CS57 questions - MVAgusta.net
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post #1 of 11 (permalink) Old 09-24-2017, 12:33 PM Thread Starter
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CS57 questions

I've read that the CS57 engine had improved oil feed to the cam shaft, as cam shaft "burning" was a major cause of failure on early engines including the CSS.

First question is, "Does anyone know what the modifications were?"

Second question is, "Should I convert mine to through the cam lobe oil feed?"

By the way, my CS engine is serial number is 473512 S and the frame is 419210. Are these correct for a CS57 (although UK logbook says it's a '58)
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post #2 of 11 (permalink) Old 09-26-2017, 01:20 AM
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Hi Mondello175,

Can't say anything about modification of the lubrification system of the camshaft.

My bike is from 1956 and it frame number is 417 280 , engine number 473 031.

Regards

Alexander
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post #3 of 11 (permalink) Old 11-14-2017, 07:14 AM Thread Starter
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I can now answer my own question

I've now removed the cam cover and can see the difference in cam oiling.
My CS57 has the oil spray tube to the side of the cam rather than over the top - see new photo. This is obviously a better system as the oil is sprayed onto the face of the rising lobe just before the rocker, rather than the earlier system that sprayed onto the back of the rocker, in the hope the oil would run onto the cam. The lobes don't show any visible signs of wear but I'll need to check the lift when I get the cam out. It should be 7.5mm as far as I can tell? If it measures OK, then I'll probably not do the "through the cam" oil mod I was planning. Only concern I have is whether the oil flow is enough for the jet to reach the lobe at idle. I guess it must be.

All I need to do now, is figure out how to make a device to compress the hairpin springs - suggestions?
NB. there's not much space below the spring to insert a compression plate.
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post #4 of 11 (permalink) Old 11-14-2017, 09:10 AM
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Compressing valve springs?
Two thoughts both have been used on my vintage Guzzi singles.
1. There is a special tool available for Guzzi Falcones which looks like it will work.
I got mine from nonsologuzzi in Italy though it is not on their website: index
He had one on his stand at Novegro Scambio (jumble) last week which I bought for a friend of mine in the US.
2. Try using a short bit of 8 mm (maybe 10mm) studding and a couple of large penny washers above and below spring and tighten up the top nut and squeeze the spring down.
I used this on my Guzzi Dondolino race machine and could change the springs without taking the head off!
Hope this helps.
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post #5 of 11 (permalink) Old 11-14-2017, 02:32 PM Thread Starter
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Solved but now I have a new question

Thanks for the suggestions Gordon but it's OK as I've now got the springs off.
I formed a piece of fairly thick mild steel to go under the lower leg of the spring and drilled it in the centre to take a 6mm coach bolt. The benefit of a coach bolt is the square under the head stops it from turning when you screw the nut down. It was very tight to get under the spring and I even had to file down the head of the coach bolt to make clearance.
Not the prettiest of tools but it worked - see photos.
I suggest anybody doing this wears safety goggles as the last spring slipped out of the clamp as I removed it and ended up behind me (over the top not through!) Also when I refit them, I'll cable tie the clamp to the coil spring so it can't come off.

Now the next question.
When I removed the lower spring support from the valve stem (item 33) it was fitted with an O ring in the counterbore on the top face. However, the MV parts diagram seems to suggest the O ring should be at the top of valve stem, above the collets - see extract from parts list. It's item 36 which is described in Italian as "Plasttico per valvola".
I've never know an O ring be fitted above the collets, so is this just an error in the diagram?
Interestingly, the O ring was moving with the valve stem and this could make it act like a pump as it goes up and down in the counterbore. I'm removing the head as the motor is making blue smoke and I wonder if this could be the cause - pumping oil down the inlet valve? Thoughts everyone?
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Last edited by Mondello175; 11-14-2017 at 02:37 PM. Reason: correct typo
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post #6 of 11 (permalink) Old 11-15-2017, 06:08 AM
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Nice tool that you have made.
Don't know about the plastic bit but I'd be tempted to have the part number 34 x-rayed. There appears to be a crack across it but hope that I am wrong.
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post #7 of 11 (permalink) Old 11-15-2017, 07:38 AM Thread Starter
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Well spotted. I noticed that but haven't examined it closely yet. I think it is just a flow mark in the casting but will at least look at it through a microscope. Thanks.
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post #8 of 11 (permalink) Old 12-06-2017, 10:47 AM
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MV tools

Guys,

Here's some of the tools my friends Barry, Dave and I have made or had made and used on our Discos. The swivel socket is very helpful as well to get in around the valve train. The clutch tool is self explanatory. The photo with the wood box is a factory shop tool kit. I am still trying to ID a couple of the less obvious pieces.

That oiler should be OK as is, for street riding. But for abusing the motor a drilled cam with pressure feed thru the small radius of the lobes of the cam is likely helpful. This requires a spring with a sacrificial foot that rides on the end of the cam shaft to direct the oil into the cam aperture.

It is imperative with these motors to careful to not allow any dirt or lint into the oil, and to change it often. Also be sparing with the sealants. One chunk of RTV loose in the motor could get expensive fast.

I don't recall seeing an 0-ring or "plasttico" part in these motors valve assembly. Is it even necessary? There is an o-ring under the cylinder stud washers to keep the oil in the head. There's no room for a proper valve seal. A bit of blue smoke only after decel wouldnt bother me much assuming the alternative is seizing a valve in the guide. Oil is cheaper than cyl head repairs.

I need to visit this forum more often, your enthusiasm helps keep me enthused about my own MV projects.

Ivan
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1954 MV 175 CSS Super Sport
1957 MV 175 CS Modello Sport
1967 Motobi 125 Sport
1974 Ducati 750 GT
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post #9 of 11 (permalink) Old 12-07-2017, 03:29 PM
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Hi Ivan,

nice to read something from you here. I missed your knowledge.

Regards

Alexander
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post #10 of 11 (permalink) Old 12-09-2017, 04:19 PM Thread Starter
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Sound advice Ivan - many thanks.
I like your 14mm socket to tighten the head bolts. I see it is commercially available, so I'll buy one to tighten the head down. BTW what torque do you suggest for the head bolts?
I've made my own copper head gasket from 1.2mm copper and just need to anneal it.
The previous engine builder had gone a little bit crazy with RTV sealant, so I'll clean the oilways as best I can and do more frequent oil changes initially. I prefer gaskets to RTV only, mainly because I like making them! (Primary casing was only RTV and leaked a little)
I've made some valve stem oil seals to fit under the lower alloy spring retainer plate (item 33 on diagram), using some automotive parts. I trimmed them to fit using a mandrel in a lathe and a very sharp scalpel. I'll post photos later. Your comment about seizing a valve in the guide has worried me. Surely this won't happen with the brass/bronze valve guides fitted to my cylinder head? or will it?
Thanks gain for your advice.

Last edited by Mondello175; 12-09-2017 at 04:37 PM.
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