2001 monster s4 worn valve guides

[gggrrrr]

Hello, first post here.
So I bought the bike 3years ago in pretty bad shape. No maintenance for at least 5years.
I'm not a mechanic and this is my first Ducati.
I'm in the process of my second valve job (this time I've also checked valve play) and here are my findings:

All 4 exhaust guides seem shot, about 0.5-1mm (.02-.04") play measured at the top of the valve stem (see video).
Looking at the valves, at least 5 seals are bad (see pics).
Did a compression test, engine was cold, exhausts and intakes removed:
horizontal dry: 10.5bar, wet: 11.8bar (152, 171psi)
vertical dry: 11.5bar, wet: 11.8bar (167, 171psi)

Bike actually starts and runs pretty good but had some weird idle issues even after fuel system rebuild and setup. No smoke and maybe 0.8L (quart) oil loss / 5000km (3000miles). There is a pretty loud valve noise-like ticking above 4200rpm which I couldn't locate and didn't seem to get better or worse since I own the bike.

Looks like I have 3 options:
- remove heads, find a machine shop and let them replace guides, seals and recut valve seats
- buy used heads on ebay
- leave it as is

Problem is, I'm on a budget and in my country the work ethic is absolute dogshit. I have nothing but negative experience with the local ducati community, especially with mechanics so I dont't trust any of them at all. There is one reputable machine shop but I'm not sure if they have experience with Ducati heads. They are closed for the holidays until next week.
Also, I'm not sure if rebuilding the heads is economically viable. I guess it would cost third / half of the bikes value.
Buying used heads online doesn't seem to be a good idea either.

What would you do? Any out of the box ideas I might have missed?
Any input would be gratly appreciated.

pics, video:

https://imgur.com/a/0fDPIlN

 

[slob]

Welcome to the forum.
I would avoid buying used heads as you might find yourself in exactly the same position you are now, just poorer.
The other choices come down whether the bike is a ‘keeper’ or not. If you see you see yourself riding it for several years get the work done, if you think you’ll be riding something else in July, leave it. (although that sounds like a lot of play to me).
Either use your trusted machine shop or send the heads to a specialist in another country.

 

[Nickj]

That doesn't sound like particularly poor compression pressures and they are pretty consistent between cylinders.
The oil use doesn't sound excessive and the lack of any smoke anywhere with the good compression tends to point to everything sealing well.
On valve guides Ducati possible did possibly put in a short run of poor grade valves which may have had too much bronze content BUT that's one of those urban myths neither proven nor unproven. The play, that's the old 'wiggle test' at the end of the valve stem near the can follower which is in the same school of accuracy as a bit of cigarette paper and ignition set up (you need to old to appreciate that one! )?? Ideally it would be tested where it matters which is using the edge of the valve. You'd want to measure at the valve lip because the guides tend to wear into an hour glass shape and usually the top of the stem is further away from any pivot so really distorts what you're seeing, make the distance shorter reduces the numbers significantly.
Seals are items that will wear out so replace them, it'll probably drop the oil consumption significantly all on it's own.
I assume this play is in one plane, along the line of the bike and much small sideways.
Ticking noise, desmo heads are intrinsicly noisey and it is easy to become a bit selective on your perceptions of what is noisey, like a drip from a water leak it's quiet until you notice it then it just gets louder. If you've come from a Japanese bike it will sound like it is going to drop apart into many pieces. I'd look at the trailing edges of the cams for wear and the followers but wouldn't be overly surprised if I didn't find anything. I might just be a combination of wear through all of the parts.

Used parts ... Heads would need a strip and full rebuild as it's likely they are being sold for a reason. You always have to assume that the 'immaculate as new used only 250 kms from new' has actually gone round the world at least once, was serviced by a monkey and was just cleaned with a carbide grit blaster before being advertised so that it looks good. Oh and the monkey left all of the oilways full of crunchy carbide.
Repair .. If the bikes for keeping then yes find a good mechanic and get the job done. It's a mechanical job, the same process on virtually all heads from anything that burns fuel so they might have never seen say a veyron head but they'd still be able to change the guides. It might be that it ends up having been just a piece of mind spend but then you'll have that piece of mind and be happy that all is well.
I'd mention that my father rebuilt a triumph triple head including all new valve guides on the kitchen table with a pretty minimal tool set.

I'd be tempted to think (feel free to shoot me down in flames on this) but if the bike is running well, is using minimal oil and isn't smoking visibly AND, if a gas analyser on the exhaust measures it as pretty clean, then it is probably good for quite a few miles before panicking and moving to potentially expensive work.

 

[Dukedesmo]

As above, compression doesn't sound too bad but, if it were me I would want to address the sloppy valve guides.

In fact I recently did exactly that with my M900 a couple of years back: It was running fine until it broke the gearbox, upon strip down I found the exhaust valve guides were badly worn and whilst it wasn't causing any problem, I knew it would in the future so I had the guides replaced.

Wasn't particularly expensive either (though the shop took ages to do them) at £240 for all 4 guides, I also had the guides on my Guzzi repaired with 'K-line' guide liners - where they essentially bore the existing guides and fit the bronze? sleeve, supposed to be better than new guides? this only cost £130 for the 4 valves (but it was 10 years ago).

So I don't think repair is likely to be extortionately expensive, probably around £400-500, if you can find a good repair shop, if so and you can do the strip/rebuild that's likely cheaper than a dealer service!

Buying used heads is likely to be more expensive and could, as above, come with the same problems (or worse) than you already have?

That said, I have got an S4 head in good condition (guide-wise) that I bought years back as part of a job lot (primarily as a donor for the rockers it contained) that I'd be happy to part with for not much - heavy item to post abroad though.

It was a rear head that came complete with cams, valves, rockers etc. but they are interchangeable rear to front as they can be assembled the opposite way round (need the right camshafts though) but I do only have the one head so if going that way you'd need to find another.

 

[jerry]

The compression figure seem very good ,,,, My S4 in Thailand has now done 57,000km burns a little bit of oil but im not worried ,, performance is still mega .... if I had to have major machine shop surgery on the valve guides or a rebore etc it could be a bit hit and miss in Thailand there are some very good shops here and a couple of race bike preparers and rebuilders but a lot are of local engineers ignorant and sloppy ..
What about getting the heads to a specialist in Austria or Italy if you dont trust the locals???

Check first with the decent local machine shop , doing valve guides is a common job they may well be able to do it if you supply the parts

 

[manwithredbike]

Plenty of sound advice above re keeping/selling on soon etc. The valve stem play does look pretty excessive in the video, stem seals would take a bit of a battering on there so not surprised that a number of seals are gone. I've replaced guides myself on a few bikes over the years with good fitting drift and some heat from the cooker!! Admittedly not on my monster but it shouldn't be an impossible job with the right size of drift etc and even better if you can find a mechanic with a press. Re the ticking, have you checked valve/shim clearances? You could do that with the heads off as well as the cam shafts & lifters/pushers. You could also lap the valves back into their seats providing they're in good enough condition. The compression you measured would indicate so.

 

[gggrrrr]

Thanks for the replies, it is very nice to hear your opinions.

I can see now buying used heads without inspection is the worst option.

The bike is a keeper, I love it and I'm not interested in newer bikes. Already done a lot of work on it and planning to visit the track this year. Now I'm in the middel of a major overhaul, bought an s4r rear shock, rebuilding the forks and also wanted to replace the clutch.

I understand now the valve guide issue is basically a financial one. So far I've been doing pretty good value vise but if I take the heads off I'm pretty sure the cylinders will come off so I have to redo the base gaskets. There is 1bar difference in dry compression so I guess the horizontal cylinder / rings are a bit worn. Machine shop may find bent / worn valve stems etc.

I can live with the idle problem but the ticking is really concerning. It starts spot on at 4200rpm and it is louder than any other engine noise. My clutch is super quiet with closed cover and the engine sounds very very nice other than the ticking. I tend to use the bike under 5000rpm because I cant stand bad noises.
I did the valve clearances two years ago, they are still good and there was no change in the ticking.
I searched for months on every forum but never found a similar case or any clue.
Do you think loose guides can produce this kind of ticking? Everybody says the only symptom is oil consumption but i could imagine the valves rattling the in the guides at a certain frequency.

 

[gggrrrr]

As above, compression doesn't sound too bad but, if it were me I would want to address the sloppy valve guides.

In fact I recently did exactly that with my M900 a couple of years back: It was running fine until it broke the gearbox, upon strip down I found the exhaust valve guides were badly worn and whilst it wasn't causing any problem, I knew it would in the future so I had the guides replaced.

Wasn't particularly expensive either (though the shop took ages to do them) at £240 for all 4 guides, I also had the guides on my Guzzi repaired with 'K-line' guide liners - where they essentially bore the existing guides and fit the bronze? sleeve, supposed to be better than new guides? this only cost £130 for the 4 valves (but it was 10 years ago).

So I don't think repair is likely to be extortionately expensive, probably around £400-500, if you can find a good repair shop, if so and you can do the strip/rebuild that's likely cheaper than a dealer service!

Buying used heads is likely to be more expensive and could, as above, come with the same problems (or worse) than you already have?

That said, I have got an S4 head in good condition (guide-wise) that I bought years back as part of a job lot (primarily as a donor for the rockers it contained) that I'd be happy to part with for not much - heavy item to post abroad though.

It was a rear head that came complete with cams, valves, rockers etc. but they are interchangeable rear to front as they can be assembled the opposite way round (need the right camshafts though) but I do only have the one head so if going that way you'd need to find another.

Thanks for the offer, I'd be super happy to buy a couple of good used heads from a trusted source but I'm afraid one head make the case more difficult. The cams and all rocekrs are in very good shape so I'd need only the heads with good guides

 

[gggrrrr]

Plenty of sound advice above re keeping/selling on soon etc. The valve stem play does look pretty excessive in the video, stem seals would take a bit of a battering on there so not surprised that a number of seals are gone. I've replaced guides myself on a few bikes over the years with good fitting drift and some heat from the cooker!! Admittedly not on my monster but it shouldn't be an impossible job with the right size of drift etc and even better if you can find a mechanic with a press. Re the ticking, have you checked valve/shim clearances? You could do that with the heads off as well as the cam shafts & lifters/pushers. You could also lap the valves back into their seats providing they're in good enough condition. The compression you measured would indicate so.

Doing the guides myself would be awesome but I'm pretty sure the seats have to be recut after guide replacement, I couldn't get away with lapping.

 

[slob]

what kind of airbox do you have and is the padding under the tank still in place?
could the noise above 4k be induction?

edit: it would be unusual for the tank padding not to have turned to powder in the last 20 years

 

[Dukedesmo]

Any good?; https://www.albertmuhely.hu/en/cylinder-head-rebuild.html

 

[Nickj]

I've replaced guides myself on a few bikes over the years with good fitting drift and some heat from the cooker!! Admittedly not on my monster but

My father replaced the guides on a few heads on the kitchen table. On one he was ably assisted doing a T160 triple by Den who was a gas fitter and a dab hand with a blowlamp plus a bit of help from a local butcher who had a very cold freezer in the days when you maybe had an ice box at home. If the job needed a hammer then they'd be up for it!

 

[Mr Gazza]

bought an s4r rear shock,

Hello and welcome to the club.

I'm sorry to be a killjoy, but S4 and S4R rear shocks are not interchangeable. They are different lengths. The rear suspension set up is quite different on the S4R.

Good luck with your valves. It would make sense to me to lift the barrels while the heads are off. it's always best to replace the base gaskets or you're doing it all again after putting it back together. There's an O-ring at the barrel base too, which can get displaced while the heads are off.
Best also to check that the Nikasil is in good order and your rings are good.

 

[jerry]

your idle issues may be down to TPS its very very sensitive when adjusting if you can get it to 152mv and keep it on that voltage when tightening the screws it really pays off ,, but its not easy as tightening the 2 TPS screws aften moves the rheostat and the voltage moves slightly

 

[jerry]

Just had a look at the video ,, definitely excess play in the guides

 

[Darren69]

Hello and welcome to the club.

I'm sorry to be a killjoy, but S4 and S4R rear shocks are not interchangeable. They are different lengths. The rear suspension set up is quite different on the S4R.

Good luck with your valves. It would make sense to me to lift the barrels while the heads are off. it's always best to replace the base gaskets or you're doing it all again after putting it back together. There's an O-ring at the barrel base too, which can get displaced while the heads are off.
Best also to check that the Nikasil is in good order and your rings are good.

Mr G beat me to it. Not sure about shock length but I think the main issue is the reservoir is horizontal and they made the frame tube a different shape and thinner so it would fit but its still very tight on the R as you can see.

 

[gggrrrr]

what kind of airbox do you have and is the padding under the tank still in place?
could the noise above 4k be induction?

edit: it would be unusual for the tank padding not to have turned to powder in the last 20 years

Standard airbox. What do you mean by padding exactly?
Definitely not induction noise. It is a sharp metallic rpm related ticking coming from the engine. I couldn't pinpoint it with the screwdriver in the ear method.

 

[gggrrrr]

Hello and welcome to the club.

I'm sorry to be a killjoy, but S4 and S4R rear shocks are not interchangeable. They are different lengths. The rear suspension set up is quite different on the S4R.

Good luck with your valves. It would make sense to me to lift the barrels while the heads are off. it's always best to replace the base gaskets or you're doing it all again after putting it back together. There's an O-ring at the barrel base too, which can get displaced while the heads are off.
Best also to check that the Nikasil is in good order and your rings are good.

Thanks for the headsup, I did my homework before buying the shock. It needs extra 2mm clearance at the right side of the frame under the seat which can be easily done by crimping the frame tube vith a press.
I already test fitted the s4r shock and it may be ok as is but to be safe I will press the frametube a bit.
If anyone is interested I have a video showing the clearance (there is only one blurry image on the net about this swap).

 

[gggrrrr]

your idle issues may be down to TPS its very very sensitive when adjusting if you can get it to 152mv and keep it on that voltage when tightening the screws it really pays off ,, but its not easy as tightening the 2 TPS screws aften moves the rheostat and the voltage moves slightly

Fuel delivery system is completely rebuilt includnig new tps, and settings are OK. The bike had a weak fuel pump and it took me a lot of time to figure it out so I replaced almost everything.

 

[gggrrrr]

Mr G beat me to it. Not sure about shock length but I think the main issue is the reservoir is horizontal and they made the frame tube a different shape and thinner so it would fit but its still very tight on the R as you can see.

Yep, there is the clearance. The s4 frame is not crimped there but when test fitting the s4r shock it seems it would be ok vithout crimping. I will make some gap there to be safe.