748 engine went bang...

[HUNT749]

I attempted to do a track day at snett yesterday but only managed 2 1/2 sighting laps , as i was 3/4 down the revetts straight not even pushing it it the engine lost power as if only running on one cylinder then started knocking very loudly i pulled of and returned her to the pits , she will fire and idle ok but as soon as you slowly increase revs she randomly knocks so this morning i draineed the engine oil and its full of little fragmentds of metal and copper coloured metal which i can only assume are the shells.

engine has done 27k miles

Now if it is just the shells cant see it being to big off a job but more worring what the cause would be any ideas ?????

dont want to fix problem with out identifying the cause etc if you see what i mean !!

I can take a pic of drain bung and gauze filter if would help???

cheers Simon

[skidlids]

Bit like Topitoo's at the Benson trackday last year and thats his second 748 bottome end that has gone

Is it an early or late engine (single or three phase alternator) if its early type I have a crank available and casings if required


I did notice there are a few water-cooled engines on ebay at the moment.

[phil_h]

Your diagnosis does sound pretty accurate.
The big end bearings are known to fail if your oil level gets low (eg when the bike is being wheelied)
The sump design lets most of the oil flow to the back, away from the pump pickup, which is why they did the deep-sump cases on later models.

[HUNT749]

its a 2000 model so not 100% sure i think its 3 phase dont you tell by the wiring ???

[phil_h]

Oh - and if there is that much debris in the oil, then it is an 'investment' to replace all the engine bearings, as all they will all probably have some in them.
A full set of bearings cost me about 500 two years ago.

[HUNT749]

oil level was just between max mark and say 3/4 would that be enough to cause starvation, plus cant wheelie for toffee so never attempt it..

[skidlids]

If Phil is right about the cost of bearings another motor sounds a better alternative.

As you mention the wiring is the easy way to tell, does it have two or three Yellow wires running from the alternator to the regulator/rectifier

[HUNT749]

just checked the wiring and there is three yellow wires...

I agree at that price a replacement engine sounds good as long as its a good one, Then you start thinking what other engine good i put in it dont you!!!!

[skidlids]

just checked the wiring and there is three yellow wires...

Then you start thinking what other engine good i put in it dont you!!!!

Yep, a 916 or 996 or even a 998.
998 is a bit more work with differnt injectors, airbox, exhausts, radiator, oil cooler, ECU, Harness
916 straight swap plus chip for ECU and ideally injectors/throttle bodies
same for the 996BP engine as I bet there is a chip that will make the A model 1.6M ECU work with the 996 injector setup

[HUNT749]

oh!!!

http://cgi.ebay.co.uk/Ducati-998-engine-in-748-frame-with-V5_W0QQitemZ320348095831QQcmdZViewItemQQptZUK_Moto rcycle_Parts?hash=item320348095831&_trksid=p3286.c0.m14&_trkparms=72%3A1689%7C66%3A2%7C65%3A12%7C39%3A1%7C 240%3A1318

[TopiToo]

Hello HUNT749

As Skids says my bike suffered the same problems again:mad:
A quick fix is indeed a second hand engine, as I did the second time round.
However, I have decided this time to get the engine rebuilt, as you take
a chance with secondhand engines, service history etc.
Good luck in your search;)

TopiToo

[TopiToo]

A full set of bearings cost me about 500 two years ago.

I hope that is not correct;)

TopiToo

[skidlids]

yep good project hence my placing a bid on it last night :)

[HUNT749]

took this pic not overly clear tho..took it on phone

[HUNT749]

yep good project hence my placing a bid on it last night :)


bbboooooooo!!!!!!! it is cheap isnt it :)

[skidlids]

bbboooooooo!!!!!!! it is cheap isnt it :)


Probably going to go for far more than I want to pay.
My 998Hybrid is a 998Bp engine in a 748RS Chassis
it will be an Excellent project for someone

[HUNT749]

topitoo.

If you dont mind me asking whats causing your failures??

(just read that back sound like a therapist)

[HUNT749]

Probably going to go for far more than I want to pay.
My 998Hybrid is a 998Bp engine in a 748RS Chassis
it will be an Excellent project for someone


more than likely but you never know hey..:)

[HUNT749]

started stripping and taking engine out but unsuprisingly swing arm bolt bloody siezed ....

[Chris Wood]

Shells went twice in my 748rs - very expenxive potentialy. I replaced Pistons/Rods/Crank/Bearings, the first time.

Second time went the above plus crankcases.

A new engine would be the best option. Baines had a low mileage 748R engine that would be great for you, give them a call.

[TopiToo]

topitoo.

If you dont mind me asking whats causing your failures??

(just read that back sound like a therapist)

LOL

The first engine just seized on the M3 on the way to Popham (Crankshaft Oil Galley Plug/main bearings) 97yr

The second engine was newer, was looked after with regular oil changes every 3K miles, with good oil,
run for 2mins from cold etc although I did drop it at Brands, even though I managed to turn the engine off quick sharp. (main bearings again)
in both cases the crank was shot . . oil starvation, even though no signs of metal in the pickup filter:mad:
after a month started all over again, but if this one goes thats it for me.:rolleyes:

TopiToo

[RickyX]

My 748 motor went bang just like you describe on my first ever trackday back in 1998. It had 45K kms on it at the time......
Ended up just getting a s/h one to replace it - loads cheaper than a rebuild.

Have fun with your decision!

[gordonparker]

Mine has 60K km and still going strong, perhaps I should have it checked over

[HUNT749]

Time for a update....

Sorry its bean a while but not had much time lately, As said before swingarm bolt was siezed so ended up cutting out to free frame and then cut swing arm to free from engine.

As you can see in the pics ,

Front cylinder shells have some damage but compared to rear cylinder look good , Rear is mullerd to hell crank is also worn quite badly so new engine needed rest ok so will sell of bits to help pay for engine and swing arm

Simon

[TopiToo]

Hello HUNT749

looks about the same as mine did after the stip down.
just another thought it is possible with this type of damage
the con rods will be shot too,

but I understand you can get them machined depending on damage,
or pick up a good set on ebay if thats the route you wish to take.

good luck

TopiToo

[HUNT749]

Hello topitoo,

I also think that the rods are shot as the surfaces are worn away quite badly . Was thinking about getting them machined but not sure yet on what to .
I know its a long shot but whats the difference in length between 748 and 916 conrods saw a crank and conrod assembly on fleabay and wondered ????

Simon

[injected]

If you want to keep it as a 748 I have a good spare engine, freshly serviced, with oil cooler if you want it. Lmk

[HUNT749]

yes would like to keep it as a 748 , whats the history on engine as in age ,mileage etc and of course money required

just realised also 916 conrod and crank assembly wouldnt fit as stroke different isnt it!!

Simon