Crankshaft dowel pins

[Tino996]

Hi to all,My name is Martyn. I am new to this forum having just purchased a 1974L 750 for restoration. I have managed so far to split the engine and remove the crank, so I can get new bearings and seals fitted. I have found a few things that need to be addressed, but I have noticed that the bearing dowel pins that sit in the bottom crankcase, have been worn down and are flush with the casing. I can't seem to be able to remove them. Has anyone else dealt with this before, and any tips please?
Thanks
Martyn.

[canaletto5]

Hi Martyn. Welcome to the forum.

It is unlikely the pins are worn down. They tend to get stuck in the locating holes. A bit of boiling water generally releases them. Have a go at that first. Kev

[Tino996]

Thanks Kev, ill try that. Unfortunately they are flush with casing, so nothing to grab hold of. So maybe hot water and a light tap from other side?
Martyn.

[canaletto5]

Hi Martyn

Yes, that should do it.

Kev

[teazer]

Dowel pins should be above the surface as you know. That raises a question of why they are flush. The most common cause is previous owners assembling the cases with the bearings not on the pins. That causes the pins to be presses through the casting and usually cracking it.

Examine the lower surface of the lower crankcase half for cracks and signs of pins pushing through. If that's the case, you may want to think about new cases. It is possible that you might be able to press the pins back into place and seal the cases with weld or Devcon F.

[Kettletimes3]

As teazer say's the dowels locate the main bearings to prevent them rotating,
Also to align crankshaft,Look on the underside of the lower case you will see where the dowels have pushed through,
You could get them welded.

[canaletto5]

If they have been pushed down that far then they will have pushed through the seat underneath them. I had this with my 750. I found that the seats were plugged rather than solid ali. I dug it out and resealed it with JB Weld.

[hardrider]

had this on kawasaki triple case drilled small hole on other side of case then use small punch then jb weld

[Tino996]

Thanks for all your replies chaps. Very helpful forum. Upon further inspection, the dowels have indeed been pushed down for whatever reason. I have managed to push them up from underside, by removing a spot of sealant that had been used to seal them in!
Maybe I can use some weld or weld mix, to keep them in situ permanently once I’ve installed the crankshaft, and made sure the pins are in place!
Martyn.

[barney01]

http://www.halfords.com/motoring/paints ... rced-epoxy