R60/2 kickstart locks at top of stroke

[haroldson]

This is a vexing problem I have with a transmission I rebuilt. It has a new kickstart quadrant and spring. The kickstart operates fine out of the bike but as soon as it is installed the kickstart locks at the top. Will operate with the clutch pulled in to get it started. When returned to to top it sticks again. Has anyone run into this?
TIA
Trig Haroldson

[Pokey]

Not sure if this is a related problem mine would stick at the top also. I pulled it apart and found worn parts. The tip of the spring finger was worn and binding on the driver gear. Please excuse for proper terminology of parts. Pictures to follow. Ron

[Slash2]

Trig,

I’d like to see a photo of your “new” kicker gear. My rudimentary understand is that the spring steel on the end needs to protrude above the first tooth for a very specific purpose. It catches the idler gear and spins it into the proper position to engage properly for the down stroke. If it has been worn down or is too low, then you’ll end up with your problem.

Chris

[Flx48]

Chris-
Yes, that's very much what I see with kickstart issues; the catch spring on the segment gear protrudes over the shortened first tooth by about 1/8", and if that catch spring tang gets worn down or is broken off, the segment and idler gears can bind.

If one installs the segment gear through the rear cover, along with the idler gear being on its spindle, and then moves the segment through its arc, the spring tang extending past the shortened first tooth can be seen to just miss contact with the peak of the first tooth of the idler gear, (this if the idler tooth is positioned such that tip to tip contact between them seems imminent) and instead sweeps the following idler gear tooth into position so as to make full contact between the next idler tooth and the second tooth of the segment gear, putting idler and segment gears in full mesh.

After the kickstart lever motion down, it will return to its upright position, while simultaneously the segment gear reverses direction as it swings back down to its resting position, both being moved by the large return coil spring.

As the segment gear is returning to its resting position and is reaching the end of its engagement with the idler gear, the tang of the catch spring again makes contact with the final tooth of the idler gear on the opposite side of its tang, and the tooth pulls the catch spring away from the segment gear, putting it under tension briefly before slipping off the end of the idler gear's tooth.
Tensing the catch spring causes it to act as a shock absorber, to slow the segment gear's return motion, just before its motion is fully arrested as it strikes the stud boss on the trans case wall.

So, the catch spring has two functions:
First, to turn the idler gear slightly if/when needed for proper tooth alignment on the kickstart downstroke.
Second, to slow the segment gear just before it hits the trans case on the kickstart return stroke.

I see the segment gear and catch spring damage being the result of two factors-
First, poor tuning/hard starting; which results in considerable overuse of the kickstart, compounded with increased operator frustration with the kickstart.
Second, and perhaps more important, questionable technique when using the kickstart.
I see folks put their foot on the kickstart pedal and hammer down from top to bottom as hard and quick as they can.
And some will also slip their foot off the side of the pedal at the bottom of the stroke, allowing the pedal to snap back to the top.
Both these actions will damage the catch spring, because making forceful abrupt contact, in either direction, between the catch spring tang and idler tooth is asking the tang to do the work of a tooth and the tang is not strong enough for that, and after the spring is damaged, tooth alignment becomes hit and miss.

Many of us choose to use a starting technique that begins with pulling in the clutch, putting foot on the kickstart and lowering the pedal till the teeth engage, (maybe a quarter of a stroke) releasing the clutch, and then a solid push through to the bottom, leaving foot on the pedal during the return stroke up to the point the ratchet gear goes quiet.

Ron's reply shows some great examples of the catch spring having been worn all the way down to the shortened tooth height and the beginnings of tooth wear, and no doubt frustrating to start.

Here's a couple of pictures of an unworn segment gear, a pic of the catch spring's tang just clearing a idler tooth, (even though it looks like they're touching) and a pic of the tang sweeping the next idler tooth into alignment.
Best-
George

[808Airhead]

Great post and great advice on starting procedure. Always engage kicker lightly ! Never stomp on it,just engage it first, as stated earlier.

[Slash2]

George,

I'll second that. Great post there! Your write up provides a better understanding of what's going on inside the gearbox during the starting sequence and a few thoughts on how to avoid this unnecessary damage. I've encountered this a few times and have had to replace the kicker segment on my old 1965 R69S when I first got it. Incidentally I've only personally seen this occur on the R69S. One point of note though is that the R69S seems to be somewhat trickier for some to start which often results in over-use and abuse of the kicker.

I have a box with at least 3 used kicker gears in it that I wish I could repair as it seems a waste to pitch them out, especially considering the cost of a new one!

[Pokey]

Slash 11

I made a repair to mine unfortunately I didn’t take follow up pictures. I tig welded a hardened piece of steel to the end of the spring. Then ground it down and hand fitted it for smooth operation. There was several hours spent in n trial and error for sure.
I cut the spring back some and used heat soak paste on the spring. Just to be clear I’ve been known to spend way too many hours trying to save a dollar and spending ten. But that’s me.