Author Topic: GB is not OK, again!  (Read 3918 times)

Online Greybeard

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Re: GB is not OK, again!
« Reply #30 on: 12.06. 2018 19:08 »
OK, how about this theory: One of those dodgy followers got stuck. I cannot see any damage on the piston crowns. I'd better check the valves.

Offline BSA500

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Re: GB is not OK, again!
« Reply #31 on: 12.06. 2018 20:36 »
I feel your pain. All winter rebuild then 200 miles and strip down for a wobbling big end *sad2*

Offline muskrat

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Re: GB is not OK, again!
« Reply #32 on: 12.06. 2018 20:53 »
G'day GB.
Your followers look different to morris's. On his (and mine) the bearing/sliding surface goes all the way to about 1/8" from the radius. Yours are relived to a lot further up with a rough (cast) surface. In your photo 4 there seems to be scuffing on the left follower in that section. What sort of fit are the followers in the barrels? Just thinking with a shorter mating surface and a loose fit could jam.
Did everything look OK under the timing cover?
A snapped crank would be obvious with movement of the conrods and/or drive side crank.
DON'T RUSH.
Cheers
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Online Greybeard

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Re: GB is not OK, again!
« Reply #33 on: 12.06. 2018 21:19 »
Musky, I'll take the followers out tomorrow, so I can have a good look. I've ordered a new set from SRM.

Online KiwiGF

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Re: GB is not OK, again!
« Reply #34 on: 12.06. 2018 21:29 »
Musky, I'll take the followers out tomorrow, so I can have a good look. I've ordered a new set from SRM.

I remember reading on this forum about new cam followers that were made slightly oversize and also with non parallel sides, so the owners had to fettle them (grind/sand etc) to get them to fit.

Did you fit the new valve springs?
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Online duTch

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Re: GB is not OK, again!
« Reply #35 on: 12.06. 2018 21:32 »
 Looking at the wear marks, it appears that the cam is off centre to the left. See how the marks on the Right Inlet (?)(Far right lifter) and Left Exhaust (3 from right) are close to the interface of the pairs, and the other two L-In & R-Ex are further away ?

 This is why I suggested in your build (but maybe a bit late on) to leave the lifters out and put the barrels on and have a dekko down the tunnel to see where the cam sits relative to the lifters (cam butted hard to bush).
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
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Offline Scott and Jay

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Re: GB is not OK, again!
« Reply #36 on: 12.06. 2018 22:37 »
I got my new cam followers from British Spares Austria. They were checked for hardness back here, and proved ok. They had to be fettled to fit in the barrels. They don't seem to be wearing out after 2.5k miles..

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Re: GB is not OK, again!
« Reply #37 on: 12.06. 2018 22:42 »
 
Quote
Looking at the wear marks, it appears that the cam is off centre to the left. See how the marks on the Right Inlet (?)(Far right lifter) and Left Exhaust (3 from right) are close to the interface of the pairs, and the other two L-In & R-Ex are further away ? ......

 The only thing I can think of that would do that is the flange of the inner R/H bush too thick *or* the pinion hasn't pulled up tight to the Cam shoulder, so when the breather goes on it pushes it away.... *dunno*

 *edit 08:17 13/6; I think this is what berger (and I think someone else mentioned 'clipping') was also referring to in a post

 Extra edit; ** also not to say that it is, or part of the current issue
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
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Online Greybeard

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Re: GB is not OK, again!
« Reply #38 on: 12.06. 2018 23:02 »
Did you fit the new valve springs?
Yes

Online chaterlea25

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Re: GB is not OK, again!
« Reply #39 on: 12.06. 2018 23:43 »
Hi GB,
Sorry to hear the gremlins have struck again  *sad2*
I would think that the grey goo on the magnetic plug is from the followers
It is very common to see the followers off set a bit on the cams,
It has happened (old topic here??) that the cam key has prevented the cam wheel from being fully tightened
The nut should feel "solid" when tightened

John

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Re: GB is not OK, again!
« Reply #40 on: 12.06. 2018 23:46 »
 I came back to 'extra edit' my above post to add that if that (and what John just suggested), may be possible the key is reaming the bush- may cause a rattle (?)  *eek*


 Re;   
Quote
Re flushing crankcase: What would you use? If I use petrol will it dry up the journals too much? What about Paraffin/Kerosene or Diesel?

 I always used kero, but was much cheaper then so now I reluctantly just use petrol
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Offline kiwipom

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Re: GB is not OK, again!
« Reply #41 on: 13.06. 2018 01:09 »
hi guys, GB as Dutch says ( I always used kero/paraffin, but was much cheaper then so now I reluctantly just use petrol) but dont light up while you are doing it!!! cheers and good luck
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Online RichardL

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Re: GB is not OK, again!
« Reply #42 on: 13.06. 2018 01:31 »
Hey, to jump on Muskrat's boat, if you ask me, those followers are hideously wrong. Apparently sand cast with no machining to fit the barrels. Then, the surfaces that ride on the cam don't seen to have been hardened with respect the rest of the part. I'm pretty sure the followers would be hardened and that it is unlikely that that hardening would equal that of the forged camshaft (metalurgists here will know for sure).

So, even though the followers seem a likely culprit (and you probably don't need me to tell you this) be sure you're sure before giving them complete blame.

Richard L.
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Online RichardL

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Re: GB is not OK, again!
« Reply #43 on: 13.06. 2018 03:00 »
Hmm, just had a thought. I'm going to be interested to see if one or more of those followers have fractured. That could cause some serious noise while still allowing you to get home.

Richard L.
Plan on signing up for the world-wide 2017 DISTINGUISHED GENTLEMAN'S RIDE on September 30, 2018. Watch website at https://www.gentlemansride.com for details.

Online berger

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Re: GB is not OK, again!
« Reply #44 on: 13.06. 2018 04:01 »
i have been to the pub...... but even I know............never rate man! and that's after looking at the first photo.. mind you I had to enlarge it and change my specks, I would be *contract*