00 748 help

[k_cotter]

I have a line on a nice 748 with low miles for a real good price, ive always had an obsession with that body style and would love to own my first duc.....that being said does anyone have experience with them? anything i need to know other then the rocker arm failures? Im not expecting it to be comfortable i know that much..
thanks for any/all knowlege

[I8A4RE]

Don't be expecting a decent amount of power from that 748. They are slow, but still look amazing. Good luck !

[jbmass]

Swap out the stator-to-rectifier cables for thicker gauge/better heat resistant stuff. A real nuisance if they fry when your riding on a hot day. Ask me how I know!

[timmyho414]

I had the alternator/fly wheel nut fall off mine. If you buy it, pull the cover and nut, lock tight the crap out of it and torque it back on. Throw a lightweight flywheel in while you're at it.

[Dmitry]

What is the "good price", what model?

I just sold mine not to long ago, loved the bike but got another toy and could not afford to keep the Duc.

Desmoquattro motors are notorious for flaking rockers and worn out clutch baskets, 748 seem to be more prone to that, I suspect extra 2,000 rpm they added when they de-stroked the 916 motor cause most of the issues. Be prepared to have a hefty maintenance bill if you take it to the dealer, 12,000 mile service could be as much as $2000!

I got my bike in rough shape with 12,000 miles and no records of service, tore it down to the frame and rebuilt it frame up (powdercoated the frame) clutch was pounded to oblivion but I was able to get a nice used one instead of dropping $500 on a new clutch and basket from the dealer. While doing timing belt and valves I found few flaking rockers but I had a whole spare engine so I just installed the rockers form that one, used the bike for a year, not thrashing it but not pussyfooting either and just as I was getting ready to do an 18K service found a chrome flake in the oil. Pulled the cams out and found one flaking rocker, couple more with visible wear. Replaced damaged rockers and cam bearings this time, back on the road...

A friend has same 748 as mine, he NEVER serviced it in 22,000 miles, cams and rockers were a mess but once again I sourced most parts from a parts motor and had it on the road with very little out of pocket expense. It did get all new bearings, gaskets and belts but reused cams and rockers from a low mileage 996 motor.

I don't suggest ignoring the maintenance, there are many catastrophic failures of those motors due to lack of it, some get lucky, others not so much.

Also the Big Scary electrical problem all come form corroded connectors, swapping the alternator wires is not necessary, just keep the big plug clean. If it starts to discolor just snip it out and Solder the wires together. Only PITA is that you will not be able to remove the RR without cutting wires

Lastly, if you get the bike use only Motul 300V, it has ZDDP which will minimize the risk of rocker failure.

[LuvDog]

Swap out the stator-to-rectifier cables for thicker gauge/better heat resistant stuff. A real nuisance if they fry when your riding on a hot day. Ask me how I know!

Ive been there too.

[Doc]

Hey Dmitry... wanna make a trip to VT and help me swap the motor in mine?

[jwm2k3]

These flaking rockers....cant they be media/vapor blasted and then its a non issue, or do the rockers require this coating that seems to flake off???

- - - Updated - - -

Or a solution is to pop a 998 motor in there and be worry free!

[Kurlon]

Once the hardfacing has been worn through or flaked off you either need to get the rockers re-hardfaced or replaced.

[Dmitry]

Hey Dmitry... wanna make a trip to VT and help me swap the motor in mine?

All depends on what's in your liquor cabinet... What happened to your Ducky?

[Dmitry]

Once the hardfacing has been worn through or flaked off you either need to get the rockers re-hardfaced or replaced.

It's not just any chrome, often I hear people suggesting to have a Haaley Chrome shop redo the plating, but this is hard chrome, once it's gone rockers and cams start to wear out pretty rapidly, metal flake does everywhere and causes serious damage. In some cases chrome flake gets lodged in the cam bearings seizing them up, belts snap and pistons smash the valves.

IIRC openers are $200 and closers $250 from Ducati
$450 per valve, times 8 is $3600 if you had to replace all 16 of them.
Megacycle charges around $90 a piece to re-surface them (grind and plate) so around $1500 for a complete set
Used ones vary in price, I have seen them as little as $20 a piece on fleaBay, or $400 a set
Last parts motor I got was under $300 and had 16 perfect rockers...

[number9]

My personal opinion (after owning a handful of Ducatis) is that the rocker issue is made out to be a bigger problem than it really is. That said, maintenance is always going to cost you more than a Japanese bike. A stock 748 is also pretty slow by comparison, it's probably not much faster in a straight line than a SV650.

IMNSHO the single most importance maintenance to perform is belt changes. Next most important is valve clearances.

[Degsy]

Wirelessly posted

My personal opinion (after owning a handful of Ducatis) is that the rocker issue is made out to be a bigger problem than it really is. That said, maintenance is always going to cost you more than a Japanese bike. A stock 748 is also pretty slow by comparison, it's probably not much faster in a straight line than a SV650.

IMNSHO the single most importance maintenance to perform is belt changes. Next most important is valve clearances.

Pretty much word for word what I told him in a text. Lol.

[Dmitry]

Valve checks and rocker inspections are by far #1, belt change is #2

in cars belts are known to last 60,000-100,000 miles, Ducati recommends 12,000 mile replacement intervals.... considering the belts are all the same (Gates) you think they might have made a mistake? or just trying to get few extra $$ for maintenance?

A friend of mine had one of the early 916's and he never had to replace a rocker in 70,000 miles... I average 2 rockers every 6,000 miles, but on a newer bike. Common belief is that early desmoquattro bikes had better rockers because they were gone in house, later bikes have rockers that were outsourced and prone to failure.

[PhilB]

Valve checks and rocker inspections are by far #1, belt change is #2

in cars belts are known to last 60,000-100,000 miles, Ducati recommends 12,000 mile replacement intervals.... considering the belts are all the same (Gates) you think they might have made a mistake? or just trying to get few extra $$ for maintenance?

A friend of mine had one of the early 916's and he never had to replace a rocker in 70,000 miles... I average 2 rockers every 6,000 miles, but on a newer bike. Common belief is that early desmoquattro bikes had better rockers because they were gone in house, later bikes have rockers that were outsourced and prone to failure.

The belts in Ducatis operate at higher RPMs than in cars, and with a much tighter bend. When they fail, it's really ugly, and they do fail if not changed regularly.

PhilB

[Kurlon]

Ducati never did any of the rocker hardening in house AFAIK. The problem was due to one or more batches ordered in that were not done properly. Ducati wasn't practicing proper inventory control at the time so as the bad batches came in they were just mixed in with the existing in house stock. No way of knowing which were good vs which were bad without individually testing every unit. Thats why there wasn't a solid pattern to which bikes had issues and which didn't for so long, no way of telling which batches of rockers were in which bikes. They've since caught up with the rest of the world on that front, but it took awhile.

[xxaarraa]

Lots of guys love the 916 generation bikes - 916, 996, 998, 748. I guess they were a breakthrough design back in the day (late 90s) but having gotten into Ducatis well past that vintage, I never got the appeal. The rear end of that generation just looks plain dated, in today's world.

Personally, I'd pass and go straight to a late 2000s Monster if you are looking for a first Ducati.

[Degsy]

Wirelessly posted

Lots of guys love the 916 generation bikes - 916, 996, 998, 748. I guess they were a breakthrough design back in the day (late 90s) but having gotten into Ducatis well past that vintage, I never got the appeal. The rear end of that generation just looks plain dated, in today's world.

Personally, I'd pass and go straight to a late 2000s Monster if you are looking for a first Ducati.

HERESY!

Check out other bikes from 1995 and you'll understand why the 916 was the most jaw-dropping thing to ever happen at the time.

[Dmitry]

The belts in Ducatis operate at higher RPMs than in cars, and with a much tighter bend. When they fail, it's really ugly, and they do fail if not changed regularly.

PhilB

each Ducati belt only turns a single camshaft, 4 valves per belt (yes, extra rockers create more drag, I know) but some car belts will have 4 cams on a single belt, as many as 8 cylinders (32 valves) also tension is pretty high since most of the later model cars have automatic tensioners, 8,000 rpm red line... like I said, I have seen Ducati belts last well over 20K while the car belts usually snap not too far past the service interval.... it's an easy job and the belts come off every 6K for the rocker inspection anyway, not saying they should be ignored but the belt failure on a Ducati is not something that happens because the belt got old, most times it's a seized cam or tensioner that causes the problem, so I replace the bearings in the belt tensioners every 18 or 24K.

Replacing the belts is secondary service when you do the other important stuff...

[Dmitry]

Ducati never did any of the rocker hardening in house AFAIK. The problem was due to one or more batches ordered in that were not done properly. Ducati wasn't practicing proper inventory control at the time so as the bad batches came in they were just mixed in with the existing in house stock. No way of knowing which were good vs which were bad without individually testing every unit. Thats why there wasn't a solid pattern to which bikes had issues and which didn't for so long, no way of telling which batches of rockers were in which bikes. They've since caught up with the rest of the world on that front, but it took awhile.

I don't have any "hard evidence" but I know that Ducati had several rocker variations over the years (I heard as many as 16!) later ones were marked with a dot on the side surface, just where the pivot is, so there is no confusion about earlier or later batches, they all still fail! As far as having them done in house, I'm pretty sure the first couple years they did it themselves (Hard chrome plating, not hardening) but once again, don't have any proof other than first year bikes never had any problems

Another thing to consider is that modern oils no longer have ZDDP additive and lack of it often causes cam failures in older vehicles, this is why I use Motul 300V, it's pricey but has the ZDDP additive, cheap insurance and piece of mind...

[Degsy]

Wirelessly posted

I have seen duc cam belts break a lot earlier than 20,000 miles.

[Dmitry]

Wirelessly posted

I have seen duc cam belts break a lot earlier than 20,000 miles.

Yes, it happens, but what I'm saying is that the cause is more likely the age of the belt (not the mileage) or some other component failure.
20,000 miles for an average New Englander is almost 10 years ( I know most of people here ride, but there are others who do less than 1000 miles in a year)
at 20,000 miles it could be seized tensioner bearings or rockers flaking (chrome gets in to cam bearings and locks up the cam)

Not suggesting to skip the belt replacement, always did mine at 12K, cheap insurance, just trying to explain the mechanics of it.
Most people think that there is a ticking time bomb in the belt, it hits 12K and BANG!

Anyway, OP has not posted in a while, guessing he is not getting the duc?

[Doc]

All depends on what's in your liquor cabinet... What happened to your Ducky?

You name it and it will be there... We have a guest room with a private bath... Just need to swap the motors. High mileage for low. Oh and I can't get the damn swingarm bolt out.

[jbmass]

If I had to do it all over again (within reason, and I still own my 916), I'd get a 998. Testastretta reliability so I could ride the shit out of it. I hope I didn't just jinx myself though.....

[Dmitry]

Oh and I can't get the damn swingarm bolt out.

Ouch, I recall mine was rusted in solid. Patience and Kroil!

I'd get a 998.

that's a big +1, not for extra power but only because the Testastretta motor is more reliable