• Don't overlook our Welcome Package, it contains many links to important and helpful information about functions at VHT like posting pictures and sending PMs (private messages), as well as finding the parts you need.

    AD

1968 CB175 K0 - kick start shaft and knock pin issue

Cromwell

Member
Joined
Feb 10, 2022
Total Posts
26
Total likes
0
Location
Alberta, Canada
I was about to close the bottom end of my engine and noticed that there was nothing holding the kick starter shaft in place. The knock pin had been pushed in and was flush with the case. I assumed that this pin had to stick out about 3mm to fit the slot at the end of the shaft. I had a shop remove the pin by welding a piece on the top. to my surprise, the pin measured 15mm - the same as the one I just ordered. Also, the hole the pin sits in runs straight through to the outside of the upper case. I do not understand how this could possibly be standard. Water will seep through into the bottom past the pin into the case of the engine. Is this how the engine was designed? Would I have to order an oversized pin? Any help would be greatly appreciated.
 

Attachments

  • 1644450443748.jpg
    1644450443748.jpg
    128.3 KB · Views: 5
  • 1644450295291.jpg
    1644450295291.jpg
    73.9 KB · Views: 5
  • 1644450426966.jpg
    1644450426966.jpg
    54.1 KB · Views: 5
As happens in some situations when people unfamiliar with Honda engine bottom end designs, if the shaft (often a transmission shaft) bearing cap or, in this case, the kickstart shaft, is not properly aligned with the locating pin before the lower case bolts are tightened, the pin gets punched through the other side of the case. I have not personally seen that happen with a kickstart shaft, but many times with the small end bearings on transmission shafts in our twins (example below). You'll need to seal that hole, probably inserting the new locating pin into the case with a bit of JB Weld on it and then after it hardens, fill the hole on the outside with JB Weld as well (maybe a little at a time if the hole is deep)

gkOAc8h.jpg
 
I am sorry. I understand now. Someone mounted the shaft off line and it pushed the pin through the case. I guess the engine was rebuilt at least once.
 
I am sorry. I understand now. Someone mounted the shaft off line and it pushed the pin through the case. I guess the engine was rebuilt at least once.

Yes, that would be my guess, we've seen it a lot with transmission shafts. Just never expected to see it with a kickstart shaft, but it's the same principle.
 
The hole is approx 18mm deep. I did notice some corrosion on the interior of the kick shaft.

Corrosion undoubtedly from the fact that the hole was open to the environment, unlike the locating pins punched through the interior of the crankcase on transmission shafts. You'll want to clean up the interior of the hole pretty well before filling/closing it. You could also have someone aluminum weld the hole closed too, but it might be costly depending on your locality.
 
The bottom definitely broke off. Lucky for me that the shop welded a piece on the end of the pin. I can stuff JB Weld in then push the pin through and plug the hole sealing it up. Thanks again for the help.
 

Attachments

  • IMG_20220210_114706.jpg
    IMG_20220210_114706.jpg
    68.2 KB · Views: 10
  • 1644518874164.jpg
    1644518874164.jpg
    96.5 KB · Views: 11
Back
Top Bottom