Yamaha Triples
Search Forums | Statistics | User Listing Forums | Calendar | Albums | Chat | Skins | Language
You are logged in as a guest. ( logon | register )

Contact Breaker Drive Pin - Successful Extraction
Moderators: Moderators

View previous thread :: View next thread
   Maintenance and Repair -> IgnitionMessage format
Posted 2017-03-24 4:49 AM (#152976)
Subject: Contact Breaker Drive Pin - Successful Extraction


Posts: 79
Location: Perth, Australia
The part that I'm referring to is a 4mm diameter pin numbered 15 on the attached diagram. Upon reassembly of the ignition components following their removal to attend to a leaking shift shaft seal, I found that I'd pushed the pin too deeply into the hole in the shaft. This left it flush with the shaft and therefor provided no means to positively engage the contact breaker plate. I tried a number of methods to try to withdraw the pin including:
- super-magnet
- superglue on a rivet shaft
- JBWeld on a rivet shaft
- drilling with a 3mm cobalt drill bit
This last attempt failed to mark the pin and possibly pushed it into the tapered end of the blind drill hole in the shaft.
Finally I decided to attempt to weld a stainless steel welding rod to the end of the pin to pull it free. The work was undertaken by a kind and gifted friend. This is what we did:

- remove petrol tank
- remove RHS muffler
- lay bike on it's RHS on a thick mattress of rags
- clean pin and surrounds
- check for access to fire extinguisher
- saw off a 12mm length of the threaded portion of an 8mm bolt, weld a short steel bar at an angle to the top of the threaded rod to use as a handle to wind it into the crankshaft until it's "flush", and then use this as an earth for the welder. This was done to avoid just using the motorcycle earth and thereby risk damage of high currents through bearings etc.
- weld (TIG) SS rod with extreme care to the small (4mm dia) pin
- grip pin with vise-grips and pull steadily and axially

This worked, but only when pulling so hard that my pal nearly fell over backwards.

The hole in the crankshaft to receive the pin measured 8mm deep and the pin that had been fitted (perhaps not original) was 8mm long. Given that the slot in the contact breaker plate is 3mm deep, it would appear that the pin should be a minimum 10mm long, and preferably around 11.7mm. Does anyone have any info on this, or the original specns?

(Screen Shot 2017-03-24 at 4.37.56 PM.jpg)


Attachments Screen Shot 2017-03-24 at 4.37.56 PM.jpg (79KB - 11 downloads)
Attachments Contact_Pin.JPG (68KB - 13 downloads)
Top of the page Bottom of the page

Jump to forum :
Search this forum
Printer friendly version
E-mail a link to this thread


Running MegaBBS ASP Forum Software
© 2002-2018 PD9 Software
(Delete all cookies set by this site)