March 2024
Not long after I completed work on this bike in late 2022 it suffered a broken kickstart return spring. When I pulled the outer gearbox cover the spring was indeed in two parts, so it was simply a replace and refit exercise.
Last week I got a call from the owner to say it had repeated the same failure, so he brought it over with the kickstart neatly tied up with string. The bike still looks spotless although I had removed the battery cover to tone it down a bit in the title pic.
After draining the gearbox oil I removed the outer cover again, noting that the kickstart cotter came out nicely thanks to my grease last time. However, the spring was not broken, only dislocated. Here are the bits after removal, although I had already put the spring in the vice and closed up the tail end loop.
Everything else inside the outer gearbox was all in order and cleaned up easily, although the oil residue looked very black as if it contained some sort of sediment. Considering that I had put fresh oil in it when doing the first work on the bike a year or so earlier this seemed a little strange.
It was at this stage I had decided to remove the pinion and ratchet assembly, as something other than the spring was now implicated.
If the loop at the outer end of the return spring could have conceivably pulled right over its mounting peg, it would need a reason to do so, considering it only tightens by a little more than 180 degrees in service.
This bike has always been a bit particular when engaging the kickstart and would most often require pulling the clutch to allow a neat engagement. I now wondered if in any way this behaviour could be responsible for the spring receiving the wrong treatment. Now that I looked at the quadrant I could see that some serious wear was evident between its teeth and those on the pinion. But wait - shouldn't there be another tooth.? Every quadrant I have gotten up close and personal with had the first tooth machined away, but this had two missing. At first glance it appears to have also been machined, but close inspection gives the impression that it has met a rather nasty fate and been chewed off.
The pinion teeth also showed signs of distress, with the outer edges of the teeth quite noticeably rounded off. Back in the day I would have ignored such signs and thrown it back together, whereas I now have much less effective eyesight and simply miss things if I don't decided to get some greater magnifying glass to see the finer details. I often take photos with my phone so that I can expand them... sigh.
I figured that the state of these meshing - or not - gears was probably introducing quite a bit more required effort when kickstarting, which was probably putting a whole lot of other bits under greater stress than it should, not least of all being the operator.
Fortunately my usual suppliers had all three of the necessary parts - quadrant, pinion and ratchet, although I decided it would be prudent to also replace the oil seal, which they also had. The arrival of Easter then disrupted play while the couriers partied.
The arrival of the bits confirmed that there was enough wear in the originals to warrant their replacement. I had not found any lumps resembling bits of the missing tooth, but seemingly there was a fair bit of metal in the oil, so the gearbox will get a sacrificial flush before refilling.
The quadrant will need to be pressed or driven off the shaft, and having never done one before I hope it does not require more effort than I can apply in a non-destructive fashion. Counting the teeth the new one has one and a half more teeth than the old one, so here's hoping it makes kickstarting a much more enjoyable affair.
I need not have worried, as the quadrant came off the shaft without much complaint at all, and I only used my copper mallet and the vice. However, the first attempt at driving the new one on met stronger resistance, so I opted to pour boiling water over the quadrant before the second attempt, which did effect an improvement, but washed away my marker pen guides in the process. I thought I had it sussed and drove it on without any great drama, only to find I had the spline one tooth out. It came off easier than it went on, but now I applied a good smear of grease to every tooth of the coarse spline as well, and it drove on perfectly and in the right position. Phew. Third time lucky.
Next job was to refit the new pinion plus ratchet and other gubbins, and heeding the warning in the workshop manual used my torque wrench to tighten it to 40ft.lb. rather than risk distorting the thin walled sleeve within. I also gave all the new teeth a coating of grease so they would play nicely and the ratchet lock washer got applied. I was rather focused on progress now and forgot to take any photos.
Next I drove the oil seal retainer out and cleaned up the recess, then fitting the quadrant and shaft into the outer cover and preloading the kickstart spring the outer cover was finally pressed home and bolted together. The oil seal and its retainer had just been driven fully home before taking this pic, and you may be able to see why I felt that it needed replacing.
It is so much easier to give cases a bit of polish while all the pegs and levers are off, so I did that after adding 850ml of synthetic gear oil to the mix. The gearlever and footpeg then went on and the kickstart last. I gave it a couple of kicks immediately, and it eased into mesh without any hesitation, so that is already a big improvement. It does feel more positive in its action, and I realise now that it had lost a bit of its arc of engagement with the missing tooth, so very glad it alerted us to the problem by flicking its spring off.
Next job will be to warm the bike up a bit and see if I can improve on its starting behaviour, but the timing is not right for that today.
