rods that connect them out of M8 rod cut to fit and then thread the rods.

Congrats!
Tom

[guzziart]

Greetings all.

Has anyone done this mod to a loop?  I'm referring to this:  https://www.thisoldtractor.com/moto_guzzi_loopframe_shift_linkage_-_footboards_and_a_5_speed_transmission.html

I followed Greg's instructions to the letter.  He reports of his mod, "the levers are completely without play now and give a really positive feel to the foot controls. It was terrible before, so I'm really happy with the modification."  Me, on the other hand, I've still got plenty of slop.  The heim joints permit an inch or two of play before they even begin to engage the gearbox splines.

Very frustrating.  The gearbox requires such long throws already, that adding additional throw to the linkage really makes shifting hit or miss.

I'm probably missing something basic.  Wouldn't be the first time.

Thanks - BrianK

I haven't performed that mod but since I'm too ignorant to do the Guzzi shift pattern sequence with a high level of consistency, I did the following mod to my '72 Eldo before I zig when I shoulda zagged.

[BrianK]

Success!  Play greatly reduced.  Road test tomorrow but all seems well.  [PS - road test went great!  Night and day difference in the shifting.  I'm very pleased.]

Tom H., I was definitely a bit squeamish about using vice grips on stud threads but managed not to bugger anything up.  Quite an accomplishment for a guy whose motto is, "tighten 'er til she strips, then back off 1/8 turn..."

Guzziart, I thought about installing the way you did - certainly a lot easier (and I think the "geometry" of the linkage would be a bit more linear that way) - but I wanted to preserve the original shift pattern.  Part of the charm!  Of course, my favorite bike is a right-hand shift (1 up, 3 down) Norton Commando so that may explain it in part....

Appreciate as always everyone's advice and moral encouragement. Much appreciated!   

[Tom H]

Congrats!!

Now I'm not sure what you have, pegs or foot boards. Here is my foot boards and linkages.





Tom

[Kiwi_Roy]

I kind of like the play in the linkages, sometimes its a 3 speed perfect for around town, other times I can usually coax it into the top two gears by a quick jab at the pedal.
It seems to me more of a pawl adjustment than linkage slop, I love the way it shifts up and down, I don't expect it to shift like a modern bike.
I'm just weird I guess.

[Muzz]

I know the OP has a big block, but I had the same problem on my B750.  Made my own pushrod out of 12mm bright steel and used good quality Heim joints.  Machined up a bush to remove the sideways movement in the gearpedal shaft; the shift is now much more positive and the linkage rod doesn't keep bending.