A few more newbie questions on 450 Desmo engine

[Paul1098]

Just wondering how easy it is to get all the oil out?
The bike had done a 50 mile run so oil was hot.
Done an oil change but seem to be 250ml short of the 2.4L required to refill the bike.

I have been informed that the dip stick is from a narrow case so would give me a too high oil level so not too sure what the correct level is.
Any idea where the level should be wrt fill tube (bottom, middle, etc) I'm assuming the bike should be level rather than on side stand?

When I was checking the valve clearances I noticed that there was movement in the guides so thinking of fitting new guides which brings me to the next question.
Do I need to remove the camshaft to fit valve guides and recut valve seats and if so does that mean I would need to reshim the camshaft and bevel to get the correct timing?
I'm debating whether to do the head myself or send the whole engine off to a bevel specialist as I've never shimmed bevel gears before.

[Jordan]

On my widecase, the dipstick indicates oil should be near the bottom end of the extension tube.

No need to remove camshaft to access guides. Even if you did, replacing existing shims will restore the shimmed clearances as they were.

You can either remove the guides cold, as per factory suggestion, and install oversized guides to compensate for the bigger holes that result.
Or you can warm up the head to expand it a little, and the guides will come out without changing the hole diameter significantly. Then replace with guides of the same outside diameter as the old ones.
The second method is unofficial, but it's what I do on my aluminium head bikes including Ducati.

[Paul1098]

Thanks Jordan,

That was where the oil was when I originally got the bike but thought i'd better check after not being able to get all the oil in. To check oil level I've assumed level ground and bike upright, both wheels on floor?
I've been waiting to get the correct dip stick off a friend but I think it's about time I invested in buying one.
I'm guessing that I've not managed to get all the oil out hence 250ml short on the refil as the extra 250ml would have the oil level part way up the fill hole.

I had seen the factory suggestion of pushing the guides out cold but heating up before replacing the guides. I'd not realised pushing the guides out cold would increase the hole size significantly. I'd better check what size guides are readily available and if required push them out hot.

[Duccout]

Hi Paul,

There is some disagreement about the best way to remove guides. Anthony Ainslie (who was the UK'S top singles specialist before Nigel Lacey) recommended driving the guides out cold, but Steve Wynne (of Sports Motorcyles and Hailwood fame) recommended driving them out hot, as does the Ducati factory bevel twins workshop manual. Apparently phosphor bronze expands at a higher rate than aluminium, which accounts for the different opinions. I don't know what method Nigel or Eldert recommend, but I have seen some experts who put the guide drift in the freezer, then heat the head, and then use the frozen drift to contract the guide and quickly drift it out.

Don't shoot me, I'm only the messenger.

Cheers,

Colin

[Andy Higham]

The safest way is to set the head on pedestal drill so the guide is vertical in both planes and concentric with the spindle, then drill the guide to within 0.5mm and then collapse the guide.

An even better method of repair is to have a K liner fitted to the guide, this removes the possibility of damaging the guide bore in the head https://cylinderheadshop.com/k-line-guide-liners/

[themoudie]

Aye Paul,

I would agree with Andy Higham, in that using K-liners removes the risk of galling and enlarging the valve guide holes. I use these on my '74 450 and have had no problems, with them.

However, I would disagree, with Andy's recommendation of using the Cylinder Head Shop to carry out the work, having had them do some work on a Ducati single head for me that required me to take it straight to my local engineer to rectify their off true work on the valve guides and sloppy job of re-cutting the valve seats off-centre to the valve guide bores.

The Cylinder Head Shop sales pitch is beguiling, but my experience was otherwise. Caveat emptor!

As for doing the job of removing valve guides, without removing the camshaft, in my opinion you are just asking for trouble. If any swarf from the valve guide refurbishment gets into the camshaft bearings, it would prove expensive! Shimming requires patience, shims and a good micrometer, whilst you keep all the shims in the order of disassembly. Hoping that whoever built the engine before was correct in their choice of shim? There are few engines about now that haven't been stripped since leaving the factory. Aye blethermaskite, I accept your 350 is a rare beasty!

Good health, Bill

[ranton_rambler]

I had my 175's head K-lined, and the same on one of my Guzzis. All seemed fine to me.

[Jordan]

Apparently phosphor bronze expands at a higher rate than aluminium

Not on my planet.

[Duccout]

Hi Jordan,

I got that info from a book called 'Ducati Tuning' by Steven Eke, who used it to explain that heads should not be heated prior to removing valve guides. Just shows that you cannot believe what is written in books!


Cheers,

Colin

[Paul1098]

Thanks Gents,

Lot's of info to take in.
I like the idea of drilling then collapsing the guide but that would certainly mean removing and reshimming the camshaft and bevel drive. I'm sure shimming does require patience but I was under the impression that it also required knowledge and skill and I'm not sure I have those hence reason for wanting to leave the camshaft insitu.

Not sure I could use the K-liners as it's a desmo head.