Rebuild & Decoke!

[Pedro]

Well, I've finally stripped my bike to find out why it burns so much oil and the good news is that it's all in pretty good nick, except the pistons rings (£90 a set, ahem..) and valve guide oil seals - all about right for 25k miles.

The worse bit is the decoke and oil residue I'm having to clean off...... see the pics for more

Ped

[A Yerbury]

nice, what did you clean them with?
alex.
ps.I have that tooth brush.

[crust]

Looking good

£90 a set :eek:

you didn't go for the hi-comp ones then?

:) Crust

you called? Sodding meeting all day :rolleyes:

[Pedro]

Cleaned the pistons with a 12inch ruler as a scraper then scotch bright to shine 'em up a bit, then polished them. The heads I did with a wire brush in a dremel.

Rings are standard, available from your local Duke Dealer. Didn't go the high comp route in the end, too much aggro to import (although I did chase a set through ebay that didn't sell - he wanted too much money for them imo).

Simon - just called for a natter, nothing urgent, thought you'd like to hear the gory details!!

[A Yerbury]

how much of a fiddle is the head removal? any tips for the cam pulleys?

[Pedro]

Left the cams in in the end, the nut on the pulley is soooper tight!!

Getting the heads off is no big deal, tank off, airbox and carbs etc, exhaust. I had the bike stripped to the heads in about 3 hours and about another hour per head after that

Go on, you know you want too....

[A Yerbury]

so the cams stay where they are (I could look at the book but its in the shed) hmmmm getting there should be easy as now I have keihins and pod filters?

go on I thik I will.

[Pedro]

I also pulled all the rockers out which is, to be truthful, a bit of a sh*t! You need a special puller to draw the shafts out and the return spring on the closers goes off like a bullet when the shaft comes out - nearly had my eye out.

Getting the closing rockers back in is no walk in the park either.....

[A Yerbury]

you see I'm getting nervous now.. it's not about desmo bits lodged in ones face.

[Pedro]

Hehehee, the spring came out with enough force to clear about 10 feet of garage and hit the door behind me!!! It only happened once, I caught the second one...

[A Yerbury]

in your teeth??

[BoozyBOB]

looking good Pedro... ;)
i am a bit thick as you know...has this clean up solved the james bond style smoke screen..?... and why was the heads like this..? is it just age..?...

[Pedro]

looking good Pedro... ;)
i am a bit thick as you know...has this clean up solved the james bond style smoke screen..?... and why was the heads like this..? is it just age..?...

Yeah Bob, oil ring was very work as were the valve guide oil seals. All will be replaced so smoke should be no more. The mess you see is a combination of carbon deposits and oil thats seeped past the seals.....

[Scotty]

i think the 'italian tune up' is for me then rather than the dismantal route

[spacemonkey]

'Only' £90 for the ring set? Blimey where did you get such bargains? I was held up to the sum of £160 for mine!!! Didn't do much about the oil usage though! Smokes a bit still on the over run and when giving it the beans. Next job, valve stems themselves. Have you checked yours thoroughly? Word is that the bores on our early models are made of monkey metal and don't last long. was wondering about getting them plated properly. Has anyone got anything to say on this front?

[Pedro]

'Only' £90 for the ring set? Blimey where did you get such bargains? I was held up to the sum of £160 for mine!!! Didn't do much about the oil usage though! Smokes a bit still on the over run and when giving it the beans. Next job, valve stems themselves. Have you checked yours thoroughly? Word is that the bores on our early models are made of monkey metal and don't last long. was wondering about getting them plated properly. Has anyone got anything to say on this front?

That's £90 per piston......

Valve guides are in good nick, well within service limits but the seals were b*lloxed to say the least - I reckon you could change these without stripping the head if needs be though. Top end gasket kit is about £15

Barrels on mine were glased but you could still see all the original honing marks so I've just deglazed them with scotchbright as recommended by Chris Kelly at California Cycleworks (top fella, very helpful!).

Ped

[spacemonkey]

The valve guide oil seals can be changed without taking the heads off, but involves a bit of ingenuity, and a length of string. I was gutted though to have forked out the best part of £500 odd to stop it using oil, only to find that within a couple of thousand miles I was back to the old oil consumption. Way-feckin-hey....

[CK & AK]

Ped, just wondering why you didnt replace the pistons then mate.

New genuine Ducati ones come complete with the rings etc - pair all in for anything around £140 - 180 (depending on where you get them)
Carbed ones take about 10 days usually to come in to order.

Alan

[Doug]

Nice pics Pedro. Pity you've had to endure the aggro. Thing is, I've got a '94 900, only 28,000 on the clock, but it's been a good'un, no oil burning or such silliness. It's not been mollycoddled either, just regular oil changes. My question is, why do you think this has happened to you? Something as simple as duff guide seals or maybe more sinister such as Luigi having a bad day when he assembled your motor ?

[A Yerbury]

Nice pics Pedro. Pity you've had to endure the aggro. Thing is, I've got a '94 900, only 28,000 on the clock, but it's been a good'un, no oil burning or such silliness. It's not been mollycoddled either, just regular oil changes. My question is, why do you think this has happened to you? Something as simple as duff guide seals or maybe more sinister such as Luigi having a bad day when he assembled your motor ?

I think it's bad karma.

[Pedro]

Ped, just wondering why you didnt replace the pistons then mate.

New genuine Ducati ones come complete with the rings etc - pair all in for anything around £140 - 180 (depending on where you get them)
Carbed ones take about 10 days usually to come in to order.

Alan

Pistons are in very good nick too Al, and I was quoted £135 each (Snells & Rapido).

Ped

[Pedro]

Nice pics Pedro. Pity you've had to endure the aggro. Thing is, I've got a '94 900, only 28,000 on the clock, but it's been a good'un, no oil burning or such silliness. It's not been mollycoddled either, just regular oil changes. My question is, why do you think this has happened to you? Something as simple as duff guide seals or maybe more sinister such as Luigi having a bad day when he assembled your motor ?

Dunno really, the bores and pistons are all ok with no serious wear and tear but the oil ring on both pistons was knackered - I guess they wer a little soft. The bores were glazed too which doesn't help in the excessive oil comsumption issue. The valve guide oil seals were just old, worn and cooked!

Ped

[Unit 18]

On higher mileage bikes its always worth checking the guides for wear by seeing if there is any rocking of the valve stem in the guide. Not uncommon. As far as I'm aware the plating in the barrels is pretty good and long lasting, the only problem being 600's especially the front cylinder which picks up and gives that familiar clanking sound.
Hope it helps.
Al.

[CK & AK]

Blimey Ped :eek: so I got a good deal for the pair then....

[Zimbo]

High compression pistons (JE 11.1-1) are $280 a pair from California Cycleworks, complete with rings pins etc, I've had no problems importing stuff from them in the past, delivered in 3 days with just a bit of duty and VAT to pay if you're unlucky enough to get picked up.