Wrist Pin Bushing R&R tool

[huntmiller]

I need to replace a wrist pin bushing on my R69s. It's 20mm. I'll tell you how I diagnosed this: I took the motor apart to clean the slingers which were 100% full but not spilling into the main bearing hole yet. With the crank out I wasn't sure how to test the bushings but got some Prussian blue applied it to the bushing and slipped the wrist pin in spinning an pushing it in the same direction a piston might. One bushing showed no color, just the slightest translucent blue. However the other bushing showed deep dark blue on both top and bottom. My first thought was to go to Cycle Works but I have not been able to get a response from Dan after several attempts via email. I've been told by another airhead peer he had to get a "real" job. I've also looked to other sources for the tool to no avail. Anyway does anyone have any advice on how to purchase or borrow a wrist pin R&R tool? This is something I'd like to take on my self but after facing dead ends for several weeks, I'd consider sending the crank to someone. I have ordered a bundle of (3) chrome hardened 20mm ball bearings from a bearing shop. Still not sure how to press the old bushing out. Thanks in advance for any help.

[schrader7032]

I see that Vech doesn't offer the tool. Of course, he can do the work...closed this afternoon.

The VBMWMO has incorporated the VMCA News Bulletins...there was a tool loan program with that club, but I suspect that it may have died...a little hard to keep up with the tools, etc.

I suspect it takes a special press to push the bushing out...I suppose a proper fitting socket could be fitted on one side, but then you need something to stabilize the conrod while it is pushed out the other side.

Another way of checking the bushings are to ensure they are concentric and square to the rods. I thought the process was to rotate both rods around to one side and then somehow slide a wrist pin through both bushing...not sure if the wrist pin is long enough to do that.

[huntmiller]

Thanks I appreciate the information. I was loaned a 20mm rod to perform that test. How can you tell if it is within specifications with that process of using a 20mm rod through both bushings? Is a tiny bit of wiggle acceptable?

[schrader7032]

I don't really know...hopefully someone might. But certainly, if the rod can't go through, you have a problem. I suspect that the Betjemann repair guide has something on it...I'm not too good at finding things in there.

I've looked at the guide, but I don't really seen any guidance on this.

[malmac]

I have not needed to do this yet though I have the parts more or less ready.

REMOVAL.
I plan to use a fine hack saw blade to carefully cut almost through the little end bush.
That should relieve much of the pressure and allow the bush to be tapped out with a suitably sized drift.
Because the bushing is quite thin walled, a suitable socket might still need the face ground to make the corner profile square.
I hope that makes sense.

INSTALLATION
Warm the end of the conrod with a heat gun to say 150F and chill your replacement bushes.
Preferably press into the conrod little ends but really that could most likely be tapped into place with a suitable drift given your crank is out of the bike..
You could also consider using say an 18mm metric fine bolt and suitable washers to act as a mechanical press.

BARRINGTON covers the subject on P164-165
A pic of the cycle works tool is on page 62.

all the best with your project.

Mal
Australia

[schrader7032]

Thanks for the reference, Mal. I guess this is the kind of thing that I have trouble with on the Barrington manual. That particular discussion is not listed in the table of contents...I searched it a lot. It seems that little tidbits like the wrist pin discussion that are in those gray boxes for highlighting are not part of the table of contents. And since there's no index at the rear of the book, it's hard to find things.

[huntmiller]

Thanks Mal,
I have the fourth edition 2019 of Barrington's manual. The wrist pin tool that I don't think Dan offers any more, is the last tool discussed in "Cycle Works Tools" my page 52. The discussion about R&R of the bushing is on my page 210 in the section "Crankshaft Evaluation and Renovation".
I purchased three of these for under $10 from simiplybearings.co.uk:
20mm Diameter Grade 10 Hardened 52100 Chrome Steel Ball Bearings
High Precision Grade 10 Hardened Steel Ball Bearings: High Quality Graded Hardened Chrome Steel Ball bearings made from Chromium AISI 52100 steel. Hardened to 60-67 Rockwell Scale equivalent to 700-900 HV (Vickers Scale) and are hardened all the way through the ball. These are the same hardened steel balls used to manufacture bearing assemblies and have a high duty and life cycle.

[malmac]

Thanks Mal,
I have the fourth edition 2019 of Barrington's manual. The wrist pin tool that I don't think Dan offers any more, is the last tool discussed in "Cycle Works Tools" my page 52. The discussion about R&R of the bushing is on my page 210 in the section "Crankshaft Evaluation and Renovation".
I purchased three of these for under $10 from simiplybearings.co.uk:
20mm Diameter Grade 10 Hardened 52100 Chrome Steel Ball Bearings
High Precision Grade 10 Hardened Steel Ball Bearings: High Quality Graded Hardened Chrome Steel Ball bearings made from Chromium AISI 52100 steel. Hardened to 60-67 Rockwell Scale equivalent to 700-900 HV (Vickers Scale) and are hardened all the way through the ball. These are the same hardened steel balls used to manufacture bearing assemblies and have a high duty and life cycle.

Hunt

Is that a self portrait you use for your avatar????

Mal

[schrader7032]

Pablo Diego José Francisco de Paula Juan Nepomuceno María de los Remedios Crispiniano de la Santísima Trinidad (aka Pablo Picasso) -

https://www.pablopicasso.org/before1901.jsp

[malmac]

Pablo Diego José Francisco de Paula Juan Nepomuceno María de los Remedios Crispiniano de la Santísima Trinidad (aka Pablo Picasso) -

https://www.pablopicasso.org/before1901.jsp

Well I should have recognized the style at least - but cant say I have seen that particular painting before.

Mal