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Scored oil pump face on G5 crankcase.

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Pentode View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pentode Quote  Post ReplyReply Direct Link To This Post Posted: 18 Dec 2018 at 15:39
So I took the plunge this afternoon and decided to have a go at using a ground steel block and some wet & dry to take the surface back.

After about an hour, the worst of the gouges had gone leaving a mass of smaller scratches. I may try and find some finer paper to finish the surface off. As it stands, it's probably a better surface than I could get with my mill.


Cheers Grahame


Edited by Pentode - 18 Dec 2018 at 21:14
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Brian UK View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 18 Dec 2018 at 17:10
That's probably better than new, provided it is still dead flat.
Brian.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Chris A Quote  Post ReplyReply Direct Link To This Post Posted: 18 Dec 2018 at 17:27
Impressive...I'd reassemble the pump ( depending on how that measured up) with a small smudge of anaerobic gasket paste  on the flange and all should be good
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pentode Quote  Post ReplyReply Direct Link To This Post Posted: 18 Dec 2018 at 17:40
Brian,

Yes, that is a concern....

I'm hoping to borrow a thin slip gauge and rest it in various places on the face whilst shining a torch behind it to see how much light bleeds underneath the gauge.


Chris, 

Depending on the results of the above decides whether I slap some 'gloop' on it to seal it.

Thanks chaps!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Kidneb Quote  Post ReplyReply Direct Link To This Post Posted: 18 Dec 2018 at 18:20
That looks good !

Together with a new HMB pump you should be good to go.
No experience with the HMB pump myself, but I would be surprised if not both the materials and the tolerances are better than the OEM one.
 Never liked the design of the single sided plain bearing of the driven wheel though.
Here's how I modified my pump, where the driven wheel runs with a bronze bushing on a slightly shrunk in and fixed shaft.
It seems though, that the Guzzi oil pumps keep working and provide sufficient oil pressure no matter how worn they are, and that most riders never look into them.




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Post Options Post Options   Thanks (0) Thanks(0)   Quote red leader one Quote  Post ReplyReply Direct Link To This Post Posted: 18 Dec 2018 at 19:57
Nice.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pentode Quote  Post ReplyReply Direct Link To This Post Posted: 18 Dec 2018 at 20:50
Hi Kidneb,

Yes, I like that. It looks much more rigid, which can't be a bad thing 👍

Many thanks for your kind words Gentleman!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pentode Quote  Post ReplyReply Direct Link To This Post Posted: 19 Dec 2018 at 20:21
So following on from Brian's post regarding whether the face was flat - no, it wasn't. In fact it wasn't good at all....

Placing a ground edge on the face and shining a torch from behind showed a dip in the middle -




Taking a step or two back 40 years (gulp...) to my apprenticeship days, I thought I'd have a go at scraping the surface flat. Using a HSS parting off tool, I scraped away in a series of arcs for about an hour until the original surface had gone then gave it a VERY light tickle with some fine emery.

Checking with the torch and 'scraper' showed a marked improvement. 




I think I'm happy with that now 👍
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 19 Dec 2018 at 22:18
Looks like you've done a pretty good job there.

It's a long time since I last used a scraper. Big end shells on a Gardiner.
Brian.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pentode Quote  Post ReplyReply Direct Link To This Post Posted: 19 Dec 2018 at 22:29
Why thank you kind Sir!

Ooh, scraping big end shells - now that's a job and a half.....
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Dave P. Quote  Post ReplyReply Direct Link To This Post Posted: 19 Dec 2018 at 22:55
There are very few design features of the Guzzi engine that I don't like but the oil pump is definitely one. It is very similar to the Laverda design in that it uses part of the crankcase casting as a precision surface against which runs a moving part. I've never understood why many, but not all oil pumps are self-contained bolt-on units. Surely the self-contained unit is a more elegant option. I've had to do the same as is described above on a Laverda SF 750 and it's a very tedious way to spend an evening.
TO LIVE OUTSIDE THE LAW YOU MUST BE HONEST.

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1970 T120 Bonnie. 2009 500 Bullet.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pentode Quote  Post ReplyReply Direct Link To This Post Posted: 20 Dec 2018 at 07:11
Yes, it's not ideal. Although there's the option of machining the face back a couple of millimeters and replacing it with plate of equal thickness.

However, as you say, a self-contained pump would be the way to go.

What other design faux pas do you feel have been made?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Dave P. Quote  Post ReplyReply Direct Link To This Post Posted: 20 Dec 2018 at 08:11
Well, as you ask, I don't like crankcase castings doubling us bearing material. So the cam follower tunnels could have been bushed. In practice, it probably doesn't matter as it takes a very high mileage to wear them out. I'm being a bit idealistic.
TO LIVE OUTSIDE THE LAW YOU MUST BE HONEST.

1971 V7 Special. 1972 850GT.
1970 T120 Bonnie. 2009 500 Bullet.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 20 Dec 2018 at 09:28
#i agree on the pump, but with other things like bushing cam follower tunnels, cost has also to be considered, and since they don't really wear out as they are, I can see why they don't.
To be honest I would prefer the oil pump case to be made of a slightly better material.
Brian.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Dave P. Quote  Post ReplyReply Direct Link To This Post Posted: 20 Dec 2018 at 09:48
Yes, the cost is always a consideration. In my ideal world, motorcycles, and other things would always be built to the best possible standards. One can but dream.
TO LIVE OUTSIDE THE LAW YOU MUST BE HONEST.

1971 V7 Special. 1972 850GT.
1970 T120 Bonnie. 2009 500 Bullet.
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